ILC Kiln Manual Ed1

PROCESS OPERATION MANUAL

OPERATING INSTRUCTIONS AND REFERENCE MANUAL FOR ILC PREHEATER SYSTEM

CUSTOMER

: RAIN INDUSTRIES LTD., (3800 TPD – NEW LINE)

PLANT LOCATION

: KURNOOL, ANDHRA PRADESH, INDIA

FLSMIDTH LIMITED WORK ORDER ORDER NO. NO.

Prepared by: Checked by: Approved Approved by:

: PRJ06-009PRJ06-009-000 000

A.SRINIVASAN N.SIVAKUMAR S.SARAVANAN S.SARAVANAN

Date: Rev.:

21.04.2008 0

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TABLE OF CONTENTS 1. GENERAL NOTES 2. CONSTRUCTION AND OPERATING PRINCIPLE 3. DRYING KILN

AND

HEATING

OF

LINING

PRIOR

TO

START-UP

OF

4. STARTING OF THE KILN PLANT 5. STOPPAGE OF THE KILN PLANT 6. OPERATION OF THE KILN PLANT 7. INTERLOCKINGS, PROGRAMMING AND CONTROL CIRCUITS 8. PREVENTION OF FIRES AND EXPLOSIONS 9. BARRING 10. CAUSE/EFFECT DIAGRAMS, OPERATING AND ALARM LIMITS.

PARAMETERS

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NOTE! The present instruction manual is dealing with the situations which, according to the experience of FLS, are the most likely to occur. An exhaustive enumeration of all conceivable situations which ay occur during the erection/operation/maintenance of the kiln plant/machine/equipment cannot be provided. Consequently, if a situation should arise, the occurrence of which is not foreseen in the instruction manual, and which the operator is/or feels unable to handle, we would recommend that FLS is contacted without undue delay for advice on appropriate action.

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1 GENERAL NOTES This manual is intended as a reference guide, which can be used in connection with the start-up, normal operation and shutdown of the plant. The majority of the directions given in the manual are of a generalized character given that a range of relevant factors of a specific or localized nature are involved, and it would be impossible to provide a detailed evaluation of all these factors in this manual without sacrifice of clarity. The manual must be regarded as a tool for optimization of the kiln plant, and it can also be used to support judgements made by the operator in a given operating situation. In this manual it is a foregone conclusion that the control panel equipment has been installed, tested and made fully operational. This manual should be thoroughly studied prior to start-up, so as to permit detailed planning of this phase. Several separate instruction manuals related to the plant under review in this manual; these manuals contain detailed information about the single machines or arrangements. These manuals must also be studied very before the plant is put into operation.

carefully

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2

CONSTRUCTION AND OPERATING PRINCIPLE

2.1

Construction of Main Elements

The kiln plant construction is schematically shown in enclosures. The clinker producing plant is a FLS-ILC (In-Line Calciner, Low NOx type) installation incorporating the following elements: Kiln tube Diameter Length No of supports Inclination Size of Kiln Drive & max. Speed No. of Preheater Strings and Stage

Size of Cyclones in Kiln String Size of Calciner Grate Cooler Type Burner Type Kiln Feed System

3.95 meters 61.0 meters 3 4.0% 493 kW, 5.00 rpm Single string with 5 Stages Stage I–II: 7.8 m Stage III-V: 8.0 m 6.9 m Øx35.2m Long SF CROSS BAR- 3x5F Duoflex Bucket Elevator

2.2 Operating Principle The ILC Calciner kiln system is installed. The Calciner is placed in-line with the kiln riser duct. The combustion gas for the Calciner is hot atmospheric

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air drawn from the SF CROSS BAR COOLER through tertiary air duct mixed with the combustion gas from the kiln. The Calciner is dimensioned for a gas retention time of approximately 4.5 seconds. The kiln and Calciner is provided with a preheater. The cyclones are of the proven FLS LP-type, which ensures a very low pressure loss of the preheater. The kiln main burner is the new Duoflex burner. The primary air consumption of this burner is lower as compared with traditional burners. The burner is provided with an oil burner for start-up. The raw meal feed i.e. the kiln feed is extracted from the homogenizing raw meal silo into a kiln feed bin. The raw meal is then transported to the preheater inlet by the Bucket Elevator. The preheater is operating as a counter current heat exchanger with the raw meal passing downwards through the preheater stages by gravity, and the hot gas moving upwards drawn by the ID-fan. Having passed 4 or 5 preheater stages - depending where to the feed is directed - then the raw meal passes a splitter gate, where the raw meal flow can be diverted into two positions in variable amounts, one to the calciner vessel, and two to the riser pipe from the kiln. This splitting and the amount of material being guided to one way or the other is depending very much on the fuel used, and the tendency of coating formation in the riser pipe.

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Approximately 55 - 60% of the fuel can be fired in the Calciner. The raw meal will be calcined to a degree of about 90-94%. The Calciner can be operated at high temperatures of more than 1000 C., which increases the combustion rate. The excess air at the top of the Calciner is foreseen to be approximately 20% corresponding to an oxygen level of 3% in the outlet gas duct of the Calciner. These measures should ensure complete combustion of the fuel applied. The combustion air used in the Calciner is a mixture of hot air (875-925 C.) drawn from the SF cooler through the tertiary air duct and the kiln gases from the rotary kiln. The material is leaving the top of the Calciner and is then passing onwards to the 5 th preheater stage. From this last preheater stage the material slides to the rotary kiln inlet. Due to the inclination and rotation of the kiln, the raw meal is transported downstream through the kiln. Simultaneously, the raw meal is gradually heated up and fully calcined by the heat supplied to the kiln. Clinkerization - clinker formation - takes place when the raw meal passes through the burning zone of the kiln. The clinker formed enters the grate cooler for cooling.

2.2.1 SF CROSS-BAR COOLER

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The cooler is the well proven SF (Smidth-Fuller) cross bar cooler. This cooler type comprises a number of unique features:   



Cross bar, separate conveying clinker device. All grate plates are stationary. Low energy grate plates with mechanical flow regulators. Modular concept. The SF cooler has a modular design. The cooler nomenclature describes the number of modules the cooler consists of (width x length). Before each row of cooler modules there is an inlet module without cross bars, serving as impact zone for the clinker leaving the kiln. Each cooler module has a width of 1.3 m and a length of 4.2 m and comprises 4 x 14 grate plates. The module has an inclination of 4 degrees. The inlet modules, 1.3 m wide and 2.0 m long, has an inclination of 15° and consist of 4 x 5 grate plates. The outer corners of the two outer inlet modules are covered with refractory. Each row of cooler module and the inlet modules has their own cooler fan. The grate plates in the cooler modules as well as in the inlet modules are stationary. The transport of the clinker is made by reciprocating crossbars located about 50 mm above the grate line. Each cooler module has 12 cross bars, 6 stationary and 6 moveable. The moveable crossbars are connected to two longitudinal profiles, which are driven by a hydraulic cylinder below the grate, one for each module. The drive system in a module is connected to the drive systems in the previous and subsequent modules. The right set and the left set of modules can then be moved independent of each other for optimum distribution and transport of the clinker.

