A chemical process plant consists of the following major equipment: ten heat exchangers, two reactors, twelve...

  
 
 

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A chemical process plant consists of the following major equipment: ten heat exchangers, two reactors, twelve pumps, two towers, two compressors, two heaters and three vessels. Five of the heat exchangers each have a duty of 1.70 GJ/h, and use cooling tower water. Two heat exchangers each have a duty of 2.30 GJ/h, and use high- pressure steam. The final three heat exchangers each have a duty of 3.60 GJ/h, and use low-pressure steam. The heaters, with a combined duty of 17.0 GJ/h, are operated with coal and both run at 87.5% efficiency. All other equipment, with a total actual duty of 350.0 kWh/h, are run with electricity (thus you can assume no efficiency losses for these electrically powered equipment). The unit costs of these utilities can be found in Table 8.3 (given below). Take credits where you can. The raw material cost is $625/h, the fixed capital investment (FCI) is $13,500,000, and the cost of waste treatment is $135/h. Operating labor costs an average $28.57/h/operator. a. (2 pts) Estimate the cost of operating labor (per year), Cou b. (2 pts) Estimate the cost of utilities (per year), CUT; c. (2 pts) Estimate the cost of manufacturing without depreciation (per year), COM d. d. (1 pt) Estimate COM, (per year), if the stream factor is 0.950. Table 8.3. Utilities Provided by Off-Sites for a Plant with Multiple Process Units (Costs Represent Charges for Utilities Delivered to the Battery Limit of a Process) Utility Air Supply Steam from Boilers Steam Generated from Process Description Pressurized and dried air (add 20% for instrument air) a. 6 barg (90 psig) b. 3.3 barg (50 psig) Process steam: latent heat only a. Low pressure (5 barg, 160°C) from HP steam With credit for power Without credit for power Other Water b. Medium pressure (10 barg, 184°C) from HP steam With credit for power Without credit for power c. High pressure (41 barg, 254°C) Estimate savings as avoided cost of burning natural gas in boiler Cooling Tower Water Processes cooling water: 30°C to 40°C or 45°C High-purity water for a. Process use b. Boiler feed water (available at 115°C)* c. Potable (drinking) d. Deionized water Cost $/GJ 13.28 14.05 14.19 14.83 17.70 12.33 0.354 Cost $/Common Unit $0.49/100 std m³* $0.35/100 std m³* $27.70/1000 kg $29.29/1000 kg $28.31/1000 kg $29.59/1000 kg $29.97/1000 kg $14.8/1000 m³ $0.067/1000 kg $2.45/1000 kg $0.26/1000 kg $1.00/1000 kg Electrical Substation Fuels Electric Distribution** a. 110 V b. 220 V c. 440 V a. Fuel oil (no. 2)** b. Natural gas** c. Coal (f.o.b. mine mouth)** 16.8 14.2 11.15 1.72 $0.06/kWh $549/m³ $0.42/std m³* $41.4/tonne Refrigeration Thermal Systems Waste Disposal (Solid and Liquid) Wastewater Treatment a. Moderately low temperature Refrigerated water in at T = 5°C and returned at 15°C b. Low temperature Refrigerant available at T = -20°C c. Very low temperature Refrigerant available at T = -50°C Cost based on thermal efficiency of fired heater using natural gas a. 90% efficient b. 80% efficient a. Nonhazardous b. Hazardous a. Primary (filtration) b. Secondary (filtration + activated sludge) c. Tertiary (filtration, activated sludge, and chemical processing) 4.43 7.89 13.11 12.33 13.88 $0.185/1000kg Based on process cooling duty Based on process heating duty $36/tonne $200-2000/tonneº $41/1000 m³ $43/1000 m³ $56/1000 m³ *Standard conditions are 1.013 bar and 15°C. **These values are used to determine the other utility costs given in this table. *Based on AT cooling water = 10°C. Cooling water return temperatures should not exceed 45°C due to excess scaling at higher temperatures. *Approximately equal credit is given for condensate returned from exchangers using steam. Based on lower heating value of natural gas. For hazardous waste, the cost of disposal varies widely. Chemical analyses are required for all materials that cannot be thoroughly identified. This does not include radioactive waste. A