because “polar compounds in the gas will reduce the equilibrium capacity” (ZEOCHEM 2007‐2008). A resulting LES of 2 m is required for the bed.
This length is not acceptable because there are many assumptions associated with it, especially that, “local equilibrium between the fluid and the adsorbent is achieved instantaneously, resulting in a shock like wave, called a stoichiometric front , that moves as a sharp concentration front through the bed” (Henley 2006). This type of wave is shown in Figure 5.1a. In a real fixed bed adsorber this will not occur and there would be a mass transfer zone (MTZ) and a length of unused bed (LUB) with a concentration front like that in Figure 5.1b. This 2 m length is an initial guess in modelling a breakthrough curve that will be used in determining a true bed length.
A breakthrough curve is a relationship between the ratio of the product and feed water concentrations, (c/cF) versus time. Using this curve the time that corresponds to a c/cF of 0.068 (max ratio giving 99.5% v/v ethanol) can be found. A theoretical breakthrough curve for the system was approximated by Klinkenberg’s equation:
1 erf √ √
(5.3)
Where,
(5.4)
And,
(5.5)
around 20 minutes was achieved. The resulting height of 3.5 m was chosen, giving an adsorption time of around 24 minutes. The resulting breakthrough curves are shown in Figure 5.2
1.2 1 0.8 0.6
2 meter bed
F
c / c
3 meter bed 0.4
3.5 meter bed
0.2 0 0
10
20
30
Time (min)
40
50
properties can be found in Table 5.1. A visual of an adsorption column can be seen in Figure 5.3.
Figure 5.3 Visual of one adsorption column
5.5
Molecular Sieve
The adsorbent used within the two identical towers is a type 3A molecular sieve zeolite. This is the most commonly used adsorbent in the application of dehydrating ethanol. This molecular sieve, “is the potassium form of the A‐type structure; and has an effective pore opening of 3 Angstrom (0.32 nm)” (ZEOCHEM 2007‐2008). In Type A structured zeolite, “the tetrahedral are grouped to form a truncated octahedron with a silica alumina tetrahedron at each point” (ZEOCHEM 2007‐2008). A visual of this can be seen in Figure 5.4. The structure is represented by the chemical formula:
0.45 K2O ∙ 0.55 Na2O ∙ Al2O3 ∙ 2 SiO2 ∙ XH2O
(ZEOCHEM 2007‐2008).
For the design calculations, values given by ZEOCHEM for their ZEOCHEM® Z3‐03 were used. These values can be seen in Table 5.2. ZEOCHEM is large manufacturer of commercially used adsorbents and, “supplies around 80% of the world market for
itself” (Henley 2006). These forces are commonly referred to as van der Waals interactions.
Figure 5.4 Visual of alumino of alumino sillicate
The physical adsorption of just just water is directly related to the effective pore size of the of the molecular sieve. This adsorbent will absorb any molecule with a diameter less then 0.32 nm and exclude those that are larger. A water molecule has a diameter of 2.8 of 2.8 Angstrom and is effectively adsorbed onto the molecular, whereas ethanol has a diameter of 4.4 of 4.4
5.5
Valves and Piping
The valves chosen for our design were pneumatic butterfly valves. The rationale for choosing butterfly valves was that they are “one of the of the most successful high‐ performance valves” (Dickenson 1999). Dickenson also mentions that these valves are ideal for smaller units, which reduces cost, weight and space requirements, and that they have few parts, creating easy maintenance, installation, and operation. operation. They were also found to have a high rating for both liquid and gas services, on/off switching, on/off switching, throttling, flow control, and quick opening. The purpose of having of having them pneumatically operated is so that a control board operator can easily monitor and manipulate the position that the valve is in. The piping being used in this design is once again carbon
steel with a inner diameter of approximately of approximately 6 inch and a thickness of inch. This was determined using Perry’s Handbook.