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As the grate plates are protected by a stationary layer of clinker they will, contrary to other modern coolers, not wear down and deteriorate the air distribution with a lot of sealing air. The grate plate is made with labyrinth air path for elimination of through fall of clinker. Transport equipment below the grate is then completely eliminated. The grate plate proper has a low pressure drop. In order to ensure an optimal air distribution every grate plate is provided with a mechanical flow regulator (MFR). The MFR maintains a constant airflow through the grate and clinker bed irrespective of clinker bed height, particle size distribution, temperature, etc; i.e. separate flow control for each grate plate. The MFR’s allow use of one fan for relative large areas and completely eliminates the use of under-grate ducts and dampers seen in other modern coolers. The modular concept of the SF cooler allows shop assembling of large part and very fast erection. Due to the cross bar system the number of wear parts are minimized and replacement of these parts are fast and easy to perform. The kiln hood is common for the kiln and the tertiary air duct. The hood is made so large, that minimum clinker dust is recirculated to the kiln and Calciner. 2.2.2 Gas treatment and distribution Whenever the kiln is in normal operation, the preheater exhaust gases or part of these can be utilized depending on the raw mill or coal mill is in operation or it is stopped. When the mill is in operation, part of the gases is used for drying raw material in raw mill or coal in coal mill.

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The dust precipitated in the kiln/raw mill filter installation is returned to either the raw meal silo or the kiln feed. The cooler excess air is treated in a separate ESP designed especially for clinker dust. The recuperated dust is returned to the clinker transport system.

2.2.3 Separate Instruction Manuals A number of other instruction manuals for the individual machines or arrangements are available for the plant concerned. STUDY THESE MANUALS BEFORE THE PLANT IS STARTED It is not all machines or equipment in this instruction manual, that are supplied by FLS. The FLS delivery range can be read acknowledgement and the order list.

in

the

order

3 DRYING AND HEAT-UP OF LINING PRIOR TO START-UP OF KILN 3.1. Preconditions and Criteria for start-up This section must be compared with the graphical form given section 9, which provides information about heating and start-up procedures. 3.1.1 Personnel Operators

and

operating

personnel

must

be

fully

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familiarized with the instruments and functions of the control panel. Furthermore, the personnel must be well informed about the layout and operating principle of the motor control system, especially all interlocking diagrams indicating protective, safety and operational interlocking.

3.1.2 Raw Materials Prior to start-up, raw materials must be available in sufficient quantities and with a well known quality in order to ensure continuous, stable kiln operation. 3.1.3 Preparations The following activities must be carried out prior to the initial start-up: 1. All kiln plant machinery should be subjected to noload testing and, where possible testing under load. The trial run of the kiln should comprise only of the kiln motor, with the coupling bolts removed. Trial run of machines loaded with material should be performed over a prolonged period. For instance 24 hours, with the kiln feed in circulation. Water and/or air must be available where necessary. 2. The entire electrical and electronic control system must be tested to ensure that all interlockings i.e. safety, protective and operational interlockings are active and that they function properly.

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3. Ensure that all alarm limits have been set. (Refer section 10 in this instruction manual). 4. The raw meal must be recirculated to sustain the operation of the feed arrangement and for calibration of the load cells. 5. Prior to the production of clinker an appropriate amount of correct quality raw meal must be available. At least 3 days consumption must be available. 6. Where possible, the oil in the firing installation should be recirculated to check the function ability of the installation. 7. Ignition burner and burner equipment must have been prepared for start-up. 8. The chemical laboratory at the plant should be on standby to perform the necessary analyses of the kiln feed and clinker, particularly to determine the content of free lime, the litre weight of the clinker, and the kiln feed analysis. 9. In order to optimize the regulation of the primary air volume in the kiln, for optimization of the flame structure, it is advisable to measure the airflow supplied to the burner by the primary air fan at different valve openings and pressures. Hence it is possible to ascertain what valve position should be used during operation.

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NOTE! Where specific demands for initial drying procedure of the concrete are stipulated by the supplier of the castable for the grate cooler, account must be taken of such criteria during the start-up phase, or, if this is not possible, it may be necessary to dry out the cooler on a separate basis.

3.1.4 Preparations Prior to Heating Before the below mentioned start-up sequence is followed and any machines are put into operation, the description in section 7 of the interlockings, the programming and the control should be read through. CHECK -

That all tools and all alien objects have been removed from all kiln plant machines.

-

That potential coatings have been removed from cyclones, flue ducts and riser ducts.

-

that all doors and clean-out hatches are closed.

-

that the motorized dampers function properly

-

that the barring device, with brake , is ready to be operated.

-

that all plant machinery has been lubricated in strict accordance with directions given in

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separate instruction manuals. -

oil must be applied to the journals of the supporting rollers to ensure that they are covered by oil when barring operation is started.

-

the water supply to kiln bearings and gas analyzer is functioning.

-

that all instruments in the control system are functioning.

-

that all alarm limits have been set.

Start the compressed-air supply and check that compressed air is present at the points of consumption at the correct pressure. Place the gas analyzer equipment in the kiln system in the state of readiness. Check that the thrust roller device and the spray lubrication for gear rim are ready with sufficient oil and grease. Refer separate instruction manual. Mount the light-up nozzle on the burner installation of the kiln and prepare the ignition burner for operation. Prepare the cooler and the clinker transportation system. Place about 300 - 400 mm layer of cold clinker on the Fixed Inlet section of the cooler. See separate instruction manual for cooler.

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If special requirements for the initial drying of the castable are stipulated by the supplier of the castable for the grate cooler, these requirements must either be met during the start-up procedure or, if this is not possible, the grate cooler must be dried out separately. Once these checks and activities have been completed, both the electrical and the mechanical department must ensure that the installation is reported ready for start-up.

3.2 Drying-out procedure 3.2.1 Kiln & Preheater

The heating and drying-out of the refractory lining must be performed very slowly and gradually in order to avoid cracking and spalling. This applies especially in places where large zones are lined with castable and are to be dried out. NOTE The given heat-up schedule is applicable for refractory supplied by FLS only. It may be necessary to modify the outlined drying out procedure in case a different code of practice is recommended by the brick supplier. However, consultations between the plant management and FLS are needed before any modifications are introduced. The initial heat-up/drying-out operation should stretch

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over a time period of approximately 72 hours as shown in the diagram given in section 9. In connection with subsequent kiln starts, the heating period can normally be reduced to 24 hours, though it depends on the type of lining repairs conducted during the intervening periods. As mentioned previously, it is recommended to extend the heat-up period if concrete castable has been used for casting operations inside the kiln system. 3.3 Initiation of Heat-up Operation See also the separate instruction manuals related to the individual equipment mentioned. Heat-up operation is started as follows: 3.3.1 Kiln and Preheater Check that the dampers in the ducts to all the mills, which will be supplied with drying gas, are closed. Start the oil circulation to the burner. Check the pressure and temperature of the oil. Start the hydraulic pump of the thrust device. Start the spray lubrication system for the kiln drive. Start the kiln bag house -fan with closed damper. Open the filter fan damper gradually, so that a negative pressure of 1-2 mmwg is maintained in the gas duct just after the ID-fan.

