OH&S Manual for Traditional Fuels

OH&S manual for traditional fuels

Issued Issued by

CSR / Albert Albert Tien

Rev.No./Da Rev.No./Date te

ProMap Tool

G3-402.2 - OH&S manual for traditional fuels

0 / 27.01.20 27.01.2005 05

The copyright for this document and al l appendices are reserved by Holcim Group Support Ltd

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Table o of C Contents 1.

GENERAL INFO

2.

OCCUPATIONAL DUTIES AND EXPOSURE POTENTIAL

3.

4.

2.1

Fuels Handlers

2.2

Lab and Quality Control Personnel

2.3

Coal - Potential Laboratory Tests for include for Raw and Ground Coal

2.4

Petcoke - Suggested Laboratory Tests for Supplied and Ground Petcoke

2.5

Heavy and Light Fuel Oils - Suggested Laboratory Tests

2.6

Natural Gas - Suggested Laboratory Tests

SAMPLE COLLECTORS 3.1

Process Staff

3.2

Coal and Petcoke Handling

3.3

Heavy and Light Fuel Oils Handling

3.4

Natural Gas Handling

3.5

General Safety Issues

3.6

Maintenance

3.7


3.8

Third parties

3.9

Ready-Mix Concrete

3.10

Aggregates

3.11

Other Operations

STAKEHOLDER RELATIONS 4.1

SD Communications Communications

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5.

6.


4.2

Product Health and Safety Risks

4.3

Handling in the Process

4.4

Coal preparation/grinding preparation/grinding

4.5

Personal Protection Equipment

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PETCOKE 5.1

Product Description

5.2


5.3

Health aspects

5.4

Safety risks

5.5


5.6

First Aid Procedures

PETROLEUM HYDROCARBON 6.1

Heavy Fuel Oils

6.2

Description

6.3

Toxicity

6.4

Handling Advice

6.5

Quality of Fuel Oil Preparation

6.6

Control Loops in the Fuel Oil Circuit


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8.


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LIGHT FUEL OIL 7.1

Introduction

7.2

Product Description

7.3

Acute Toxicity

7.4

Health Aspects

7.5

Handling and Storage of Light Fuel Oils at Holcim Facilities

GASOLINE 8.1

Introduction

8.2

Product Description

8.3

Product Properties

8.4

Health Aspects

8.5

Personal Protection

8.6

First Aid

8.7

Emergency Response

8.8

Handling and Storage of Gasolines at Holcim Facilites

8.9

Safety Precautions


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10.


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NATURAL GAS 9.1

Introduction

9.2

Product Description

9.3

Product Properties

9.4

Health Aspects

9.5

Toxicology

9.6

Protective Equipment

9.7

First Aid

9.8

Handling of Natural Gas in the Cement Manufacturing Process

9.9

Safety precautions

9.10

Specific Hazards and Corrective Actions

SELECTION AND USE OF PERSONAL PROTECTIVE EQUIPMENT 10.1

Introduction

10.2

General Industrial Practices

10.3

Airborne Exposures

10.4

Dermal Exposures

10.5

Other Potential Exposures

10.6

Supplementary Supplementar y Reference Materials


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11.


WORKPLACE MONITORING AND RECORDKEEPING 11.1

12.

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Workplace and Perimeter Air Monitoring

SPILL PROCEDURES/EMERGENCY RESPONSE 12.1

Introduction

12.2

Coal or Petcoke

12.3

Heavy and Light Fuel Oils

12.4

Natural Gas


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CHAPTER 1: GENERAL INFO

Holcim OH&S Pyramid The Holcim Executive Committee has clearly stated as a goal that the Group companies achieve "accepted good practice" with respect to Occupational Health and Safety (OH&S) performance. To achieve this goal a Holcim OH&S Pyramid has been established and the OH&S Manual will be a tool to perform these targets. The purpose of this Pyramid, its elements (blocks) and associated documentation documentation (inclusive OH& S Manual), is to indicate the key requirements within each of these elements for establishing "accepted "accepted good practice" in OH&S Management System performance.

Legend

Health & Wellness Issues

Occupational Rehabilitation

Safe Working Procedures

Induction & Training

Roles Responsibilities and Accountabilities

Management of Changes

Procurement

Inspection & Testing

Incident Investigation & Corrective Action

Hazardous Work Activities

Implementation isPlanned planned

Design Safety

Industrial Hygiene & Monitoring

Hazard Identification and Risk Assessment

Audit and System Improvement

Employee Communication & Involvement

Planned Inspections

Implementation hasBegun started

Fully implemented

Information & Reporting

Legal Obligations

Management Commitment & Planning

OH&S Performance Targets: Zero deaths or injuries causing permanent disablement annually A Lost Time Injury Frequency Frequency Rate of < five five achieved annually annually A Lost Time injury injury Severity Rate of < 60 achieved achieved annually annually

  

Holcim is striving for continual improvement improvement in the actual results which are achieved, with a long term goal of zero harm to people and a green OH&S pyramid in all Group companies by end 2005. The main elements within the pyramid are people, process and management related, what is also valid for the OH&S Manual. OH&S manual for traditional fuels.doc

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Risk Assessment; Engineering/Design; Operational Issues The management has to provide, for the correct implementation and application of fuels in the plant, following elements: Risk Assessment Engineering / Design Operational Issues

  

Figure 1:

Risk Assessment

ELIMINATION SUBSTITUTION ENGINEERING ADMINISTRATIVE PERSONAL PROTECTIVE EQUIPMENT


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Main Considerations for AFR OH&S

OH&S Management Systems Training  Communications  Recordkeeping  Audits 

Corrective actions  Personal Protective Equipment 

AFR OH&S

Risk Assessment Environmental monitoring

Engineering Design Fire suppression





Biomonitoring  AFR Input monitoring  AFR Product monitoring





Toxicological assessments




Ventilation design  Explosion proofing  Wastewater collection  First aid stations

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Risk Assessment: Hazard identification and risk assessment are key building blocks of modern OH&S Management Systems. From legal point of view, OH&S legislation often specifies that organization must undertake risk assessment on the tasks and conditions existing in their workplaces. A risk-based approach requires that hazards are identified, risk are analyzed and evaluated, and strategies put in place for effective managing and monitoring those risks. The use of burnable respectively explosive fuels requires the realization of a risk assessment in the facility.

Engineering / Design: There are many ways of controlling risk in the workplace. However, the most effective way of is to ensure that, where practicable, hazards are eliminated at the design stage, or where this is not practicable, the mechanism for control of those hazards, is incorporated intrinsically intrinsically into the design. For all new designs have to be reviewed and hazards identified prior to construction of the plant or implementation of the particular change. The arrangement of the machinery equipment equipment has to provide that the risks of failures due to the use of burnable/explosive burnable/explosive fuels are minimized.

Operational issues: Under this topic you have to understand all issues which are in relation to the use of fuels in the operation process. Both adequate plant operation and staff culture of OH&S awareness are included. The basis for any program aimed at the prevention of risk exposures or accidents is to cultivate a culture of OH&S awareness, and to provide each person with the skills and knowledge necessary to ensure that they operate and work in a safe and healthy way.

Fire and Explosion Triangle What enables an fire or explosion to occur? The three conditions as shown in the fire and explosion triangle must be fulfilled simultaneously: There must be fuel, there must be sufficient oxygen and there must be an ignition source. In order to enable an explosion to happen the fuel must be finely dispersed in air of sufficient oxygen content, in the right fuel/air concentration range. And the ignition source must be powerful enough. When it would be possible to avoid one of these three conditions, fires and explosions are not possible anymore. Therefore all safety measures have to be aimed at, either oxygen of air (inertization) or ignition sources are excluded, or the creation of an ignition qualified mixture of the burnable material and the air is avoided.


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Fire and Explosion Triangle

Oxygen

Ignition Source

Fire and Explosion

Combustible Material

Personal Protective Equipment (PPE) The last risk control strategy is the use of personal protective equipment equipment (PPE). This is a way of controlling risk by selecting a particular type of equipment that will provide a barrier between hazard and the worker. The purpose of a glove or mask is t o provide a barrier between the fuel and the worker at the exterior of the body. Therefore, PPE does not in any way alter the nature of the of hazards that exist at a workplace. PPE will only be effective if the risk is clearly understood and correct type of PPE is identified. For PPE to continue to be effective in controlling a hazard, it is essential that the equipment is properly maintained, or in a situation where maintenance is not appropriate, appropriate, that it is replaced when it no longer is able to do the job. In many circumstances, circumstances, this may require require an extensive extensive program of monitoring monitoring the quality quality and the performance of PEE. To be effective, PPE also requires the cooperation of the person who is required to wear it. Therefore if PPE is chosen as a risk control option it is essential that the persons who are required to wear the t he equipment are given appropriate training. This training should include:


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An understanding understanding of the nature of the the hazard and the the degree of

risk   

The reason why PPE is required How to use the equipment properly Maintaining the equipment


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CHAPTER 2: OCCUPATIONAL DUTIES AND EXPOSURE POTENTIAL Many operational management management issues concerning the safe handling of traditional fuels can be reviewed by following the listed Holcim OH&S pyramid block elements: definition of roles, responsibilities responsibilities and accountabilities; accountabilities; induction and training; implementation of safe working procedures; and hazardous work activities. However, one must first identify hazards and perform risk assessment on the activity or system in question before operational management management systems can be implemented. In the case of an accident occurring, a system of rapid emergency response and a system of follow up through incident investigation and corrective actions - including internal communications - can prevent a similar incident from occurring. When reviewing the occupational duties of employees that will most likely be in contact with traditional fuels, a risk assessment also known as a "job hazard analysis" should be performed. From this information, hazardous work activities can be defined and safe working procedures implemented. Potential exposure to traditional fuel constituents primarily will involve those who handle or transfer the traditional fuel materials. However, laboratory and quality control, process and maintenance, or other staff and third parties may occasionally encounter a situation involving potential exposure to traditional fuel chemicals. Therefore, all employees of cement manufacturing facilities, ready-mix concrete, aggregates and all other operations should become familiar with those sections of this Manual that may be applicable to their specific job duties and responsibilities. More focused information and chemical-specific chemical-specific precautions are provided for traditional fuels constituents in Chapter 3 of 3 of this Manual.

2.1

Fuels Handlers

The primary duty of fuel handlers are to unload fuel from inbound transport to central storage areas such as coal/ petcoke bunkers or fuel oil tank t ank farms. Additional duties entail the internal transport of fuels to interim storage areas for further processing and distribution. Exposure routes for fuel handlers include inhalation of vapors or dust, dermal contact and to a lesser degree ingestion. A job hazard analysis is suggested to determine the level of personal protective equipment necessary. Generally, for fuel oils handling, safety glasses, petrochemical resistant gloves i.e. nitrile, Tyvex suits and slip resistant safety boots. For extended exposure to fuel oils use of fitted respirator with organic vapor cartridge is suggested For handling of coal and petcoke, generally, safety glasses, particulate filter mask, work gloves (cotton or leather) and working clothes are suggested. In the case of natural gas handling, this task is usually performed by externals or highly trained internal maintenance maintenance staff. Issues to take into account is that as natural gas is under pressure contact with eyes, skin or mucous membranes may cause freeze burns or frostbite. Suggested PPEs include positive pressure air supplied respirator in oxygen deficient environments (oxygen content < 19.5%), cold resistant gloves, safety glasses and normal working clothes.


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As a general rule, rule, eating or drinking drinking while working working is highly highly discouraged due due to exposure route route via ingestion. Smoking while working with all traditional fuels is strictly forbidden.

2.2 Lab and Quality Control Personnel The primary duty of laboratory and quality control personnel is to characterize incoming materials in order to see if terms of the t he contract from the supplier have been fulfilled with regards to the specifications agreed upon. Typically issues of net calorific value, ash content, water content, granulometry (where (where applicable) and viscosity (where applicable) applicable) Secondarily Secondarily albeit the most import for the cement manufacturing plant are the properties of the post ground solid fuels in regards to mill through put and behaviour during kiln firing.

2.3 Coal - Potential Laboratory Laboratory Tests Tests for include for Raw and Ground Coal Coal • • • • • • •

determination of net calorific value ash content water content volatility (for low rank coals) coals) grindability (~2% residue on 200 micron sieve or "rule of thumb" ½ volatile content as % residue on 200 micron sieve) control of supplied granulometry heavy metals content

2.4 Petcoke - Suggested Laboratory Tests for Supplied and Ground Petcoke Petcoke • • • • • • • o o o

determination of net calorific value ash content water content volatility ( for new suppliers or sources) grindability (3%residue on 90 micron sieve) heavy metals content circulating elements Sulfur Alkalis (Na+ and K+) Chlorides

2.5 Heavy and Light Fuel Fuel Oils- Suggested laboratory tests • • • •

determination of net calorific value ash content solid contents water content


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viscosity heavy metals content

2.6 Natural Gas- Suggested Laboratory Tests • o o o o o

determination of average calorific value during contract period C1-C4 content CO2 N2 Odorant Water vapor

It is recommended that samples of solid and liquid fuels from deliveries be maintained for a minimum of 3 months. Data from analyses should be maintained in case of process related problems that might have originated from due to heterogeneity heterogeneity of the contracted stock or storage related of issues. Laboratory personnel and quality control personnel are potentially exposed on a regular basis to traditional fuels and laboratory chemical reagents. Because of the unique operational operational circumstances that typically are present within the laboratory, specific health and safety guidelines should be followed (i.e. Good Laboratory Practices (GLP) or OHSAS 18000). If laboratory is also used for AFR analysis, Holcim AFR Quality Control Manual and Health & Safety Manual for Facilities using Alternative Fuels and Raw Materials for Holcim Ltd should also be consulted.


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CHAPTER 3: SAMPLE COLLECTORS Sample collectors are responsible for meeting incoming deliveries, collecting samples of the traditional fuels (less so for natural gas), and transporting them to the laboratory for analysis. A sample typically typically is taken from each solid or liquid liquid fuel contracted shipment shipment and sent sent to the laboratory for analysis to check for discrepancies. discrepancies. Sample collectors must be knowledgeable regarding the various safe opening mechanisms for tankers and barrels etc. Contracted traditional fuels may arrive as liquids or solids via rail cars, tankers, trucks or ship. Sample collectors must be familiar familiar with appropriate sampling sampling techniques for each fuel fuel form, should determine what information is available regarding the general chemical character of the material, and should identify Personal Protective Equipment which is applicable. applicable. General procedures for obtaining samples from these containers are presented below. Facility-specific procedures procedures or requirement requirement should take precedence over these general guidelines. Protective equipment should be appropriate for the class(es) of chemicals known or anticipated to be included in the delivery. More specific recommendations for available types of protective equipment are presented in the appendix section of this Manual. (Later put in number).

3.1

Process Staff

The general duties of the process staff with regards to traditional fuels is to guarantee that the appropriate amount amount and type of fuel is available. In many cases, the process staff are responsible for simple maintenance and cleaning.

3.2

Coal and Petcoke Handling

With regards to solid fuels such as coal and and petcoke, this means guaranteeing guaranteeing the mill, the dedusting system (EP or bag), the dosage system, and transport system to the burner are functioning properly. For handling of coal and petcoke, generally, safety glasses, particulate filter mask, work gloves (cotton or leather) and working clothes are suggested.


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Heavy and Light Fuel Oils Handling

In the case of fuel oils, the general duties of the process staff are to guarantee that the heaters for fuel oil, pumps/valves (control array), flow meters and piping to the burner are functioning as designed. Generally, for fuel oils handling, safety glasses, petrochemical resistant gloves, Tyvex suits and slip resistant safety boots. For extended exposure to fuel oils use of fitted respirator with organic vapor cartridge is suggested

3.4

Natural Gas Handling

For natural gas, the general duties of the process staff are to guarantee that flow meters, control valves and piping to the burner are all in good working condition. Additionally, safety devices such as pressure monitors, pressure release valves or vents, explosion arrestors should be routinely controlled. In the case of natural gas handling, this task is usually performed by externals or highly trained internal maintenance staff. Issues to take into account is that as natural gas is under pressure contact with eyes, skin or mucous membranes may cause freeze burns or frostbite. Suggested PPEs include positive pressure air supplied respirator in oxygen deficient environments (oxygen content < 19.5%), cold impervious, insulating gloves, safety glasses and normal working clothes.

3.5


As a general rule, rule, eating or drinking drinking while working working is highly highly discouraged due due to exposure route route via ingestion. Smoking while working with all traditional fuels is strictly forbidden.

3.6

Maintenance

The general duties of maintenance are to ensure that equipment are in working order. Maintenance tasks are divided into two types: • •

Unplanned or process disturbance Scheduled/Planned

It is certain that maintenance staff will be exposed to traditional fuels during their activities. A risk assessment will be necessary for duties in which maintenance staff will come into contact with traditional fuels. A job hazards analysis (JHA) plus training in understanding what activities are considered Hazardous Work Activities are necessary e.g. Hot work permit in a coal mill. OH&S manual for traditional fuels.doc

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Furthermore implemented implemented Safe Working Procedures will assist maintenance workers in safely performing required tasks. Proper personal protective equipment equipment should be determined by the facility OH&S responsible.

3.7


Working with equipment used in the handling, processing, storage or transportation of coal or petcoke, it is suggested that the following PPEs be used: safety glasses, particulate filter mask, work gloves (cotton or leather) and working clothes. If working with equipment used in the treatment, storage or distribution of fuel oils, use of safety glasses, petrochemical resistant gloves, Tyvex suits and slip resistant safety boots are suggested. As a general rule, rule, eating or drinking drinking while working working is highly highly discouraged due due to exposure route route via ingestion. Smoking Smoking while working with all all traditional fuels is strictly forbidden. forbidden. Risk assessment should be performed performed to see where intrinsically intrinsically safe devices must must be used. Cell phone use is strictly discouraged. discouraged.

3.8

Third Parties

Due in part for the desire to reduce headcount, third parties play a greater role in support functions for cement manufacturing facilities. Deaths and permanent disability of third parties are tracked by Holcim Ltd. We however are unable to track long term injuries or severity rates for long term injuries as these individuals are not covered or tracked by Holcim's insurance carrier. Identified are types of services typically provided in which third parties may come in contact with traditional fuels. • • •

Housekeeping Specialized contractors Cleaning/servicing Cleaning/servicing firms

The following points must be included in contracts: • • •

A demonstration demonstration of good OH&S practices practices (PPE, Training Training records, SOPs, Hazardous work permit system…), and agreement to conform to the site safety rules. Third parties should either provide or coordinate emergency procedures with site personnel.


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Ready-Mix Concrete

For ready-mix facilities, traditional fuel use is limited to gasoline, diesel and heating oil. Personnel coming into contact with these fuel types include drivers, fleet maintenance personnel (own or third parties) or responsible persons persons for operating generators or heating plant. In general, no PPE are suggested for the occasional exposure to gasoline or diesel fuels e.g. filling the tank of vehicles. Proper design of fuel depots is necessary to avoid environmental and OH&S risks. Generally, for fuel oils handling, safety glasses, petrochemical resistant gloves, Tyvex suits and slip resistant safety boots. For extended exposure to fuel oils use of fitted respirator with organic vapor cartridge is suggested For fleet maintenance workshops, proper ventilation is suggested. Waste oils should be properly stored in a covered well ventilated area with secondary containment in case of leakage. If working maintenance maintenance the use of safety glasses and slip slip resistant safety boots and work clothes are suggested.

3.10 Aggregates For aggregates facilities, traditional fuel use is limited to gasoline, diesel and heating oil. Personnel coming into contact with these fuel types include drivers, fleet maintenance personnel (own or third parties) or responsible persons persons for operating generators or heating plant. In general, no PPE are suggested for the occasional exposure to gasoline or diesel fuels e.g. filling the tank of vehicles. Proper design of fuel depots is necessary to avoid environmental and OH&S risks. Generally, for fuel oils handling, safety glasses, petrochemical resistant resistant gloves, Tyvex suits and slip resistant safety boots. For extended exposure to fuel oils use of fitted respirator with organic vapor cartridge is suggested. For fleet maintenance workshops, proper ventilation is suggested. Waste oils should be properly stored in a covered well ventilated area with secondary containment in case of leakage. The use of safety glasses and slip resistant safety boots and work clothes are suggested for mechanics.

3.11 Other Operations Other operations have been defined as terminals (rail or port), granulated blast furnace slag operations (i.e. Salzgitter facility in Germany), or any other operation within the Holcim group.


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Traditional fuel use is limited to gasoline, diesel and heating oil. Personnel coming into contact with these fuel types include drivers, fleet maintenance personnel (own or third parties) or responsible persons for operating electrical generators, steam generators or heating plants. However, operation of these type of equipment have their own inherent risk. JHA's are suggested for these activities. In general, no PPE are suggested for the occasional exposure to gasoline or diesel fuels e.g. filling the tank of vehicles. Proper design of fuel depots is necessary to avoid environmental and OH&S risks. For fleet maintenance workshops, proper ventilation is suggested. Waste oils should be properly stored in a covered well ventilated area with secondary containment in case of leakage. For mechanics the use of safety glasses and slip resistant safety boots and work clothes are suggested.


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CHAPTER 4: COAL 4.1 Product Description 4.1.1 Format and classification of coals Colliers's Encyclopedia defines coal as a "combustible, sedimentary rock formed of vegetable matter by physical and chemical alteration through geologic processes". The first intermediate product of these processes is peat which is not yet considered as coal. Then follows lignite (or brown coal) several types of bituminous coal, and finally anthracite. During this transformation the carbon content and with it the caloric value increase continuously while the volatile matter (mainly hydrocarbons), decreases. decreases. Thus coals are classified according to their contents of volatile matter and/or their caloric value. Appendix 1 shows the ASTM classification of coals by rank. The following table shows the coal types according to the content of volatile matter. Table 1:

Coal types according to content of volatile matter (German classification)

Type

Lignite (brown coal) Very high volatile hard coal High volatile hard coal Medium volatile hard coal Low volatile hard coal Semi-anthracite Anthracite

Volatile matter (water, ash, free) % 45 - 50 33 - 40 28 - 35 18 - 30 14 - 20 10 - 14 7 -10

4.1.2 Chemical and physical properties The carbon and hydrogen contents of the fuels determine their most important property, namely their heat of combustion or caloric value. For practical application the net calorific value is used, calculated from cross calorific value, water and hydrogen content. Proximate analysis covers the determination of moisture, volatile matter, fixed carbon, and ash by determining the weight losses at certain temperatures. Proximate analysis simple and fairly quick. Ultimate analysis determines the elementary composition. composition. It requires special equipment and can only be carried out in laboratories with appropriately trained personnel. Further important components for process and environmental purposes are Sulfur, Chlorine, Potassium and Sodium,. Not all types of coal are equally suitable for industrial facilities.