Table 5.3 Ethanol dehydration equipment Equipment
Heat Exchangers
Vacuum Pump
Adsorption Tower
Type
Equipment Name
Size
U‐Tube
E‐112
1.96 m2
Bayonet (Heating)
E‐122
15.2 m2
Bayonet (Cooling)
E‐132
10.0 m2
Liquid Ring
G‐113
21.7 kW
D‐110
Diameter: 0.55 m
D‐120
Height: 4.5 m
Tower 1 or 2
*Sample calculations can be seen in Appendix D
Chapter 6.0: Economics
6.1
Introduction
Once sized, the prices of each piece of equipment were then estimated using the program EconExpert (EconExpert 2008), which has a built‐in equipment economics calculator. The calculator uses prices and correlations from the mentioned textbook by Ulrich and Vasudevan. These prices were then scaled up using the appropriate cost
break the azeotrope of ethanol at 95%v/v in a distillation column versus using PSA.
6.2
Equipment Costs
As mentioned earlier, the costs for the equipment were calculated using methods presented by Ulrich and Vasudevan in the program EconExpert. To scale up these prices, a Chemical Engineering Plant Cost Index of 528.2, retrieved from the Chemical Engineering Journals, was used. The scaled up costs of each individual piece of equipment is summarized in Table 6.1. The total grass roosts capital was calculated to be approximately $370,000. This cost breaks down into a total module cost and an auxiliary facilities cost. Within the total module cost, it includes sub sections including bare module costs as well as contingency and fee costs. The bare module costs take into account freight, taxes, insurance, construction overhead, and engineering
TABLE 6.1 Summary of equipment economics
Equipment
Heat Exchangers
Vacuum Pump
Type
Bare Module Cost
U‐Tube
$11,000
Bayonet (Heating)
$33,000
Bayonet (Cooling)
$27,800
Liquid Ring
$49,500
Tower 1
$59,500
Tower 2
$59,500
Total Bare Module Cost
$240,000
Contingency(15%) and Fee(3%)
$43,300
Adsorption Tower
6.3
Molecular sieve costs
The molecular sieve needs to be replaced approximately every 4000 cycles, which works out to be about approximately every 3 months resulting in three bed changes per year. The cost of the sieve is approximately $9 per kilogram. With each column having 600kg in it, a cost per replacement is equal to $10,800 with a total cost of $32,400 per year.
6.4
Alternative Economic Comparison
To determine the cost of energy required in azeotropic distillation, the steam flow rate within the system needed to be determined. A paper on saline extractive distillation was first used to find the energy requirement to be approximately 5 MJ for breaking the azeotrope. Comparing this value with the energy requirement for the proposed design,
Table 6.2 Summary of alternative comparison
Pressure Swing Adsorption
Azeotropic Distillation
40
40
Pressure, P, (kPa)
250
250
Price of Fuel, CS,f, ($/GJ)
4.75
4.75
Plant Cost Index
528.2
528.2
Utility Price ($/kg)
0.0173
0.0173
Operating Time Per Year (s)
3.02E+07
3.02E+07
Steam Flow Rate (kg/s)
4.2
12.6
Annual Energy Cost
$2,200,000
$6,610,000
Aux. Boiler Steam Capacity,
s, (kg/s)
Chapter 7.0: Safety Analysis
7.1
Introduction
Another important aspect of any design project is the evaluation of its safety. For this project, it was specified that a safety analysis, including a hazard and operability (HAZOP) analysis and a DOW Fire and Explosion Index analysis be performed on one piece of equipment. The safety analysis was performed on one of the columns as it has the most potential for problematic occurrences. The chemical properties of the system
7.2
Chemical Properties 7.2.1
Ethanol
MSDS sheets were found for solutions of 95% v/v ethanol, 5% v/v water and for 100% ethanol as these are the minimum and maximum concentrations of ethanol found in our system. From these MSDS sheets it was found that the values for both concentrations are equivalent. The threshold limit value of pure ethanol was found to be 1000ppm. Although ethanol is a non‐reactive substance, it is very explosive and flammable with the lower and upper flammable limits for both solutions being 3.3 % and 19% respectively. It also has a very low flash point of 17.78 C or 64 F. On the ˚
˚
basis of a four hour exposure time, the acute oral toxicity (LD50) of ethanol was found to be 3450
39000
mg m3
mg kg
and the acute toxicity of the vapour (LC50) of ethanol was found to be
. All of these values can be found in Appendix G. This classifies ethanol to be
7.2.2 Alumino Sillicate
An MSDS sheet was also found for the type 3A molecular sieve, which is alumino silicate and can be found in Appendix G. This is a very stable, non‐flammable substance and is only slightly hazardous in the case of inhalation. It is non‐toxic to humans with exception to the case of chronic exposure which can possibly result in damage to the lungs due to inhalation of dust formed by the molecular sieve. It can also be classified as a slight irritant to the skin as it can react with moisture to create heat. This is not a serious effect and can be easily removed with soap and water. The personal protective equipment that is recommended when directly handling alumino silicate are safety goggles, safety gloves, lab coat, and a dust respirator.