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The damper for the ID-fan are opened 10-15% so that there is created a slight negative pressure in the kiln hood. Start the primary air fan and close the primary air damper to 10%. Start the ignition burner. Start the oil burner by opening the oil valve for the light-up nozzle. Check that the oil is ignited; if necessary adjust the primary air valve to facilitate the flame formation. Adjust the draught in the kiln by means of the exhaust gas damper, the filter fan speed and the damper. Start the barring of the kiln in accordance with the barring programme outlined in section 9. Check lubrication of supporting rollers. The journals must not become dry. During barring it may be required to pour additional oil directly on the journals. The specified barring program must be adhered to; however, if the thrust device equipment for indication of kiln position gives alarm, barring must be continuous until the alarm can be cancelled. Continuous barring is also required if the kiln is subjected to cooling, for instance due to heavy rain. Soon after the start of the burner, the gas analyzer in

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the riser duct should be put into operation. Start the fans for the cooler inclusive the nose ring fan (it is the fan at the kiln outlet). Start the Bag house-fan for excess air from the cooler with closed damper. Set the Set the automatic negative pressure control in the kiln hood to a set point of -0.5 mmwg. Open the Open the hoisting damper in the tertiary air pipe 50%.

Start the burner in the kiln hood, if supplied, the oil volume is set to 10-20% of full capacity. Over heating of the lining in the TA duct is thus avoided. Regulate Regulate the kiln string exhaust fan damper to get oxygen content of 8-10% in the kiln inlet. When the kiln has become hotter after some hours this level can be reduced to 3-4%. The ignition burner can be extinguished after approximately 8 hours or as soon as the lining is hot enough to support the ignition of the oil. 3.3.2 Air 3.3.2 Air Supply during the Heat-up Phase During the heat-up period, the maximum amount of the heat input should be utilized for heating of the kiln, i.e. only the necessary air volume should be drawn through the kiln. However, an adequate air surplus must be present for

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the complete combustion process. It could be necessary to start 2-3 cooling air fans and to start the excess air fan to be able to control the negative pressure in the kiln outlet. The oil flame must not cause sooting. Often, this would require that the oxygen content indicated by exit gas analysis in the riser duct is 8-10%. When the kiln has become hotter after a couple of hours, then the oxygen content can be reduced to about 3-4%. An oxygen content smaller than this might cause a sooting flame. An exit gas analyser after the preheater is not of much use during the heat-up phase, since air infiltration from the preheater system would influence the analysis. 3.4 Inspection during heat-up period The programme for heat-up period is graphical indicated in section 9. Following major lining repairs, a heat-up period of approximately 72 hours is recommended, whereas for normal starting of cold-state kiln the period should be approximately 24 hours. It is very important that no attempt is made to speed up the programme. In case of interruptions during the heat-up period compensation is needed by extending the time period, so that the actual heating period has the stipulated

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duration. The heat-up speed, as measured at the kiln inlet and the outlet from the preheater tower, should very closely follow the curves as indicated in section 9. It is advisable to record operational experience gained during initial heat-up periods, so that the curves in the enclosure can be adjusted in accordance with the local conditions. A regulation of fuel rate, draught level and oxygen level is needed to ensure strict adherence to the curves for the temperature rise. Overall, the prime aim is, as previously mentioned, to ensure retention of the supplied heat inside the kiln. Any increase in the draught level will rapidly cause the temperature in the cyclone tower to rise at the expense of the temperature in the kiln, and this is not desirable. The following inspection and during the heat-up period:

check-up

must

be

made

Kiln Lining Inspect the kiln lining at regular intervals. The lining in the burning zone must not be exposed to fast and local overheating. The lining temperature must not exceed 1000

C.



If the lining temperature rises too quickly becomes too high, reduce the amount of fuel.

and/or

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Kiln Shell Temperature Check the kiln shell temperature. Special attention must be focused on the burning zone where high surface temperatures may occur. Temperatures of up to 350 C. will be acceptable. If the kiln should become too hot in the burning zone, and the temperature after the preheater is relatively low, i.e. it permits that surplus heat is drawn from the kiln upstream to the preheater by increasing the draught. Alternatively the flame shape must be adjusted regulating the air volume to the main burner.

by

Bearings for supporting rollers Check the lubrication. Dry running of the bearing journals must not occur. When the kiln is barred, it may be necessary to apply additional oil directly to the bearing journals. Barring Strict observance of the specified barring programme is needed, but in the event that an alarm is tripped by the thrust device equipment indicating the position of the kiln, then the kiln must be barred continuously until the alarm can be cancelled. Continuous barring is also subjected to cooling, for rainfall.

needed if the kiln is example due to heavy

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Clearance between kiln shell and live ring The clearance between the kiln shell and the kiln tires must be checked at regular intervals during heat-up and start-up phase, especially at piers I and II. Clinker transport If the kiln has been filled with raw materials, it may, from time to time, be necessary to start the grate cooler and the clinker conveying system in order to transport away the materials, however, do not empty the cooler. To ensure effective cooling at the cooler inlet, it may as previously stated be necessary to start the first fans of the cooler.

4 STARTING THE KILN PLANT 4.1 Getting Ready for Operation Operational status must be prepared approximately 3 hours in advance of the anticipated time for start-up with feed. At this stage the temperature of the kiln lining is sufficiently high to ensure ignition of the coal from the burner, which is put into operation as follows: - Reduce the oil flow to the burner. - Start coal firing with minimum coal. - Finally stop the oil & continue heating with necessary coal until the desired temperature profiles have been achieved, as indicated below.

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Start the transport lines for dust and clinker after the kiln. Start the recirculation of raw meal if the equipment has been out of operation over a prolonged period of time. Start the burner in the kiln hood, if installed, unless it is already in operation. The oil quantity is adjusted so the lining temperature does not exceed 1000 C. Start the dust conveyance system after the kiln bag house, and the cooler ESP. Check that the dividing or splitter gate after the 2nd lower most cyclones is adjusted so all the raw meal is directed to the riser pipe. 4.2 Starting of kiln Feed When the temperature at the top of the 2nd lower most cyclone stage is about 750 C., and assuming compliance with the heating programme as outlined in enclosure, the kiln is ready to accept feed material. Personnel must be stationed in the cyclone tower in order to watch the raw meal as it passes through the cyclone preheater. Supervision is performed cyclone. The flaps must ascertain that the raw risk of jamming in the

at the sluice flaps under each move freely. This is done to meal is passing through. The cyclones is particularly high

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during start-up. The control room must have the possibility to contact the supervising personnel via mobile communication equipment, radio or telephone; so that early warning can be given from the supervising personnel to the control room in event of jamming symptoms in cyclones are observed. 4.3 Starting of Kiln Main Motor Stop the barring motor, disengage the barring gear and start the kiln main motor at the lowest speed. Start the exhaust gas fan with closed damper. Sometimes it is necessary to stop the burner if it takes a long time to establish the draught as the fan is started with closed damper. However, it should be possible to operate the burner at minimum rate. Therefore the draught and fuel rate must be reset to levels applicable prior to the starting of the exhaust gas fan. Please make sure that the filter fan speed is adjusted to maintain sufficient suction after the kiln exhaust gas fan. Start the clinker transport system, with clinker breaker, and the cooler drives and fans (refer to separate manual for the SF-cooler). 4.4 Establishing Normal Production Rate Perform the following operations in RAPID but PROPER , sequence: - Start the raw meal feed to the preheater.

