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Process Evaluation and Design II – Spring 2016
Process Evaluation and Design II – Spring 2016
CHEG 407 – A
CASE 2: PROCESS...
2
Table of Contents
Executive Summary........................................................................................
3
EXECUTIVE SUMMARY
Production ethanol from sugarcane included of four process: milling, juice clarification,
fermentation...
4
product of ethanol solution. The figure below is present whole process of producing ethanol from
sugarcane at St. Mary S...
5
of juice. The 6400 US ton/day with 40% solid and 60% moisture of bagasse comes from the third
mill is combusted by boile...
6
Figure 4: Juice Clarification Process Flow Diagram
The 22,600 US ton/day of raw juice coming to setting tank is transpor...
7
Figure 6: Energy Balance of Juice Clarification Process
For three evaporator are used in this process, total heat duty e...
8
and conversion of invert sugars by yeast:
2𝐶6 𝐻12 𝑂6 → 4𝐶2 𝐻5 𝑂𝐻 + 4𝐶𝑂2
Following by these above equations, after 11,072...
9
then next will lead to distillation column. After eliminate carbon dioxide in the solution, 9000
US tons/day of ethanol ...
10
Most of the unit to calculate major equipment of the process is calculated by mass and energy
balance equations that ar...
11
Table 2: Total Equipment Cost for whole Process
The total equipment cost for whole process equals $20.7MM
PROCESS ECONO...
12
Utilities Consumption/day Cost $/unit Cost $/day Cost $/year
Water (gal) 24,285,377.26 0.005 121,426.89 18,214,032.94
E...
13
E. Cash Flow and
NPV Analysis
The sell price of ethanol is $2.03/gal with 71.5 MM gal/year of ethanol is produced, the ...
14
The NPV of this plant after 20 years is $60 MM. The payback period is 1 years; the profit being
earned on the second ye...
15
B. Hazard and Operability Study (HAZOP)
Table 8: Hazard and Operability Study (HAZOP)
16
Figure 13: Boston Square for Clean Juice of Evaporator
Figure 14: Boston Square for Reactor and Stripping Column
1, 2
3...
17
Figure 15: Boston Square for Cooling Water of Condenser
ENVIROMENT
This process produces ethanol, and also carbon dioxi...
18
gal/year of ethanol is produced, the revenue of this project is $145 MM/year. The payback period
of this project is one...
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An Minh Tran - Case 2 - Cheg 407A (1)

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An Minh Tran - Case 2 - Cheg 407A (1)

  1. 1. Process Evaluation and Design II – Spring 2016 Process Evaluation and Design II – Spring 2016 CHEG 407 – A CASE 2: PROCESS DESIGN FOR ETHANOL PRODUCTION FROM SUGARCANE Instructor: Dr. Jacob R. Borden Submitted by: An Minh Tran College of Engineering and Technology McNeese State University Date Submitted: May 6, 2016
  2. 2. 2 Table of Contents Executive Summary........................................................................................................................ 3 Introduction..................................................................................................................................... 3 Overall Process Description............................................................................................................ 3 Mass and Energy Balance…………………...........................…………………………………….4 A. Milling…………………..………………..…………………………………………….4 B. Juice Clarification………………………..…………………………………………….5 C. Fermentation…………………………………………………………………………...7 D. Ethanol Distillation………………………………………………………………….....8 Major Equipment List and Purchased Cost…………………………………………………….....9 Project Economics……………………………………………………………………………….11 A. Annual Depreciation………………………………………………………………….11 B. Variables Cost of Production…………………………………………………………11 C. Annual Labor, Maintenance, and Fixed Charges……………………………………..12 D. Variables cost per gallon ethanol production…………………………………………13 E. Cash Flow and NPV Analysis………………………………………………………...13 Safety Concerns………………………………………………………………………………….14 A. Over Process………………………………………………………………………….14 B. Hazard and Operability Study (HAZOP)……………………………..………………15 Environment…………………………………………..………………………………………….17 Conclusion and Recommendation ................................................................................................ 17