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If the volatile contents are too low ignition of the coal particles is delayed and the flame becomes long. On the other hand, high volatile contents increase the risk of self-ignition and explosions. For a long time about 20 % of volatile matter was considered an acceptable compromise, and preferably bituminous bituminous coal of that composition was used, or, if that was not available, a corresponding mixture of coals with higher and lower volatile contents. I n the meantime engineers have learned to master the risk of self-ignition and explosions and lignite containing 50 % of volatiles or even more can be employed.

4.2


4.2.1 Introduction The health and safety risk (Chapter 3.1.2.4) of coal comes mainly not directly form the stuff itself but almost exclusive from the application as burnable material for industrial purposes. Considering the number of coal grinding plants in operation worldwide, it seems amazing that the application of explosion vents on mill-to-dust separation ducts is so poorly covered by existing guidelines, guidelines, and there is so little information available on appropriate means of protections. Obviously, if there were never any incidents or accidents in this area, there would possibly be no need to discuss this topic. However, accidents do occur, although they are neither properly reported nor understood.

4.2.2 Development Development of dust explosions and fires In order to effectively ensure the safety of a solid fuel preparation plant, you have to be aware of the sequence of the possible fuel reactions. Dust explosions can only occur if the following three conditions are simultaneously simultaneously fulfilled: Stirred-up, combustible dust in explosive concentration; Air or oxygen above above the critical concentration, concentration, for coal coal dust as a rule, above 14%, for lignite above 12%; An ignition source source possessing energy above the minimal ignition ignition energy. After the ignition of of an optimally explosive explosive mixture in an an enclosed space, space, the pressure increases more or less rapidly until it reaches the maximal explosion pressure P max, and then decreases more or less slowly to the original pressure, depending on the aerodynamic conditions.  




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Figure 4: Pressure rise curve during explosion, typical pressure/ time curve for suppressed and unsuppressed explosion

[bar] P1 Explosion Pressure Unsuppressed Explosion

Suppressed Explosion Plant Strength

Extinguishing Detection Ignition t 1 Time (after ignition) [ms]

While the maximum explosion pressure is almost independent of the container's form and size, and in case of coal and lignite dusts, amounts to approximately seven to nine times the initial pressure, the maximum rate of pressure rise (dp/dt) max, which is a measure of the explosion violence, is dependent on the vessel volume (V) in accordance with the cubic law: (dp/dt)max * V1/3 = constant = KSt KSt is a material coefficient that depends on the type of dust, the degree of turbulence of the dust/air mixture at the moment of ignition, the grain size distribution, and the type of ignition source. The method for determining K St is given in the VDI Guidelines No. 3673. The degree of explosion violence of dusts is subdivided in industrial praxis into explosion classes, whereby the explosion class and K St are related in the following manner: Table 2: 2:

Dust explosion classes

Dust explosion class

KSt (bar *m)/s

St 0 St 1 St 2 St 3

0 > 0 - 200 > 200 - 300 > 300


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All types of mineral mineral coals as well as as the majority of lignites lignites belong belong to explosions class class St 1. The next table illustrates arbitrarily selected comparative values for K St characterizing characterizing different types of dust.

Table 3: 3:

Dust type

KSt (bar *m)/s

Hard coal Lignite Organic pigments Aluminum

85 150 300 550

This comparison shows, that hard coal dust develops a less violent explosion than aluminum dust. It must be noted, however, that the value "K St" does not allow any conclusion as regards the risk involved with that particular dust. The main significance of K St is for the dimensioning of design related protective measures. Smoldering fires, characterized by slowly smoldering combustion, can occur wherever combustible dust is stored for a longer period of time, whereby the ignition sources can be spontaneous combustion, initiated by external heat sources, mechanical sparks, or electrical sparks and arcs. Combustion propagation in smoldering fires is quite possible in very oxygen concentrations.

4.2.3 Approximate Approximate values of explosion limits and ignition temperatures The numerical values of the following data depending on the procedure applied and can vary within certain limits according to the origin and geological age of the coals. Dust concentration: - lower explosion limits - upper explosion limits

40 - 130 g/m 3 2000 - 6000 g/m 3

Oxygen concentration: - Hard coal - Lignite

14 % 12 %

Concentration of non-combustible parts (ash): - Hard Hard coal (-medium volatile) 65 %


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Ignition temperatures, depends also on method of determination determination

Solid fuel

Ignition of dust cloud °C

Ignition of dust layer °C

Lignite Hard coal Petrol coke

380 - 400 590 - 710 690

225 - 300 245 - 380 280

4.2.4 Health risks Chronic inhalation of coal and charcoal dust may present potential health risks to exposed individuals, and exposure should be minimized.

4.3

Handling in the Process

4.3.1 Storage of raw coal Raw coal is effected by self-ignition and weathering. Any coal at its surface absorbs oxygen from the atmosphere which tendency is enhanced with coal rich in gas and oxygen. The absorption is linked to heat development development which leads to heating of the coal if the heat cannot be dissipated. The rate of oxygen absorption increases with coal temperature. In particular is the chemical reactivity of the oxygen that becomes more pronounced at elevated temperature which leads to continuous disintegration of the coal substance and heat development, development, finally causing self -ignition. If, on the other hand, the heat produced is released to the environment , no temperature increase takes place. In such case, there will take place a slowly progressing weathering effect at the coal surface with the consequence of certain losses in calorific value. Self-ignition will be enhanced by: by: Too high storage temperature or contact to heat sources. Inclusions of foreign bodies (impurities) that result in irregularities in heat development. development. Larger proportions of pyrite will increase the tendency of self-ignition. Mixed storage of coals of various types. If it cannot be avoided entirely, then at least the most sensitive types of coal should be stored separately. Mixed storage of coals of various grain sizes. Since coarse grain coal favors the access of air to the fine grains the two grades are to be stored separately. Storage of too large amounts of coal. Monitoring and heat dissipation of the lower layers is rendered difficult. Air circulation in the coal heap. Hereby, the oxygen supply will be increased causing accelerated weathering. External factors leading to mechanical weathering. Sun exposed corners and only scarcely irrigated spots tend to self-ignition. Changes in ambient temperature and precipitation often call for self-ignition.


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Fast coal heating with imminent danger of self-ignition self-ignition appears at the following temperatures: temperatures: Hard coal and hard coal briquettes - starting at 70 °C Brown coal, brown coal briquettes and low temperature coke - starting at 50 °C Recommendations for appropriate for appropriate storage storage:: Storage area to be far away any heat source (burners, boilers, steam pipes, slag piles). Storing under roof cover especially recommended for sensitive coal for protection against sun, rain and snow. Storage floor to be dry and free from any superstructures and ditches. Girders that cannot be removed as well as corners are to be coated by concrete. Before initial use of a storage floor it is to be entirely cleaned from any coal dust because the latter may cause self-ignition. Sub-division of coal heaps. One-piece coal heaps may only attain a size that permits removal of the coal, at least up to the point of the source of a fire within 3 x 24 hours by means of the conveying equipment installed. Aisles and ditches are to be incorporated between individual heaps. Of one or several heaps are than what is permitted according to paragraph before an aisle of at least 3 m width will have to be installed. Additional sub-division sub-division by narrow ditches or fire walls is recommended. Temperature monitoring of the coal stock pile. Methods of storing: storing: Handling with coal has to be done with care to prevent production of additional slack. Large amounts of coal must not be dumped in cones but deposited layer by layer over the total storage area. Coal of different types and grades are to be stored separately. Nests of coarse and fine coal are to be avoided in particular. Coals of certain mines having a reputation for selfignition are to be stored separately in heaps the height of which shall not exceed 2-3 m. To reduce oxygen access the coal should be packed as tightly as possible. exception: stapling of brown coal briquettes. Inclusions of foreign bodies (impurities) as dust, sand, earth, wood, iron, easily inflammable matter like paper, cleaning rags, etc, are to be avoided. Stapling heights: heights: Stapling heights depend on gas content and hardness of the coal, the quality of the storage ground and on conveying and fire fighting equipment at hand. Therefore, there do not exist any universally applicable applicable rules. The subsequent figures (Table ( Table 5) 5) are to be understood as guidelines guidelines whereby the lower figure applies to standard cases, the higher one to special solutions. Stocks that are to be stored presumably for long periods of time should not contain any run of mine coal and fine coal, but rather coarse grain coal of even grain size. Coating of the surface of coal heaps by a thin layer of bitumen is a method sporadically applied for very large storage amounts. It is an expensive method. Besides, the bituminous material impairs subsequent processing processing of the coal like mixing and fine grinding. A preferable method - also applicable for mixtures of fine coal and small sized nuts - is the rolling of the coal so as to increase the bulk weight and to limit oxygen access to a rate where self-ignition becomes hardly possible any more.


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Bunker storage is preferably being applied in connection with inert gases (CO 2, N2).

Table 5: 5:

Stapling heights of unground coal

Type

Stapling height m

Anthracite Hard coal, lean in gas Hard coal, rich in gas Fine coal* Hard coal briquettes Raw brown coal Brown coal briquettes Coke Low temp. carbonized lignite in pieces fine grained and humid

6 6 4 5 6 4 4 6 2 2-8

-

unlimited 10 8 -10 unlimited unlimited 6 unlimited 4

* To be stacked tightly and in heaps of small surface area, whereby the slope angles have to be large approaching the natural angle of repose of dumped fine coal.

Monitoring of coal stocks: Continuous monitoring monitoring of the center part is mandatory. Temperature readings are to be taken at least once a week. If mixtures of types and grades cannot be avoided daily readings are be taken if by all means possible. Random measurements at other Locations during changes of weather conditions and at indications of temperature increases. If at a certain location a temperature of more than 45°C is measured, watering in a surrounding area area of 2 - 3 m is required until a temperature drop is felt. Indications for a temperature increase are: smell, gas fumes, melting snow, ash spots, and in vertical bunkers condensation of water on the top covers. Fire fighting: At temperatures above above 60 to 70 °C and for fighting of fires fires of small extent (to be detected detected by the development of whitish steam, flickering air, sweating of the coal) the hot centers shall be uncovered, the hot coal shall be allowed to burn or shall be drenched in water. The surrounding coal shall be reshuffled. If a fire of small extent shall be extinguished by water, plenty of water shall be used to prevent the formation of water gas which would increase even the danger of inflammation. If there is noted a temperature increase in a bunker, the latter is to be emptied and the coal to be reshuffled by measure of its temperature. Hot coal is to be consumed at once. Fires of large extent are difficult to extinguish. Fire fighting can be carried out but require specialized training and risk mitigation.


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Storage in bunkers: Most effective by means of suppression of any fresh air supply, preferably under simultaneous cooling. Fan induced scavenging from bottom to top by CO 2 or N2 has been applied successfully. Open air storage: through suffocating by covers of wet earth or through water drenching upon removal of coal layers in the vicinity of the source of fire. Dissociation of water steam and explosions can occur too, if water is sprayed into burning coal heaps directly. Suffocation by means of dry-fire extinguishers (chemicals). Submersion of coal in water. Reshuffling and suffocating of coal in bunkers. Reclaiming of fine coal by means of grab buckets, submerging in water for 1-2 minutes and spreading in an open area.

4.4

Coal Preparation / Grinding

4.4.1 Quality of coal preparation for cement clinker kilns Inadequate coal preparation (fineness) can result in both burn-out problems (CO formation) and the presence of fuel in the material bed. The combustion time of coal depends on the content of volatile elements. The aim is to comply with the following simple rule as an upper limit: Residue on the 90 µm sieve < ½ % of volatile components Residue on the 200 µm sieve < 2 % For low volatile and difficult to burn coal types such as petrol coke and anthracite, the above mentioned rule has to be tightened: Residue on 90 µm sieve for petrol coke and anthracite < 5 % Residue on 200 µm sieve for petrol coke and anthracite anthracit e < 1 % It has to be pointed out, that both values, the residues on 90 µm and on 200 µm are important. The 90 µm values influence flame length and CO formation, excess residues on 200 µm create reducing conditions in the material bed and can be responsible for increased volatilization of sulfur.

4.4.2 Pulverized coal dosing For coal firing, in order to obtain perfect fuel feed, the entire feed system - from discharge from the coal dust silo, through weighing and dosing, to coal dust transport to the burner - must function as well as possible. The feed bin design has a decisive impact on feed rate control. A feed bin design ignoring a product's flow characteristics may result in inconsistent discharge rates due to problems such as arching, erratic flow and flushing, conditions that can not be corrected by any feeder system. The feed bin has to be designed for mass flow.


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The discharge opening should be activated preferably by using mechanical discharge device such as paddle or agitator. Pulsed aeration systems can help to solve discharge problems at existing bins. The dosing system should meet the following requirements: requirements: Weighing accuracy: +/- 2% is normally accepted. Short term variations (referring to 10 sec. measurements): measurements): < +/- 1% (short term variations are responsible for CO peaks) Long term variations (approx. 10 min. to 1 hour): < +/- 0.5% Sensibility: < +/- 0.5% Adjustment range: 1:20 (of the maximum capacity). The best indicator for the accuracy of the dosing is the oxygen level at kiln exit. Poor dosing of coal dust leads to big fluctuation of the oxygen concentration. Most Common Pulverized Coal Dosing Systems on the market nowadays: Rotor Feed Scale (Pfister) Coriolis Scale (Schenk) Only second choice are the following systems: Loss-In-Weight Loss-In-Weight System (complex setup requiring skilled maintenance) maintenance) Impact-Flow Meter (limited accuracy)

4.4.3 Protective measures against dust explosions In dust explosion protection techniques a distinction is made between active protective measures (prevention of the occurrence of explosions) and design related explosion protection (explosion resistant construction).

4.4.4 Active explosion protection The active explosion protective techniques aim to exclude at least one of the three preliminary conditions necessary for an explosion, i.e.: Stirring-up of combustible dust Oxygen content above the critical concentration of generally 12% for lignite or 14% for hard coal Ignition source

Ignition source In a pulverizing plant, ignition sources cannot be excluded with absolute certainty. It is always possible that mechanical sparks will be generated by the action of foreign bodies or by friction between moving machine part or that the hot gas or coal feeding system will supply smoldering fuel particles.


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Combustible dust It is of course impossible to replace the combustible dust with a non-combustible material in the preparation of fuel. Thus, the only remaining possibility is the exclusion of air or oxygen respectively, or the reduction of the oxygen content in the fuel preparation plant. Air and oxygen Dust explosions can be effectively prevented through inertization, i.e. the replacement of the oxygen in the air by a non-combustible non-combustible gas, particularly CO 2 or N2, if it can be ensured that the inert gas atmosphere will be maintained as long as combustible dust is present in the system. The maximal O 2 concentration, below which no explosive propagation reactions of mineral coal dust are noted, is approx. 14%, the one for lignite approx. 12%. However, this concentration can vary in accordance with the type of fuel processed. As a safety margin of at least 2% O2 is required, the maximal permissible limit of O2 concentration for mineral coal dust is therefore as a rule 12%, for lignite 10%.

4.4.5 Design related explosion protection Reduction of the effects of already proceeding explosions, and therewith the protection of people and machines, can be achieved by: Explosion pressure resistant construction Explosion pressure venting measures Explosion suppression techniques Figure 5:

Passive Protection Measures

Source: Passive Protection Measures" from Holcim Cement Course CD, C04 Firing Systems


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Explosion pressure resistant construction Explosion pressure resistant construction restrict any possible explosion to the dust conveying installation, whereby whereby a certain amount of minor damage to the installation commensurate with the complexity of the facility is accepted. All dust conveying conveying installation parts parts as well as the adjacent adjacent equipment equipment and sealing sealing elements must be designed to resist the maximal explosion pressure of 9 bar expected in the case of coal or lignite dust. I f deformation of the container is accepted, the maximum permissible explosion pressure may be up to 50% above its design value (pressure shock resistant design). A design for 6 bar static overpressure overpressure is required for an an expected maximum maximum explosion explosion pressure of 9 bar. Such construction methods are of course quite complex and expensive. However, in the event of an accident the installation is again operational within a short t ime.

Explosion pressure venting measures In a broader sense explosion venting means all measures that serve to open temporarily or permanently the previously closed installation in a safe direction, at the beginning or after a certain spreading of an explosion. The purpose of this is to prevent any overstressing of the mechanical equipment equipment beyond its pressure shock resistance. The strength of the equipment does not have to be designed for Pmax, but only for the reduced explosion pressure pressure Pred. A deformation of the container may again be acceptable, but it must not burst. Figure 6:

Pressure Response in Explosion-Pressure-Reli Explosion-Pressure-Relief ef Techniques

Source: "Pressure Response in Explosion-Pressure-Relief Techniques " from Cement Course CD, C04 Firing Systems)


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The explosion pressure venting technique operates in the following manner: When the dynamic response pressure of the pressure venting installation is reached, predetermined breaking points, rip foils or doors open to vent the shock wave outdoors, mainly by means of amply dimensioned discharge channels. Immediately after the pressure venting system responds an increase in the temporal rate of pressure rise can often be observed which is due to the higher turbulence caused during the venting of the shock wave. The pressure rise then quickly stops at P red. Guidelines concerning the design layout and dimensioning dimensioning of the explosion pressure venting installations are contained in VDI Guidelines No. 3673. If the method of explosion venting is applied applied not only the inserts of the t he containers such as filter cloths etc. must be considered but the expected recoil forces as well. With a pressure venting area of 1 m 2, a reduced explosion pressure of 2 bar, and under the assumption that the shock wave escapes with the velocity of sound, a thrust of approx. 15 t acts upon the housing to be protected. This must be properly supported or else the container may be torn from its foundations.

Explosion suppression In the explosion suppression techniques, the shock wave preceding the combustion front or the infrared radiation of the combustion area is detected by a device which quickly distributes extinguishing extinguishing agents under a propellant pressure of 60 to 120 bar by means of detonatoroperated valves. With a programmed dynamic response pressure threshold (P dyn) of the detectors, the maximal explosion pressure is again lowered to a reduced level (P red).

Limitation: Explosions from ducts into containers The described constructive protection techniques are effective under the condition that the reaction takes place as described above. The description is applicable to most explosions that occur in pulverizing plants. However, if an explosion strikes from a duct into a container, and in doing so the residual dust deposited there is stirred up with great turbulence and ignited, the reaction within the duct and the adjacent container can develop into a detonation of such dimensions that the resulting pressures can amount to 50 times the original pressure, accompanied by a combustion front traveling at supersonic speed, so that any relief or suppression installation installation is too sluggish in action. However, such events are, fortunately, relatively rare in coal operations. As a limit for a spontaneous spontaneous explosion propagation, an -1 explosion characteristic of 100 bar *m* s was observed under particular conditions in a 200 m long pipeline of 1800 mm diameter located at the experimental mining research station in Dortmund, while the usual values for coal are generally lower (approx. 85 bar *m* s-1). However, if the principles of design related explosion protection are to be consequently pursued, every duct conveying combustible dust in an explosive concentration and whose length exceeds five times its diameter must be safeguarded by an explosion vent placed ahead of its inlet into a container (such as a filter) (Figure ( Figure 7). 7). Through this any explosion originating in the pipeline will be vented so that the protective measures taken with respect to the adjacent container can be designed in accordance with the criteria of an explosion starting in the container itself.


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Venting of a duct in front of a precipitator

Source:"Venting Source:"Venting of a Duct in Front of a Precipitator" from Holcim Cement Course CD, C04 Firing Systems

Prevention of smoldering fires Smoldering fires in dust deposits are best prevented by preventing the possibility of greater quantities of dust accumulating. This is achieved through the appropriate design and slope of surfaces, pipelines and supports, as well as sufficiently high gas speeds within the conveyor systems. In silos where great quantities of combustible dust are stored for the plant’s own specific purposes, any combustion that may occur must be detected as early as possible by carefully monitoring of the dust temperature and the CO content of the silo atmosphere so that proper countermeasures countermeasures can be taken.


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4.4.6 Application Application of preventive safety measures The fire and explosion protection measures described above result for practical applications on the one hand in a network of preventive safety measures that significantly reduce the risk of an accident in the operation of combustible dust installation, and on the other hand in actual explosion protection techniques techniques that can prevent explosions, or at least shall hold the explosions within acceptable limits.

Preventive safety measures The primary aim of preventive safety measures is to exclude possible ignition sources as causes of conflagration or explosion if at all possible. In addition, they are also intended to prevent secondary damage caused by the expulsion or stirring up of vast quantities of dust and their subsequent ignition. These essentially preventive safety measures can be listed as follows: Temperature measurement of mill exhausts and stored dust, preferably in silo entry and exit CO analysis of the silo atmosphere and at mill exhaust after the filter Prevention of local overheating caused by friction in conveyor belt systems, high speeds of screw conveyors, bucket elevators, rotary valves, and bearing, and/or the detection of increasing temperatures temperatures by measuring techniques. Relative velocities of moving parts < 1 m/s are considered safe, > 10 m/s are considered as potential ignition sources. Spark separators in air heaters Metal separator prior to the mill Prevention of electrostatic discharges by conductive connections and grounding of all installation parts Prevention of arcing in electrofilters by appropriate voltage control measures Prevention of dust accumulation possibilities: possibilities: All surfaces to have a slope of at least 70° to the horizontal plane, especially in filter or silo cones Regular disposal of dust deposits Gas speeds in conduits of more than 22 m/s Protection of the stored dust from the effects of external heat, for instance by spraying the silo externally with cooling water Provision of inert gas supplies (e.g. CO2) for inertization of the silos in the case of smoldering fires Cleanliness Cleanliness of operating rooms Effective removal of the dust generated by means of proper dedusting installations installations Safe elimination of dust deposits by means of suitable auxiliary material From the point of view of safety a solid fuel pulverizing plant must be operated as continuously continuously as possible, as critical situations often arise when the plant is not in operation. This fact must be considered when the capacity of the t he installation is being decided upon.