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- Increase the draught level by opening the damper for the exhaust gas fan as well as the speed of the fan. - Increase the fuel rate accordingly. - Increase the feed rate to 55-60% of full production, with simultaneous increase in kiln speed to 1.4-1.6 rpm. - Start the fuel supply to the Calciner at minimum rate. As soon as the kiln feed has reached the lower most cyclone stage, then increase the fuel rate in order to maintain the temperature of this lower most stage of about 860 C. - Set the draught level and fuel rate so the fuel supply rate is 5-10 % in excess of the normal operational level at the same production rate. The reason is that the kiln system is colder at start-up as compared with normal operation. The draught must always be increased prior to any increase in the fuel rate in order to avoid COformations. Also remember to regulate the damper in the tertiary air duct for the Calciner. The temperature after the preheater must not exceed 400 C. The gas analyzer after the preheater will typically indicate an oxygen level of 6-8% during start-up. However, the oxygen level should be in the range of 34% at the kiln inlet. When it has been ascertained that the clinker in the

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burning zone is well-burned, the kiln speed can gradually be increased to match the production level. The kiln feed rate and the kiln speed rpm should be synchronized to maintain constant material level, for instance 4.0 rpm corresponds to 100% production level. It is of critical importance that the first material is well burned in order to avoid circulation of dust between kiln and cooler. Dust circulation may cause cooling of the burning zone so more time is needed to stabilize the kiln operation. Since, as mentioned above, the heat input to the kiln at the beginning exceeds the amount required for clinker formation, the kiln system will gradually be heated. When there is solid evidence of satisfactory clinker formation at low free lime levels, the kiln output can gradually be increased with simultaneous increase of draught level, feed rate and fuel rate. Especially the kiln torque and visual inspection of the clinker are useful parameters to use in order to judge whether the clinker are well burned. Further analyses of the clinker litre weight and content of free lime are useful for judgment of the clinker quality. The duration of the period from starting of the kiln feed to full production level is reached, will normally be 5 - 8 hours.

4.5 Starting and Operation of the Cooler

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See also separate instruction manual. 4.6 Preparations for Calciner Operation As mentioned above the firing in the Calciner must be started at the same time as feed taken to the preheater. However, the following interlockings must be fulfilled: -

-

Kiln main burner in operation with ID-fan in Operation. Kiln main drive in operation. The temperature in the lower most cyclone stage must be higher than minimum (750 C.) and lower than max I (920 C). The feed to the preheater is on. CO content in the gases after the preheater must not be higher than max II (0.9%) for more than 10 seconds, and then the fuel rate to the Calciner must automatically be reduced by minimum 20%. The burner is then automatically changed to manual control mode.

The combustion gas/air to the Calciner is controlled both by adjustment of the ID-fan speed and by changing the position of the damper in the tertiary air duct. The draught adjustment should maintain 3-4% oxygen at the preheater outlet with CO content lower than 0.05% and an oxygen level between 3-4.5% at the kiln inlet. Always increase draught before fuel rate is increased to prevent formation of explosive gases. 4.6.1 Achieving Nominal Capacity

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During the first couple of hours after the production has been started the feed rate is increased gradually, however, only concurrently with production of well burnt clinker. Adapt feed and fuel so the temperature in the lower most cyclone stage is maintained at approximately 880 890 C., which would correspond to a degree of calcination of 90-94%. This calcining temperature should be maintained automatically by the CCR-control system. Consequently follows: -

the

kiln

production

is

increased

as

Increase the draught Increase the feed. (Synchronously with the kiln Speed). Increase the fuel supply to the Calciner (possibly automatically). Check whether a change of the kiln fuel is needed. (Depending of free lime level, litre weight and torque).

The temperature of the hot air from the cooler to the Calciner through the tertiary air duct will increase progressively as the clinker volume is increased. Therefore the fuel rate to the Calciner will be reduced.

5 SHUTDOWN 5.1 Normal shutdown of the plant

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It is advisable to shutdown the kiln plant in a controlled manner by following the sequence outlined below: -

Reduce the total air-flow to the cooler. Stop the fuel to the Calciner. Stop the exhaust gas fan and close the damper (automatically) This automatically involves that:

-

The kiln burner is stopped The kiln feed is stopped or switched over to recirculation back to the CF silo. Stop the kiln motor. Stop the filter fan and close the motorized damper ahead of the fan. Reduce the amount of primary air to a minimum.

-

However, a certain amount of primary air is needed to cool down the burner pipe, if the burner remains in the kiln. -

Reduce the cooler grate speed. After a few minutes they can be stopped.

-

The cooling air fans can be stopped one by one gradually.

Start barring BARRING.

operation

as

outlined

in

section

9.

Where the shutdown period of the kiln extends over a prolonged period of time, then all machinery not required for barring of the kiln and cooling of the

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burner pipe must be stopped. i.e.: -

Stop the dust conveyance system when the system is empty. Withdraw the gas analyzer from the riser duct. Stop the compressors. Draw up plans for subsequent clean-up operation in the cyclones, flue ducts and riser ducts. Make sure that the cooling water supply for the kiln bearings is functioning as long as the kiln is barred.

After the kiln has cooled off: -

Stop the primary air fan and retract the burner.

-

Stop the clinker conveying system.

-

Inspect the kiln, the cooler, the hot gas ducts and the preheater.

-

Planning of the maintenance- and repair work required prior to renewed start-up.

NOTE! The kiln must always be cooled off slowly to prevent too rapid cooling of the lining in relation to the kiln shell. Otherwise, the lining may become loose, involving risk of twisting and drop-out of bricks.

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5.2 Unscheduled shutdowns In the following a description is given of the most common types of operational disorders. 5.2.1 Total Power failure All machines and motors are stopped. The emergency power generator must be started making it possible to bar the kiln, to close the fan dampers, to cool down the burner pipe, to start the nose-ring fan and to start the first 3 fans of the cooler. Cooling water for cooling of the support roller bearings must be available as long as the kiln is barred. 5.2.2 The kiln main burner stops functioning. If operational status cannot be restored immediately, the exhaust gas fan must be stopped; thereafter the shutdown procedure outlined in subsection 5.1 must be initiated. 5.2.3 The Calciner burner stops functioning If the Calciner burner can be restarted immediately, then there is a possibility of restoring stable operation. Otherwise, the kiln may have to be stopped. Until the burner can be restarted the kiln feed as well as the draught should be reduced. The draught in the Calciner and the preheater is likely to be too low causing drop-through of material from one preheater

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stage to another. So if the Calciner burner is not restarted fairly quickly then kiln operation must stop, and the shutdown procedure outlined in subsection 5.1 must be initiated. 5.2.4 Kiln Feed Failure If the kiln feed cannot be restarted immediately, it will be necessary to shut down the kiln. Stop the exhaust gas fan and follow the shutdown procedure outlined in subsection 5.1. 5.2.5 Blockage of Cyclones Blockage symptoms are normally indicated by a drop in the negative pressure at the bottom of the cyclone or a drop in the temperature of the material after the cyclone. If blockage is ascertained in a cyclone, it is essential, that the kiln is brought to immediate standstill in order to avoid overfilling. Stop the exhaust gas fan and the kiln motor. The feed is stopped by interlocking. Then follow the subsection 5.1.

shutdown

procedure

outlined

in

Before the clean-up operation is started, a negative pressure can be generated by means of the filter fan. 5.2.6 Hot spots on the kiln shell A shutdown of the kiln will normally be required if the

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kiln shell temperature is higher than 400



C.