  3. 3. 3 EXECUTIVE SUMMARY Production ethanol from sugarcane included of four process: milling, juice clarification, fermentation, and ethanol distillation. In this report, a process design for the production of ethanol from sugarcane at St. Mary Sugar Coop plant in Jeanerette, Louisiana is introduced. With the basic is 20,000 US ton/day of raw sugarcane that is running in 150 days/year to produce 1569 US ton/day or 71.5 MM gal/year of ethanol, the mass and energy balance, cost of major equipment, cash flow and NPV analysis up to twenty years, and safety concern for whole of the process are presented in this report. With the price of ethanol is $2.03/gal, the total equipment cost is $21 MM, the revenue each year is $145 MM, tax is 34% net income, using 7% internal rate of return, the net present value at the end of year 20th is $60MM. INTRORUCTION Ethanol is one of the most important substances that is used in different area such as a solvent in producing perfumes, or making medicines and drugs. Moreover, ethanol is used as a fuel and gasoline additive. Louisiana is one of the main states in the US that produce many important substances from ethanol; and St. Mary Sugar Coop plant in Jeanerette, Louisiana is one of the biggest plant of producing ethanol from sugarcane. OVERALL PROCESS DESCRIPTION The basic of the process is 20,000 US ton/day of sugarcane that is operated in 150 days/years to produce ethanol. There are four main sections to produce ethanol from sugarcane. The first section is cane milling where sugar is leached out from the bagasse through milling sugarcane. The second section is juice clarification that is clarified juice is made from clean juice through multi evaporators. The third section is fermentation which ethanol solution is produced with 15% wt of ethanol, and the last section is ethanol distillation that produces 50% wt of ethanol in final
  4. 4. 4 product of ethanol solution. The figure below is present whole process of producing ethanol from sugarcane at St. Mary Sugar Coop plant in Jeanerette, Louisiana. Figure 1: Overall Process Flow Diagram of System MASS AND ENERGY BALANCE A. Milling Figure 2: Milling Process Flow Diagram In the milling process, 20,000 US ton/day of raw sugarcane is broken using knife mill and hammer mill, then the crushed cane are grinded using three set of roller mill. 9000 US ton/day of water is applied at the third roller mill and is transported to 2nd and the 1st mill for more extration
  5. 5. 5 of juice. The 6400 US ton/day with 40% solid and 60% moisture of bagasse comes from the third mill is combusted by boiler to generate steam and electricity. After the milling process, 22,600 US ton/day raw juice with 14.7% wt% sugar and 84% wt% water is produced and is transported to setting tank of juice clarification process. The figure 3 and figure 4 are present for mass balance and energy of the boiler of milling section. Figure 3: Mass Balance of Milling Process Table 1: Energy of Boiler For 6400 US ton/day with 40% solid and 60% moisture of bagasse, at P = 1 bar, the heat duty of boiler that need to combusted that amout of bagasses is Q = 121,287.32 kW. B. Juice Clarification P 1 bar m water 3483590.4 kg/day T in 20 C T sat 99.61 C delta H 2675 kJ/kg Cp 4.185 kJ/kg-K Q 121,287.32 kW
  6. 6. 6 Figure 4: Juice Clarification Process Flow Diagram The 22,600 US ton/day of raw juice coming to setting tank is transported to filter to eliminate mud; then that clean juice with 15% wt% sugar and 85% wt% water is going to multi evaporator with 12,439 US ton/day of steam to heat water and concentrated juice. In the concentrated juice, the percent weight of sugar is 30% and percent weight of water is 70%. It means this process is eliminated 11,289.6 US ton/day of water to make the juice to be more purity. It helps the reactions in the next section that produce ethanol solution is reacted easier. Figure 5 and figure 6 are shown in mass and energy balance of juice clarification process. Figure 5: Mass Balance of Juice Clarification Process
  7. 7. 7 Figure 6: Energy Balance of Juice Clarification Process For three evaporator are used in this process, total heat duty equals to 265,413 kW, and the heat transfer coefficient is assumed 4000 W/m2-K (from chemical book), the area for eat evaporator equals 250 m2. This number will be used to calculate the equipment cost for evaporator. C. Fermentation Figure 7: Fermentation Process Flow Diagram Fermentation process is process to produce ethanol composition based on these following equations: Inversion of sucrose by hydrolysis: 𝐶12 𝐻22 𝑂11 + 𝐻2 𝑂 → 2𝐶6 𝐻12 𝑂6
  8. 8. 8 and conversion of invert sugars by yeast: 2𝐶6 𝐻12 𝑂6 → 4𝐶2 𝐻5 𝑂𝐻 + 4𝐶𝑂2 Following by these above equations, after 11,072 US ton/day of concentrated juice with 30% wt% sugar coming out of reactor, the yeast of 11,072 US ton/day of yeast that 14% wt% ethanol is produced. Then, it is transported to centrifugal; and the ethanol solution with 15% wt% ethanol, 71% wt% water and 14% wt% CO2 is produced to lead to stripping column. Figure 8 is show in mass balance of fermentation process. Figure 8: Mass Balance of Fermentation Process D. Ethanol Distillation Figure 9: Ethanol Distillation Process Flow Diagram Ethanol distillation process is the last process of ethanol production from sugarcane process. Ethanol solution from previous process coming to stripping column to eliminate carbon dioxide;