7.3
Hazard and Operability Analysis
The HazardReview Leader2008 software, created by ABS consulting, was used to conduct the identification portion of the HAZOP analysis. This software gives a list of possible deviations for specific pieces of equipment. For the tower in this design, it gave the following possible deviations; high temperature, low temperature, high pressure, low pressure and leaks (ABS Consulting 2008). The possible causes and possible consequences were then listed and analyzed and each deviation was then rated, based on the severity of the consequences and the likelihood of the deviation occurring. With this rating system, each deviation was given a value from 1 to 4 based on the severity of its consequences, with 1 being the least severe, causing a single first aid injury, and 4 being the most severe, causing multiple severe injuries. They were then given a value from 1 to 4 based on the likelihood of occurrences, with 1 signifying that it is not expected to occur ever, and 4 representing that it could potentially occur at least once a year. Multiplying both values together gave the overall rating for the
a leak, with ratings of 4 and 8, respectively. These two should therefore be given priority for preventative action.
High temperature on the column could be caused by either of the two proceeding heat exchangers not working properly. If this were to occur, the pressure inside the column would be increased, increasing the chances of condensation occur inside the column and damaging the molecular sieve. Damage to the molecular sieve has no safety related consequences itself, however, replacing the molecular sieve can be a potentially hazardous job as it requires direct exposure to the ethanol and the molecular sieve. If the temperature were to reach the auto‐combustion temperature of ethanol (363 C) an ˚
explosion could occur. Even though this is not expected to ever occur in the lifetime of the system, the extreme nature of the consequences makes this a very hazardous deviation. In order to prevent this, a high temperature alarm that will sound at 200 C ˚
control the vacuum pump to make certain the regeneration column is being depressurized adequately.
As seen in Figure F.1 flow rate transmitters have been placed on streams, 12, 18, 20 and 29 to control splitters 5 and 6. These controls were added to ensure that 40 % of the product be sent to the regenerating tower to aid in the regeneration process. These splitters are also controlled by a set of controls that measures the concentration of water in stream 25 leaving the regeneration tower. Once the concentration in this stream reaches zero, it is no longer necessary to purge the desorption tower with the product. At this point the splitters are changed to ensure that 100 % of the product is sent to the final heat exchanger for cooling.
The cooling water being fed into the third heat exchanger is regulated by temperature
In Figure F.1, it can also be seen that valves have been placed in the system so as to make the isolation of every piece of equipment possible. This is necessary to carry out maintenance, replacement of equipment, and for in the case of emergencies.
7.4
DOW Fire and Explosion Index Analysis
A Fire and Explosion Index analysis was completed on one of the towers. This concluded that this adsorption system had a fire and explosion index of 95.5 which means that it is a moderate hazard. The radius of exposure was found to be approximately 80ft. The total value of equipment for this system is about $400,000, however, because the value of the rest of the facility is unknown, an extra $10,000,000 has been added to the value of area of exposure to account fort the rest of the facility. This gives a base and actual maximum property damage (MPPD) of $6,000,000 and $4,360,000 respectively. The MPDO and Business Interruption Loss were found to be
present to bring forward any safety concerns they may have. Scheduled preventative maintenance and scheduled shutdowns will also be carried out as seen necessary.
The training for new employees will have a very safety oriented outlook, with job shadowing, operating manuals and videos, and the completion of certain safety courses. It is recommended that all employees complete the WHMIS, basic fire extinguishing, confined space, and first aid courses before starting work with this process.