An attempt can be made to maintain the kiln in operation to postpone the shutdown to a more appropriate time, provided the temperature can be lowered by means of cooling fans with concentrated cooling at the hot spot(s). It is prudent practice to keep the kiln motor running on minimum speed until the temperature of the hot spot has been substantially reduced. If, however, it is not possible to cool the hot spot, then a kiln shutdown for repairs of the lining is described in subsection 5.1. It may be advantageous to make a partial discharge of material from the kiln by prolonged barring before the repair of the lining is initiated.

5.2.7 Failure of Clinker Transport In event of clinker transport failure, the kiln can normally be maintained in operation for a couple of minutes before it must be shutdown. During this period of time an attempt to restart the clinker transport must be made, but if operation cannot be resumed, it will be necessary to shutdown the kiln in accordance with the procedure outlined in subsection 5.1. 5.2.8 Failure of the Cross bar Cooler

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In this case, the precautionary measures which should be taken are identical to those outlined in subsection 5.2.7. 5.2.9 Failure of dust handling system Normally, kiln operation may continue for a short period (if some accumulation of material in the dust transport system is found to be acceptable, and if the authorities will allow short periods of kiln operation without dedusting). If it is not possible to restart the dust conveyance in this short period, the kiln must be stopped in accordance with procedure outlined in subsection 5.1.

6 OPERATION 6.1 General Notes The kiln performance is optimized by ensuring that operational kiln adjustments are restricted to an absolute minimum. The necessary adjustments must be phased in gradually. Once all control loops are active, these will ensure maintenance of: -

the pressure after the exhaust stabilization of the draught.

gas

fan

for

-

the outlet temperature from the Calciner, ensuring a constant degree of calcination.

-

the pressure at the kiln outlet, this contributes

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towards stable cooler operation, and secondary and tertiary air conditions. -

stable

the operation of the cooler, with a battery of regulators providing uniform cooling by adjustment of air flows and grate speeds.

The fuel supply rate to the kiln installation is determined on the basis of an evaluation of the clinker quality, i.e. the litre weight, free lime content and the general appearance of the clinker. Another determinant is the current status of the kiln, i.e. the trend of the torque curve, the potential presence of coating formation or other operational disorders recently encountered.

6.2 Specific Conditions related to kiln operation In the following a review is made of a range specific factors affecting the kiln operation.

of

6.2.1 Exit Gas Analysis The exit gas analysis constitutes the most important source of information for the evaluation of the combustion process. Therefore, it is of crucial importance to ensure that the analysis equipment is functioning properly. The smoke gases must not contain any unburnt substances i.e. C (Carbon) or CO (Carbon Monoxide).

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Presence of such gases may, under adverse circumstances, cause fires or explosions and further, the loss incurred by wasting the latent heat of the unburnt part of the gases may be quite substantial. A CO level of more than 0.1% in the smoke gases may entail added calorie consumption in the kiln. Any presence of unburnt substances would indicate inadequacy of air for the combustion of the fuel. Even with an adequate air volume, the smoke may contain unburnt substances due to the fact that the mixture of fuel and air is not ideal. Therefore, a certain air surplus should be applied during the combustion process. As previously mentioned, the exit gases from the preheater should contain 3-4% of oxygen. It is possible to set a lower alarm limit for the oxygen level. For example, a limit of 2% can be applied. This alarm will inform the operator about the risk of unburnt substances in the exit gases. After the preheater the gas analyser will continuously monitor the CO level in the exit gases. The alarm limits should be set as follows: MAX I

:

0.5% CO

MAX II

:

0.9% CO

MAX I will signal alarm. Then the operator must make the necessary adjustments to the combustion process.

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MAX II will signal alarm and after 10 seconds automatically reduce the fuel rate to the Calciner by minimum 20%. The Calciner burner is then in manual control mode. 6.2.2 Primary Air Volume The primary air is supplied through the burner pipe, ensuring an effective mixture of air and fuel. Normally the primary air volume supplied by the fan constitutes 5-6% of the air volume needed for combustion. 6.2.3 Temperatures after Cyclone Preheater. The exhaust gas fan is designed to withstand operating C. temperatures up to 400 However, short term temperature rises up to 450 C. can be tolerated. The following alarm limits should be set: MAX I

: Giving alarm which is 400



C.

MAX II : Causing alarm tripping and Stoppage of the exhaust gas fan at a temperature level which is 450 C. but never higher than 450 C. Note: Also one bleed air damper is provided in the downcomer duct to cool the preheater hot gases whenever the temperature rises beyond 450 oC. 6.2.4 Bearing Temperatures

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An excessive temperature in any fan bearing will cause alarm tripping and automatic switch the fan off. This applies to the exhaust gas fan, the filter fan and the grate cooler excess air fan. An excessive temperature in any supporting roller bearing will only cause alarm indication, but the operator must ensure, that immediate action is taken for the remedy of the situation, if kiln operation is continued. 6.2.5 Bag-Filter The operating temperature of the filter must never exceed the maximum temperature specified by the supplier. The thermocouples at the inlet and the outlet of the Bag-filter casing are connected to electrical interlockings that will stop the filter fan in case of elevated temperature.

6.2.6 Blockage in the Cyclones Changes in the temperatures of the material at the discharge point from the cyclones, may be signs of incipient - the beginning stages of a - blockage in the cyclones. Negative pressure meters are installed at the bottom of all the cyclones. If the negative pressure drops during normal operation, this is, combined with a possible

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change in temperature, confirms a sure sign of pressure gauges will cause alarm blockage. The indication, if the negative pressure should drop below the set minimum value. It is then up to the operator to assess, on a case by case basis, whether a kiln shutdown is required. A drilled hole, with a diameter of about 2 mm must be present in the connecting bushings for the negative pressure meters, and it is very important to keep this hole clean. In case of blockage in the cyclones, the pressure measurement will gradually move towards zero as the tube is filled with atmospheric air. Once blockage in a cyclone has been ascertained, the operator must ensure that the kiln is shutdown, thereafter the blockage is removed manually. Normally, air lances in appropriate effective tools. Extreme caution must during the clean-out operation.

lengths are be exercised

NOTE! The temperature of the material cakings may be as high as 800 C., with attendant risk of sudden outflow of hot raw meal, flowing as if it were a liquid. Therefore, it is essential that extreme caution and care is being exercised during the operation, and it is advisable that the operators involved are equipped with heat-insulated protective suits during the clean-out operation.

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A number of precautionary measures to be taken in a cement plant are outlined in a separate instruction manual. 6.2.7 Cakings in the Riser Duct and kiln Inlet It is possible to detect major cakings in the riser duct and kiln inlet by checking the difference between the negative pressures at the kiln outlet and at the lower most cyclone. The safety precautions which must be taken during the clean-up operation are similar to those stipulated for the cyclones. Operational experience will show whether the extent and locations of potential cakings would make it appropriate to equip the installation with additional clean-out hatches. Also it may be practical to install air shock blasters at appropriate locations. 6.2.8 Kiln Position The axial position rollers is monitored limits must be set manual for the thrust

of the kiln on the supporting by the thrust device. The alarm as directed in the instruction device.

The MAX I alarm is a signal instructing the operator to undertake inspection of the thrust device and/or the position of the supporting rollers.