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4.4.7 Application of explosion protective techniques Inert Gas Operation Active explosion explosion protection in solid solid fuel pulverizing pulverizing is practically practically limited to inert inert gas operation, i.e. operation with a maximum of 10 to 12% oxygen in the pulverizing plant, depending on type of fuel, as ignition sources and the stirring-up of dust can never be excluded with absolute certainty. Active explosion explosion protection can be be applied if hot hot inert gases such as as the kiln exhaust exhaust from cement kilns or hot gases from a combustion chamber, combined with a corresponding corresponding design for the mill’s recirculation gas are available. In the last case the dew point problem becomes significant, therefore this solution is rarely applicable for very moist fuels, or special measures will have to be taken for drying of the t he circulation gases. If the inert gas atmosphere can be maintained with absolute certainty through appropriate design and interlocking of the installation for as long as combustible dust is present in the system, design related protection measures become in principle redundant. In those cases where these conditions cannot be guaranteed, for example, because hot gases with higher oxygen content are being used such as clinker cooler exhausts, or because of dew point problems, design related explosion protection techniques must be rigorously applied. Explosion Pressure Resistant Construction Explosion pressure resistant construction, i.e. the dimensioning of the installation section to resist maximal explosion pressure, are mainly applicable where pressure venting methods cannot be used at all or only with difficulty, for geometrical reasons. This is mostly the case in mills, and definitely in all conduit pipe systems where the length of the system exceeds five times the tube diameter. As a rule such components are designed to withstand a static overpressure of 10 bar. Explosion Pressure Venting Measures All combustible dust conveying components that are are not in themselves themselves designed to be be explosion pressure resistant, such as cyclone, filters, pulverized fuel silos, etc. are to be provided with properly dimensioned devices for explosion pressure venting. Thereby containers and all interconnected aggregates aggregates such as bin vent filters, etc. must be dimensioned in pressure shock resistant design to withstand the reduced explosion pressure. Explosion venting openings within a particular building must be connected to properly dimensioned exhaust exhaust channels leading into the open. In order to prevent an explosion originating in the mill spreading into the f ilter via the conduit pipe, the conduit pipe must be equipped with an explosion vent in front of its connection to the filter. This measure is not required for pneumatic conveying systems as in this design the dust concentration is normally above the explosion limit. In addition, the minimal ignition energy is significantly higher under the operating conditions of pneumatic conveying than it is in the case of stirring-up combustible dust in containers. The area containing the vent opening for explosion pressure venting must not be accessible to anyone when the installation in operation. VDI Guidelines No. 3673 can serve as a basis for the design of such an explosion pressure venting system. Naturally, the system must be inspected regularly.


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Underpressure Protection After venting an explosion explosion in very large large enclosures enclosures such as pulverized pulverized fuel silos silos through explosion flaps considerable considerable underpressure can develop inside the silo due to dynamic effects and due to cooling down of the hot gases remaining in the silo after the explosion. Typical examples for the size of underpressure underpressure valves are given in Table 6. 6. Guidelines for the individual design of underpressure underpressure valves can be taken from the relevant literature.

Table 6: 6:

Example for the size of underpressure underpressure valves Volume

m3

100

1100

Diameter Cylindrical length Plate thickness Max. negative pressure Required aspiration area

m3 m3 mm mbar

3.4 9.5 6 100

7.5 22.0 8 25

m2

0.1

1.0

Explosion suppression Techniques of explosion suppression can basically replace all the previously mentioned methods. However, in practical experience it has been seen that in pulverizing plants, the costs involved in the consequent application of explosion suppression techniques are significantly higher than they are for explosion pressure venting techniques and explosion pressure resistant construction methods, both with respect to procurement and maintenance of the sensitive equipment. Thus applicability of explosion suppression may be primarily limited to existing, insufficiently protected pulverizing plants whose retrofitting in accordance with alternative protection techniques would be entirely uneconomical.

Fire Extinguishing Measures If an accumulation of considerable quantities quantities of combustible dust can be prevented inside the actual pulverizing plant (except in pulverized fuel silos), any fires that may arise following an explosion will not be able to grow to any significant size. The installation of a fire extinguishing system can nevertheless still be recommended for cloth filters and electofilters. In the case of smoldering fires in pulverized fuel silos, all further fuel supply must be stopped immediately. Following Following this, the silo exit must be made airtight and the silo atmosphere flooded with CO2. Sufficient time must now pass until the temperature conditions conditions have normalized. An underpressure valve is required in order to avoid collapsing of the silo due to the vacuum produced during cooling down. The above procedures can take several days, depending on the size of the smolder location. An alternative technique is to deliver the fuel as quickly as possible to the burner system via the dosing and conveyor systems. Of course this method is possible only when the dosing and conveying systems are heat-resistant, dustproof and explosion resistant. In addition, under no circumstances is glowing fuel to be returned to the silo, as for instance via overflow feeders. In Figure 8 the 8 the application of design related protective measures for solid fuel preparation is illustrated. OH&S manual for traditional fuels.doc

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Figure 8: 8: Example to Show the Application of Design Related Explosion Protection

Source: "Design related explosion" from Holcim Cement Course CD, C04 Firing Systems

4.4.8 Storage of fine coal With pulverized coal, handling problems are similar to that with raw coal, although the mechanical properties properties of these t hese two coal qualities are quite different. As raw coal to the mill, pulverized coal must be fed at a controlled rate to the burner as to guarantee complete combustion. Prerequisite Prerequisite for an accurate feed rate control is again reliable material discharge from the storage bin. And again, mass-flow would be the most suitable flow sequence in a pulverized coal storage bin. Nowadays, storage bins of a standard design are offered for pulverized coal by specialized suppliers. Such bins are pressure shock resistant and fully equipped with feeding and flow rate control systems, with the necessary monitoring equipment like load cells for bin content control, temperature and CO measuring devices, with safety equipment as explosion doors and inertization systems ( Figure 9). 9).


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Preventive and Safety Measures for Coal Dust Silos

Source: "Preventive and Safe Safety ty Measures for Coal Dust Silos" from Cement Course CD, C04 Firing Systems

Suppliers design bin discharge hoppers with a standard slope of not less than 70 degree and made of stainless steel. To prevent caking due to condensation effects the discharge hoppers are provided with a thermal insulation. Most discharge problems problems from pulverized coal bins are due to a deficient design of the bin outlet section. To overcome bridging and ratholing discharge aids have been installed either of a mechanical type such as paddle wheels or of a pneumatic type such as pulsed air nozzles. In operational practice it also became manifest that the standard hopper slope of 70 degree even with stainless steel is not sufficient in all cases. As a result ratholes have formed in the bins. Again, aeration systems were installed as to promote material flow ( Figure 10). 10).


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Flow promotion by aeration

Source: "Flow promotion by aeration " from Cement Course CD, C03 Design of bins and feeders)

The flow regime can also be influenced when changing the wall frictional behavior. A UHMW PE lining in a 70 degree sloped bin discharge hopper would in most cases induce mass-flow. Nevertheless, it is not recommended to base the design of new storage bins for pulverized coal on a UHMW PE lining due to PE’s low melting point (~ 135 ° C). But a PE lining is accepted to be an effective measure to convert a funnel-flow sequence sequence to mass-flow in an existing bin. In Appendix 2 a 2 a check list for coal grinding systems is shown and in Appendix 3 experience 3 experience values are displayed.

4.5


General Maintain a clean working environment when handling or transporting coal or charcoal materials. Wash hands before eating or drinking. Ensure that any exposed wounds are properly bandaged and that damaged bandaging is replaced. Face Protection Use safety glasses or goggles.


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Hand Protection Use normal work gloves. Body Protection Use normal work clothes with dust protection such as antistatic material. Shower at the end of shift. Respiratory Protection: Use fitted particulate filter mask such as 3M N95. Provide adequate ventilation when handling coal and charcoal materials, especially in enclosed spaces.

4.5.1 First Aid Procedures Remove and isolate contaminated clothing and shoes. Following direct skin contact, promptly wash exposed area thoroughly with soap and water. For eye contact, remove any contact lenses and flush eye with water for at least 15 minutes. For inhalation, move the affected individual to an area of fresh air, resuscitate and provide respiratory support if necessary. For ingestion, do not induce vomiting. For all injuries or suspected significant exposure events, the employee should see a health care specialist identified by Holcim. An accident report should be filed with the employee’s direct supervisor and the Occupational Health and Safety Coordinator.


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CHAPTER 5: PETCOKE 5.1

Product Description

5.1.1 Petcoke types Petroleum coke is a black solid, obtained mainly by cracking and carbonizing residue feedstocks and from the distillation of heavier petroleum oils. The main commercial applications applications of petroleum cokes depend on their properties and they are typically used as energy sources for solid fuel applications such as lime and cement kilns and sometimes as fuel for boilers and power generation. generation. Some calcined cokes are used in the manufacture of electrodes for aluminium and steel electrosmelting. electrosmelting. Petroleum coke is a black granular or needle-like substance, basically carbon, produced during the thermal decomposition of heavy oils. Petroleum coke exists in the following basic forms: 1.

Green coke is the immediate product of a semi-continuous semi-continuous batch coking process known as delayed coking, which contains a significant residual hydrocarbon content.

2.

Calcined coke, a product derived from green coke, in which the hydrocarbons hydrocarbons have have been removed by heating under reducing conditions in kilns to temperatures in excess of 1200°C.

3.

Fluid coke, the product of a continuous fluidized-bed fluidized-bed coking process.

4.

Flexicoke, a product from continuous fluidized-bed fluidized-bed coking process, in which the major part of the coke is gasified to a low calorific value gas for refinery use.

Green coke (delayed coke) has a distinctive hydrocarbon smell. smell. It can contain up to 15 % volatile material, mostly hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs). Calcined coke purity is largely feedstock dependent. Needle coke and regular coke are calcined cokes of different purities, the needle coke being the purer form, which is used for electrodes production. Calcined Calcined coke, as a consequence of the calcining process, has a virtually zero volatile content. It is inherently a much dustier material than green coke and depending on its use it is usual to add a small amount (0.3 % wt or less) of high viscosity oil or a very small amount of surfactant usually in a water solution to act as a dust suppressant. Fluid coke has spherical grains and contains less volatile material than green coke. The normal grain size of fluid coke is less than 6 mm. Flexicoke is similar to fluid coke but contains even less volatile material and has much finer grains and thus is more dusty. There are three entries for petroleum coke in the European Inventory of Existing Commercial Chemical Substances (EINECS) and these are shown in Appendix 1.


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5.1.2 Composition of petcoke The compositions of all petroleum cokes are highly feedstock dependent and also vary from location to location depending on the types of processes used. Generally speaking, petroleum cokes contain some proportion of all the t he elements, which exist in the crude oil/feedstock used in the process. Therefore, each form of petroleum coke has its own distinctive qualities. The compositions of calcined cokes are directly related to the green cokes from which they are produced, except for the effects of the lower volatiles content noted above. Because of the dependence of a petroleum coke's properties on the crude oil source of the feedstock and the specific process used, the analyses can have a wider or smaller spread than t han those indicated. The compositions of the petroleum cokes typically lie in the following ranges: Carbon 84 - 97 % Sulfur 0.2 - 6 % Volatile matter 2 - 15 % Hydrogen Up to 5 % Iron 50 - 2000 mg/kg Vanadium 5 - 5000 mg/kg Boron 0.1 - 0.5 mg/kg Nickel 10 - 3000 mg/kg Analytical data for for examples of uncalcined uncalcined cokes produced produced by three three different processes processes are shown in Table 7.


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Analysis of uncalcined cokes prepared by three different Table 7: processes Analysis conducted conducted by Gulf (1980) (1980) Sample

Fluid Process Coke

Delayed Process Coke

Micronized Delayed Coke

Elemental Analysis, (% wt) Carbon Hydrogen Oxygen Sulphur Nitrogen

84.58 2.15 2.56 6.08 1.45

89.93 3.71 1.30 3.36 1.10

89.97 5.04 1.62 3.27 1.10

Other Analysis (%wt) SiO2 (Chemical) Ash

0.04 0.81

0.04 0.21

<0.04

<0.001

<0.001

5.3 113 410 160

4.5 <1 145 95

0.3 <0.2 <1 140 78

0.15

1.79

2.08

50 197 276 38 35 138 314 176 280 32 ND ND ND ND ND

440 110 439 544 ND 126 ND ND ND ND 11 ND ND ND ND

175 85 120 280 T 210 165 ND ND ND ND ND ND ND ND

Trace Metals, (ppm) Arsenic Selenium Mercury Vanadium Nickel

0.19

Benzene extractables (% wt) Polynuclearaomatic hydrocarbons (PAHs), (ppm) Benz(a)pyrene Benz(e)pyrene Benzo(g,h,i)perylene Benzo(a)anthracene Dibenzo(a,h)anthracene Chrysene Pyrene Benzo(b)fluoranthene Phenanthrene Methyl Benzo(a)pyrene Benzo(a)pyrene Fluorene Benzo(g,h,i)fluoranthene Benzofluorenes Perylene Coronene ND = Not Detected at limit of 1 ppm T = Trace, could not be quantified


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5.1.3 Typical Properties Petroleum cokes are marketed in the form of dry or de-dusted solids or as slurries in oil or water. There are only a limited number of t ypical general properties, such as bulk and real densities, which have proved useful to define any particular petroleum coke product and most analytical reports are related closely to specific end user applications. applications. Other properties, which may be important for particular end uses, include: the contents of individual metals, calorific value, hardness and screen analysis of particle sizes, amongst many others. In the case of calcined cokes the levels of de-dusting oils are also regularly quoted.

Two examples of the ranges of general properties reported are:

Bulk Density (kg/dm3)

Real Density (kg/dm3)

Green Coke

Calcined Coke

0.70 - 0.90

0.75 - 0.95

1.35 - 1.45

2.06 - 2.16

5.2 Product Health and Safety Risks 5.2.1 Health risks

5.2.1.1 Toxicity Toxicity studies have been conducted on green fluid cokes and the analyses of the samples are shown in Table 1. 1. Because calcined cokes are produced by more severe processes and they consist even more predominately of carbon, their toxicities are, if anything, likely to be less than that of green coke.

5.2.1.2 Acute Toxicity There are no acute toxicity studies reported on petroleum coke. From the physical and chemical properties of the material in both its uncalcined and calcined forms it is considered unlikely to be acutely toxic by the oral and dermal routes. No skin effects are expected following exposures exposures of short duration but it may be irritant to the eye due to abrasiveness of the material. Irritation of large quantities of coke dust but this would be due to its physical form rather than its chemical nature.


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5.2.1.3 Chronic Toxicity The data are limited to chronic inhalation studies on coke in its green form in rats and monkeys using the micronized delayed coke sample referred to in Table 1. 1. In this study three groups of animals, each consisting of 150 male and 150 female Sprague-Dawley rats and 4 male and 4 female Cynomolgus monkeys were exposed to either clean air, 10.2 or 30.7 mg/m3 petroleum coke dust, aerosols for two years. Clinical, haematology and clinical chemistry, body weight and ophthalmic measurements were made during and at the end of the study and gross and histopathology histopathology analyses were carried out at termination. No significant toxic effects during the study and at termination to determine any chromosome abnormalities.

5.2.1.4 Mutagenicity Ames bacterial mutagenicity mutagenicity studies, studies, mouse lymphoma lymphoma and in vivo bone marrow assays were conducted on samples of delayed process coke and fluid process coke. In the Ames assays in strains TA 1535, 1537, 1538, TA98 and TA100, neither material was mutagenic either in the presence or absence of metabolic activation. The results of the mouse lymphoma test indicated that neither material was mutagenic in this assay either in the presence or absence of metabolic activation. The effects of these petroleum coke samples were evaluated in the and in vivo bone marrow cytogenics assays. Groups of 8 Sprague-Dawley Sprague-Dawley rats were exposed at 10 and 40 µg/l for 6h/day, 5 days/week. Untreated controls were exposed to filtered air under the same experimental conditions. conditions. The groups treated with 0 and 10 µg/l received 20 exposures whereas the group treated at 40 µg/l received only 5 exposures. The fluid coke caused no effects in this study. However, rats exposed to the delayed process coke only exhibited increased numbers of chromosome aberrations at the 40 µg/l dose level. An in vivo study evaluations were performed vivo study was conducted in which complete cytogenetics evaluations on groups of 10 Strague-Dawley Strague-Dawley rats (10 rats/sex/group) exposed to 10.2 or 30.7 µg/l of delayed process coke for 6 h/day, 5 days/week, 12 and 22 months duration. No treatmentrelated effects were seen. Another cytogenetics cytogenetics assay has also also been conducted conducted and reported but since technical technical flaws in the study have been identified which cast doubt on the results they are not considered in this chapter.

5.2.1.5 Carcinogenicity Carcinogenicity The skin carcinogenicity of delayed and fluid petroleum coke samples was investigated in a study using groups of 50 C3H/HeJ mice (25 of each sex). Samples of either delayed process coke or fluid process coke, 25 % in mineral oils as carrier, were painted onto the backs of these animals three times per week for their lifetime. Other groups were mineral oil-treated negative and untreated negative and two positive control groups that received benzo(a)pyrene (BaP) at either 0.05 or 0.15 % in mineral oil two times per week. Neither coke sample caused skin cancer in this study. Mammary gland tumours, subcutaneous fibrosarcomas fibrosarcomas and other spontaneous cell neoplasms that were judged to be


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pre-malignant pre-malignant or malignant. In addition the survival time in these positive control groups was significantly reduced. The only effect observed in the mice treated with petroleum cokes was an increased Incidence of epidermal acanthosis when compared to the untreated controls.

5.3 Health Aspects 5.3.1

Human Experience

There have been several health surveillance studies conducted at manufacturing plants where petroleum coke was in use. The common feature of these studies was the examination of the effects of dusts and of PAH on the workforce but in none of them was it possible to identify the contribution of the coke to the effects observed. One study was conducted to evaluate the effects of coke dust on respiratory function. 90 employees (55 % of the workforce) participated in a medical investigation that included a questionnaire questionnaire relating to pulmonary function. Pulmonary tests and chest X-ray. The medical evaluation revealed abnormal abnormal pulmonary function test results in 9 of the t he workers and these findings were significantly related to the amount of exposure to coke dust. Chest X-rays showed no evidence of pneumoconiosis. pneumoconiosis.

5.3.2 Health Hazards Calcined coke is regarded as a relatively non-toxic material in the "nuisance dust" category. Excessive concentrations concentrations of nuisance dust may cause unpleasant deposits in the eyes, ears and nasal passages and may irritate the skin or mucous membranes by mechanical means. means. Although green coke contains PAHs PAHs at low levels, levels, laboratory tests, and health health surveys have have failed to establish a causal relationship between exposure to carcinogens exists, exposure to green coke and other cokes should be minimized. Inhalation As with other nuisances nuisances dusts, inhalation inhalation of excessive excessive concentrations concentrations of dust may cause transient lung irritation and may exacerbate existing chronic lung disease such as chronic bronchitis. There is no evidence that pneumoconiosis has been associated with exposure to petroleum coke. Ingestion Ingestion is an unlikely route of exposure during normal use and it is also unlikely to be associated with any adverse health effects. Skin Contact Prolonged contact with the skin may cause mechanical irritation and subsequent subsequent dermatitis. Eye Contact Direct eye contact may cause mechanical eye irritation.


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5.3.3 Exposure Limits There are no national occupational exposure limits established for petroleum coke. To provide adequate workforce protection, guidance should be taken from the established occupational occupational exposure limits as detailed below.

5.3.3.1 Green Coke The limited available evidence from animal studies indicates that green coke is not carcinogenic. It is recommended that one of the current Coal Tar Pitch Volatile Exposure Standards should be applied to control exposure to the PAH associated, albeit at very low levels, with green coke. These standards vary from country to country. The current American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) for coal tar pitch volatiles is 0.2 mg/m3 (as the benzene soluble fraction). fraction). The Occupational Safety and Health Administration (OSHA) in the USA has adopted this standard but additionally requires requires that if this TLV is exceeded, the presence of one or more of five specific PAHs must be confirmed using gas chromatography. The 0.2 mg/m3 exposure limit (as benzene soluble fraction) is widely applied although in the UK, this has recently been changed to 0.14 mg/m3 (as the cyclohexane soluble fraction). There is no requirement to establish the presence of specific PAHs but exposure limits based on the benzene soluble fraction are published in a number of other European countries. For routine monitoring purposes were the benzene soluble fraction in the airborne particulate is known beforehand. It is possible to determine total dust concentrations and calculate the fraction. The highest probable benzene soluble fraction content for the situation being monitored should be used and should be confirmed in the initial survey.

5.3.3.2 Calcined Coke In view of the very low hydrocarbon content content of calcined coke and the relatively low levels of other contaminants such as heavy metals, it is appropriate to treat it as biologically inactive and apply the appropriate standards published for inert dusty materials. These vary from country to country but, most comprehensively the Health and Safety Executive in the UK specifies exposure limits of 10 mg/m3 (Total Inhalable Dust) and 5 mg/m3 (Total Respirable Dust) for dusts where no component exposure limits are applicable. Adherence to these figures will ensure that the limits for nickel and vanadium, the two principal heavy metals, cannot be exceeded, given the current known maximum levels of these metals in petroleum coke product.

5.3.3.3 Other Cokes For these types of petroleum cokes, the appropriate sections from the guidance given above and the handling advice given below should be applied.


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Safety Risks

5.4.1 Fire and Explosion Hazards There is a slight possibility of an explosion hazard if coke in the form of a dust is exposed to heat or flame. All forms of petroleum petroleum coke will burn burn if exposed to heat. heat. The fire hazard is likely likely to be greater greater with green coke, which contains more volatile hydrocarbons than the other types of coke. To fight a fire of burning petroleum petroleum coke use: water, mist, foam or dry chemical.

5.4.2 Handling in Process Petcoke is considered as solid fuel with similar handling properties properties than coal respectively anthracite. The handling procedure for coal is described in chapter

5.4.3 Disposal Petroleum cokes are normally used up in their normal applications as a fuel, as a component of electrodes and so on. Whenever petroleum cokes need to be disposed of, disposal via waste incineration plants, preferably with heat recovery, is possible. As a last resort, secure landfill is a technically acceptable disposal route.

5.5


General Maintain a clean working environment when handling or transporting petcoke or coal petcoke/coal mixtures. Wash hands before eating or drinking. Ensure that any exposed wounds are properly bandaged and that damaged bandaging is replaced. Face protection Use safety glasses or goggles. Hand protection Use normal work gloves. Body protection Use normal work clothes with dust protection such as antistatic material. Shower at the end of shift. Respiratory protection Use fitted particulate filter mask such as 3M N95. Provide adequate ventilation when handling coal and charcoal materials, especially in enclosed spaces. The principal health hazards assumed to be associated with exposure to green coke are irritant effects on the skin, eyes and respiratory system arising from both the hydrocarbon OH&S manual for traditional fuels.doc

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content and the abrasive nature of the material. The hazards associated with other cokes arise mainly from their abrasive nature. Irritation of the eyes, upper respiratory tract and possibly the skin may occur as a result. Dust-suppressed cokes and coke slurries avoid the need for the other handling precautions precautions against dust.

Green Coke Although a carcinogenic carcinogenic potential potential has not been demonstrated, it would would be advisable advisable to minimize contact with hydrocarbons, which may be present in green coke. Consequently any handling systems should utilise the highest degree of containment to minimize direct contact or release into the working environment. environment. Where total containment containment is not possible, the method of handling should ensure that the generation of airborne dust is minimized. At points where dust dust generation may may occur (e.g. conveyor conveyor transfer points), adequate adequate measures (local exhaust ventilation, filtered air ventilation systems for the cabins of cranes, front-end loaders etc.) should be applied whenever these are practicable. practicable. Suitable personal protective equipment equipment should be employed to prevent direct skin contact. This should include boots, overalls and gloves, which resist dust penetration, helmet and goggles (with an additional face visor when this is appropriate). High efficiency respiratory protection should be used when significant airborne duet concentrations are generated. High standards of personal hygiene are essential for workers handling green coke and the effective segregation of work clothing from street clothing is important to ensure that the agent is not taken home. All workers exposed to green coke should shower at the end of their working shift and the use of skin cleansers and reconditioning reconditioning cream is important.