Chapter 8.0: Conclusions
After conducting extensive research, performing calculations, and testing simulations, Halo Consulting has determined that pressure swing adsorption is the best solution for dehydrating a feed of 95%v/v ethanol to a final product of 99.5%v/v ethanol. The design would consist of three heat exchanges, one liquid ring vacuum pump, and two identical adsorption towers filled with a Type 3A molecular sieve.
The areas of the three heat exchangers used in this process were calculated to be 1.96, 15.2, and 10.0 m2. The vacuum pump was sized to be 21.7 kW.
After an economic comparison, it was established that the annual cost of energy required for azeotropic distillation was approximately three times that of pressure swing adsorption, being approximately $6.6 MM and $2.2 MM respectively. The total module cost and the overall grass roots capital for the pressure swing adsorption design were calculated to be approximately $284,000 and $369,000, respectively.
Finally, after completing
analysis for both
and Dow’s
and Explosion Index
Chapter 9.0: Recommendations After completing this design process, the following recommendations have been suggested.
1. Gathering of experimental data at these conditions to observe the actual decline in adsorption rates over time is strongly recommended. This data would be used to perform a scale up operation of the design.
2. It is recommended that a simulation package with adsorption processes to
References Aliasso, Joe. How to Size Liquid Ring Vacuum Pumps. Pumps and Systems Magazine. 2003, 1‐3.
Africa, Michael; Kendrick, Robert; Scramlin, Jeff; Catalano, Sam; Messacar, Julie; Palazzolo, Joseph. Chemical Engineering Equipment. Macromedia, Inc. 1996.
Basmadjian, Diran. The Little Adsorption Book: A Practical Guide for Engineers & Scientists. CRC Press, Inc: 1997.
Change, Hua; Yuan, Xi‐Gang; Tian, Hua; Zeng, Ai‐Wu. Experiment and prediction of breakthrough curves for packed bed adsorption of water vapour on cornmeal. Elsevier B.V. 2006, 1‐8.
HazardReview Leader 2006 Software. ABS Consulting. January 2008 – April 2008.
.
Henley, Ernest J.; Seader, J. D. Separation Process Principles. 2nd Ed. . John Wiley & Sons: New York, 2006.
Kirk, Othmer. Concise Encyclopedia of Chemical Technology . 4th Ed. John Wiley & Sons: New York, 1999.
March Consulting Associates Inc. Homepage. March Consulting Associates Inc.
September 2007 – April 2008. http://www.marchconsulting.com.
Nevers. Noel De. Fluid Mechanics for Chemical Engineers . 3rd Ed. McGraw – Hill: New York, 2005.
Ruthven, Douglas M.; Farooq, Shamsuzzaman; Knaebel, Kent S. Pressure Swing Adsorption. VCH Publishers, Inc, 1994.
Suzuki, Motoyuki. Adsorption Engineering. Kodansha Ltd, 1990.
Tien, Chi. Adsorption Calculations and Modeling. Butterworth‐Heinemann, 1994.
Ulrich, Gael D.; Vasudevan, Palligarnai. Chemical Engineering: Process Design and nd
Economics: A Practical Guide. 2
Ed. Process Publishing: Durham, New
Hampshire, 2004.
ZEOCHEM Homepage. Zeochem. September 2007 – April 2008.
.