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The MAX II alarm automatically stops the kiln drive for prevention of damage to the smoke chamber seal, kiln hood seal or thrust roller. It may be necessary to check the thrust direction of the supporting rollers. See separate instruction manual. In a critical situation, it may be necessary to apply oil directly to the supporting rollers if the rollers tend to thrust the kiln upwards, but it is very important to ensure that the oil is removed as soon as possible following the re-alignment of the supporting rollers. The lubrication between the supporting rollers and the kiln tyre must be provided by means of dry graphite lubrication. See separate instruction manual. 6.2.9 Kiln Lining The temperatures in the kiln system are so high that most of the system is protected by means of a lining which consists of bricks and castable. It is a prerequisite for smooth kiln operation that the kiln lining is intact. Consequently, proper maintenance of the lining is of paramount importance. Normally, the lining in the preheater, hot-air duct and in most parts of the cooler will have a lifetime of several years with no need for replacements. However, especially the lining installed in the burning zone of the kiln will require more frequent replacement

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of bricks. The exact frequency depends on a range of factors, but, generally, replacement is recommended in case the thickness of bricks has been reduced to half the original size owing to wear. Any damage to the lining involves risk that the kiln shell will be overheated. Particularly the kiln burning zone should be kept under continuous supervision. If the kiln shell temperature should rise to 380-400 C, the affected area must be cooled by means of fans. In event of a further rise in temperature, the kiln must be shutdown for repair of the lining. During operation the condition of the kiln lining can be checked by installing a radiation pyrometer (scanner) for monitoring of the kiln shell temperature. This alarm level should not exceed 400 C. Whenever access to the kiln is possible during a shutdown period the opportunity should be taken to inspect the lining, so appropriate time schedules for replacement or repair can be worked out.

7.0 INTERLOCKINGS, CIRCUITS

PROGRAMMING

AND

CONTROL

The various motors, machines, dampers and other equipment are operated and controlled by the central control system. In the following the proposed structure of the control system is described seen from the

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operational and process point of view. A proposal for grouping of the motors is given below. The general and special rules of interlockings are listed. A survey of all process related measurements and their treatment is given in section 10. Finally the list of control loops is presented. 7.1 Interlockings The detailed interlockings, as programmed, are described in the interlocking diagrams, however, main philosophy is given below. The general rule of operational interlockings is that no machine can be started before the subsequent machine has been started. Inversely, stop of any machine will cause the stop of the machine ahead. This follows the process order. Protection interlockings like -

bearing temperature vibrations winding temperature minimum oil level speed monitors skew running maximum material level, etc.

will stop the machine in question immediately. Examples: -

If the speed monitor of an air sluice does not indicate any rotations, then the motor for this air

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sluice will stop. - If the vibration level of the kiln exhaust gas fan is high, then the motor of this fan will stop. - If the bearing temperature of the clinker breaker is above the maximum temperature allowed, then this breaker will stop. Special interlockings The special interlockings will be described in the section of programming as well as in the diagrams giving the process instrumentation (CAUSE/EFFECT DIAGRAMS as described in section 10.). In the control system the various motors and machines will be arranged in a number of groups for common start and stop. 7.2 Programming From the central control room the kiln department can be operated by selection of a number of programs and a number of direct functions. The programs installed in the control system will perform the start and stop procedures for the machines divided into groups. Further the operation is automatically supervised, checking constantly all interlockings for operation, protection and safety. The direct functions consist of opening and closing the dampers and speed control of motors.

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The following programs are proposed. (Please note that the groupings of machines may be carried out differently to the proposal, but the main ideas should be kept). The following programs are proposed: 1. Blending silo 2. Kiln feed 3. Filter fan 4. Dust transport 5. Bag House control 6. Kiln exhaust gas fan 7. Gas analyzers 8. Kiln auxiliaries 9. Kiln drive 10. Kiln barring 11. Kiln burner fans 12. Kiln burner 13. Calciner burner 14. Clinker transport system 15. Cooler excess air fan 16. Cooler drives 17. Cooler fans 19. Scanners and cameras The following equipment can be operated individually: Fan dampers Changeover gates and dividing gates Position of valves - oil valves and feed valves Motors with speed regulation, such as kiln drive and grate drives. 7.3 Comments to Programs

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For the details of the programming reference is made to the separate documentation for the PLC system, however, in the following some important notes are pointed out in relation to each program. In general all bag filters should stop with a minimum delay of 15 minutes to empty the system. 1. Blending Silo Machines: Blending silo extraction system Blower for aeration Gate Filter Conditions to be fulfilled before start: The filter, the blowers and the silo sequence can be started at any time.

extraction

Conditions to be fulfilled in order to produce: No conditions. The extraction sequence will be stopped whenever the kiln feed hopper reaches maximum level. 2. Kiln feed Machines: Air slide Dosing valve Bottom Gate, dividing gate Blower for aeration of feed bin Bucket Elevator Bag filter

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Sampler Conditions to be fulfilled before start: Filter on top of the homogenizing silo is in operation. The dividing gates are in the correct position directing the kiln feed or in recirculation mode back to the Inverted cone-homogenizing silo. Conditions to be fulfilled in order to produce: Same as for start: However, once the program is running, the operator can change the gates so the raw meal is transported towards the kiln and Calciner - becoming kiln feed - provided the exhaust gas fan are operational. If the feed stops (program 2) for more than 30 seconds, then the exhaust gas fan must be stopped to prevent overheating of the preheater. This interlock can be bypassed during heating up before feeding the kiln. 3. Bag Filter fan Machines: Filter fan with damper Conditions to be fulfilled before start: Damper to be closed, and filter inlet temperature lower than the maximum allowed. Dust transport operational. Conditions to be fulfilled in order to produce: Filter inlet temperature below the maximum allowed for the filter. Once program 4 is in operation a certain allowed stop

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time of program 5 can be allowed before the filter fan program 3 will have to be stopped. 4.Dust transport Selection of which way to send the dust: 1. dust to Blending silo 2. dust to kiln feed Machines: Screw conveyor Air slide Bucket Elevator Filter Gate Conditions to be fulfilled before start: For all possible selections, the subsequent transport equipment must be in operation and the silo level must not have maximum level alarm. Conditions to be fulfilled in order to produce: Same as for start. NOTE, delayed stop for emptying. 5.

Bag filter control

Machines: Filter fan Damper

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Conditions to be fulfilled before start: Damper to be closed. Conditions to be fulfilled in order to produce. None. 6.

Kiln exhaust gas fan

Machines: Fan Damper Conditions to be fulfilled before start: Bag filter fan in operation. Preheater outlet temperature lower than MAX I. Damper to be closed Conditions to be fulfilled in order to produce: Bag filter fan in operation. Preheater outlet temperature lower than MAX II. The kiln feed - program 2 - has not been stopped for more than 30 sec. after having run simultaneously with the kiln exhaust fan. 7.

Gas analyzers

Machines: Analyzer Pump Conditions to be fulfilled before start: availability of compressed air and cooling water.

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Conditions to be fulfilled in order to produce: Same as for start.

8.

Kiln Auxiliaries

Machines: Grease pump Thrust device Spray lubrication Cooling fan Outlet seal fan Conditions to be fulfilled before start: None. Conditions to be fulfilled in order to produce: None. 9.

Kiln Drive

Machines: Main drive with oil pumps Conditions to be fulfilled before start: Barring disconnected. No alarm for kiln position. Cooler grate in operation. Cooler fans in operation. (These interlockings can be bypassed during kiln startup). Conditions to be fulfilled in order to produce:

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Barring disconnected. No MAX II alarm for kiln position. Cooler grate in operation or not stopped for more than 3 minute. Cooler fans in operation. 10.