Calcined Coke Calcined cokes are inherently dustier than green cokes and it is recommended that the basic precautions be taken to minimize airborne dust and control exposure. Where there is a need to use respiratory protection, the half mask respirator fitted with a particulate filter cartridge and the disposable particulate filter respirator types are both suitable. All workers exposed to calcined coke should shower shower at the end their working shift and the use of skin cleaners and reconditioning reconditioning cream is important.

5.6

First Aid Procedures

Remove and isolate contaminated clothing and shoes. Following direct skin contact, promptly wash exposed area thoroughly with soap and water. For eye contact, remove any contact lenses and flush eye with water for at least 15 minutes. For inhalation, move the affected individual to an area of fresh air, resuscitate and provide respiratory support if necessary. For ingestion, do not induce vomiting. For all injuries or suspected significant exposure events, the employee should see a health care specialist identified by Holcim. An accident report should be filed with the employee’s direct supervisor and the Occupational Health and Safety Coordinator. Emergency treatment may be required following excessive inhalation or eye contact:


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Inhalation If symptoms occur following inhalation, inhalation, remove to fresh air. If breathing Is difficult give oxygen and seek medical assistance. Ingestion No specific treatment is required as the material is not likely to be hazardous by ingestion. Skin contact The skin should be thoroughly washed with soap and water if direct contact occurs. If skin irritation results, medical treatment should be sought. Eye contact Irrigate with copious amounts of water to t o remove dust particles. Medical treatment should be sought if symptoms persist


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CHAPTER 6: PETROLEUM HYDROCARBON

6.1

Heavy Fuel Oils

6.1.2 Introduction Heavy fuel oils are blended products based on the residues from various refinery distillation and cracking processes. They are viscous liquids with a characteristic characteristic odour and require heating for storage and combustion. Heavy fuel oils are used in medium to large industrial plants, marine applications and power stations in combustion equipment such as boilers, furnace and diesel engines. Heavy fuel oil is a general term and other names commonly used to describe this range of products include: residual fuel oil, bunker fuel, bunker C, fuel oil No 6, industrial fuel oil, marine fuel oil and black oil. In addition, terms such as heavy fuel oil, medium fuel oil and light fuel oil are used to describe products for industrial applications to give a general indication of the viscosity and density of the product. This chapter on heavy fuel oils collates the currently available data on all grades of heavy fuel oils and covers the health, safety and environmental properties of these products as sold for the industrial and marine markets.

6.2

Description

Heavy fuel oil consists primarily of the residue from distillation or cracking units in the refinery. Historically, fuel oils were based on long residues from the atmospheric distillation column and were known as straight run fuels. However, the increasing demand for transportation fuels such as gasoline, kerosine and diesel has led to an increased value for the atmospheric residue as a feedback for vacuum distillation and for cracking processes. As a consequence, consequence, most heavy fuel oils are currently based on short residues and residues from thermal and catalytic cracking operations. operations. These fuels differ in character from straight run fuels in t hat the density and mean molecular weight are higher, as is the carbon/hydrogen ratio. The density of some heavy fuel oils can be above 1,000 kg/m 3, which has environmental environmental implications in the event of a spillage into fresh water. To produce fuels that can be conveniently handled and stored in industrial and marine installations, and to meet marketing specification limits, the high viscosity residue components are normally blended with gas oils or similar lower viscosity fractions. In refineries with catalytic cracking units, catalytically cracked cycle oils are common fuel oil diluents. As a result, the composition of residual fuel oils can vary widely and will depend on the refinery configuration, configuration, the crude oils being processed and the overall refinery demand. Residual fuel oils are complex mixtures of high molecular weight compounds having a typical boiling range from 350 to 650 °C. They consist of aromatic, aliphatic and naphthenic hydrocarbons, typically having carbon numbers from C 20 to C50, together with asphaltenes and smaller amounts of heterocyclic compounds compounds containing sulphur, nitrogen and oxygen. They have chemical characteristics similar to asphalt and hence, are considered to be stabilised suspensions of asphaltenes in an oily medium. Asphaltenes are highly polar aromatic compounds of very high molecular weight (2000 - 5000) and in the blending of heavy fuel oils, it is necessary to ensure that these compounds remain in suspension over the normal range of storage temperatures t emperatures..


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Heavy fuel oils also contain organo-metallic compounds from their presence in the original crude oils. The most important of these metals is vanadium. Some crude sources, for example from the Caribbean area and Mexico are particularly high in vanadium and this is reflected in high vanadium contents in heavy fuel oils produced from these crudes. Vanadium is of major significance for fuels burned in both diesel engines and boilers because when combined with sodium (perhaps from seawater contamination) and other metallic compounds in critical proportions it can form high melting point ashes which are corrosive to engine exhaust valves, valve seats, and superheater elements. Other elements that occur in heavy fuel oils include nickel, iron, potassium, sodium, aluminium and silicon. Aluminium and silicon are mainly derived from refinery catalyst fines. Significant concentrations concentrations of hydrogen sulphide (H 2S) are known to accumulate in the headspaces of storage tanks that contain heavy fuel oils. Heating of such tanks may cause decomposition of some of the sulphur-containing compounds, compounds, which release H 2S. In addition to the hazard from H 2S, there is also evidence that accumulations of vapours of light hydrocarbons are also to be found in the headspaces of heavy fuel oil tanks. Appreciable concentrations concentrations of polycyclic polycyclic aromatic aromatic compounds (PAC) (PAC) can be present present in heavy fuel oils depending on the nature and amount of the low viscosity diluent used and whether the residue component is cracked or un-cracked. If the residue components are from the atmospheric or vacuum distillation columns, the concentrations of three to seven ring aromatic hydrocarbons is likely to be in the order of 6 to 8 %; if heavy catalytically cracked or steamcracked components are used, the level may approach 20 %. One of the diluent fractions commonly used is catalytically cracked cycle oil, which has been reported to contain58 % three to five ring aromatic hydrocarbons.

6.2.1 Typical properties Marketing specifications specifications have been established by a number of authorities to ensure the satisfactory operation of industrial and marine equipment utilising heavy fuel oils. Such specifications specifications include ASTM D-396, BS 2869 for inland fuels, ISO 8217 for marine fuels and CIMAC requirements for residual fuels for diesel engines.


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Typical properties for heavy fuel oils can vary widely within the specification limits: normally they would be expected to fall within the ranges listed in Table 8: Property

Unit

Test Method

Typical range

Kinematic viscosity at 100°C (1)

mm2/s

ISO 3104

6.0 to 55.0

Density at 15°C

kg/m3

ISO 3675 or ISO 12185

950 to 1010 (2)

Flash Point

°C

ISO 2719

> 60

Pour Point

°C

ISO 3016

< 30

Carbon Residue

% (m/m)

ISO 10370

< 22

Ash

% (m/m)

ISO 6245

< 0.20

Water

% (v/v)

ISO 3733

< 1.0

Sulphur (3)

% (m/m)

ISO 8754

Inland: < 3.5

(2)

Marine: < 5.0 Vanadium

mg/kg

ISO 14597

< 600

Aluminium plus plus Silicon

mg/kg

ISO 10478

< 80

Notes: (1) Throughout this chapter the SI units for kinematic viscosity, mm2/s, are used, although in technical literature and specifications kinematic viscosity is often expressed in centistokes (cST). (1 mm2/s = 1 cST) (2) ISO heavy heavy fuel oil grades grades ISO-F-RML 45 and and RML RML 55 have unrestricted unrestricted density and carbon residue values. (3) It is proposed to reduce reduce the the sulphur sulphur content content of of certain certain liquid liquid fuels (including heavy fuel oil). The purpose is to reduce SO2 emissions from combustion. It is proposed to restrict as from the year 2005 the sulphur content of these fuels to < 1%.

6.3

Toxicity

6.3.1 Products studied The toxicity of a heavy fuel oil depends on the toxicity of the individual stocks from which it is blended. API, CONCAWE, and others have investigated the toxicity of a number of heavy fuel oil components. Heavy fuel oils are generally minimally irritating to the eye and skin and are not appreciably toxic after a single oral or dermal exposure. Repeated dermal exposure may cause significant toxicity or dermal carcinogenicity. When cracked stocks and high-boiling high-boiling distillates are present, the fuels may be systematically toxic as well as dermally carcinogenic. carcinogenic. OH&S manual for traditional fuels.doc

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6.3.2 Health aspects

Effects in Man Where proper precautions are taken, health risks for individuals individuals are minimal, particularly bearing in mind the closed systems in which fuel oils are normally handled and used. Inhalation Mist and vapours will be evolved from heavy fuel oils at the elevated temperatures encountered in storage and use and these are likely to cause eye and respiratory irritation. However, such exposure is minimal under normal use conditions and significant exposure is most likely during maintenance operations; in undertaking the latter, adequate personal protective equipment must be worn. Hydrogen sulphide may be evolved from fuel oils under certain conditions such as elevated temperatures. temperatures. It is highly toxic, causing effects which include eye irritation, nervousness, nausea, headache, insomnia and, in severe causes, unconsciousness and death. Hydrogen death. Hydrogen sulphide can also paralyse the olfactory system, making it inadvisable to rely on detecting its odour as a warning of its presence. Ingestion Given the nature of residual fuel oil and the fact that it is normally handled hot, its ingestion must be regarded as highly improbable. However, in the unlikely event of it happening, happening, spontaneous vomiting would be expected to occur. There could also be irritation of the gastrointestinal tract. Aspiration Because of the high viscosity of fuel oil, direct aspiration into the lungs is only a remote possibility. Skin contact Because of high handling temperatures, particularly with the heavy grades, a major hazard is the possibility of skin burns. However, this possibility, together with the unpleasant smell and colour of the fuel, provides a deterrent against direct skin contact. Nevertheless, where exposure arises and precautions and personal hygiene hygiene are poor, there is the possibility firstly of skin and eye irritation of a relatively mild nature, and secondly of dermatitis on more prolonged contact either directly on the skin or via fuel-soaked clothing. clothing. Prolonged or repeated skin contact, particularly under conditions of poor personal hygiene, may lead to effects ranging from dry skin with irritation to oil acne and oil folliculitis. Some individuals may be particularly susceptible to skin cracking and dermatitis. With exposure under such conditions, in such rare cases serious disorders such as skin cancer could eventually occur. This is because blended materials may contain carcinogenic components. Since the person concerned is very unlikely to know the composition.

Eye contact Eye contact from splashes or high mist levels is likely to cause irritation.


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Exposure limits No occupational exposure limits have been established for heavy fuel oil. Nevertheless, Nevertheless, it is advisable to reduce exposure to heavy fuel oil or vapour to a minimum. However, one of the constituents of heavy fuel oil vapours can be hydrogen sulphide, which can accumulate in storage tank head spaces. Exposure limits set for hydrogen sulphide by various agencies are listed in Table 9. Table 9:

Occupational exposure limits for hydrogen sulphide Agency/Country

8-hour TWA

15 min STEL

Reference

ACGIH

14 mg/m3

21 mg/m3

ACGIH, 1996

France

7 mg/m3

14 mg/m3

INRS, 1993 INRS, 1995

Germany

15 mg/m3

15 mg/m3 (Ceiling)

DF, 1996

Netherlands

15 mg/m3

None established

MAC, 1996

Sweden

14 mg/m3

20 mg/m3 (Ceiling)

AFS, 1996

UK

14 mg/m3

21 mg/m3

UK HSE, 1997

Notes: ACGIH: American Conference Conference of Government Government Industrial Hygienists Hygienists TWA: Time weighted weighted average for an 8-hour 8-hour day and 40 hour week week STEL: Short - term exposure limit over a 15 min min period.

6.4

Handling Advice

Heavy fuel oils are stored and handled in closed systems and involve the use of insulated storage tanks and lagged and trace-heated transfer lines. Exposure to fuel oil is therefore limited except on tank filling and during maintenance operations. operations. It is recommended that the following advice be observed: 



•

Individuals handling handling or using heavy fuel oils should be advised of the hazards, proper procedures and precautions, including health effects and recommendations recommendations for emergency treatment. Safety data sheets should be obtained from the suppliers. Storage tanks in land-based applications should be surrounded by oil tight bund walls to prevent escape of heavy fuel oil into the environment in the event of a major spillage or tank failure. In the event of a spillage, absorb or contain liquid sand, sand, earth or other spill control material. Prevent from entering drains, ditches or waterways. If this cannot be done, inform local authorities.


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A marine spillage spillage should be reported reported to the nearest nearest coastal state and and additional guidance sought from the owner of the vessel, or the charterer. The cleaning inspection and maintenance of storage tanks is a specialist operation, which requires the implementation of strict confined-space entry procedures. These include the issuing of permits, gas-freeing of tanks, use of manned harness and lifeline, and wearing air-supplied breathing apparatus.



The headspaces of fuel oil storage tanks should be considered as hazardous and potentially flammable. Electrical equipment within the space must meet the appropriate safety standards.



Prior to entry into a tank, the atmosphere in the tank should be monitored using an oxygen meter and/or an explosimeter. In addition, appropriate appropriate electrochemical sensors or indicator tubes must be used to check for the presence of hydrogen sulphide. sulphide.



Fuel storage temperature may be up to 50°C, line transfer temperatures up to 55°C and fuel atomisation temperatures up to 130°C depending on the grade of fuel being used. Precautions should be taken to avoid skin burns from unprotected pipelines and equipment components.



Skin contact with heavy fuel oil should be avoided during transfer operations and maintenance work by impervious gloves e.g. of nitrile rubber or PVC.






A full-face shield shield should be worn worn if splashes are likely to occur.





6.4.1

Overalls should be used to minimise contamination of personal clothing. Chemical resistant safety shoes or boots should be worn. The cleaning of combustion deposits from boilers and furnaces is a specialist operation; suitable breathing apparatus apparatus must be used to prevent the inhalation of dust and ash.

Emergency treatment

Symptoms and Effects: Exposure to hydrogen sulphide at concentration above the recommended occupational exposure standard may cause headache, dizziness, irritation of the eyes, upper respiratory tract, mouth and digestive tract, convulsions, respiratory paralysis, unconsciousness unconsciousness and even death. Unconsciousness Unconsciousness as a result of exposure to hydrogen sulphide may occur extremely rapidly and without other symptoms. Contact with hot product may cause skin burns, including tissues underlying the skin. Owing to its high viscosity, this product does not normally constitute an ingestion hazard. Ingestion will only occur in grossly abnormal circumstances. If ingested, it can lead to irritation of the mouth, throat and digestive tract; vomiting may also occur. Aspiration into the lungs may occur directly or following ingestion. This can cause chemical pneumonitis, which may be f atal. Prolonged exposure to vapour/mist concentrations may cause headache, dizziness, nausea, asphyxiation, unconsciousness unconsciousness and even death.


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Protection of first aiders Wear self-contained breathing apparatus if presence of hydrogen sulphide is suspected.

Inhalation Remove to fresh air. If breathing but unconscious, place in the recovery position. If breathing has stopped, apply artificial respiration. If heartbeat absent give external cardiac compression. Monitor breathing and pulse. OBTAIN MEDICAL ATTENTION IMMEDIATELY.

Skin If high pressure injection injuries occur, obtain medical attention immediately. In the case of burns, wash skin thoroughly with water using soap if available. Do not use kerosine, gasoline or solvents. Contaminated clothing must be removed as soon as possible. It must be laundered before reuse. If persistent irritation occurs, obtain medical attention.

Eye Flush eye with water. If persistent irritation occurs or if there is any suspicion of damage from hot product, obtain attention immediately.

Ingestion Do not include vomiting. Protect the airway if vomiting begins. Give nothing by mouth. If breathing but unconscious, place in the recovery position. If breathing has stopped, apply artificial respiration. DO NOT DELAY, OBTAIN MEDICAL ATTENTION IMMEDIATELY.

Advise to Physicians Treat symptomatically: symptomatically: 







High-pressure High-pressure injection injuries early surgical intervention and possible steroid therapy to minimise tissue damage and loss of nerve function. X-ray examination is required to assess the extent of the injury. Local anaesthetics or hot soaks should not be used with such injuries since they can contribute to local swelling, vasospasm and ischaemia. Prompt surgical decompression, debridement debridement and evacuation of foreign bodies should be carried out under general anaesthetic. Because injected material may be deposited at somedistance from the point of injection, wide exploration is essential. Prolonged exposure to high concentrations of hydrogen sulphide may lead to a delayed chemical pneumonitis and/or pulmonary oedema. In cases of excessive inhalation, observe in hospital for 48 hours for signs of pulmonary oedema. Diagnosis of ingestion of this product is by the characteristic odour on the victim's breath and from the history of events. In cases of ingestion, consider gastric lavage. lavage. Gastric lavage must only be undertaken after cuffed endotracheal intubation intubation in view of the risk of aspiration. In cases of chemical pneumonitis, pneumonitis, antibiotic and corticosteroid therapy should be considered.


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6.4.2 Disposal Heavy fuel oils are primarily used as fuels for combustion and disposal as waste is seldom necessary. When it is required to dispose of fuel oil, for example, following a spillage or tank cleaning operations, operations, this should be done through a recognised waste contractor. In marine applications, applications, all waste fuel oil should be collected and disposed of on land in accordance with local regulations.

6.4.3 Fire and explosion hazards Heavy fuel oils have flash points above 55°C and are not therefore classified as flammable. Flammability limits for fuel vapour/air mixtures lie between approximately 1.0 to 6.0 % (V/V); autoignition temperatures temperatures are in the range of approximately 220 to 300°C. Ignition of heavy fuel oils at ambient temperature may be difficult, but if ignited at elevated temperatures, the product will burn. However, despite not being classified as flammable, heavy fuel oils are capable of producing light hydrocarbon vapours in a tank head space at concentrations in the flammable range. This can occur even when the temperature of the liquid is below the flash point. In consequence, it is recommended that the head space of all heavy fuel oil tanks should be considered potentially flammable and appropriate precautions taken. In designing heavy fuel oil installations, installations, it is also important to ensure that heating elements and their corresponding thermostats are always placed below the level of the tank draw-off line so that they never become uncovered by fuel oil during normal operations. If they do become uncovered, there could be a danger of an explosion and subsequent fire from fuel oil contacting over-heated elements or heating coils. Heavy fuel oils burner systems (elements also applicable to light fuel oils) The handling of fuel oil in a cement plant can be subdivided into the following steps: 1) 2) 3) 4) 5)

Transfer to the storage tanks Storage and extraction from storage tanks Preparation, measuring, dosing Atomization and combustion Burners and Flames

6.4.4 Fuel oil transfer from delivery point to the storage tank For easy handling, fuel oil must have a temperature of about 50 to 60°C. If it is delivered at lower temperatures, which - due to the insulation of the wagons - is rather seldom, it has to be heated up. This can be done by circulating saturated steam (8 to 12 atm), thermal oil or electricity through the heating coils at the bottom of the railway wagons or trucks. Heating time depends on the boiler output, on the capacity of the wagon, on delivery temperature of the oil and on ambient temperature and lies between 2 and 6 (12, 24) hours (200 to 250 kg/h of steam is needed for a 20 tons capacity wagon). It is therefore common practice to do this whenever required - in the afternoon, to heat up the oil during the night and to empty t he wagons in the following morning. Via coarse strainers (for pump protection) the fuel oil is then pumped to the storage tanks (Fig. 10). 10).


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Fuel oil handling

6.4.5 Fuel Oil storage The main storage requirements depend depend on the situation of the plant with respect of the fuel oil supply possibilities. possibilities. A few plants are located sufficiently close to a refinery so that the oil is received by pipeline, directly from the refinery. Such cases require a minimum storage capacity. Where oil is delivered by truck or by rail, typical main storage capacities allow a kiln operation of 2 to 10 weeks. Tanks are usually designed as welded steel constructions. constructions. Due to the fuel oil forming an insulating layer on the walls, any particular insulation efforts are unnecessary. Suction heaters are used to maintain the fuel oil locally - i.e. in t he area of the tank suction point - in a pumpable condition, i.e. at temperatures between 50 and 60°C. This is done in order to minimize the rate of deposit forming reactions, which doubles with each 10°C increase in fuel oil temperature.

6.4.6 Fuel oil preparation Successful burning of oil requires that it is heated to approx. 140 - 170°C (see Chapter 3.4) in order to reduce its viscosity enough to allow it to be properly atomized by pressure atomization. Heating up of the fuel oil is usually accomplished accomplished through an assembly of equipment all contained on a common base. This minimizes expensive piping and valving and centralizes the equipment for ease of maintenance and control. Due to the foreign matter that all residual oils contain and the high rate of deposits that form at elevated temperatures, resulting in frequent maintenance, all equipment associated with and on the final heat and pump set is duplicated. Such a set would contain (see Fig. 11): 11): ¨ 2 strainers with coarse meshes for pump protection ¨ 2 oil pumps (gear pumps or screw pumps) ¨ 2 heat exchangers for heating up the fuel oil to atomization temperature ¨ 2 strainers with fine meshes for control equipment and atomizer head protection. The supply of heat mainly to the heat exchangers of the fuel oil preparation set, but also to the storage tank suction heater as well as to all oil carrying piping can be accomplished by:

6.4.7 Heating with steam Steam has certainly been the most popular heat carrying medium for oil heating in the past (see Fig. 8). The principal problems associated with steam generation and its use are: ¨ feed water treatment ¨ steam trapping ¨ condensate handling ¨ high pressure operation ¨ freezing problems during plant stop


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Steam can be produced by: ¨ conventional oil fired steam generators ¨ electrical submersion heaters in a pressure vessel ¨ waste heat based steam generators (e.g. cooler exhaust air)

Figure 12:

Fuel Oil Preparation System Based on Steam

6.4.8 Heating with Thermal Oil The essential advantages of these inorganic, low flammability oils as a heat transfer medium are: ¨ operation in a constantly liquid phase ¨ low pressures even at operating temperatures of 250 to 300°C ¨ no freezing problems They might be treated up by: ¨ oil fired thermal oil heaters ¨ electrical submersion heaters ¨ waste heat based thermal oil heater (e.g. cooler exhaust air) Thermal oils are subjected to aging. Their quality has therefore to be checked in regular intervals of about one year. About every five years replacement by a new charge is required (see Fig. 9).

Figure 13:

Fuel Oil Preparation System Based on Thermal Oil

6.4.9 Heating with Electricity Due to high operating costs, direct electrical heating of fuel oils is used for low capacities only. However, it is sometimes used as auxiliary heating for large systems to permit starting when the system is cold. Electrical power is also used in heating oil lines through "resistance heating". The oil line itself is used as the conductor for high current, low voltage power.