Appendix A: Process Flow Diagrams
Figure A .1: Process Flow Diagram mimicking the dehydration system in HYSYS when bed 2 (BAL‐2) is in regeneration
63
Figure A .2: Process flow diagram mimicking the dehydration system in HYSYS when bed 2 is done regenerating
64
Appendix B: Mass Balances
Table B.1 Mass balance for adsorbing column (Bed 1) time span for balance Streams
0.106
h Flowrate (kgmole/h)
Mole Fraction
Amount (kgmole)
Water
Ethanol
Feed
Water
Ethanol
Feed
Water
Ethanol
IN
0.14
0.86
41.86
6.04
35.81
4.42
0.64
3.78
OUT
0.02
0.98
36.39
0.58
35.81
3.84
0.06
3.78
1
0
5.47
5.47
0.00
0.58
0.58
0.00
0.293
h
ACCUMULATED (adsorption rate) time span for balance Streams
Flowrate (kgmole/h)
Mole Fraction
Amount (kgmole)
Water
Ethanol
Product
Water
Ethanol
Feed
Water
Ethanol
IN
0.14
0.86
25.11
3.63
21.48
7.37
1.06
6.30
OUT
0.02
0.98
21.84
0.35
21.48
6.41
0.10
6.30
ACCUMULATED (adsorption rate)
1.00
0.00
3.27
3.28
0.00
0.96
0.96
0.00
time span for balance
0.399
h Amount (kgmole)
=
23.94
Total
Water
Ethanol
IN
11.79
1.70
10.08
OUT
10.25
0.16
10.08
ACCUMULATED (adsorption rate)
1.54
1.54
0.00
Stream
Adsorption Time
67
Table B.2 Mass balance for desorbing column (Bed 2) time
0.11 Streams
h Flowrate (kgmole/h)
Mole Fraction
Amount (kgmole)
Water
Ethanol
Feed
Water
Ethanol
Feed
Water
Ethanol
IN
0.02
0.98
14.56
0.23
14.33
1.54
0.02
1.51
GENERATED (desorption rate)
1.00
0.00
14.58
14.58
0.00
1.54
1.54
0.00
OUT
0.51
0.49
29.14
14.81
14.33
3.08
1.56
1.51
Amount (kgmole)
Stream IN OUT GENERATED (desorption rate)
Total
Water
Ethanol
1.5366284 3.076000272 1.54
0.024366 1.563738 1.54
1.512262083 1.512262083 0.00
68
Table B.3 Mass leaving system Flowrate (kgmole/h)
Mole Fraction
Amount (kgmole)
Time (hours)
Water
Ethanol
Product
Water
Ethanol
Product
Water
Ethanol
0.11 0.29
0.02 0.02
0.98 0.98
21.84 21.84
0.35 0.35
21.49 21.49
2.31 6.41
0.04 0.10
2.27 6.31
Total
8.71
0.14
8.58
Table B.4 Overall system mass balance Substance (kgmole)
Stream Water
Ethanol
Total
IN (feed) OUT (Product) ‐ OUT (By‐Product)
1.70 0.138 1.56
10.08 8.58 1.51
11.79 8.71 3.08
=
0.00
0.00
0.00
‐
69
Appendix C: Adsorption Data
Figure C.1 Isothermal data for water adsorption on a type 3A molecular sieve
71
1.4
1.2 e v e i s 1 r a l u c e l o m f 0.8 o . t w % n 0.6 i g n i d a o l r 0.4 e t a W
0.2
0 0
10
20
30
40
50
60
Vapor Pressure in kPa
Figure C.2 Water vapour isotherm at 120 C for type 3A molecular sieve ˚
72
3
2.5 q / p , g n i d a o l r e t a w d n a e r u s s e r p l a i t r a p f o o i t a r
y = 0.048x + 0.039 R² = 0.998
2
1.5
1
0.5
0 0
10
20
30
40
50
60
Partial Pressure, p (kPa)
Figure C.3 Graph for the determination of equilibrium constant using Langmuir's form
73
Table C.1 Table of given and calculated data for determining the breakthrough curve
MW mix, Mab Diffusion Volume ethanol, νa Diffusion Volume water, νb Diffusivity, Dab Effective Diffusivity, Deff Average molecular velocity, νi Knudsen diffusion, Dk Surface Diffusion, Ds
Value 25.90 51.17 13.1 1.03E‐01 1.03E‐05 1.08E‐02
Units g/mol
1.08E‐03
2
m /s
4.45E+02 4.75E‐10 4.75E‐14 9.40E‐05 9.40E‐09
cm2/s m2/s cm2/s m2/s
cm2/s m2/s cm2/s
Description 3‐37 Henley Table 3.1 Henley Table 3.1 Henley 3‐36 Henley 15‐75 Henley 14‐20 Henley 14‐19 Henley 15‐76 Henley
Reynolds Number, NRe
7.21E+02
Table 3.3 Henley
Schmidt Number, NSci
2.60E‐01
Table 3.3 Henley
Sherwood Number, Nsh
1.23E+01
15‐62 Henley
Mass Transfer Coefficient, kc
4.20E‐02 4.20E+00
m/s cm/s
15‐60 Henley
overall mass transfer coefficient, k
3.39E‐01
s1
15‐106 Henley
K
245
‐
See Isotherm Sheet
74
Appendix D: Sizing Calculations
Column Sizing: 1. Calculation of max velocity through column
. .. . 137 . 0.699 2. Calculation of the column diameter:
547. 3 0.699 3600 0.217
. . . .