chemical process plant consists of the following major equipment: ten heat exchangers, two reactors, twelve pumps, two towers, two compressors, two heaters and three vessels. Five of the heat exchangers each have a duty of 1.70 GJ/h, and use cooling tower water. Two heat exchangers each have a duty of 2.30 GJ/h, and use high- pressure steam. The final three heat exchangers each have a duty of 3.60 GJ/h, and use low-pressure steam. The heaters, with a combined duty of 17.0 GJ/h, are operated with coal and both run at 87.5% efficiency. All other equipment, with a total actual duty of 350.0 kWh/h, are run with electricity (thus you can assume no efficiency losses for these electrically powered equipment). The unit costs of these utilities can be found in Table 8.3 (given below). Take credits where you can. The raw material cost is $625/h, the fixed capital investment (FCI) is $13,500,000, and the cost of waste treatment is $135/h. Operating labor costs an average $28.57/h/operator. a. (2 pts) Estimate the cost of operating labor (per year), Cou b. (2 pts) Estimate the cost of utilities (per year), CUT; c. (2 pts) Estimate the cost of manufacturing without depreciation (per year), COM d. d. (1 pt) Estimate COM, (per year), if the stream factor is 0.950. Table 8.3. Utilities Provided by Off-Sites for a Plant with Multiple Process Units (Costs Represent Charges for Utilities Delivered to the Battery Limit of a Process) Utility Air Supply Steam from Boilers Steam Generated from Process Description Pressurized and dried air (add 20% for instrument air) a. 6 barg (90 psig) b. 3.3 barg (50 psig) Process steam: latent heat only a. Low pressure (5 barg, 160°C) from HP steam With credit for power Without credit for power Other Water b. Medium pressure (10 barg, 184°C) from HP steam With credit for power Without credit for power c. High pressure (41 barg, 254°C) Estimate savings as avoided cost of burning natural gas in boiler Cooling Tower Water Processes cooling water: 30°C to 40°C or 45°C High-purity water for a. Process use b. Boiler feed water (available at 115°C)* c. Potable (drinking) d. Deionized water Cost $/GJ 13.28 14.05 14.19 14.83 17.70 12.33 0.354 Cost $/Common Unit $0.49/100 std m³* $0.35/100 std m³* $27.70/1000 kg $29.29/1000 kg $28.31/1000 kg $29.59/1000 kg $29.97/1000 kg $14.8/1000 m³ $0.067/1000 kg $2.45/1000 kg $0.26/1000 kg $1.00/1000 kg Electrical Substation Fuels Electric Distribution** a. 110 V b. 220 V c. 440 V a. Fuel oil (no. 2)** b. Natural gas** c. Coal (f.o.b. mine mouth)** 16.8 14.2 11.15 1.72 $0.06/kWh $549/m³ $0.42/std m³* $41.4/tonne Refrigeration Thermal Systems Waste Disposal (Solid and Liquid) Wastewater Treatment a. Moderately low temperature Refrigerated water in at T = 5°C and returned at 15°C b. Low temperature Refrigerant available at T = -20°C c. Very low temperature Refrigerant available at T = -50°C Cost based on thermal efficiency of fired heater using natural gas a. 90% efficient b. 80% efficient a. Nonhazardous b. Hazardous a. Primary (filtration) b. Secondary (filtration + activated sludge) c. Tertiary (filtration, activated sludge, and chemical processing) 4.43 7.89 13.11 12.33 13.88 $0.185/1000kg Based on process cooling duty Based on process heating duty $36/tonne $200-2000/tonneº $41/1000 m³ $43/1000 m³ $56/1000 m³ *Standard conditions are 1.013 bar and 15°C. **These values are used to determine the other utility costs given in this table. *Based on AT cooling water = 10°C. Cooling water return temperatures should not exceed 45°C due to excess scaling at higher temperatures. *Approximately equal credit is given for condensate returned from exchangers using steam. Based on lower heating value of natural gas. For hazardous waste, the cost of disposal varies widely. Chemical analyses are required for all materials that cannot be thoroughly identified. This does not include radioactive waste.

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a Fuel Unit Cost h Coal 0050 Natural gas 100 Fuel oil 120 Electricity 025 Cooling tower water 00005 ... View the full answer