6.4.10 Heating with with Flame Radiation Radiation The heating medium in this case is the flame itself. The thermal oil heater is an example of the direct fired heater. Replace the thermal oil with fuel oil and this, then, is the direct fired fuel oil heater. Since fuel oil cannot be heated to the same high temperature as the thermal oils, burner flame modulation (shape and length) within the heating chamber must be closely controlled to maintain a narrow oil temperature range, e.g. (120°C ± 2+C) over a wide range of oil flow. This close burner flame control must be maintained to prevent overheating and carbonization of the residual oil.


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Quality of Fuel Oil Preparation

For heavy oil combustion, the kinematic viscosity at the burner nozzle must lie within the range of 12 to 20 cSt - preferably 12 - 15 cSt (upper limit 20 cSt) - this ensures that the droplet size needed for good combustion can be achieved. In today's heavy oil market, particularly in the South American OPEC countries, heavy oil is offered which has a significantly higher viscosity than the limit specified by DIN 51 603. It is therefore essential to keep track of the relationship viscosity viscosity - temperature and adjust the oil temperature as necessary. Fig. 10 shows the kinematic viscosity of different fuel oil types in function of temperature. The upper limits for atomization and pumping are indicated. Fig. 11 shows a conversion table for the different viscosity units. Furthermore it is important to keep the oil temperature constant within a very narrow range to have a stable flame. Figure 14:

Kinematic Viscosity of Current Fuel Oils

Figure 15:

Conversion of Different Viscosity Scales

6.6

Control Loops in the Fuel Oil Circuit

Between storage tanks and fuel oil burners, there are generally four control loops installed, which have to keep constant the following values: 1)

Fuel oil temperature at the storage tank suction point.

2)

Pressure in the oil circuit line between storage tanks and preparation station (Bypass of a part of the flow back to the storage tank; (see Fig. 11). 11).

3)

Temperature of the fuel oil to be atomized (Preparation Station).

4)

Atomizing pressure: Accomplished Accomplished by by means means of a bypass valve which leads part of the the flow back to the storage tank (see Fig. 11) or pressure 11) or by means of variable speed high pressure pumps, which are directly controlled by the oil flow meter.

For burner nozzles with separate feed for f or axial and radial oil (Pillard, Unitherm), the oil pressure difference for optimum atomizing atomizing is set to 1,0 – 1,5 bar. However, as the accuracy of the reading on the oil manometer at the operating pressure of about 40 bar is unsatisfactory, it is recommended that both channels are equipped with flow meters. The pressure (flow characteristics given by the nozzle suppliers) can be taken into account in optimizing atomization. Furthermore, whenever a kiln stop occurs, the oil lance and the atomizer head have to be cleaned automatically automatically by steam or compressed air in order to avoid overheating and coking of the oil. Continuation of burner cooling has to be assured by having the primary air fan connected to the auxiliary power generators. In cases of prolonged kiln stops removal of the oil lance is preferable, thus, also providing the opportunity to check the condition of the atomizer plate, which is very important for complete combustion.


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Properly prepared in terms of filtering, heating up and delivering to the burner with constant pressure and viscosity, the fuel oil must be atomized for effective mixing with the combustion air. Therefore fuel oil atomizing nozzles are used. These nozzles are located in the center of the burner, surrounded by the injection of the primary air. The oil nozzle is held in place by a jacked tube which which is a fixed part of the burner. burner. Thus the atomizing atomizing nozzle is is retractable, which which is necessary to change the orifice plate when increasing the throughput (only mechanical atomizers with fixed orifice - see below) or to take out t he oil nozzle whenever it is not needed (e.g. switching to coal firing) to prevent overheating or coking of the unused atomizer. For fuel oil atomization different principles principles are employed: ¨ Mechanical atomization with fixed orifice and variable pressure ¨ Mechanical atomization with variable orifice and constant pressure ¨ Assisted atomization with steam or compressed air

6.6.1 Mechanical Mechanical Atomizers with Fixed Orifice and Variable Pressure This type of atomization is the most common. Hereby the oil throughput is governed by the pressure of the fuel oil (within the range given by the selected discharge opening/orifice opening/orifice plate). With these atomizers the fuel oil flow in the atomizer head is often subdivided into an axial and a radial component. By adjusting the pressure and thus the ratio of these components, it is possible to alter the spray angle of the fuel jet. In general, an increase of the radial/tangential oil pressure leads to intensified swirling of radial and axial oil which has the tendency to shorten the flame. Typically the differential pressure is in the range of 1.5 bar (tangential minus axial oil pressure) with an overall pressure of approx. 40 bar. Since the reading accuracy of such small values, compared to the operating range of 40 bars, is unsatisfactory, it is suggested to equip both, radial and axial oil flow with oil flow measuring devices and optimize on flow basis using the flow-pressure flow-pressure curve of the nozzle supplier or to install a separate measurement of the pressure difference between radial and axial oil pressure. Flame shape control is, however, not only a result of atomizer adjustments, but also a function of primary air control. Fig. 8 and 9 show two current atomizers (Pillard and Unitherm) with radial-axial flow or alternatively return-flow for start-up operation. For return-flow, the axial oil flow is used to return a portion of the radial oil flow to t he storage tank, in order to have a high flow velocity and oil pressure in the nozzle head (swirl chamber) despite the small amount of oil injected in the kiln (start up phase). Thus the turndown ratio can be increased, still with a good atomization. Atomizer turndown turndown ratios of 10 to 1 are are often given by the suppliers. suppliers. Practical Practical turn down ratios ratios (without changing the orifice plate) however, are limited to values below 5 to 1 (even for return flow operation during start up). As an additional additional feature, the length of the swirl chamber chamber in the Unitherm Unitherm atomizer is adjustable. Fig. 17 (Coen Tri-Tip Nozzle) shows a mechanical atomizer with fixed orifice without radialaxial oil flow division.

Figure 16:

Pillard MY Atomizer

Figure 17:

Unitherm Atomizer

Figure 18:

Coen Tri-Tip Nozzle


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6.6.2 Mechanical Mechanical Atomizers with Variable Orifice and Constant Pressure This type of atomizer employs the adjustable needle valve principle for throughput control. By moving the needle position, contrary to the above described types, the orifice can be adjusted. Atomizing pressures pressures are in the range range of 20 bar. The turndown turndown ratio are also limited. Needle Needle value atomizers are mainly used by FLS for long wet kilns (see Fig. 11). Flame shaping is accomplished accomplished by adjusting the needle position, oil pressure and primary air. Figure 19: 1) 2)

FLS Atomizer (Needle Valve Principe)

tangential slots swirl chamber

6.6.3 Nozzles with Assisted Atomization through Steam or Compressed Air This type of atomizer (Fig. 12) uses steam or compressed air instead of radial oil to create an intense swirl in front of the orifice plate. The advantage of these atomizers is the higher turndown ratio because even a small amount of oil can be atomized effectively with steam or compressed air. The disadvantage of these atomizers is the need for a significant amount of steam or compressed air, which cost money to produce. Figure 20: 20:

Pillard Atomizer with Assisted Atomization

6.6.4 Fuel Oil Flame Adjustments A faster burn out of the fuel fuel oil can be achieved achieved by lowering lowering the oil viscosity / increasing increasing the oil temperature (recommendations (recommendations for optimum oil temperature: see paper "Firing Systems Handling and Preparation of Noble Fuels") or by better.


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CHAPTER 7: LIGHT FUEL OIL

7.1

Introduction

This chapter collates the available health, safety and environmental environmental data on gas oils. Together with kerosines, the gas oils constitute a category of petroleum substances commonly known as middle distillates. Gas oils are used primarily in the production of fuels that are used in diesel engines and for both industrial and domestic heating. Some of these products may also be used as solvents.

7.2

Product Description

Gas oils are complex and variable mixtures of hydrocarbons, predominantly predominantly of carbon number range C11 to C25 and boiling over the temperature interval 150 to 450°C. The generic chemical compositions compositions of gas oils depends on the nature of the crude oils from which they are derived and the refinery processes that they have undergone. Gas oils must meet specifications based on technical performance requirements. The principal marketed products are: Automotive fuels for diesel diesel engines engines automotive gas oil (AGO) automotive diesel fuel (DERM) diesel fuel No 2 railroad engine gas oil 

Heating oils domestic heating oil industrial heating oil industrial gas oil (IGO) No 2 fuel oil 

Marine fuel distillate marine diesel fuel (DMD) 

The concentration ranges of gas oil components present in these products may vary, depending on availability of refinery processes and overall product demand patterns. Although straight-run gas oils (i.e. products of atmospheric distillation) distillation) are the major components, secondary processing of heavier fractions is increasingly necessary in order to meet product demand. Some of the refinery streams may have undergone further treatment such as hydrodesuolphurization. Gas oils contain straight and branched chain alkanes (paraffins), cycloalkanes (naphthenes), (naphthenes), aromatic hydrocarbons and mixed aromatic cycloalkanes (cycloalkanoaromatics). (cycloalkanoaromatics). Olefins are present in cracked gas oils and fuels containing these blend stocks will contain these hydrocarbons. The EU requirement for diesel fuels to contain less than 0.05 % sulphur is likely to result in these products containing much less cracked gas oil stocks. Performance requirements for gas oil fuels are defined primarily in terms or physical properties, the sulphur content typically being the only significant compositional parameter.


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Most commercial gas oils contain polycyclic aromatic compounds (PACs). In straight-run gas oil components these are mainly 2 and 3-ring compounds, with relatively low concentrations of 4 to 6-ring PACs. The use of heavier atmospheric, atmospheric, vacuum or cracked gas oil components is likely to result in an increase in the content of 4 to 6-ring PACs, some of which are known to be carcinogenic. Commercially Commercially available gas oils may contain low concentrations of performance additives such as flow improvers, corrosion inhibitors, defoamers, dyes/markers, anti-oxidants, stability improvers, cetane improvers, detergents and anti-static additives. There are 68 substances listed in EINECS, which describe the gas oils, which may be used for the vehicle and heating fuels covered in this chapter. The substances are grouped as follows: • • • • • •

Straight run gas oils Cracked gas oils (excluding hydrocracked gas oils) Hydrocracked gas oils Vacuum gas oils Other gas oils (excluding distillate fuels) Distillate fuels

Heavy gas oils normally used in the production of heavy fuels oils are not considered in this chapter.


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7.2.1 Typical properties Typical properties for gas oils marketed in Europe are shown in Table 10.

Table 10: Typical 10: Typical properties of gas oils Property

Unit

Boiling Range

°C

Kinematic Viscosity at 40 °C

Test Method

Automotive Gas Oil

Heating Oil

Distillate Marine Fuel

ASTM D86

160-390

160-400

170 - 420

mm2/s

ASTM D445

2-4.5

2 - 7.4

1.5 - 7.4

Flash Point, min

°C

ASTM D93

56

56

60

Flash Point, max

°C

ASTM D93

-5

0

-6

Density at 15°C

g/ml

ASTM D1298

0.82 - 0.86

0.81 - 0.90

0.82 0.92

ca 0.4

ca 0.4

ASTM D2889 Vapour Pressure at 40 °C

kPa

Sulphur max+

% m/m

IP 336 or ASTM D1552 or ASTM D129

0.05*

0.2

1.5 - 2.0

+ Stricter maximum sulphur limits may apply in some countries * This figure was reduces from 0.2 to 0.05 % (m/m) as from 1 October 1996 in all EU countries Typical physio-chemical physio-chemical properties for 5 gas oils that have been evaluated in toxological studies for the American Petroleum Institute (API) are given in Table 11.


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Typical physio-chemical properties properties of gas oil components tested Table 11: by the American Petroleum Institute (API, 1987a) Property

Unit

Hydrosuphuriz Straight-run ed middle middle distillate (CAS distillate (CAS 64742-80-9) 64741-44-2)

Light cat-cracked distillate (CAS 64741-59-9)

API 81-09

API 83-11

API 83-11

API 83-07

API 83-08

Pour Point

°C

ND

ND

ND

-12

-15

Density at 15°C

G/ML

0.835

0.849

0.844

0.972

0.908

Boiling Range

°C

261301

172344

185-391

240-372

185-351

Closed Cup Flash Point

°C

124

71

ND

ND

61

Kinematic viscosity at 40°C

mm2/s

ND

ND

4.16

4.42

2.98

3.9 to >6.0

3.9 to >6.0

3.9 to >6.0

3.9 to >6.0

3.9 to >6.0

Log Kow*

Sulphur

% m/m

0.15

0.28

0.27

3.08

0.93

Paraffins

% v/v

46.0

48.9

54.1

13.7

23.2

Naphthenes

% v/v

26.5

20.25

25.6

10.3

8.2

Olefins

% v/v

2.5

>0.1

>0.1

3.7

7.8

Aromatics

% v/v

25.0

30.9

20.3

72.4

60.8

ND = Not Determined * Kow = octanol/water partition coefficient, calculated range (by CONCAWE) from known hydrocarbon composition


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Acute Toxicity

7.3.1 Oral, skin and inhalation Acute systematic toxicity toxicity data (oral, dermal dermal and inhalation) inhalation) for a number number of gas oils are summarized in Table 12. Table 12: Material

Oral LD50, rat (g/kg)

Dermal LD50 rabbit (g/kg)

Inhalation LC50 rat (mg/l)

Reference

Straight-run middle distillate, API 8311

>5

>2

1.8

API, 1985a API, 1987b

4.66 (M), 3.20 (F)

>2

4.8

API, 1985b API 1986a

7.18 (M), 6.79 (F)

>2

4.65

API 1985c API, 1986b

>2

>2

>2.7

>5

>2

4.6

API, 1982a API, 1983a

>5

>2

7.64

API, 1982b API, 1983b

7.4

>4.1

ND

API, 1980a

ND

>40

ND

NTP, 1986

ND

API, 1980b

ND

API, 1980c

Light catalytic cracked distillate, API 83-07 Light catalytic cracked distillate, API 83-08 Steam-cracked gas oil

Hydrodesulphurize d middle distillate, API 81-09 Hydrodesulphurize d middle distillate, API 81-10 Diesel Fuel, API 79-6 Marine Diesel Fuel No 2 heating oil (10 % cracked stocks), API 78-3 No 2 heating oil (30 % cracked stocks), API 78-2

11.9

15.6

(mice)

>4.1

>4.1

DSM, 1989° DSM, 1989b DSM, 1990

17.3 >4.1 No 2 heating oil API, 1980d ND (50 % cracked stocks), API 78-4 ND = Not Determined From the above data, it is apparent that the Oral LD50 values for gas oils generally are greater than the highest dose tested. One sample, a light catalytically cracked distillate, API 83-07 had


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Oral LD50 values of 4.7 and 3.2 g/kg for male and female rats, respectively. Clinical signs observed in these studies included hypoactivity, ataxia, incontinence and hair loss. Gastric haemorrhage/irritation haemorrhage/irritation was commonly seen at autopsy in those animals, which died as a consequence of treatment. Acute dermal Oral LD50 values in rabbits were above 2 g/kg for all samples following a single application of the test samples to the clipped skin for 24 hours under occlusion. Marked irritation in the treatment area, characterised by slight to serve erythema and oedema, followed by drying/flaking, crusting or thickening of the skin.

7.4

Health Aspects

Under normal conditions of storage, handling, or use as fuels, gas oils will not present a hazard to health, providing excessive skin contact is avoided. Special care must be exercised where they are used as solvents, or in circumstances where significant or repeated skin contact is possible. The need for suitable precautions to control exposure is emphasised by the evidence of potential dermal carcinogenicity particularly particularly for products containing significant amounts of cracked components.

7.4.1 Human experience

There is no epidemiological evidence that occupational exposure to gas oils is associated with significant health effects, other than those described under "skin contact" below. Two case-control studies have been published. One, a population-based population-based case-control study, detected an excess of lung cancer in workers exposed to diesel fuel. The population was small and the reported odds ratio was 1.6 with a 95 % confidence interval interval of 1.1 - 2.4. However, no account was taken of the concurrent exposure to diesel exhaust, which may have occurred. The other population-based case -control study consisted of only 13 cases. In this study, an excess of oat cell lung cancer was reported in workers exposed to heating oil. The odds ratio in this study was 1.7 with 90 % confidence interval of 1.2 - 3.4. There were no exposure data in either of these studies, nor any information relating to smoking habits. This lack of information combined with the normal limitation of small population-based, population-based, case-control studies render the information of limited relevance. Inhalation Under normal conditions conditions of storage and use, the vapour pressure of gas oils is too low for significant concentrations concentrations of vapour to develop. However, where temperatures are high and ventilation poor, vapour inhalation may result in health effects such as central nervous and respiratory system depression with eventual loss of consciousness. In some uses, a mist may be generated; at concentrations well above 5 mg/m 3 this mist could irritate the mucous membranes of the upper respiratory tract.


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Ingestion Ingestion of gas oil is an unlikely event in normal use. The taste and smell will usually limit ingestion to small amounts. Although gas oils are of low acute oral toxicity, spontaneous vomiting may occur, with the associated risks of aspiration of gas oil into the lungs. Ingestion may also give rise to irritation of the mouth, t hroat and gastrointestinal gastrointestinal tract.

Aspiration Aspiration of gas oil oil into the lungs, lungs, either directly or or as a consequence consequence of vomiting following following ingestion, may result in damage to lung tissue. Breathing difficulties may arise and a potentially fatal chemical pneumonitis may follow.

Skin contact In common with other low viscosity hydrobarbons gas oils will remove natural fat from the skin; repeated or prolonged exposure can result in drying and cracking, irritation and dermatitis. Some individuals may be especially susceptible to these effects. Excessive exposure under conditions of poor personnel hygiene may also lead to oil acne and folliculitis and with some products, development development of warty growths may occur and these may become malignant subsequently. Gas oils should not be used as solvents for cleaning the skin.

Eye contact Accidental eye eye contact with liquid liquid gas oil may cause cause mild, transient transient stinging and/or redness. redness. Exposure to high concentrations of mist or vapour may also cause slight eye irritation

Exposure limits Legislative limits for inhalation exposure to gas oils have not been established. However, the guidance provided by the UK for an occupational exposure may help in setting an appropriate exposure limit. In any case it is advisable to reduce the exposure to mist or vapour of gas oils to the lowest level practicable.

7.4.2 Emergency treatment

Inhalation If symptoms arise from inhalation of gas oil vapour or aerosol, remove the casualty to fresh air taking all appropriate steps, possibly including the use of breathing apparatus, apparatus, to avoid exposing rescuers to a contaminated atmosphere. Precautions should also be taken to avoid aggravation of any existing injuries. Keep the casualty warm and at rest. If unconscious, unconscious, place in the recovery position and give oxygen, if available. Monitor breathing and pulse. If necessary, assist breathing, preferably by an exhaled air method. Give external cardiac massage, if necessary. Obtain medical assistance urgently


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Ingestion The diagnosis of ingestion of gas oil is by the characteristic smell of the product on the breath. If gas oil has been ingested, do not give anything by mouth and do not induce vomiting. If the victim is unconsciousness, unconsciousness, place in the recovery position and protect the airway if vomiting begins. (Note: Spontaneous vomiting is a likely consequence of ingestion and carries the risk of aspiration). Obtain medical assistance urgently

Aspiration If there is any suspicion that aspiration of even small amount of gas oil into the lungs has occurred, either directly or as a result of vomiting after ingestion, obtain medical assistance immediately. Observe breathing and assist if necessary. Give oxygen if available.

Skin contact Where significant skin contact has occurred, wash affected areas thoroughly with water, using soap if available. Contaminated clothing should be removed as soon as possible, and affected skin areas washed thoroughly. If irritation occurs and persists, obtain medical advice. (Note: Contaminated clothing should be dry-cleaned and laundered before re-use. Badly contaminated footwear should be discarded)

Eye contact If the eyes have been affected they should be flushed gently with copious amounts of cold water for up to 10 minutes. If irritation develops and persists, obtain medical attention.

Information for Doctors Administration of liquid liquid medicinal medicinal paraffin or carbon carbon for medicinal medicinal use (carbo medicinals) medicinals) may may reduce absorption of gas oil from the intestinal tract. Gastric lavage must only be undertaken after cuffed endotracheal intubation, in view of t he risk of aspiration and subsequent chemical pneumonitis, for which antibiotic and corticosteroid may be indicated.

7.4.3 Disposal Because gas oils are primarily used as fuels, disposal of large quantities is seldom necessary. When disposal is necessary, for example, from spillages or tank cleaning, this can be done by combustion. Alternatively, Alternatively, re-distillation for re-use or blending with other fuel oils is possibilities. possibilities. CONCAWE'S "Field guide to inland oil spill clean-up techniques" notes that contaminated material and oil/water mixtures could be shipped to refineries and other treatment plants for separation and re-utilization. Advice on the handling handling of waste or or spilled material material can be obtained obtained from previously previously published published CONCAWE reports.


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7.4.4 Fire and explosion hazards for gas oils

Gas oils have flash points of 56°C and greater. The lower flammability limit is about 1 % volume; the upper limit is about 6 % volume. A typical autognition temperature for these products is around 220°C. If ignited, gas oils can burn fiercely. However, their low vapour pressure (in comparison with lighter products) reduces the risk of flashback or the formation of explosive atmospheres. atmospheres. Sources of ignition should be avoided in areas where gas oils are stored, handled or used. In the event of a fire involving gas oil, the most effective extinguishing agents are dry chemical powder, foam or CO2. Water jets should never be used but water fog may be used by properly trained fire fighters for large fires. For small fires, sand or earth may be useful for smothering the fire.

7.4.5 Fire and explosion hazards for light fuel oils Light fuel oils have flash points above 60°C and are not therefore classified as flammable. Flammability Flammability limits for fuel vapour/air mixtures lie between approximately 1.0 to 6.0 % (V/V); auto-ignition tempera temperatures tures are in the range of approximately 220 to 300°C. Ignition of light fuel oils at ambient temperature can occur due to volatility of light fractions. Light fuel oils are capable of producing light hydrocarbon vapours in a tank head space at concentrations concentrations in the t he flammable range and are considered to be highly flammable. This can occur even when the temperature of the liquid is below the flash point. In consequence, it is recommended that the head space of all light fuel oil tanks should be considered extremely flammable and appropriate precautions taken.

7.5

Handling and Storage of Light Fuel Oils at Holcim Facilities

7.5.1 Light fuel oil firing systems Light fuel oils are often used in the kiln warm-up phase before switch over to the primary fuel. For more information see Chapter 3 Heavy fuels, Oil firing systems.

7.5.2 Handling Advice With sensible precautions in handling and use, gas oil pose minimal health and safety hazards, particularly in view of the normal use in closed systems. However, in all situations involving the storage, handling and use of gas oils, it is recommended recommended that the following precautions should be observed: Individuals handling handling or using gas oils should be advised of the hazards, proper procedures and precautions, including health effects and recommendations recommendations for emergency treatment. 