Barring

Machines: Barring drive Conditions to be fulfilled before start: Main kiln drive stopped. Conditions to be fulfilled in order to produce: Main kiln drive stopped.

11. Kiln burner fans Machines: Primary air fan Emergency air fan Conditions to be fulfilled before start: None Conditions to be fulfilled in order to produce: Once the kiln burner - program 12 - has been put into operation, then the emergency fan must start automatically when the primary air fan stops. 12.

Kiln burner

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Machines: Oil/Coal supply: Pump Station Conditions to be fulfilled before start: bag filter fan - program 3 - is in operation. Kiln exhaust fan - program 6 - are in operation, during heating up of the kiln a special interlock permission can be given, that a start-up of the burner without fans in operation is allowed, however, when the fan have been started this special interlocking is automatically cancelled. Primary air fan in operation - program 11 -. Conditions to be fulfilled in order to produce: Same as for start up. 13.

Calciner Burner

Machines: Oil/coal supply: Pump Station Conditions to be fulfilled before start: Kiln burner in operation - program 12 Kiln fan in operation - program 6 Calciner outlet temperature must be above minimum level and below MAX II level. Kiln feed is on - program 2

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Conditions to be fulfilled in order to produce: Same as for start, however, if the Calciner temperature rises above MAX II or the CO level after the preheater has been above MAX II (0.9%) for more than 10 seconds, then the fuel rate is reduced to minimum level. 14.

Clinker transport system

Selection to clinker silo De-dusting of clinker transport and dust transport Machines: Deep pan conveyor Hammer Crusher Air sluices below ESP Screw conveyor Conditions to be fulfilled before start: Clinker storage area must not be full. Conditions to be fulfilled in order to produce: Same as for start.

15. Cooler Excess Air Fan Machines: Fan Damper Conditions to be fulfilled before start: Clinker transport group and cooler dust should run

transport

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Conditions to be fulfilled in order to produce: Same as for start. 16.

Cooler dedusting unit

Machines: ESP Charging Conditions to be fulfilled before start: Clinker transport group and cooler dust should run ESP fan in operation.

transport

Conditions to be fulfilled in order to produce: Same as for start. 17. Cooler drives (Please also refer to cooler instruction manual) 18.

Cooler Fans

(Please also refer to cooler instruction manual) 19.

Scanners and cameras

Television cameras, monitors and kiln shell scanner can be operated separately.

7.3 Control Loops The following control Loops are foreseen.

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1. The kiln feed is synchronized with the kiln speed. 2. The Bag-filter fan speed controls measured just after the exhaust gas fan.

the

pressure

3. The temperature in the top of the lower most cyclone controls the fuel supply to the Calciner burner. 4. The pressure in the kiln firing hood is maintained by the speed of the cooler excess air fan. 5. The operator can select between the modes of cross bar control 6. For all cooler fans the measured air flow will be controlled by the Fan speed. 7.4

Cause/effect diagram

In section 10. cause and effect diagrams are shown. All instrumentation related to process parameters are listed. The handling and the use of these signals are presented. 8. PREVENTION OF FIRES AND EXPLOSIONS 8.1 General Precautions On no account must, soot non-combustible, unburned exit gases be allowed to accumulate in the kiln, the cyclones, the flue ducts etc., since this would involve a serious risk of explosion or fire. Therefore strict adherence to the following rules is

Page 55 of 68


needed: 1) In connection with renewed light-up of the kiln, following a temporary shutdown, it must be firmly established that the kiln heat (material surface temperature) is sufficient to ignite the fuel. If the kiln is too cold, the kiln must be lit in the normal manner, using the light-up equipment, and, if necessary, the light-up nozzle, under procedure similar to that applied during normal heat-up phase prior to start-up. 2) Always ensure that the burner is not operating with an air deficiency. 3) Inject the fuel at sufficient primary air velocity, i.e. with a nozzle velocity for the primary air of about 180-200 m/s. 4) Never increase the fuel supply rate too suddenly or excessively at any one time. In any case, the draught must always be increased first, and the upward adjustment of the fuel supply must take place evenly and slowly.

8.2 Precautionary measures relating to the burners In the following the interlockings for the burners and the gas analyzers are summarised. The main purpose of the interlockings is to reduce the risk of any fire or explosion. Whenever working with fuels, these risks are present. Although measures are taken to prevent the dangers, the operator should always observe and act

Page 56 of 68


carefully when working with fuels and firing equipment. It is therefore an important interlocking, burner can only operate, if at least one of analyzers after the preheater is in operation any unit alarms or without analyzer fault on channel.

that a the gas without the CO

Further it is conditional for the calciner burner operation that the CO level has not been over MAX II (0.9% CO) for more than a few seconds (less than 10 seconds). In this case the fuel rate must be reduced to minimum automatically. If the CO level is above MAX I (0.5% CO) or MAX II (0.9% CO), then the operator must take actions to reduce this immediately. Depending on the circumstances these actions could be either to reduce fuel rate or increase draught.

PROCEDURE FOR GAS ANALYZER TEST MODE The analyzer has a digital input for permission to test mode. This input must be set before any local test can be performed. The test permission is selected by the operator in the central control room and is automatically deselected whenever the analyzer is put into test mode, or if not, is deselected after 10 minutes by a timer. The test permission for analyzers must be separated in three test permissions, one for each analyzer. The test

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mode must always be clearly indicated to the operator. For further safety, test permission possible for one analyzer at a time. 8.3

should

only

be

Fuels

For precautionary measures to be taken when using fuel oil, see separate instruction manual. Reference is also made to the regulations of the local authorities.

9 BARRING 9.1 General Instructions If the kiln is stopped while hot, barring of the kiln is required to avoid kiln shell deformation. Normally, barring should always be restricted to an absolute minimum to prevent damage to the lining. The hydraulic thrust device and the spray lubrication system of the kiln drive must be in operation while barring operation is being performed. The following guidelines apply to a situation where the kiln is stopped in a hot condition and is to be barred: 1) As long as the kiln is hot, the barring operation must not be stopped for more than 10 minutes. 2) If the axial position of the kiln should cause the

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alarm to be tripped, then barring must be continued until the correct position has been reestablished. 3) If the kiln shell is exposed to strong external cooling, for example due to heavy rainfall, then continuous barring is required. 9.2 Barring programmes The barring programmes are divided into stages of 100 deg. rotation. This is done to ensure variations in the position of the kiln during standstill.

9.2.1 Barring during initial start-up. 0 24 64

- 24 hours: - 64 hours: - 72 hours:

drying

of

the

lining

before

About 100 degrees every 30 minutes About 100 degrees every 15 minutes Continuous barring.

