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Dimethyl Ether Production
University of TN-ChattanoogaENCH 4290-Intro to ChemE Design
Submitted By: Aziz Albatattah, Alwabari Abdulmohsen, Marquita Beard & Alston Casseday
Outline• Introduction• Objective• Design Constraints• Assumptions• CHEMCAD Design• Sizing• Costing• Conclusion & Questions
What is Dimethyl Ether?
• A clean burning, diesel alternative• Inexpensive• Able to meet strict emissions standards• Used in transportation, agriculture and construction
industries• Can be produced from bio or natural gases
Objective
• Design a production process to produce 50,000 metric tons of 99.5 wt% dimethyl ether using 99 mol% methanol.
• Plant operating hours: 8,375 hours per year
Constraints
• Feed Stream: 25 degrees Celsius and 100 kPa• 80% single pass conversion @ reactor & 100% overall
conversion• Pressure Drops:
• Heat Exchangers: 35 kPa• Mixing Points: 10 kPa• Reactor: 50 kPa• Distillation Columns: 15 kPa
Initial Assumptions
• 50,000 metric tons of DME in 8,375 hours = 129.8 kilomoles per hour
• 259.6 kmol/hr methanol required to produce 129.8 kmol/hr DME
• Pure methanol recycle stream• The reactor feed enters at 250 degrees Celsius.
Block Flow Diagram of DME Production
Separator Feed Prep
Methanol
Reactor
Separator Feed Prep
Storage
Wastewater Treatment
Separator
Separator
DME 99.5wt%129.8 kmol/hr
80% Conversion Methanol
99 mol%259.6 kmol/hr
Process Flow Diagram of DME Production
1
2
35
6
8
97
17
10
3
1112
P-1 01 A/B H-1 01
R-1 01
E-1 01
cw
P-1 02 A/B
cw
T-1 01
lps
cw
E-1 02
cw
T-1 02
lps
P-1 03 A/B
1
2
6
7
13
14
4
5
8 9 10
1112 15 16
18
Figure 1: Process F low Diagram of the Production o f Dimethyl Ether
Design• 1 Storage Tank• 3 Pumps• 1 Fired Heater• 1 Reactor• 2 Distillation Columns (Each w/ 2 Heat Exchangers & 1 Reflux
Pump)• 2 Heat Exchangers• 1 Recycle Stream
Stream PropertiesStream No. 1 10 18 17Stream Name Temp C 25.0 44.98 51.04 111.60 Pres kPa 100.0 1010.00 1045.00 155.00Enth MJ/h -64666 -26673 -17850 -38258Vapor mole frac. 0.00 0.00 0.00 0.00 Total kmol/h 269.70 132.55 74.11 137.16 Total kg/h 8575.80 6097.18 2249.41 2479.41 Total std L m3/h 10.69 9.06 2.84 2.84 Total std V m3/h 6044.96 2971.08 1661.10 3074.19 Flow rates in kg/hDimethyl Ether 0.00 6075.31 78.28 0.00Methanol 8491.13 21.88 2071.03 19.49 Water 84.67 0.0002 140.10 2459.42
Heat Exchangers E-101 E-102 E-103 E-104 E-105 E-106Type S&T S&T Kettle S&T S&T KettleArea(m2) 45.8 41.6Duty (MJ/h) -15718 -1454 4046 -3149 -4444 4690
Temp.(oC) 343 (Tmax) 79 (Tmax) 153 45 51 112Pres. (kPa) 950 (max) 105 (max) 1060 1010 105 155Phase V to L V to L L to V V to L V to L L to VMOC SS CS CS CS CS CSVessels/Tower/Reactors V-101 R-101 T-101 T-102 V-102 V-103Temp.(oC) 31 343 153 112 45 51Pres. (kPa) 1045 1000 1060 155 1010 105Orientation Horiz. Vertical Vertical Vertical Horiz. Horiz.MOC CS SS CS CS CS CS
Height/Length (m) 9 15 8.54 9.76 17.5 11.79Diameter (m) 10 5 0.76 0.76 5.85 3.93Internals s.p. Sized for 2X 14 Valve 16 Valve
Catalyst Vol. Trays TraysTray MOC CS CS CS CS
P-101 P-102 P-103 P-104 P-105(A/B) (A/B) (A/B) (A/B) (A/B)
Flow (kg/h) 8576 10866 2289 2214 1409Fluid Density (kg/m3) 786 654 768 622 768Power (shaft) (kW) 2.86 0.554 0.778