Avoid spillages. spillages. Should a spillage spillage occur, sand sand and earth are useful useful for containment and absorption. 


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Where high vapour concentrations or mists occur, such as in high temperature use or in spraying applications, suitable precautions should be adopted to avoid build up of high concentrations concentrations and to minimize exposure, for example, by the use of good ventilation and personal respiratory protection. 

Where significant aerosol or vapour is generated and cannot be eliminated through engineering modifications, local/general exhaust ventilation should bee installed to reduce airborne concentrations. Repeated or prolonged skin contact should be avoided to prevent drying, cracking, irritation, dermatitis or more serious skin problems. If such contact is likely, impervious gloves or other protective clothing should be worn to avoid skin contact. If the need to carry out delicate manipulations manipulations makes the wearing of gloves impracticable, contact with gas oil should be minimised as far as possible and care should be taken to ensure proper skin cleaning by washing thoroughly with soap and water, followed by applications of a skin reconditioning reconditioning cream. Gas oils should not be used as skin cleansers. Gas oil soaked clothing should be removed as soon as possible. Overalls and protective clothing should be changed regularly, dry-cleaned and laundered before re-use. •



Where there is a possibility that splashing may occur, goggles or a face shield should be worn to avoid eye contact. 

7.5.3 Storage of Light Fuel oils and cleaning of storage tanks Storage tanks should also be protected from heat and properly ventilated. Secondary containment and pressure/vapor release system should be implemented to prevent rupture and potential environmental release or fire or explosion risk.

•

Proper hazards communication via international hazards signs placed in areas of greatest risk as determined by hazards identification and risk analysis.

•

Fire extinguisher systems systems should be readily available available at tank farms, fuel depots, tanking tanking stations or automotive maintenance areas. Personnel should be trained in the use of fire extinguishers and follow emergency notification procedures.

•

Diesel or light fuel oil pump lines should should be inspected for cracks or leakages. leakages. Vapor flaps should be installed on nozzles to reduce vapor loss.

•

Gas oils should only be stored in properly labelled containers and not transferred to unsuitable, unlabelled unlabelled or incorrectly labelled containers such as soft drying bottles. All containers should be kept out of the reach of children and properly sealed when not in use. •

The cleaning inspection and maintenance of storage tanks is a specialist operation requiring the implementation of strict confined-space confined-space entry procedures and precautions. These include the issuing of permits, gas-freeing of tanks, use of manned harness and lifeline, and wearing air-supplied breathing apparatus. apparatus. An appropriate appropriate safety code should be consulted for detailed advice. (European Model Code of Safe Practice in the Storage and Handling of Petroleum Products, 1973)

•


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CHAPTER 8: GASOLINE

8.1

Introduction

Gasoline is one of the most important energy sources and is the primary product of most petroleum refinery. It is used as a fuel in automotive engines for industrial and domestic purposes. In excess of 700 million tones are consumed annually worldwide. In Holcim, gasoline is used to power our automotive fleet and more often stored on the site of most manufacturing facilities.

8.2

Product Description

Gasolines are a complex mixture of volatile hydrocarbons distilling between approximately approximately 30°C and 220°C and consisting of compounds in the C4 to C12 range. They are produced by blending refinery streams to meet required performance specifications. Many gasolines also contain blending components of non-petroleum origin, especially oxygenates (mainly ethers and alcohols), and additives may be used to boost certain performance features. In earlier times, lead alkyls were added to meet octane requirements, but due to environmental environmental and health reasons an increasing proportion of gasolines are "unleaded". The composition of the hydrocarbon content of gasoline can vary widely depending on the type and nature of the crude oil processed, the refinery processes available, available, the process conditions, the overall balance between gasoline and the other refinery products, and product specifications. specifications. Table 13 gives the normal range of hydrocarbons in gasolines). gasolines). Table 13:

Normal ranges for hydrocarbons in gasoline Hydrocarbon type (% vol)

Motor gasoline

Aviation Gasoline

Paraffins*

30-90

75-100

Cycloparaffins (naphthenes)

1-35

0-1

Aromatics

5-55

0-25

Olefins

0-20

* the paraffin fraction includes n-hexane, typically 1-2 %vol and generally no more than 5% vol

The refinery streams most commonly used are derived from the following sources: • • • • • •

Crude distillation (naptha) Alkylation, isomerization isomerization and solvent solvent refining Cracking (hydrogenation, (hydrogenation, catalytic, thermal and steam) Catalytic reforming Hydrotreating Oxygenates (MTBE, TAME etc)


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Many additives are of proprietary nature and in general used in concentrations of less t han 0.1% wt are used. Additives used in gasolines include: • • • • • • • •

8.3

Anti-knock agents agents (octane improvers) improvers) Antioxidants Corrosion inhibitors Metal de-activators Combustion chamber scavengers, inlet system detergents, carburetor anti-icing compounds Dyes (color enhancers)

Product Properties

8.3.1 General Gasoline is a sweet smelling liquid. The color ranges from a light gold to red depending on additives.

Physical and Chemical Properties for Motor gasoline Boiling range: Vapor Pressure: Vapor density (air =1) Specific gravity (H 20=1) Solubility (H2O)

22-220°C 37.8 atm.@ 350-900 >3 0.72-0.79 0.006%

Stable under normal conditions or storage and handling.

8.3.2 Physical hazards Extremely flammable nature and will rapid vaporization at normal ambient temperatures. Potentially explosive mixtures of vapor with air may also travel substantial distances to remote ignition sources. Keep away from heat, sparks, flames, or other sources of ignition (e.g. static electricity, pilot lights, mechanical/ electrical, non-intrinsically safe electronic devices such as radios, cell phones and cameras with flash). Gasoline vapor is heavier than air. Hazardous levels may accumulate in poorly ventilated areas. Do not enter storage areas or confined space unless adequately ventilated.

8.3.3 Decomposition products The burning of any hydrocarbon in an area without adequate ventilation may result in hazardous levels of combustion products including carbon monoxide, carbon dioxide and non combusted hydrocarbons (smoke)


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Health Aspects

8.4.1 Exposure Risks Misuse of gasoline products can cause potential health problems as a result of excessive skin contact, aspiration, ingestion or vapor inhalation. Correct handling is therefore important to minimize health risks. Due to the complex and variable composition of the product, no widely accepted exposure limit has been specified (see Table 14) Table 14:

Exposure limits for Gasoline COUNTRY

USA* USA* (ACGIH)1

Threshold limit valve (TLV) valve (TLV) 8hr total weighted average

Short term exposure limit (STEL)

300 ppm

500 ppm (15 min)

Sweden2

100 ppm 70 ppm

* based upon typical vapor composition of gasoline in the USA; ACGIH - the American Conference of Governmental Industrial Hygenists Hygenists 2 aromatic content of European gasolines generally lower at 46% vol compared with USA 1

Toxicology Evidence from numerous epidemiological studies assessing the health risks from exposure to gasoline suggests that severe adverse effects are unlikely when exposure time is short and in well ventilated areas. Carcinogenicity Based upon evidence from experimental animals and supporting evidence including the presence of benzene and 1,3 butadiene, the International Agency for Research on Cancer (IARC) has listed gasoline in the classification of Group 2B, i.e. possibly carcinogenic carcinogenic to humans.

8.5

Personal Protection

8.5.1 General During normal fueling of vehicles in a well ventilated area, no PPE usually required. For unloading of bulk fuels special precautions are suggested:

Face protection Use splash proof safety goggles and / or faceshield. Hand protection Petrochemical resistant gloves.such as nitrile. OH&S manual for traditional fuels.doc

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Body protection Tyvex suit, nitrile boots Respiratory protection Risk assessment and personal monitoring is suggested to determine the level of respiratory protection. Factors to consider are: • • •

Degree of ventilation (open air vs. confined space) Vapor concentration in immediate vicinity Exposure duration

For personnel unloading bulk fuel, a fitted organic vapor cartridge respirator should be used. For personnel that may need to enter confined areas in which gasoline vapors are above occupational limits, use approved positive pressure, supplied air respirator with escape bottle or self contained breathing apparatus. A risk assessment with consideration consideration of flammability flammability limits (explosion hazard) should be performed before exposing personnel to concentrations requiring respiratory protection in confined spaces.

8.6

First Aid

Eyes If the eyes are affected, they should be gently flushed with copious amounts amounts of water for up to 10 minutes. If irritation persists, obtain medical advice. Skin Where significant skin contact has occurred, wash affected areas thoroughly with water, using soap, if available. Drench heavily contaminated clothing in water and remove as soon as possible, keeping clear of any sources of ignition. If irritation persists, obtain medical advice. Inhalation If exposure to gasoline vapor causes symptoms such as nausea, dizziness, mental confusion or loss of consciousness, the victim should be moved to fresh air, with all appropriate steps including use of breathing apparatus to avoid exposing rescuers to a contaminated atmosphere. Precautions should be also taken to avoid aggregation of any co-existing injuries. Keep the victim warm and at rest. If unconscious, place in the recovery position and give oxygen if available. Monitor breathing and pulse. ( note: cardiac irregularities may occur after exposure to high concentrations of gasoline vapor). If necessary, assist breathing, preferably by an exhaled air method. Give external cardiac massage if the heart has stopped. Obtain medical assistance urgently.


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Ingestion If gasoline has been ingested, do not give anything by mouth. Do not induce vomiting. If victim is unconscious, unconscious, place in a recovery position and protect airway if vomiting begins. (Spontaneous vomiting is a likely consequence of ingestion and carries the risk of aspiration) Seek medical attention immediately. immediately. Note: For Note: For all injuries or suspected significant exposure events, the employee should see a health care specialist identified by Holcim. An accident report should be filed with the employee's direct supervisor and the Occupational Health and Safety Coordinator.

8.7

Emergency Response

Flammable properties (Gasolines) (Gasolines) Flash point: Autoignition point point Lower explosive explosive limit (% vol) Upper explosive explosive limit (% vol)

-40°C 300°C 1 6

8.7.1 Fire and explosion hazard Gasoline due to rapid vaporization at normal ambient temperature is extremely flammable. Dangerous fire and explosion hazard when exposed to heat, sparks, flames or other sources of ignition (e.g. static electricity, pilot lights, mechanical/ electric equipment, equipment, and nonintrinsically safe electronic devices such as radios, cell phones, cameras with flash). Gasoline vapor is heavier than air and may travel considerable distances to a source of ignition where they can ignite, flashback, or explode. May create vapor/air explosion hazard indoors, outdoors or in sewers. If container is not properly cooled, it can rupture in the heat of a fire. Container may explode in heat or fire.

8.7.2 Extinguishing media Large fires, foam/ water fog f og should be used as an extinguishing agent. Small fires, foam, dry chemical, carbon dioxide, Halon, sand or earth. Use caution when applying carbon dioxide or Halon in enclosed spaces. Assess if the situation situation can be handled handled alone or require require assistance. assistance. Water should never never be used as it will spread the area of the fire.

8.7.3 Fire fighting instructions Gasoline fires should not be extinguished with water. Foams or water fog should be used to prevent dispersal of burning fuels. If spill or leak has not ignited, determine if sorbents or containment may be to mitigate potential environmental, health and safety risks. Use water fog or foams to cool equipment, surfaces and containers exposed to fire and excessive heat. Move undamaged containers from immediate hazard area if it can be done with minimal risk. OH&S manual for traditional fuels.doc

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I Withdraw immediately in the case of rising sound from a safety venting device. Large fires typically require specially trained personnel personnel and equipment to isolate and extinguish the fire. Firefighting activities that may result in potential exposure to high heat, smoke, or toxic byproducts of combustion should require NIOSH/MSHA approved pressure-demand-selfpressure-demand-selfcontained breathing apparatus apparatus with full face piece and full protective clothing.

8.7.4 Accidental release measures • •

Activate site emergency emergency response plan. Notify fire authorities and appropriate local or government agencies.

Evacuate non-essential personnel personnel and secure all ignition sources. No road flares, smoking or flames in the hazard area. Consider wind direction, stay upwind, if possible. Evaluate the direction of material travel. Stop the source of the release, if safe to do so. Consider the use of water fog to disperse vapors. Sorbents, sand or earth should be used contain spills. Isolate the area until vapor has dispersed. Ventilate and test area before entering.

8.8

Handling and Storage of Gasolines at Holcim Facilities

Gasoline is used in Holcim facilities as fuel for the vehicle fleet. Gasoline is stored in fuel depots as barrels, underground storage tanks, or above ground storage tanks. Gasoline is distributed directly from barrels (manual pumps) or from tanking stations. Fuel depots should be designed with proper ventilation, heat protection, and environmental release protection in mind.

8.9

Safety Precautions

8.9.1 General considerations considerations 8.9.1.1 Risk assessment Use hazards identification and risk assessment to determine the level of PPE and precautionary precautionary measures necessary for the prescribed task or operation.

8.9.1.2 Engineering controls Use adequate ventilation to keep gas concentrations of this product below occupational occupational exposure and flammability limits, particularly in confined spaces. Where explosive mixtures may be present, consult appropriate electrical codes for electrical systems safe for that location. Use explosion-proof equipment and lighting in such designated or controlled areas. Grounding equipment equipment is highly suggested during the unloading of rail tankers, tanker trucks. OH&S manual for traditional fuels.doc

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8.9.1.3 Operational controls Familiarize employees employees with the risks and hazards of using gasoline. Put in place a hazardous work permitting system (i.e. Hot work, or confined space entry) when working on or near gasoline storage and distribution systems. Put into place a planned inspection program program of critical parts or equipment.

8.9.1.4 Specific considerations considerations Storage tanks should also be protected from heat and properly ventilated. Secondary containment and pressure/vapor release system should be implemented to prevent rupture and potential environmental release or fire or explosion risk. Proper hazards communication via international hazards hazards signs placed in areas of greatest risk as determined by hazards identification and risk analysis. Fire extinguishers should be readily available at fuel depots, tanking stations or automotive maintenance areas. Personnel should be trained in the use of fire extinguishers and follow emergency notification procedures. Gasoline pump lines should be inspected for cracks or leakages. Vapor flaps should be installed on gasoline nozzles to reduce vapor loss. Transfer of gasoline to unsuitable or inappropriately labelled containers is strictly discouraged. Use of gasoline as a solvent or degrading agent is to be discouraged except in designated areas and with the use of proper PPEs.


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CHAPTER 9: NATURAL GAS

9.1

Introduction

Natural gas is a complex mixture of light gases separated from raw natural gas. The main commercial application application of natural gas is typically used as a gaseous fuel for boilers and power generation. Sometimes used as an energy source for lime and cement kilns.

9.2

Product Description

Natural gas is a complex mixture of light gases separated from raw natural gas consisting of aliphatic hydrocarbons hydrocarbons having carbon numbers in the range of C1 to C4, predominantly predominantly C1 compound methane(<90%) methane(<90%) and the C2 compound ethane ethane (<10%); may contain carbon carbon dioxide (CO2) and in some cases traces of nitrogen (N2). Natural gas that has been processed and is in commerce will contain trace amounts of an odorant (typically <0.1% ethyl mercaptan).

9.3

Product Properties

9.3.1 General Natural gas is a colorless gas. Cold vapor cloud may be white but the lack of visible gas cloud does not indicate absence of natural gas. Natural gas has a distinctive, disagreeable disagreeable "natural gas" type odor when treated with an odorizing agent (typically <0.1% ethyl mercaptan)

9.3.2 Physical and chemical properties properties (for methane) methane) Boiling point: Vapor Pressure: Vapor density (air =1) Specific gravity (H 20=1) Solubility (H2O)

-162°C 40atm.@ -86°C 0.6 0.4 @-164°C 3.5%

Stable under normal conditions or storage and handling.

9.3.3 Physical hazards Extremely flammable gas. Can cause flash fire. Keep away from heat, sparks, flames, or other sources of ignition (e.g. static electricity, pilot lights, mechanical/ electrical, non-intrinsically safe electronic devices such as radios, cell phones and cameras with flash). Natural gas displaces oxygen available for breathing. Do not enter storage areas or confined space unless adequately ventilated. Contact with pressurized vapor may cause frostbite or freeze burn.


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9.3.4 Decomposition products The burning of any hydrocarbon such as natural gas in an area without adequate ventilation may result in hazardous levels of combustion products including carbon monoxide, carbon dioxide and non combusted hydrocarbons (smoke)

9.4

Health Aspects

9.4.1 Exposure risks In general, exposure to natural gas is not harmful in well ventilated areas. In closed or confined spaces, natural gas can displace oxygen resulting in the risk of asphyxiation. Eyes Not irritating. However, direct contact with pressurized vapor may cause frostbite, freeze burns and permanent eye damage. Skin Not irritating. Direct contact to skin or mucous membranes with pressurized vapor may cause freeze burns and frostbite. Signs of frostbite include a change of color of the skin to gray or white, possibly followed by blistering. Skin may become inflamed and painful. Ingestion Risk of ingestion is extremely unlikely due to the gaseous nature of the product. Direct contact to mucous membranes with pressurized vapor may cause localized freeze burns.

Inhalation Natural gas is considered non-toxic by inhalation. Inhalation of high concentrations may cause central nervous system depression such as dizziness, drowsiness, headache, and similar narcotic symptoms but have no long-term effects. Numbness, a "chilly" feeling and vomiting have been reported from accidental exposure to high concentrations. This product is a simple asphyxiant. In high concentrations it will displace oxygen from the breathing atmosphere, particularly in confined spaces. Signs of ashyxiation will be noticed when oxygen is reduced to below 16%, and may occur in several stages. Symptoms may include rapid breathing and pulse rate, headache, dizziness, visual disturbances, mental confusion, incoordination, incoordination, mood changes, muscular weakness, tremors, cyanosis, narcosis, and numbness of the extremities. Unconsciousness Unconsciousness leading to central nervous system injury and possible death will occur when the atmospheric oxygen concentration is reduced to about 6% - 8% or less.

9.5 Toxicology Methane and ethane, the primary components of natural gas, are considered practically inert in terms of physiological physiological effects. At high concentrations, concentrations, these materials act as simple asphyxiants and may cause death due to lack of oxygen.


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9.5.1 Carcinogenicity Carcinogenicity Natural gas exposure has not been linked to carcinogenicity carcinogenicity (OSHA, IARC, ACGIH)

9.5.2 Medical conditions conditions aggravated aggravated by exposure Individuals with pre-existing conditions conditions of the heart lungs and blood may have increased susceptibility to symptoms of asphyxia. Exposure to high concentrations concentrations of natural gas may increase the sensitivity of the heart to certain drugs. Persons taking epinephrine and other sympathomimetic sympathomimetic drugs may have a greater chance of cardiac arrhythmias.

9.6

Protective Equipment

General Safety glasses, work gloves, steel toe working boots, and work clothes is sufficient. Follow safety signage in the zones to be worked in. Avoid introduction of potential ignition sources. When working with pressurized natural gas special precautions should be applied.

Face protection Use splash proof safety goggles and / or faceshield for protection from pressurized natural gas. Cold-impervious, Cold-impervious, insulating gloves when working with pressurized natural gas.

Body protection When working with pressurized natural gas, normal work clothes plus an impervious apron is sufficient

Respiratory protection Use approved positive pressure, supplied air respirator with escape bottle or self contained breathing apparatus for natural gas concentrations concentrations above occupational exposure limits, for potential for uncontrolled release, if exposure levels are not known or in an oxygen deficient atmosphere. A risk assessment with consideration of flammability limits (explosion hazard) should be performed before exposing personnel personnel to concentrations requiring respiratory respiratory protection.

9.7

First Aid

Eyes If irritation or redness develops, move victim away from exposure andinto fresh air. Flush eyes with clean water. If symptoms persist seek medical attention


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Skin For general exposure, first aid is normally not required. In the case of frost bite or freeze burns from pressurized natural gas, slowly warm the affected area as not to cause tissue damage. If symptoms persist seek medical attention

Inhalation If respiratory symptoms develop, move victim away from source of exposure and into fresh air. If symptoms persist seek medical attention. If the victim is not breathing, clear airway and immediately beigin artificial respiration. If breathing difficulties develop, oxygen should be administered by qualified personnel. Seek immediate medical attention. Note: For Note: For all injuries or suspected significant exposure events, the employee should see a health care specialist identified by Holcim. An accident report should be filed with the employee's direct supervisor and the Occupational Health and Safety Coordinator.

9.7.1 Emergency response Flammable properties (NFPA Natural Gas) Flash point: Autoignition point point Lower explosive limit (%) Upper explosive limit (%)

flammable gas 482-632 °C 3.8 -6.5 13-17

9.7.2 Fire and explosion hazard Dangerous fire and explosion hazard when exposed to heat, sparks, flames or other sources of ignition (e.g. static electricity, pilot lights, mechanical/ electric equipment, equipment, and nonintrinsically safe electronic devices such as radios, cell phones, cameras with flash). Natural gas is lighter than air and may travel considerable considerable distances to a source of ignition where they can ignite, flashback, or explode. May create vapor/air explosion hazard indoors, outdoors or in sewers. If container is not properly cooled, it can rupture in the heat of a fire. Container may explode in heat or fire. Liquified natural gas (LNG)releases flammable gas at well below ambient temperatures and readily forms a flammable mixture with air.

9.7.3 Extinguishing media Dry chemical, carbon dioxide, Halon or water. Use caution when applying carbon dioxide or Halon in enclosed spaces. Fire should not be extinguished unless flow of gas can be shut off immediately. Assess if the situation can be handled alone or require assistance.


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9.7.4 Fire fighting instructions Natural gas fires should not be extinguished unless the flow of gas can be immediately stopped. Shut off gas source and allow gas to burn out. If spill or leak has not ignited, determine if water spray may assist in dispersing of natural gas or vapors to protect personnel attempting to stop leak. Use water to cool equipment, surfaces and containers exposed to fire and excessive heat. Move undamaged containers containers from immediate immediate hazard area if it can be done with minimal minimal risk. For large fires, the use of unmanned hose holders or monitor nozzles may be advantageous to further minimize personnel exposure. I Isolate area, particularly around ends of storage vessels, let vessel, tank ca, or container burn unless leak can be stopped immediately. Withdraw immediately in the case of rising sound from a safety venting device. Large fires typically require specially trained personnel and equipment to isolate and extinguish the fire. Firefighting activities that may result in potential exposure to high heat, smoke, or toxic byproducts of combustion should require NIOSH/MSHA approved pressure-demand-selfpressure-demand-selfcontained breathing apparatus apparatus with full face piece and full protective clothing.

9.7.5 Accidental release measures • •

Activate site emergency emergency response plan. Notify fire authorities and appropriate local or government agencies.

Evacuate non-essential personnel personnel and secure all ignition sources. No road flares, smoking or flames in the hazard area. Consider wind direction, stay upwind, if possible. Evaluate the direction of material travel. Cold vapor cloud may be white, but will soon dissipate as the cloud disperses - fire and explosion hazard is still present. Stop the source of the release, if safe to do so. Consider the use of water spray to disperse vapors. Isolate the area until gas has dispersed. Ventilate and gas test area before entering.