  9. 9. 9 then next will lead to distillation column. After eliminate carbon dioxide in the solution, 9000 US tons/day of ethanol solution will have 17% wt% ethanol and the rest is water. And distillation process will increase the purity of ethanol to be 50% wt%, which means 1569 US ton or 71.5 MM gallons of ethanol is produced per day. Figure 10: Mass Balance of Ethanol Distillation Process Figure 11: Energy Balance of Ethanol Distillation Process Ethanol solution is cooled by cooling water of the condenser. The total heat duty of the condenser equals 157,986 kW, and with the heat transfer coefficient equals 3000 W/m2-K. The area of the condenser is 2178.3 m2. MAJOR EQUIPMENT LIST AND PURCHASED COST
  10. 10. 10 Most of the unit to calculate major equipment of the process is calculated by mass and energy balance equations that are shown above. And some of other units equipment that are used to calculate the cost of setting tank, filter, centrifuge, stripping column, and distillation column are shown in the figure 12 below. Figure 12: Cost Equipment Calculation Units Based on those units value above, and other units value that are calculate in mass and energy balance part, the total cost of major equipment is estimated following by table 1 below.
  11. 11. 11 Table 2: Total Equipment Cost for whole Process The total equipment cost for whole process equals $20.7MM PROCESS ECONOMICS A. Annual Depreciation Annual depreciation is calculated by straight-line depreciation with the salvage value of all equipment is estimated to be 15% of the equipment cost with the expected life of the equipment is 20 years. Total Equipment Cost $ 20,659,256.34 Salvage Value (15% Tot. Equip. Cost) $ 3,098,888.45 Depreciable Asset Cost $ 17,560,367.89 Depreciation Rate/Year (20 years) 5% Annual Depreciation $ 878,018.39 Table 3: Annual Depreciation Annual depreciation of the process equals $0.88MM B. Variables Cost of Production To calculate variables cost of production, the number of water comes from cooling water of condenser and steam for the boiler, and natural gas is used for the boiler to heat water the run the system. 101,335 US ton/day equals 24.3 MM gal/day of water is used.
  12. 12. 12 Utilities Consumption/day Cost $/unit Cost $/day Cost $/year Water (gal) 24,285,377.26 0.005 121,426.89 18,214,032.94 Electricity (kWh) 624,987.00 0.06 37,499.22 5,624,883.00 Natural - gas (MM BTU) 10,107.28 2.178 22,013.65 3,302,047.35 Raw Material Consumption/day Cost $/unit Cost $/day Cost $/year Sugarcane (US ton) 20,000 30 600,000 90,000,000.00 Total variable cost $/year $ 117,140,963.29 Table 4: Variable Cost of Production The total variable cost per year of the process is $118 MM. C. Annual Labor, Maintenance, and Fixed Charges The calculation for annual labor, maintenance, and fixed charged are shown in table below with the maintenance charged are 5% of the initial total equipment cost, and fixed charges excluding depreciation are 10% of the initial total equipment cost. Number of operators/shift 18 Operator salary $/h 20 Number of engineers 3 Engineer Salary/season 25000 Plant Manager 1 Manager salary/season 40000 Over head 100% labor cost Total labor cost $/year $ 3,512,000.00 Maintenance (5% Total equipment cost/year) $ 1,032,962.82 Fixed Charge ( 10% Total equipment cost/year) $ 2,065,925.63 Table 5: Annual Labor, Maintenance, and Fixed Charges D. Variables cost per gallon ethanol production From all the costs that are calculated above, with 1569 US tons/day or 71.5 MM gal/day of ethanol, the variables cost per gallon from ethanol production is shown in table below Table 6: Variable Cost per Gallon Ethanol Production $/year $/gal of Ethanol Utilities $ 27,140,963.29 $ 0.38 Raw Material $ 90,000,000.00 $ 1.26 Depreciation $ 878,018.39 $ 0.01 Labor $ 3,512,000.00 $ 0.05 Maintenance $ 1,032,962.82 $ 0.01