P-101 P-102 P-103 P-104 P-105(A/B) (A/B) (A/B) (A/B) (A/B)
Type/Drive Centrif./ Centrif./ Centrif./ Centrif./ Centrif./Electric Electric Electric Electric Electric
Effi ciency (Fluid 1 1 1 1 1Power/Shaft Power)
MOC CS CS CS CS CSTemp. (in) (oC) 25 77 51 45 51Press. (in) (kPa) 100 915 105 1010 105Pres. (out) (kPa) 1045 1035 1045 1010 105
Pumps/Compressors
Pumps/Compressors
Shell
Size
Equipment Summary
SizingMethanol Storage Tank:
Volume-519 m3
Height-9 m Diameter-10 m
Reactor: Catalyst Volume-5.89 m3
Reactor Volume-11.78 m3
Height-15 m Diameter-5 m
Sizing
• Heat Exchangers:• E-101: 45.8 m2
• E-102: 41.6 m2
• Pump Power:• P-101 A/B- 2.86 kW• P-102 A/B-0.554 kW• P-103 A/B-0.778 kW
Sizing• Distillation Column 1, T-101:
• 14 CS valve trays• Height-8.54 m• Diameter-0.76 m
• Distillation Column 2, T-102:• 16 CS valve trays• Height-9.76 m• Diameter-0.76 m
Economic Information Calculated From Given Information
Revenue From Sales $ 42,944,796 material
CRM (Raw Materials Costs) $ 20,110,251 material
CUT (Cost of Utilities) $ 1,510,000 COM
CWT (Waste Treatment Costs) $ 747,544 material
COL (Cost of Operating Labor) $ 758,030 custom
Factors Used in Calculation of Cost of Manufacturing (COMd)
Comd = 0.18*FCIL + 2.76*COL + 1.23*(CUT + CWT + CRM)
Multiplying factor for FCIL 0.18
Multiplying factor for COL 2.76
Facotrs for CUT, CWT, and CRM 1.23
COMd $ 30,387,551
NPVProject 1
0 1 2 3 4 5 6 7 8 9 10Revenue (42,944,796)$ (42,944,796)$ (42,944,796)$ (42,944,796)$ (42,944,796)$ (42,944,796)$ (42,944,796)$ (42,944,796)$ (42,944,796)$ (42,944,796)$ Cost of Manufacturing 30,387,551$ 30,387,551$ 30,387,551$ 30,387,551$ 30,387,551$ 30,387,551$ 30,387,551$ 30,387,551$ 30,387,551$ 30,387,551$ Depreciation 313,207$ 313,207$ 313,207$ 313,207$ 313,207$ 313,207$ 313,207$ 313,207$ 313,207$ 313,207$ Net Income before tax (12,244,038)$ (12,244,038)$ (12,244,038)$ (12,244,038)$ (12,244,038)$ (12,244,038)$ (12,244,038)$ (12,244,038)$ (12,244,038)$ (12,244,038)$ Tax @ 35% 4,285,413$ 4,285,413$ 4,285,413$ 4,285,413$ 4,285,413$ 4,285,413$ 4,285,413$ 4,285,413$ 4,285,413$ 4,285,413$ Income after tax (7,958,624)$ (7,958,624)$ (7,958,624)$ (7,958,624)$ (7,958,624)$ (7,958,624)$ (7,958,624)$ (7,958,624)$ (7,958,624)$ (7,958,624)$ Depreciation (313,207)$ (313,207)$ (313,207)$ (313,207)$ (313,207)$ (313,207)$ (313,207)$ (313,207)$ (313,207)$ (313,207)$ Cash Flow 3,132,074$ (8,271,832)$ (8,271,832)$ (8,271,832)$ (8,271,832)$ (8,271,832)$ (8,271,832)$ (8,271,832)$ (8,271,832)$ (8,271,832)$ (8,271,832)$ Discounted Cash Flow ($37,174,326)NPV (34,042,252)$
Cummulative Cash Flow 3,132,074$ (5,139,758)$ (13,411,590)$ (21,683,422)$ (29,955,253)$ (38,227,085)$ (46,498,917)$ (54,770,749)$ (63,042,581)$ (71,314,413)$ (79,586,244)$ Internal Hurdle Rate 18%
Conclusion
• Based off the NPV spreadsheet there is never a breakeven point
• The discounted cash flow over ten years is - $37, 000, 000
References
Bondiera, J., and C. Naccache. “Kinetics of Methanol Dehydration in Dealuminated H-Mordenite: Model with Acid and Base Active Centres.” Applied Catalysis 69 (1991): 139-148.
“DME Basics.” Oberion Fuels. http://www.oberonfuels.com/technology/dme-basics-2/ (accessed
November 30, 2015).