9.8

Handling of Natural Gas in the Cement Manufacturing Process

9.8.1 General considerations Benefits for the use of natural gas are many: Clean operations (No sulfur) • No need for grinding • No need for atomization • Burner easy to start • Gas throughput is easily and quickly regulated • No storage costs • Low labor and maintenance (Favors automation) •


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Disadvantages: Costs ( region dependent) • Larger volume of exhaust gas than oil firing • Slightly higher specific heat consumption than oil firing • Calorific value variation (+ 300 kJ/Nm 3) • Low emissivity of the flame f lame •

9.8.2 Natural gas preparation Gas distribution by means of pipelines is accomplished at pressures pressures of 30 to 80 bars. At consumer's site the gas pressure is reduced to the required operational pressure, mostly by means of a two stage expansion process. The first stage takes place in the NG transfer station while the second runs off in the NG pressure reduction station. As a standard solution solution the NG transfer station station is an independent, independent, self-sustaining self-sustaining installation installation contained in a separate building (noise suppression). Similarly to the fuel oil preparation plant, all equipment is duplicated and provided with a number of bypass possibilities. The main equipment list is as follows (see figure XX Natural Gas Firing Systems for more details): Remote controlled main shut-off safety valve Transfer station inlet filters for protection of equipment from solid • particles originating from the pipeline Thermal oil heated exchangers to preheat the natural gas to a level that • the following temperature drop due to expansion will not cause ice formation on the internal or external portions of valves (Joule - Thompson effect: 0.3 to 0.5°C/bar) Safety shut off valves • Pressure reduction valves (for reduction of the gas pressure to the • pressure level of the plant internal distribution network network of 3 to 10 bar) . The heat value of the natural gas can be measured and recorded continuously continuously by means of on-line calorimeters. calorimeters. Use of this device is not common practice - as plant personnel tend to rely on the heat values given by the gas suppliers - it would be worthwhile, since in some instances the calorific values might vary in range of ±300 kJ/Nm 3 from day to day. •

A powerful odorizer odorizer (e.g. ethyl mercaptan) mercaptan) is added to the gas just after the gas leaves the transfer station. As the odorizer can be detected in the parts per billion level by the human nose, leaks from the gas pipes can be detected easily. The second stage of pressure reduction, taking place in the pressure reduction station, is located near the point of consumption consumption (Fig.XXX secondary Pressure Pressure reducing Unit). With the exception of the NG heaters it contains about the same equipment as the transfer station. The aim of this installation is to completely even out supply network pressure fluctuations and to set the final pressure according to the requirements of the consumer i.e. the burner and kiln systems. Immediately before the kiln, the gas stream is split up in order to supply the radial and the axial gas nozzle of the burner (Fig. XXX Kiln Ramp Unit).


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9.8.3 Gas burners In order to overcome the low emissivity of natural gas flame, gas burners are designed with the possibility of producing a reverse-flow zone in the center of the flame in order to optimize heat transfer in the sintering zone. This design produces a locally reducing atmosphere where the hydrocarbon molecules molecules polymerize to form soot. For more details on the use of gas for firing, evaluation of burner systems see TCH report Nr. VA 72/4349/E.

9.9

Safety precautions

9.9.1 General considerations considerations 9.9.2 Risk assessment Use hazards identification and risk assessment to determine the level of PPE and precautionary precautionary measures necessary for the prescribed task or operation.

9.9.3 Engineering controls Use adequate ventilation to keep gas concentrations of this product below occupational occupational exposure and flammability limits, particularly in confined spaces. Where explosive mixtures may be present, consult appropriate electrical codes for electrical systems safe for that location. Use explosion-proof equipment and lighting in such designated or controlled areas. In conduction systems, integrate pressure monitoring, pressure relief and explosion proofing design. Please refer to local codes, national regulations or guidelines in regards to safe construction and design for and in the presence of potentially flammable or explosive gases.

9.9.4 Operational controls Familiarize employees employees with the risks and hazards of using natural gas. Through training and the use of standard operational procedures. procedures. Put in place a hazardous work permitting system (i.e. Hot work, or confined space entry) when working with natural gas storage, distribution or control systems. Implement a system of inspection and testing of the natural gas distribution system, flexible hoses, and burner.

9.10 Specific Hazards and Corrective Actions

9.10.1 Flexible hoses hoses bursting bursting There is a risk that t he flexible gas hoses between kiln burner burner and gas supply line can burst or that the proceeding valves fail. Pressure monitors which measure maximum and minimum pressure differentials should be inserted directly before these hoses as an early warning system. In the event of an emergency stop, a safety stop valve, or two in series, are actuated to immediately stop any further input of fuel.


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9.10.2 Leak tests To check the gas pipes and fittings inside the plant for leaks the following methods methods are used: Normally leaks can be detected naturally as a result of adding odorizer. When machines are switched off, the hissing sound of the escaping gas • is easily discernible. Use of gas detection devices ("sniffers" or "snooping" devices) which • measure methane or ethane from leaks. •

Note: Do not use this practice. practice. Running a naked flame along the gas pipe has been a traditional means of detecting gas line leaks and was even taught in the Holcim Cement Manufacturing Course. Although there is little risk of this flame back flashing into the supply pipe (quenching distance, lack of oxygen), escaping gas , however, could cause an explosion. When constructing buildings which contain gas pipes, it is essential to allow for sufficient ventilation. Certain items of equipment equipment can be fitted with guard flames from the start. Their task is to ignite any gas that t hat escapes before a large quantity of explosive mixture has a chance to collect. A further possibility possibility is to install gas detectors detectors in critical critical places such as the the gas preparation preparation station or the burner tunnel.

9.10.3 Explosions in the kiln The most important requirement is that the fuel should not be allowed to enter the kiln unintentionally unintentionally or at an uncontrolled rate, as this is essential to prevent explosions occurring in the kiln itself or in the systems following it (e.g. preheater tower, EP). In short the fuel input must be stopped immediately immediately in the event of the flame going out. In this respect it must be said that extinction of the flame in a hot kiln has never been observed so far, even during material rushes. Nevertheless during the start up of the cold kiln, lifting off and extinction of the f lame can occur, for example caused by partly blocked burner outlets which lead to increased injection speed of the gas. If the gas is injected with too high speed, the flame can be blown out. Therefore careful observation observation of the flame during the whole start up period is of utmost importance. In the case of the flame going out, fuel supply has to be cut off immediately to prevent explosions. Methods to monitor the flame include: Human observation • Optical flame detectors • Video camera monitors for sintering zone and consequently the flame • Experience has shown that during start up, engineered monitoring monitoring systems still need to be supplemented with human observation. Excessive fuel input can also cause CO accumulations due to incomplete combustion and result in explosions. Therefore careful monitoring of CO concentrations is important. It is important not to set the CO monitor at too sensitive a level which contributes to low OEE due to frequent shutdowns. (See Avoiding CO Trips TPT report # ……).


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The EP is most often the piece of equipment affected by explosions. The reasons include: • • • •

Potential source of ignition Design Structurally (Point of least resistance for explosion pressure pressure wave) Engineered safety vents

However, one should consider that from a risk analysis standpoint, the EP also serves indirectly as a safety system which protects other critical equipment and is fully automated which decreases the potential of human casualties in the case of an explosion.


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CHAPTER 10: SELECTION AND USE OF PERSONAL PROTECTIVE EQUIPMENT

10.1 Introduction Personal Protective Equipment, or PPE, is available for a wide range of potential exposure conditions and one or more PPE types are designed to be protective against virtually any chemicals. However, However, even the highest level of PPE will not protect the employee if the PPE is not worn, or if not worn correctly. This simple statement should not be overlooked. overlooked. While the conditions requiring requiring the use of PPE may arise only infrequently at Holcim facilities, when the situation warrants it, the use of PPE must be enforced. For some facilities, this may be a workplace practice change and an employee training issue. The principal concerns from exposure to traditional fuels are inhalation of and dermal contact with the potentially dangerous substances that may make up traditional fuels. While incidental ingestion also represents a viable exposure route, PPE is less effective in these instances compared to behavior modification (e.g., no smoking or eating in work areas; washing hands prior to these activities). The majority of this section will address PPE with respect to airborne exposures and dermal exposures to traditional fuel -specific chemicals. However, a brief discussion of PPE as it relates to general industrial practices is warranted.

10.2 General Industrial Practices As introduced in Section 4 and 4 and described on Table XX, XX, personal protection of health and safety at industrial facilities like cement manufacturing plants, concrete batching plants, and aggregate operations includes the use of some “general practices”. General practices provide the minimum level of protection that is recommended for each occupational activity (e.g, hard hat, eye protection, leather gloves, cloth coveralls, and steel-toed boots for Fuels Handlers). For those activities that involve more direct contact with the traditional fuels, the general practice recommendation recommendation includes the use of fuel-specific PPE for potential airborne exposures and for potential dermal exposures. exposures. For heavy fuel oils that must be heated (up to 120 C) to reduce viscosity, care must be taken to choose PPE that also protect against potential burns.

10.3 Airborne Exposures Inhalation of volatile substances, semi-volatile substances, and airborne particulates may occur in many situations, to a greater or lesser degree, in all facilities . This represents both the most important potential exposure route, and the most difficult one to control in most cases. Because the use of respiratory protective equipment equipment in and of itself is inherently hazardous (i.e., can cause laborious breathing, CO 2 buildup), or at the very least uncomfortable (heat buildup), buildup), it should only be recommended in the event that workspace air concentrations concentrations exceed applicable occupational guidelines. A tabular summary of occupational air standards and recommendations from the United States, Germany, and Switzerland, for the indicator chemicals chemicals that have been identified for traditional fuel categories, is presented in Table XX in XX in Appendix XX. XX. A more complete list of other OH&S manual for traditional fuels.doc

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chemicals and their associated occupational guidelines is presented in Appendix XX. XX. Applicable air air quality standards standards and criteria criteria may be available available for the country country in which an individual facility is located. Where those criteria or requirements are in place, they must be met. If explicit criteria are not available, the facility should select a policy and set of available guidelines by which to ensure employee safety from exposure to airborne substances. In addition, generally applicable air guidelines may be obtained from other international organizations organizations such as the World Health Organization (WHO). The WHO has developed air exposure guidelines for a number of commonly encountered substances, substances, and these may be useful in the absence of available country specific requirements or recommendations. recommendations. The following link may be of interest for additional information: WHO Air Quality Guidelines - litygd.htm> Many European nations have adopted a "best general practices" approach with regard to occupational air exposures. The following link may be of interest for additional information concerning these general safe practices. European Agency for Health and Safety at Work - It should be clear from an understanding of operations involving traditional fuels and other industrial applications applications that exposure circumstances may involve single substances or a mixture of substances. Most environmental and occupational agency approaches to chemical exposures establish acceptable levels based upon the assumption that employee contact will be to one substance, or at most a few substances. Because of the conservative calculations calculations by which occupational guidelines are set, this typically is adequate. However, several agencies and organizations have developed approaches approaches to deal with the problem of potential multiple chemical exposures (e.g., ACGIH, NIOSH). In general, when two or more hazardous substances are present, and the substances have similar reactivities and toxic effects, their combined effect should be given primary consideration. consideration. Unless information to the contrary is available, the potential effects of the mixture should be considered additive. Thus, in the case of three comparable substances cooccurring in a work environment, it may be determined that the threshold t hreshold limit for the mixture has been exceeded if the following is true: C1/T1 +C2/T2 + C3/T3 .> 1 where; C = measured atmospheric concentration concentration T = respective Threshold Limit Value or other guideline If, however, the sum is less than 1, the mixture can be considered to be below the combined threshold limit. Additional information on determining workspace concentrations is presented in Section XX. XX. Ideally, the maintenance of air concentrations below protective levels by vapor controls (e.g., air curtains) and by adequate ventilation is the most effective tool for employee safety. The majority of the job descriptions that were presented in Section II are characterized primarily primarily by outdoor work w ork activities that provide unlimited ventilation and circulation of fresh air. In many instances, however, it is necessary to supplement such controls with the use of respiratory protective protective equipment if local concentrations in the work area exceed guidelines or standards.


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There are several types of respiratory protection that may be appropriate depending on the specific substance and concentration that is present. Section XX presented generalized generalized information regarding respiratory respiratory protection that may be appropriate for each traditional fuel category and Table XX in Appendix XX presents chemicals and the XX presents a list of indicator chemicals appropriate respirator type that will provide sufficient protection. If workspace monitoring indicates the presence of chemicals that are not on the list of indicator chemicals, consult Appendix XX for XX for a more complete list of chemicals and associated respirator recommendations. Appendix D also D also includes information on respirator use training, respirator cartridge change-out schedules, and respirator fit testing.

10.4 Dermal Exposures In addition to the potential for inhalation exposures, dermal contact with traditional fuels components may represent a significant potential risk. For this reason, it is necessary to establish and implement procedures to limit such exposures. Typically, local and national guidelines or standards are not in place regarding dermal exposure. However, a number of organizations (e.g., ACGIH, NIOSH) include notations concerning the potential for absorption of chemicals, especially organic substances, through the skin following exposure to airborne chemicals (i.e., “Skin” designation). The most common and appropriate methods for protecting against dermal exposure are those which employ impermeable personal protective equipment (e.g., gloves, coveralls, face shields). Various types of glove (e.g., latex, butyl rubber, nitrile) or coverall (e.g., Tyvek, plastic, Nomex) materials will confer variable protective benefits, and it is important that the appropriate composition composition be selected. Failure to make the appropriate decision can result in injury if the selected PPE is not resistant to the chemical or physical condition to which exposure occurs. (As ( As an illustration of this caution, one only need consider the case of a viscous heavy oil that has been heated to reduce viscosity and increase flow. In that instance, petroleum resistant gloves would be highly effective against damage from the petroleum compounds, but would be ineffective against the heat, possibly permitting adverse effects to occur. Proper selection of neoprene, butyl rubber, or latex gloves would provide effective protection against both conditions. Table XX in Appendix XX presents a list of) recommended glove materials for protection against potential exposures to selected indicator chemicals. In addition to the very good (VG), good (G), fair (F) and poor (P) designations for some indicator chemical/glove chemical/glove material combinations, this table also presents an indication of the length of time (minutes, hours) that a particular chemical/glove material combination may be safely used. This should only be used as a guide. Good judgment should dictate when PPE is showing signs of wear. As with gloves, footwear footwear and coverall coverall materials vary in in their degree of of protection against against different substances. Significant exposure to the feet or body is not anticipated during general handling of the traditional fuels, except perhaps in spill situations, and the general practices for each occupational category of duty typically will be sufficient ( see Table XX in Appendix XX). XX). Steel-toed leather boots and cloth or Tyvek coveralls will suffice even in the event of minor spills or releases. In the event of a larger spill or catastrophic release, Fuel Handlers and other nearby employees should leave the area and initiate emergency response procedures as described in Section VIII. Chemical resistant boots and suits are available for such instances, but may not be needed on a day-to-day basis.


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10.5 Other Potential Exposures Although inhalation inhalation and dermal dermal contact represent represent the most significant significant potential exposure exposure routes in most circumstances, it is possible to have exposure via incidental ingestion and it is possible for the seriousness of dermal contact to be dramatically increased as a result of lacerations, abrasions, or puncture wounds. As discussed in the the Protective Equipment Equipment subsections subsections of Section IV, incidental incidental ingestion of potentially hazardous materials can be prevented through attention to proper hand washing and control of hand-to-mouth behavior (e.g., eating and smoking). Strict adherence to the apparel recommendations in the general industrial practices subsection of Section VI and on Table II-1 will help to prevent cuts and scrapes. During maintenance of pumps or normal operations operations with heavy or light fuel oils, puncture-resistant puncture-resistant gloves and coveralls may be appropriate. Ocular (eye) exposure to splashes of liquids or to high airborne concentrations concentrations may represent a potential route of exposure as well. Thus, eye protection is important not only to prevent direct damage to the eye itself, but also to minimize or prevent absorption of materials through the eye. Multiple shower stations with eyewash attachments will provide quick access to water if splashes of harmful liquids do occur.

10.6 Supplementary Reference Materials The following resources provide both introductory and chemical-specific PPE information: How to Choose Gloves http:/www.cdc.gov/niosh/nasd/psa http:/www.cdc.gov/niosh/nasd/psas/ia10500.htm s/ia10500.htm Iowa State University Cooperative Extension Service http://www.ae.iastate.edu/safety.htm EPA Chemical Resistance Category Chart .htm> DuPont Protective Apparel


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CHAPTER 11: WORKPLACE MONITORING AND RECORDKEEPING The purpose of this section of the Manual is to identify potential exposure circumstances that may result from the handling of traditional fuels. This section is concerned primarily with methods for characterizing occupational conditions so that appropriate planning can be conducted and appropriate protective equipment equipment can be made available for employees. A variety of passive and active air monitoring techniques are available for different applications and for different levels of information detail. In order to identify situations that potentially may lead to exposure of employees to traditional fuels, the indicator chemical or chemicals that may be present must be quantified. For the traditional fuels, which indicator compound monitored depends on the physichemical state of the material. For heavy fuel oils, polyaromatic hydrocarbons hydrocarbons and volatile organic compounds should be monitored while while for light fuel oils, mainly volatile volatile organic compounds compounds will be the indicators of concern. In most cases, inhalation will be the major route of exposure. However for some polyaromatic hydrocarbons, dermal contact will also be a route of exposure. In the case of coal and petcokes, polyaromatic hydrocarbons hydrocarbons will normally be the indicator chemicals of concern and inhalation and dermal contact of the dust as the primary route of exposure. occupational inhalation exposure Table XX in Appendix XX provides XX provides information on occupational guidelines for the indicator chemicals that may be encountered when handling handling or working in close proximity to traditional fuels. Appendix XX presents XX presents a more detailed list of chemicals for which occupational inhalation exposure guidelines have been developed.

11.1 Workplace and Perimeter Air Monitoring Monitoring of general workplace air quality may be routinely performed to provide critical information concerning the potential for and the degree of exposure to airborne chemicals. This information can be used to determine the appropriate level of respiratory and dermal (for chemicals that can be absorbed directly through the skin) protection that is needed to keep potential exposures within safe limits.

11.1.1 Grab sampling of air Grab samples provide a measure of the short-term air quality within a limited area. Such measurements are of value in situations such as entry into a confined space or where high air chemical concentrations concentrations are suspected in the area of an unplanned release. An example of grab samplers are Draeger tubes, or similar devices from other manufacturers, which act by exposure of an absorbent matrix by pulling air through a reagent-filled tube using a small hand pump. The extent of color change in the absorbent reagent material provides an indication of the chemical concentration. Draeger-type Draeger-type tubes can be selected to detect a wide variety of materials, including volatile volatile organics and many other compounds that may be of interest.


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11.1.2 Longer term sampling of of air Long-term area sampling is useful in providing information about the general levels of chemical exposure in specific work areas. Sampling devices are typically operated during normal operating conditions conditions and hours and involve the passage of air at known rates (e.g., liters/minute) through an absorbent material. At the appropriate interval (e.g., 1 hour, 8 hours, etc.), the absorbent canister can be sent to the laboratory for desorption and analysis. One drawback to this method is that it may be days before data are reported. In any case, such knowledge can form the basis for the institution of engineering controls (e.g., ventilation) to reduce potential exposures or, where effective engineering controls are not feasible, to assist in establishing the types of appropriate protective equipment. Properly chosen area air monitoring equipment can also permit warnings to be issued in the event that a preset exposure limit is exceeded. Draeger, SKC, Radiello, and Casella, for example, supply active and passive area sampling devices that can provide measurements of ambient workplace air chemical levels over a work-shift or can sound an alarm in the event of elevated chemical concentrations. There are now available real-time chemical analyzers for air that can be selected to detect some chemicals such as the OPSIS system. This approach may be investigated by individual facilities. The equipment can be quite expensive.

11.1.3 Personal air monitoring “Personal monitoring” describes the measurement of a particular employee’s exposure to airborne contaminants that theoretically reflects actual employee exposure. Although personal air sampling pumps, operated to sample air in the breathing zone, can provide an estimate of individual exposure, exposure, these devices may not provide accurate exposure estimates for chemicals that can be absorbed directly through the skin from the air.

Powered personal monitoring devices (e.g., personal air pumps) can be cumbersome to wear and typically require routine maintenance and calibration to provide satisfactory results. They can be useful, however, in situations where short-term measurements measurements (i.e., 15 minutes to 1 hour) of exposure are of interest. For continuous monitoring over the full workday period (8-10 hours) passive diffusive devices may be more appropriate. appropriate. Draeger, SKC, 3M, and Radiello are among the major manufacturers of passive diffusive monitors for personal use. These "badge" devices can be selected to detect a wide variety of organic chemicals including aldehydes, organic acids, VOCs, chlorinated and brominated hydrocarbons, hydrocarbons, nonhalogenated nonhalogenated organic solvents, carbon monoxide (CO) and carbon dioxide (CO 2). Passive monitoring devices also are available for detection of mercury vapor, hydrogen chloride vapors or mists (HCl), sulfides, sulfur dioxide (SO2), oxides of nitrogen (NOx), and ammonia (NH3). The badge devices are small, light in weight, can clip onto a shirt collar or pocket, and typically require no additional attachments or power source. The devices are designed to adsorb the vapors in an activated carbon filter bed that can be extracted with a suitable solvent, such as carbon disulfide, and subsequently analyzed by gas chromatography (GC). Unless in-house analytical capability capability is available, these badge-type devices will need to be sent to a laboratory for analysis, with the turnaround time and cost for analysis primarily related to the project requirements and facility location (distance and accessibility of the OH&S manual for traditional fuels.doc

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laboratory). The devices typically are accurate to within + 25% as recommended for air monitoring techniques, techniques, and can be used in conjunction with other air monitoring data and employee exposure logs to make appropriate decisions concerning the need for or type of respiratory protection. Draeger and SKC, for example, make active and passive direct color reading tubes for determining chemical air concentrations. In general, the active air sampling devices, while of a simple type, are designed to obtain short-term spot measurements, while the passive devices (e.g., badges) are more suitable for assessing "averaged" exposures that are more representative representative of the aggregate working day for an individual (i.e., 8-10 hours). The following links represent sources for additional detail regarding some of the simple and readily available active and passive air sampling devices: Draeger tubes and measuring devices Radiello passive sampling systems od/amb3310/> SKC passive sampling guide Casella diffusive sampling tube information ge=1> 3M Technical Data Bulletin 1028 on organic vapor monitors (to download .pdf file) Types, availability and prices of Draeger air monitoring tubes, as one example of the technology, can be obtained at the following link:

11.1.4 Biological monitoring Biological monitoring monitoring can be useful in obtaining information about the long-term or short-term impact of absorption of chemicals on the physiological functions of an exposed individual. Material such as blood, urine, hair, or exhaled air all can be analyzed for the presence of various indicators of chemical exposure. Biological monitoring may be designed to measure levels of the contaminant itself (i.e. vanadium and other heavy metals prevalent in Flexicokes) in the body, the presence of a metabolite of a chemical (i.e. mandelic acid indicating exposure to styrene), or the levels of enzymes and other functions (i.e., elevated liver enyzme levels from chronic solvent exposure). Each of these endpoints may reflect potential harm caused by chemical exposure. In some circumstances, maintenance maintenance of sequential employee exposure logs may be appropriate, while in other cases, medical screening or surveillance may be recommended. An extensive list of of medical tests for exposure exposure to specific chemicals chemicals may be found at the following link: NIOSH/Specific Medical Tests medname.html>


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One example of a company that offers biological testing services for a wide variety of chemicals can be found at the following link: Pacific Toxicology Laboratories Chemicals that are analyzed in blood or urine samples typically have a turnaround time on the order of two to five days, with a limited number of specialized analyses analyses requiring up to 10 days to complete. Employee medical monitoring plans should be developed by each facility to address the specific needs and requirements of cement manufacturing facilities, ready-mix concrete, and aggregates operations. operations. One important element of such a plan is the establishment of “baseline conditions” when an employee begins work, or transfers to another job responsibility. This permits the evaluation of how physiologic conditions may change with time. Checklists/guidance Checklists/guidance documents detailing the purpose of and general procedures for instituting a medical surveillance/monitoring surveillance/monitoring program are presented in Appendix XX. XX.