  13. 13. 13 E. Cash Flow and NPV Analysis The sell price of ethanol is $2.03/gal with 71.5 MM gal/year of ethanol is produced, the revenue of this project is $145 MM/year. Net Present Value (NPV) method is applied to assess the economic value of the project. A common Internal Rate of Return (IRR) of 7% is used for calculation. Tax is incorporated and equals 34% of the net income. The NPV of this plant is calculated in 20 years. Cost Revenue Tax Cash Flow NPV Total NPV to year 0 $ 20,659,256.34 $ (20,659,256.34) $ (20,659,256.34) $ (20,659,256.34) 1 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 12,574,506.14 $ (8,084,750.20) 2 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 10,688,330.22 $ 2,603,580.01 3 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 9,085,080.69 $ 11,688,660.70 4 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 7,722,318.58 $ 19,410,979.28 5 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 6,563,970.80 $ 25,974,950.08 6 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 5,579,375.18 $ 31,554,325.26 7 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 4,742,468.90 $ 36,296,794.16 8 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 4,031,098.56 $ 40,327,892.72 9 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 3,426,433.78 $ 43,754,326.50 10 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 2,912,468.71 $ 46,666,795.21 11 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 2,475,598.41 $ 49,142,393.62 12 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 2,104,258.65 $ 51,246,652.27 13 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 1,788,619.85 $ 53,035,272.11 14 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 1,520,326.87 $ 54,555,598.99 15 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 1,292,277.84 $ 55,847,876.83 16 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 1,098,436.16 $ 56,946,312.99 17 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 933,670.74 $ 57,879,983.73 18 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 793,620.13 $ 58,673,603.86 19 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 674,577.11 $ 59,348,180.97 20 $ 124,629,870.14 $ 145,116,194.90 $ 6,965,350.42 $ 13,520,974.34 $ 573,390.54 $ 59,921,571.51 Table 7: Cash Flow and NPV Analysis Fixed Charge $ 2,065,925.63 $ 0.03 Total $ 124,629,870.14 $ 1.74
  14. 14. 14 The NPV of this plant after 20 years is $60 MM. The payback period is 1 years; the profit being earned on the second year. With the NPV equal $60 MM, which is 3 of the capital investment, this project is worth implementing. SAFETY CONCERN A. Overall Process The plant produces ethanol from sugarcane. Ethanol is a highly flammable; therefore, the prevention for this plant, especially at fermentation and ethanol distillation process are no open flames, no sparks, no smoking or contact with strong oxidants at that area. The acute hazards of ethanol that effects to human body such as cough, headache, fatigue, drowsiness, dry skin, redness, pain, or burning eyes; therefore, when people working with areas that have high concentration of ethanol, they need to wear breathing protect, also protective gloves, and safety goggles, specially, prevention eating, drinking, or smoking during work.
  15. 15. 15 B. Hazard and Operability Study (HAZOP) Table 8: Hazard and Operability Study (HAZOP)
  16. 16. 16 Figure 13: Boston Square for Clean Juice of Evaporator Figure 14: Boston Square for Reactor and Stripping Column 1, 2 3 4 5 6 7, 8 0 1 2 3 4 5 6 7 8 9 10 0 2 4 6 8 10 Severity Likelihood Boston Square for Clean Juice of Evaporator 11 12 9, 13 10, 14, 15 16 0 1 2 3 4 5 6 7 8 9 10 0 2 4 6 8 10 Severity Likelihood Boston Square for Reactor and Stripping Column Concentrated Juice of Reactor" Ethanol Solution of Stripping Column
  17. 17. 17 Figure 15: Boston Square for Cooling Water of Condenser ENVIROMENT This process produces ethanol, and also carbon dioxide, one of the harmful gas that give negative effects to environment. The high concentration of carbon dioxide in the atmosphere will increase the temperature of atmosphere. And this is the cause for GREEN HOUSE EFFECT. The higher temperature of atmosphere also affect to the climate and affect the life being. The temperature is increasing average 1oC each year. It cause the melting polar ice caps and glaciers; so increase ocean water level; hence affects to wild life. CONCLUSION and RECOMMENDATION This report presents the process of producing 71.5 MM gallons of ethanol per year from the basic is 20,000 US tons of sugarcane per day. The total capital cost of the project is $21MM, and annual $125 MM cost for production. The sell price of ethanol is $2.03/gal with 71.5 MM 17 18, 24 19, 20, 23 2122 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 Severity Likelihood Boston Square for Cooling Water of Condenser
  18. 18. 18 gal/year of ethanol is produced, the revenue of this project is $145 MM/year. The payback period of this project is one year and the project starts to earn profit from 2nd year. At the end of 20th year, NPV is $60 MM. The recommendation for this project is adding a treatment system for carbon dioxide to reduce amount of carbon dioxide to environment, also can use it to produce soft drink such as coke or diet coke.

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