1.92 2.00
Breakthrough Curve Calculation:
‐sub A is ethanol, sub B is water
1. Calculation of the molecular weight of the mixture:
2 12 1 46.07/ 25. 9 1 18.01/ 1
2.
Determination of the Diffusion volume of ethanol:
26 1
0.0888 4.
Calculation of the average molecular velocity:
/ / 8 8 8 . 3 14/ · 3 93. 1 5 42.02/ 445.1
5. Calculation of the Knudsen Diffusion Coefficient:
3 . 2 10 4 45. 1 / 3 3 4.7510 1.610 0.45 0. 45990 18.01
6. Calculation of the Surface Diffusivity:
8.
Calculation of the Schmidt Number:
8. 5 610 3.21 0.0888· 0.3 9. Calculation of the Sherwood Number:
20.60 20.607.21100.3 1.28 10. Calculation of the Mass Transfer Coefficient:
1 . 2 80. 0 888 0.003 3.78 11. Determination of breakthrough time:
1erf√ 2.50 √ 302 √ . √ 0.999 Solver for a c/cF = 0.068 for a 2 meter bed gave adsorption time of around 13.15 minutes. Length scaled up to 3.5 meters which gave adsorption of around 23.9 minutes.
Equipment Sizing: Heat Exchanger – First Bayonet (heating) 1. Calculation of sensible heat area: 1a. Calculation of heat capacity of mixed stream:
% % 4.174 ·0.06192.46 ·0.9381 2.57 ·
1b. Calculation of heat duty:
∆ 1759 2.57 · 96.685.0 52364.7
∆ ∆∆∆∆ .... 92.89
1d. Calculation of sensible heat area:
∆ 52365 1 900 ·· 92.89 0.174
2. Calculation of the phase change area:
2b. Calculation of heat duty:
1759 941.97 1657 2c. Calculation of log mean temperature:
∆ 457393 64 ∆
2d. Calculation of phase change area:
∆ 1656924 1900 ·· 3600 1000 80.1 14.61
3. Calculation of superheating area: 3a. Calculation of heat capacity of mixed stream:
% % 4.174 · 0.0619 2.46 · 0.9381 2.57 ·
3c. Calculation of log mean temperature:
∆ 457393 64 ∆ 456.6369.6 87
∆ ∆∆∆∆ 74.91
4. Calculation of total heat exchanger area:
0.174 14.61 0.435 15.22
Vacuum Pump 1. Calculation of the pump capacity:
2 15.92 3.2808 10 6060 324.72
2. Calculation of the shaft work:
Table D.1 U‐Tube heat exchanger calculated data for pre‐heating feed Value 2.57 50.00 225709.97
Units kJ/kmol*K K kJ/h
ΔT2
35.00 53.21
K K
ΔTLM
43.47
K
2.21
m2
Cp,mix Delta T Heat Duty (Q) ΔT1
A=
Tables D.2. Bayonet heat exchanger calculated data for feed vaporization Table D.2a Calculated data for sensible heating Value
Units
2.57 11.60 52364.71
kJ/kg*K K kJ/h
ΔT2
87.40 98.60
K K
ΔTLM
92.89
K
0.17
m
Cp,mix Delta T Heat Duty (Q) ΔT1
A=
2
Table D.2c Calculated data for superheating Value 2.57
Units kJ/kmol*K
23.40 105632.27
K kJ/h
ΔT2
64.00 87.00
K K
ΔTLM
74.91
K
0.44
m
Cp,mix Delta T Heat Duty (Q) ΔT1
A=
2
Tables D.3 Bayonet heat exchanger calculated data for product condensation Table D.3a Calculated Data for phase change Value
Units
-941.97 938390.02
kJ/kmol
ΔT2
65.89 20.00
K K
ΔTLM
38.49
K
λ,mix
Heat Duty (Q) ΔT1
kJ/h
Table D.4 Calculated Data for liquid ring vacuum pump Value 191.116 5.412 324.72
Units 3 ft /min 3 m /min 3 m /h
Shaft Work(ws)
21.733754
kW
Fluid Power
16.300315
kW
Size
Appendix E: Economics Calculations
Cost Summary