11.1.5 Recordkeeping Maintenance of adequate medical records on employees is essential in documenting occupational exposures exposures and their effects on individual employees. These records can be valuable for tracking changes in employee health to ensure that appropriate medical treatment treatment is provided and for detecting changes in process controls that may indicate weaknesses in employee protection. Employee exposure monitoring information /medical test results should become a permanent part of each employee’s personnel record.


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CHAPTER 12: SPILL PROCEDURES/EMERGENCY RESPONSE 12.1.Introduction As discussed previously, previously, for the majority majority of anticipated anticipated or potential exposures exposures to traditional traditional fuels, the general “good industrial practice” recommendations recommendations will be sufficient to ensure worker safety (see text Section XX and Table XX). XX). This remains true even in the event of minor spills (i.e., less than 50 liters), for the majority of the traditional fuel categories. In the event of a major release, fire, or explosion, specific procedures procedures may be warranted that may include the use of specialized PPE, firefighting equipment, equipment, or emergency spill response. These are discussed below. This section discusses recommended cleanup procedures procedures for small spills, as well as appropriate emergency emergency response procedures in the event of a major release, explosion, explosion, or fire. Specific spill procedures that are in place for an individual facility should take precedence over these general approaches. Each facility should maintain a current list of emergency services contacts (e.g., local Fire Department, Emergency Medical Service, law enforcement). Each facility should establish a team of individuals who receive additional specific specific training in emergency response procedures, procedures, emergency medical treatment and incident command. This team would be “on call” to respond to large events, and can be available to maintain or stabilize conditions until a professionally professionally contracted spill response team arrives. The medical training of this team does not replace the need to identify and maintain contact with expert medical care facilities, but provides a first line of response for accidents. These individuals should be specially designated, should be responsible to the facility’s Occupational Health and Safety Coordinator, and representatives representatives of the team should be present on each shift at a facility.

12.2 Coal or Petcoke 12.2.1 General Spill Handling and Cleanup Procedures Sweep up dry material and containerize for disposal or reuse. If material is of a fine nature and dust is generated during cleanup, use a fitted particulate filter mask such as 3M N95, safety glasses, cotton gloves and overalls while performing activity.

12.2.2 Major release and emergency emergency response procedures procedures While major spills of solid materials such as coal or petcoke certainly may occur, there typically are not specialized procedures or additional PPE required to conduct cleanup. However, it is suggested that if the material is of a fine nature, the above suggested protective measures should suffice.


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The risk of fire or explosion resulting resulting from the routine handling of coal or petcoke is limited. In the event of fire involving coal or petcoke, toxic fumes (e.g., CO, CO2) may be generated. Immediately contact emergency services. Evacuation of plant personnel and nearby residents may be advisable. This decision can be made in conjunction with local fire and law enforcement personnel.

12.3 Heavy and Light Fuel Oils 12.3.1 General spill handling handling and cleanup procedures procedures Ensure that the cause of the spill has been addressed (e.g., repair transfer hose, tighten connections, reposition hopper, transfer oil from leaking receptacle). Obtain and deploy, according to manufacturer’s directions, an appropriate size petroleum spill cleanup kit or its equivalent (e.g., 3M SRP-PETRO). These commercially available kits typically contain sorbent pads, small absorbent boom materials and plastic bags for temporary containment of used cleanup materials. The used cleanup materials and any contaminated PPE should be placed into the plastic bag(s) for subsequent disposal. If the spill occurs over bare soil, remove the visibly contaminated soil with a shovel and containerize for subsequent disposal or reuse.

12.3.2 Major release and emergency emergency response procedures procedures Containment booms should be deployed as soon as possible in the event of a large release of fuel oil. If the spill is too large to be cleaned up with on-hand sorbent material, a vacuum truck may be required. Individuals conducting large fuel oil spill cleanups will require specific PPE (e.g., Nitrile gloves and boots, Tyvek suit, and an organic vapor respirator with full face shield). Toxic fumes may be produced from fires or explosion. Contact emergency services at the facility immediately in the event of a fire or explosion. Evacuation of plant personnel and nearby residents may be appropriate depending on the severity of the event. This decision can be made in conjunction with local fire and law enforcement personnel.

12.4 Natural Gas 12.4.1 General handling and cleanup procedures Ensure that the source of the leak has been identified and the local shutoff valve activated. In a well ventilated area, small leaks in the absence of an ignition source are not difficult to identify. A gas "snooper" can be used to identify the source of the leak so that it may be repaired. If the area is enclosed, obtain a confined space permit and use a supplied air respirator. As natural gas is lighter than air, proper venting should of the enclosed space should remove the smell of the odorant methylmercaptan and the potential explosivity risk. If the natural gas is under pressure, the pipe or leaking region may be subfrigid and require the use of insulated gloves during repairs.


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12.4.2 Major release and emergency emergency response procedures procedures Contact emergency services at the facility immediately. Follow catastrophic event plan for major natural gas release. Notify natural gas supplier and shut of all supply valves. Shut off potential ignition sources. Local fire and law enforcement personnel should be notified and placed on standby status. In the event of a fire or explosion, evacuation of plant personnel and nearby residents may be appropriate depending depending on the severity of the event. This decision can be made in conjunction with local fire and law enforcement personnel. personnel.

12.4.3 References Amerada Hess Corporation. Corporation. 1998. 1998. MSDS for Natural Natural Gas. MSDS No. 8010 American Petroleum Petroleum Institute, Robust Robust Summary Information Information on Petroleum Coke. Coke. 27 March 2000 Arbeitssicherheit. Arbeitssicherheit. 1981. Gerhartz, Gerhartz, Moegling and Pfefferkorn Redaktion. Redaktion. Ullmanns Encyclopädie der technischen Chemie (German) 4. Auflage, Band 6. Umweltschultz und Arbeitssicherheit. Arbeitssicherheit. Verlag Chemie, Chemie, Basel p.683-793. Cashdollar, Kenneth Kenneth L. 1996. Coal dust explosibility. J. Loss Prev. Process Ind. Vol 9, No. 1. pp 65-76. Bartknecht, W. 1981. Explosions -Course Prevention Protection. Springer Verlag. Berlin. CMR. Gas Explosion Handbook. Handbook. Bergen 1997. CONCAWE, Heavy Fuel Oils, product dossier no. 98/109 CONCAWE, Gas Oils (Diesel fuels/heating oils) product dossier no. 98/107 CONCAWE, Gasolines, product dossier no. 92/103 CONCAWE, Petroleum Coke, product dossier no. 93/105 Holcim Group Cement Production: MEDOS Report 2001 Holcim Occupational Health and Safety Management Handbook, Version Nov. 2002 Holcim. Assessment Audit Protocol for Occupational Health & Safety of Holcim Ltd, Version Nov. 2002 Holcim Occupational Health & Safety Manual for Facilities using Alternative Fuels and Raw Materials, Version 2003. Holcim Petcoke Workshop. Miami, Fla 2002 Holcim Petcoke Applications in Kilns, Holderbank, Switzerland 2002 Holderbank Cement Course 2000, Complete Technical Documentation Holderbank. 1976. Coal firing in Cement Rotary Kilns. (German) VA 76/4528/D. OH&S manual for traditional fuels.doc

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Holderbank, Technical Technical Center. 1972. The Use of Natural Gas for Firing Rotary Cement Kilns. Report Nr. VA 72/4349/E Holderbank. 1972. Literature Collection Collection of the t he State of Gas Combustion Technology (German) VA 72/4348/D Holderbank. 1982. Firing Systems. VA 82/4898/E Holderbank. 1993. Flames and Burners. VA 93/4056/E Holderbank. 1996. State of Technology of Rotary Kiln Burners. PT 96/14078/E Holderbank. 1996. Proportioning of Bulk Materials. PT 96/14071/E Holderbank. 1996. A Review of Coal Firing Systems and their Influence on Heat Consumption ,Production and Kiln Operation. PT 96/14210/E International Program on Chemical Safety. 1982. Environmental Health Criteria 20 - Selected Petroleum Products. World Health Organization. Litton, Charles D. 1991. The Role of Specific Absorption in Defining Explosibility of Coal Dust / Air and Coal Dust Dust / Rock Dust/ Air Mixtures. Mixtures. In Transport Phenomena in Combustion. Vol.2 NASG. Explosionsschultz. Teil 1: Grundlagen und Methodik. EN 1127-1:1997. NIOSH. Coal dust. Pocket Guide to Chemical Hazards.1996 OSHA. Occupational Safety and Health Guideline for Coal Dust. 1996 Portland Cement Association. Recommended Guidelines Guidelines for Coal System Safety. Prepared by the Ad Hoc Committee on Coal System Safety. May 1983. StBG. Unfallverhütungsvorschritt-Ko Unfallverhütungsvorschritt-Kohlenstauban hlenstaubanlgen. lgen. BGV C15. Ausgabe 2001 StBG. UnfallverhütungsvorschrittUnfallverhütungsvorschritt- Silos. BGV C12. April 2002 StBG. UnfallverhütungsvorschrittUnfallverhütungsvorschritt- Schweissen, Schneiden und Verwandte Verfaren BGV D1. October 2001. StBG. BG-Vorschrift- Allgemeine Vorschriften. BGV A1. April 2000 UNOCAL. 1999. MSDS for Produced Natural Gas, Sweet. Product code:1971 StBG. Regeln für Sicherheit und Gesundheitsschutz an Arbeitsplätzen mit Arbeitsplatzlüftung. Ausgabe 7. 1997. 1997. Abruf-Nr. 361 StBG. Regeln für die Ausrüstung von Arbeitsstätten mit Feuerlöschern Streit, Norbert. 2001 No problem with petcoke. International Cement Cement Reviews, March 2002 p.71-73 VDE. Electrical apparatus for use in the presence of combustible dust-Part 1-1: Electrical apparatus protected by enclosures -Construction and testing. (German) EN 50281-1:1998


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Van de Kamp, and J.P. Smart. No date. The effect of burner design and operation and fuel type of cement kiln flames. IFRF Research Report CEMFLAM1 VDE. Electrical apparatus for use in the presence of combustible dust-Part 1-2: Electrical apparatus protected by enclosures - Selection, installation and maintenance. (German) EN 50281-1-2:1998 50281-1-2:1998 + Corrigendum:1999. Corrigendum:1999. VDI. Dust fires and Dust Explosions, Hazards, Assessment, Protective measures. VDI 2263. May 1992. VDI. Dust fires and Dust Explosions, Hazards, Assessment, Protective measures. Test methods for the Determination of the Safety Characteristics of Dusts. Supplement to VDI 2263 Part 1. May 1990 VDI. Dust fires and Dust Explosions, Hazards, Assessment, Protective measures. Inerting. Supplement to VDI 2263 Part 2. May 1992 VDI. Dust fires and Dust Explosions, Hazards, Assessment, Protective measures. Pressure shock resistant Vessels and and Apparatus-Calculation, Apparatus-Calculation, Construction and and Tests. Supplement to VDI 2263 Part 3. May 1990 VDI. Dust fires and Dust Explosions, Hazards, Assessment, Protective measures. Suppression of Dust Explosions. Supplement to VDI 2263 Part 4. April 1992. VDI. Sichere Handhabung Brennbarer Staübe Seminar. 18-19 Juni 1998 Friedrichshafen VDMA. Bauliche Explosionsschutzmassnahmen Explosionsschutzmassnahmen an Ventilatoren. VDMA 24 169 Teil 2. Juni 1990. VDZ. Sicherheihtstechniches Einrichtungen Einrichtungen und Massnahmen bei der Mahltrocknung von Kohle. Merkblatt Vt 7. Juni 1986 ZKG. Sicherer Betrieb von Kohlenmahlanlagen-Ergebness Kohlenmahlanlagen-Ergebness des VDZ-Arbeitskreises "Feste Brennstoffe".37:4: 163-166. ZKG. Erfarrungen beim Einsatz von filternden Abscheidern in Kohlemahltrokens- und Dosieranlagen 35:9: 500-506


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APPENDICES


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Appendix 1 (Chapter 3.1) Fixed Carbon Limits, percent (Dry mineralMatterFree Basis) Class

I. Anthracite

Group

r r o e l t a a s n u e s a q r e h E G L T

Volatile Matter, Limits, percent (Dry, MineralMatter-Free Basis)

n r a o h l t a s u s q e E L

r e t a n a e r h G T

Calorific Values Limits, Btu per pound (Moist b MineralMatter- Free Basis

n a h t s s e L

r r o e l t a a u e n q r a h E G t

Agglomerating Character

1. Metaanthracite 2. Anthracite 3. Semi anthracite c 1. Low volatile bituminous coal 2. Medium volatile bituminous coal 3. High volatile A bituminous coal 4. . High volatile B bituminous coal 5. High volatile B bituminous coal

98 92 86

… 98 92

… 2 8

2 8 14

… … …

… … …

Nonagglomerating Nonagglomerating Nonagglomerating

78 69 … … …

86 78 69 … …

14 22 31 … …

22 31 … … …

… … 14000

… … … 14000 13000 11500

Commonly agglomerating e Commonly agglomerating e Commonly agglomerating e Commonly agglomerating e Commonly agglomerating e Agglomerating

III. Subbitumous

1. Subbituminous A coal 2. Subbituminous B coal 3. Subbituminous C coal

… … …

… … …

… … …

… … …

10500 9500 8300

11500 10500 9500

Nonagglomerating Nonagglomerating Nonagglomerating

IV. Lignite

1. Lignite A 2. Lignite B

… …

… …

… …

… …

6300 …

8300 6300

Nonagglomerating Nonagglomerating

II. Bituminous


d

13000 d

11500 10500

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Appendix 2 Check List "Safety of Coal Grinding Systems" Plant:

Date:

CRITERIA

ACTUAL Situation

Assessment

General installation O2 monitoring after filter Inert operation: O2-limits hard coal = 12% O2-limit lignite = 10% Strict temperature control (temperature after mill) during start-up, operation and shut down (never exceed max. temperature, never below min. temperature; limits?) Sufficient preheating time of installation before start up (no build-up caused by cold spots below dew point) Shut off gate in hot gas line to the mill (to avoid overheating overheating in case of feed interruptions; self closing in case of power failure) Shut off gate after filter (self closing in case of power failure) Monitors of rotational speed for all important motors Explosion doors directed to the outside; min. 15m distance to next workshop, office or laboratory building Entire system can be completely emptied after the stop Gas-dust ducts min. 70° inclination (no deposits) Grounding of all metal parts Electrical equipment equipment (e.g. motors, switches): IP54 (certified, no source of ignition) Written operating instructions available Maintenance plan and procedures available Written procedures for fires and explosions available Written alarm plan available Equipment of plant fire brigade Periodical check of safety measures Periodical check of the installation for build-ups Building No coal dust accumulations (house keeping!) Avoiding of possibilities possibilities for (hidden) (hidden) dust accumulations accumulations Support of electrical cables covered (min. 60°) Marking of safety zones Marking of emergency exits Good ventilation and lighting Stationary vacuum cleaner (certified for combustible dust) Lighting, switches, electrical socket: Completely closed design Marking of CO2 flooding areas Poster safety instructions Cleaning free building design and fire retardant construction material


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ACTUAL Situation

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Assessment

Raw coal feed hopper Installation with roof, side walls and dedusting Sieve for lumps and big alien pieces Transport to raw coal silo Conveyors with scrapers for spillage underneath Dedusting of transport equipment equipment Over belt magnetic separator IR detector (the detect nests of smoldering fires) Velocity of conveying equipment < 1m/s (e.g. bucket elevator, screw conveyor; >1m/s = ignition source) Raw coal silo Capacity max. 3 days (usually ( usually several hours) Silo cone min. 70°, stainless steel Radius silo angles min. 0.3m (if no cylindrical silo) Dedusting of silo Raw coal silo discharge and mill feed Drag chain or pan conveyor with spillage scraper, pressure shock resistant Velocity of conveying equipment < 1m/s (e.g. bucket elevator, screw conveyor; >1m/s = ignition source) Mill Pressure shock resistant 8-10bar (design pressure?) 3 CO2 flooding (2 kg CO2/m ) Sealing of raw coal inlet (e.g. triple flap valve, rotary feeder, material column min. 3m height) Vertical mill: Water injection before mill for temperature control and emergency cooling in case of feed failure (optional) Vertical mill: Handling of mill rejects Ball mill: Water injection into mill for temperature control and emergency cooling in case of feed failure Ball mill inlet design (no direct contact of returned dust from classifier with hot gas) Ball mill: Inertization of returned material from classifier with raw meal during shut down (optional) Classifier (ball mill) Pressure shock resistant or equipped with explosion venting (venting doors water and air tight)


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Assessment

Filter (incl. cyclone separator) Explosion chimney before filter (water and air tight) Pressure shock resistant (min. 300mbar) and equipped with explosion venting (water and air tight) Monitoring of explosion doors/discs (e.g. wire detection) Cone: Stainless steel, min. 70° Heating of cone (cold climate) Isolation of filter and cone (no bridging spots in the isolation → condensation → build ups) No material deposits inside the filter; Inclination of all surfaces: min. 60°; (e.g. covers on internal reinforcement beams) No material left in filter or filter cone after stop of installation No bearings of discharge screw conveyor inside the filter (screws < 6m) Velocity of screw < 1m (>1m/s = ignition source) CO monitoring in filter (alarm limits?) Gas temperature measurement before and after filter (alarm limits?) Material temperature measurement measurement at filter discharge (to detect smoldering fire; alarm limits?) Measurement Measurement of pressure difference before-after filter (alarm limits?) Monitoring of dust concentration after filter (filter break through can lead to explosive concentration; fan is an ignition source; alarm limit?) 3 CO2 flooding (2 kg CO2/m ) Water spray for rinsing in case of fire (bag filter only cone); special water/sludge outlet (e.g. reverse operation of screw below filter) Fire extinguishing foam available Grounding of all metal parts incl. filter cages Bag filter: No reverse air filter (cleaning with pressurized air) Bag length max. 3600mm Pressurized air for bag cleaning water free (dry) Heating of air valves for bag cleaning EP: Avoiding of electrical flashover by adapted voltage control


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Assessment

Fine coal silo Explosion pressure relieve venting (water and air tight) Under-pressure protection valve (prevention of negative pressure after opening and closing of explosion doors and during cool down after sealing of silo due to smoldering fire) Dedusting with bag filter, explosion pressure shock resistant 3 CO2 flooding (2kg CO2/m Silo) Possibility for air tight sealing - no fresh air leakage (to seal off smoldering fires for CO2 flooding) Cone min. 70°, stainless steel Isolation of cone (cold climate, build-ups) CO monitoring of silo atmosphere atmosphere (alarm values?) Temperature measurement measurement at silo outlet and on silo roof (alarm values?) Cooling of transport air for pneumatic silo filling Protection against radiation from outside (optional water spray) Radius in corners min. 0.3m (if no cylindrical silo) Dosing and feed bin Scale: Pressure shock resistant Feed bin: Pressure shock resistant (incl. dedusting) Feed bin: CO2 flooding Velocity of equipment < 1m/s (>1m/s = ignition source) Transport line to burner No coal dust deposits in transport line after stop of feeding Pneumatic transport lines quality ND10 (10 bar)


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Appendix 3 Safety of Coal-Milling Plants Empirical Values

T at ….warehouse: ….warehouse: - above 50 °C seal stronger and possibly flatten embankment - above 80 °C: clear away, spread, leave cooling walls if part is 0 -3 mm too big (BS 25 - 40 %), LD) and H20 • Fine coal creates overlapping walls > 12 % • Bucket excavator ….. if and H20 > 12 %: rubber, plastic, V24 helps little • With cell-channels in raw coal….: maximum size of grain: 50 mm grinding body at ball ball mill: 50 -90 g/t g/t • Abrasion of grinding • Clogging of dividing wall by sticky coal (within 8 h), textiles, rubber, wood • Service life of grinding tool of WS mills: - abrasive: 3000 - 6000 h - ……….: 6000 - 8000 h - non-abrasive: 8000 - 17000h applicable with furnace • Early recognition of glowing fire in filter: CO-alarm on 70 ppm (not applicable exhaust gas) • Normal CO content of dust silo atmosphere: 1500 ppm (2000 for brown coal) • Necessary dew point difference in E-filter: app. 30 °C (LD) • Caking on and glowing fire in E-filter-cone with > 32 % ….. • T in dust silo as low as possible: USA regulation: max. 60 °C • … gas plant: 1. alarm at 10 % O2, stop at 12 % O2 •


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Appendix 4 Petroleum Cokes Listed in Einecs

Einecs No.

CAS No.

265-080-3

64741-79-3 Coke (petroleum) A solid material resulting from high temperature treatment of petroleum fractions. It consists of carbonaceous material and contains some hydrocarbons having a high carbon-to-hydrogen ratio.

265-209-3

647-04-0 Coke (petroleum) recovery A carbonaceous substance recovered fro acid sludge after removal of acidic material at high temperature (e.g., approximately 537.8 °C (1000 °F))

265-210-9

647-05-1 Coke (petroleum), calcined A complex combination of carbonaceous material including extremely high molecular weight hydrocarbons obtained as a solid material from the calcining of petroleum coke at temperatures in excess of 1000 °C (18000 °C). The hydrocarbons present in calcined coke have a very high carbon-to-hydrogen ratio.


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OH&S Manual for Traditional Fuels

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