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Natural Gas to BTX via Methanol
OH BOYS Ali Almubarak, Rashed Alrashed, Weston Hubele, Ben Pelton, and Shane Whipple
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Project Statement Goal: Produce 1 Billion lb/year of BTX (Benzene, Toluene, Xylene) from natural gas Methanol will be synthesized from natural gas Use BTX patent to react the intermediate methanol to BTX Crude product will be a BTX mixture containing naphthalene Plant will be situated in prime location Close to feedstock, and product sales
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BTX Uses Benzene Ethylbenzene Styrene Polystyrene Polystyrene
Plastics, Foams (Styrofoam) Toluene Toluene Diisocyanate Polyurethane Polyurethane Adhesives, Foams, Plastics Xylene Terephthalic acid Polyesters Polyesters Fabrics, Plastics, Lacquers
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Natural Gas Prices by Region ($/MMBTU)
Why use Natural Gas? Natural Gas Prices by Region ($/MMBTU) Cheap and abundant Expected to remain in high supply US compared to rest of world
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US Natural Gas Pipeline Network, November 2011
Location: Bay Town, TX US Natural Gas Pipeline Network, November 2011 Easy access to natural gas Easy distribution of products No state corporate tax Excellent talent pool
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Overall Process BTX Reactor Methanol Tower Olefins Recovery Syngas
Olefins Recycle Syngas Recycle Olefins Recovery BTX Reactor Steam Syngas Reactor Methanol Reactor Pure Methanol Product Stream Methane Product Separation Syngas Olefins: Ethylene Propylene Water Recycle
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Syngas and Methanol Reactors
Hydrogen Separator Hydrogen PURGE STREAM 5% Recycle Gas Methanol/ Recycle Gas Separation Gas Recycle Water Feed Boiler Methane Feed Crude Methanol Syngas Reactor Methanol Parallel Reactors Compressor
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Syngas Reaction CH4 + H2O CO + 3H2 Packed bed reactor 800 oC, 40 atm
Up to 60% of methanol plant cost is from synthesis gas production Single stage steam reforming Relatively low capital investment Doesn’t require pure oxygen, just steam and water Excess hydrogen could be sold CH4 + H2O CO + 3H2 Packed bed reactor 800 oC, 40 atm NiO/MgO catalyst Endothermic
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Hazardous byproduct: discussed later
Methanol Reaction Packed bed reactor 250 oC, 20 atm Copper composite catalyst Exothermic WHSV 1.82 h-1 CO2 + 3H2 CH3OH + H2O CO + 2H2 CH3OH CO2 + 2H2 CO + H2O Hazardous byproduct: discussed later
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BTX Reactor Hydrogen Prism Separator Olefins Recycle Hydrogen
Olefins Feed BTX Reactor Gas Purge Light Gas Separation Crude Methanol Methanol/Water Tower BTX Mixture Decanter Water: Recycled Back to Boiler Water: Recycled Back to Boiler
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BTX Reaction Packed bed reactor 450 oC, 1 atm
La containing zeolite catalyst Endothermic WHSV 0.5 h-1 Difficult mass balance Many components Ethylene & Propylene BTX/Water Naphthalene BTX Reactor Methanol Ethane/Methane Hydrogen Olefins Recycle
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Product Separation - Xylene is 56% of product
Benzene Product Olefins Stream Benzene/ Toluene Separation Tower BTX Mixture Toluene Product Olefins Separation Tower Olefins Tower Separation BTX Separation Tower Xylene Product Xylene/ Naphthalene Separation Tower - Xylene is 56% of product - Much more energy efficient to separate it earlier Naphthalene Product
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Olefin Separation Tower
Olefins Recovery Olefins Recycle – To BTX Reactor Ethylene Stream Mixer Olefin Separation Tower Ethylene + Ethane Stream Olefins Stream Propylene Tower Ethane Stream Propylene Stream
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Pricing Basis Feedstock Prices Ethylene - $0.44/lb
Propylene - $0.40/lb Methane - $0.08/lb
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Installed Capital Costs
Total: $418 MM $76MM $79MM $29MM $25MM $90MM Values from: Plant Design and Economics for Chemical Engineers ISBL + OSBL values Extrapolated to 2016 $94MM $25MM
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Variable Costs Total: $401 MM/yr $76 MM/yr $20 MM/yr $305 MM/yr
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Economic Sensitivities
Discounted at 15% Promising economics, especially in volatile crude markets Base Case 50% Decrease in Byproducts 25% Increase in Feed 25% Decrease Product
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Environment Issues Contaminated water from process Use of Freshwater
Pay process fees to clean Use of Freshwater Recycling reduced water consumption by 90% CO2 emissions Heat integration
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Heat Integration $52 MM/yr savings in natural gas for process heat
Texas world’s 8th largest emitter of CO2 (compared to other countries) Six heat exchangers inserted into simulation Optimized all distillation towers (8 total) Reduced required heating $52 MM/yr savings in natural gas for process heat Saved nearly 1.4 MM ton/yr of CO2 emmissions
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Heat Integration Example
Water Feed Boiler Heat Exchanger Syngas Reactor Syngas Reduced required energy for boiler by 94% Capitalized on the hot effluent streams 92% of total process heat duty met by fuel credits
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Safety Safety High temp and pressures in select reactions
Durable materials of construction (stainless steel due to hydrogen) Flammable materials Proper PPE worn by personnel Strict OSHA and EPA adherence Toxic materials CO will be burned under proper conditions for heating requirements
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Conclusion 1.14 Billion lb/yr of BTX being generated IRR: 26.2%
NPV: 446 MM$ Process proved highly economical in volatile markets Highly dependent on propylene and ethylene prices
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Acknowledgements Dr. David Bell: Mentor
Professor John Myers: Simulation assistance Dr. Joseph Holles: Process assistance
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Questions?
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