The cost index is 528.2 Heat Exchangers : Shell and Tube : Fixed tube sheet and U-tube Total purchased cost = $ 3461 Material factor = 1.00 Pressure factor = 1.00 The bare module cost is = $ 11006 Heat Exchangers : Shell and Tube : Bayonet Total purchased cost = $ 10391 Material factor = 1.00 Pressure factor = 1.00 The bare module cost is = $ 33044 Heat Exchangers : Shell and Tube : Bayonet Total purchased cost = $ 8733 Material factor = 1.00 Pressure factor = 1.00 The bare module cost is = $ 27772 Gas Movers and Compressors : Blowers and compressors (cost of drive excluded) : Liquid ring Total purchased cost = $ 22517 The bare module cost is = $ 49538 Process Vessels (including towers) : Vertically oriented : With adsorbents, ion-
Economics of an Azeotropic Distillation 1. Calculation of utility cost coefficient “a”:
2.310. . 2.310 40 8.3210 units?
2. Calculation of utility cost coefficient “b”:
3.410. . 3.410 2.5 3.5610 ?
3.0210 5. Calculation of the annual cost:
$ 0.01735 $ 3.0210 12.6 6,610,000
Appendix F: Piping and Instrumentation Diagram
Figure F.1 (1) Temperature controls to control HX #2; (2)Pressure controls for leak detection and to ensure feed is at a high enough pressure to prevent condensation inside the column; (3) Pressure controls for leak detection and to control vacuum pump; (4) Concentration transmitters to regulate the use of the purge stream; (5) Flow rate controls to control the splitters 5 and 6; (6) Concentration transmitters to ensure product quality; (7) Flow rate controls to control output rate; (8) Temperature controls to regulate the amount of cooling water to HX #3.
95
Appendix G: Material Safety Data Sheets
Appendix G: Material Safety Data Sheets
Halo Consulting
Pl ant:
Method: HAZOP
Unit: Tower #1
Site:
Type: Column
System : Dehydration of Ethanol
Design I ntent: Packed bed of aluminosilicate to be used to dehydrate Ethanol
eam Members: M rk Baier, Jamie Hiltz, Zack Taylor
No.: 2
To er (D-120)
Drawing: PID Item
2.1
Devi t i o n
High temperature
Causes
HX #1 not working properly HX #2 not working properly
Consequenc s
Cat
Increased pressure in column
S
1
L
3
R
3
Safeguards
Te mperature control on HX #
Action Items
Rec 2. Consi er putting temperat re control on H #1
Hi h temp alarm on col umn (at 200C)
2.2
Low temperature
HX #1 not working properly HX #2 not working properly
High enough(500C) amage to sieve
1
4
Auto-combustion of thanol = 363C
1
4
1
2
Possibility of condensation in column
2
Te mperature control on HX # Low temp alarm on the column (100C)
2.3
High pressure
High temperature from HX #1
Damage to molecular sieve
1
2
2
High temperature from HX #2
Pr ssure relief valve on column
High flow rom supply
Flow control on splitter (S5)
Block in pr ocess after column
2.4
Low pre sure
Pr ssure control on val e (V 2)
Low temp rature from HX #1
Hi h pressure alarm on stream entering colum Possibility of condensation in column
2
1
2
Reduced product
1
1
1
Low temp rature from HX #2
Pr ssure control on val e (V 2) Pr ssure relief valve on column
112
Rec 2. Consi er putting temperat re control on H #1