Keep a close check on the longitudinal expansion of the kiln and its position on the supporting rollers during the entire period. See separate instruction manual for thrust device. 9.2.2 Barring during normal start of cold-state kiln 0 - 8 hours: About 100 degrees every 30 minutes 8 - 16 hours: About 100 degrees every 15 minutes 16 - 24 hours: Continuous barring. Keep a close check on the longitudinal expansion of the

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kiln and its position on the supporting rollers during the entire period. See separate instruction manual for thrust device. 9.2.3 Barring during stoppage and shutdown of the kiln 0 - 1 hour : About 100 1 - 24 hours: About 100 24 - 48 hours: About 100 48 hours: Barring conditions mentioned in necessary.

degrees every 10 minutes degrees every 15 minutes degrees every 30 minutes as required, if some of the subsection 9.1 makes it

During the final period the kiln must be barred for a few minutes, if the axial migration of the kiln exceeds the maximum value for normal kiln operation. This barring operation is required to prevent damaging or possibly rupturing of the thrust roller shaft during the kiln tube contraction which still may take place up to the 72nd hour. Proper graphite lubrication of the supporting roller surfaces must be ensured. The graphite blocks must rest loosely in their holders so that the pressure against the supporting roller surfaces is not hampered. To protect the surfaces of the supporting rollers and live-rings against damage as the live-ring slides over the supporting rollers during the axial movement of the kiln, it is essential that the mentioned dry matter lubrication is in order.

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Refractory Dryout Schedule 900 800 700 C .

g

600 e

D

Bottom Cyclon

500 e r

u a r 300 e p 200 m e T 400 t

Top Cyclone

100 0

1

5

9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 Hours

24 hr. Preheat Schedule 900 800 700 C .

g

600 e Bottom Cyclon

500 400 300 Top Cyclone

200 100

D e r u t a r e p m e T

0

1

2

3

5

6

7

9 10 11 12 14 15 16 18 19 20 22 23 25 Hours

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9.3

Braking

If the barring operation is stopped, the kiln is automatically braked and maintained in an arbitrary position. Therefore, the kiln may be side heavy; this fact must be taken into account when the brake is slackened. Reference is also made to the instruction manual for the barring device.

10 CAUSE/EFFECT ALARM LIMITS.

DIAGRAMS,

OPERATING

PARAMETERS

AND

The following tables are a survey of the expected normal operating parameters and the normal alarm limits. The operating parameters stated are for guidance only and apply to the normal, stable operating situation. The operating limits stated are meant as guidance for start-up. It will be possible to adjust many of these with advantage later on in order to make them more suitable for the actual operation. Concerning many of the alarm limits they too will have to be adjusted according to local conditions as factors like the lubrication oil selected, the ambient temperature, etc., will affect the values. The mechanical and/or the electrical departments must, in every single case, approve the change and fixing of the alarm limits for protection of the machines.

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Normally, the alarm limits for the operating parameters will be the responsibility of the production management. SEE ALSO INSTRUMENTATION INSTRUCTION MANUAL AS WELL AS FLOWSHEET FOR CODES AND INSTRUMENTATION. The following process instrumentation/indications are required: Notes used in the instrument and alarm table: a: Refer to mechanical and electrical documentation for the equipment. b: To be set empirically at a level not activating the alarm under normal operating conditions. x: To be evaluated during commissioning. Kiln feed

Raw meal feed kW of elevator

Uni t

Ran ge

Exp . Val ue

t/h

0307

256

kW

a

Uni t

Ran ge

Min . 2

Min . 1

Max . 1

Max . 2

Comme nts

Min . 2

Min . 1

Max . 1

Max . 2

Comme nts

Preheater Exp . Val ue

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Temperatu re of gases in the down comer duct Pressure in the down comer duct Temperatu re of gases in the duct after the 1st cyclone Temperatu re of material from 1st cyclone Pressure in the duct after the 1st cyclone Pressure in bottom of 1st cyclone

Uni t

Ran ge

Exp . Val ue

°C

0600

332

mmw g

700 to 0

446

°C

0600

334

°C

0600

329

mmw g

700 to 0

420

mmw g

700 to 0

420

Min . 2

Min . 1

Max . 1

Max . 2

380

450

380

450

Comme nts

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Temperatu re of gases in top of 2nd cyclone Temperatu re of material from 2nd cyclone Pressure in the duct after the 2nd cyclone Pressure in bottom of 2nd cyclone Temperatu re of gases in top of 3rd cyclone Temperatu re of material from 3rd cyclone Pressure in top of 3rd cyclone

Uni t

Ran ge

Exp . Val ue

°C

0600

527

°C

0600

522

mmw g

600 to 0

340

mmw g

600 to 0

340

°C

0100 0

690

°C

0100 0

685

mmw g

600 to 0

295

Min . 2

Min . 1

Max . 1

Max . 2

Comme nts

150

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Pressure in bottom of 3rd cyclone Temperatu re of gases in top of 4th cyclone Temperatu re of material from 4th cyclone Pressure in top of 4th cyclone Pressure in bottom of 4th cyclone Temperatu re of gases in top of 5th cyclone Temperatu re of material from 5th cyclone Pressure in top of 5th cyclone

Uni t

Ran ge

Exp . Val ue

Min . 2

mmw g

600 to 0

295

120

°C

0100 0

821

°C

0100 0

811

mmw g

400 to 0

250

mmw g

400 to 0

250

°C

0120 0

890

°C

0120 0

870

mmw g

400 to 0

200

Min . 1

Max . 1

Max . 2

750

920

980

Comme nts

80

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Uni t

Ran ge

Exp . Val ue

Min . 2

Pressure in bottom of 5th cyclone Position of divider gate after 4th cyclone O2 out of 5th cyclone CO out of 5th cyclone.

mmw g

400 to 0

200

60

%

0100

%

010

3.0

ppm

0

O2 out of cyclone preheater CO out of cyclone preheater

%

0 to 200 00 010

ppm

0 to 200 00

0

Uni t

Ran ge

Exp . Val ue

°C

0120 0

950

Min . 1

Max . 1

Max . 2

Max. 1 5000

Max. 2 9000

Max. 3 1200 0

Max .1 500 0

Max . 2 900 0

Max . 3 120 00

Min . 1

Max . 1

Max . 2

Comme nts

3.9

Calciner

Temperatu re of tertiary air

Min . 2

Comme nts

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Temperatu re in the reduction zone Temperatu re in exit of calciner Pressure in tertiary air duct Position of hoisting damper Coal flow to calciner burner

Uni t

Ran ge

Exp . Val ue

Min . 2

Min . 1

°C

0120 0

°C

0120 0

895

750

820

mmw g

200 to 0

100

%

0100

t/h

2.0 -20

1.4 14. 7

Uni t

Ran ge

Exp . Val ue

Min . 2

Min . 1

rpm

0-5

3.6

mm

-30 +30

Max . 1

Max . 2

Comme nts

Max . 1

Max . 2

Comme nts

Kiln

Kiln torque Kiln speed Axial movement of the kiln

Amp

a

a

Page 68 of 68


Uni t

Ran ge

Exp . Val ue

Pressure in kiln inlet

mmw g

-30

Temperatu re in kiln inlet O2 in kiln inlet CO in kiln inlet

°C

100 to 0 0 to 120 0

%

010

4.2

ppm

0200 00

0

NOx kiln inlet

ppm

0200 0

Uni t

Ran ge

Exp . Val ue

Coal feed to kiln

t/h

1.0 10. 8

Primary air fan speed Power for primary air fan Primary air pressure

%

1.3 13. 5 0100

in

Min . 2

Min . 1

Max . 1

Max . 2

Max .1 500 0

Max . 2 900 0

Max . 3 120 00

Min . 1

Max . 1

Max . 2

Comme nts

108 0

1

Kiln Burner

kW

a

mmw g

a

Min . 2

Comme nts

Page 69 of 68

ILC Kiln Manual Ed1

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