DKRW Selects ExxonMobil’s Methanol-to-Gasoline (MTG) Technology for Coal-to-Liquids Project
17 December 2007
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| MTG is one of the pathways for converting syngas to transportation fuel. Both the Fischer-Tropsch and MTG processes are 3-step processes. Thermal efficiencies are essentially governed by the thermal efficiencies of the syngas production process and feed. Click to enlarge. Source: ExxonMobil and Uhde |
DKRW Advanced Fuels (DKRW) has selected ExxonMobil Research and Engineering Company’s (EMRE) methanol-to-gasoline (MTG) technology as part of DKRW’s coal to liquids (CTL) project in Medicine Bow, WY. DKRW recently stated that it has switched the initial finished product of its planned CTL plant from diesel to gasoline. (Earlier post.)
The Medicine Bow project will gasify the coal, convert the synthetic gas to methanol, and then convert the methanol to gasoline via the MTG process. The plant will produce up to 20,000 barrels per day of transportation fuels, electricity, steam, off-gas, slag, chemicals (including sulfur), other fuels and energy products which will be sold into the market. The plant intends to capture CO2 emissions from the process and send it to northeast Wyoming for use in enhanced oil recovery projects.
The approximately 15,000 barrel per calendar day MTG unit will be based on commercially proven technology which incorporates improvements since the technology was originally commercialized by Mobil 20 years ago in New Zealand.
Mobil (now ExxonMobil) began with a 4 bpd pilot plant in the US, then scaled up pilot operations to 100 bpd in Germany (with Uhde). In 1979, the New Zealand government decided to build a commercial 14,500 bpd plant in Montunui, NZ, owned 75% by the NZ government, 25% by Mobil. The plant started up in 1985 and operated successfully for ~10 years till conversion to chemical grade Methanol production.
The conversion of methanol to hydrocarbons and water is virtually complete and essentially stoichiometric in the MTG process. The reaction is exothermic with the reaction heat managed by splitting the conversion in two parts. In the first part, methanol is converted to an equilibrium mixture of methanol, dimethyl ether (DME), and water. In the second part, the equilibrium mixture is mixed with recycle gas and passed over a shape-selective catalyst to form hydrocarbons and water. Most of the hydrocarbon product boils in the gasoline boiling range. The low-sulfur, low-benzene gasoline product from the process is a premium quality clean gasoline and can be blended with refinery gasoline directly or sold separately.
From 1,000 tons of methanol, the process will produce 387 tonnes of gasoline, 46 tonnes of LPG, 7 tonnes of fuel gas and 560 tonnes of water, which is recycled as process water.
| Comparison of Fischer-Tropsch with MTG | |||
|---|---|---|---|
| Compound | Low Temp FT Co Catalyst @428F | High Temp FT Fe Catalyst @644F | MTG |
| Methane | 5 | 8 | 0.7 |
| Ethylene | 0 | 4 | – |
| Ethane | 1 | 3 | 0.4 |
| Propylene | 2 | 11 | 0.2 |
| Propane | 1 | 2 | 4.3 |
| Butylenes | 2 | 9 | 1.1 |
| Butane | 1 | 1 | 10.9 |
| C5 - 160C | 19 | 36 | 82.3 |
| Gasoil/Distillate | 22 | 16 | – |
| Heavy Oil/Wax | 46 | 5 | – |
| Oxygenates | 1 | 5 | 0.1 |
| 100 | 100 | 100 | |
In 2006, China-based JAM (Shanxi Jincheng Anthracite Coal Mining Co. Ltd. ) awarded a contract to Uhde for the engineering and supply of a coal-based MTG plant. (Uhde licenses the MTG technology from EMRE.)
The new MTG plant is part of a complex on a pilot-plant scale, which is being constructed at Jincheng, Shanxi Province, some 600km south-west of Beijing. This complex also includes a fluidized-bed hard-coal gasification plant and a methanol plant. It is planned to produce 100,000 tonnes of gasoline annually from the year 2008.
Resources
An Alternative Route for Coal to Liquids: Methanol-to-Gasoline (MTG) Technology (ExxonMobil, Uhde)
Sigmund M. Csicsery, “Catalysis by shape selective zeolites — science and technology” Pure & Appl. Chem., Vol. 58, No. 6, pp. 841—856, 1986.
Why not mix 10 % Methanol in Gasolene and sell it as M10.
Chinese have plans to sell as M15 & M85.
Posted by: Max Reid | 17 December 2007 at 03:17 PM
The number of intermediate steps will lower the EROEI. I'd like to know the real reason the Kiwis abandoned the petrol end target. Conversely a problem with M10 is that methanol corrodes aluminium.
Call me sceptical but assurances that process water will be recycled and CO2 will go to EOR sound like a 'coulda' that may just get overlooked. Unless this is the start of something big it will make little dent in oil depletion.
Posted by: Aussie | 17 December 2007 at 07:24 PM
Aussie
Not sure that there is more intermediate step than in standard FT process, the problem with standard process is that the output is scattered in different byproducts you are not looking for. This process has a high yield in gazoline. The overwole yield looks quite ok for a FT process : ~ 1 Metric tonne of gazoline for 3 Metric tonnes of coal.
Posted by: Treehugger | 17 December 2007 at 09:02 PM
Call me sceptical but assurances that process water will be recycled and CO2 will go to EOR sound like a 'coulda' that may just get overlooked.
Injecting dirty process water back into the gasifier is probably the cheapest way of disposing of it, I would think.
Posted by: Paul D. | 17 December 2007 at 10:06 PM
Apparently the drop in the oil price a decade ago killed the project http://www.techhistory.co.nz/ThinkBig/Petrochemical%20Decisions.htm
If the zeolite process works on biomass and natural gas feedstocks instead of coal this could help. Seems Exxon Mobil hold the patent though.
Posted by: Aussie | 18 December 2007 at 01:30 AM
The PR says "synthetic gas", but it really means "synthesis gas [CO + H2]", right?
Posted by: richard schumacher | 18 December 2007 at 08:30 AM
@Aussie -
the nominal inputs for MTG are methanol and water. How you produce the ethanol is basically irrelevant for this downstream process, as long as there are no contaminants that foul or degrade the catalyst. Unfortunately, the biggest issue is coking, which will happen with any carbonaceous feedstock.
Also, MTG is supposedly harder to control than F-T. Of course, you could avoid both if your vehicle fleet can use the methanol and DME precursors directly.
Posted by: Rafael Seidl | 18 December 2007 at 12:44 PM
All the advancements are made only to use available fossil fuels to suit our needs but the problem still remains. one day these fuels will be gone and until the time we find a truly renewable source of fuel and a method to convert them to usable form oil prices will continue to climb.
Posted by: Vaskar De | 16 March 2008 at 11:46 PM
I have been awfully frustrated but evidently someone is doing something. I am a thermal engineer (that is thermodynamics). I will mention a few key words: Otto Cycle, Diesel Cycle, Turbine Cycle. Why is London no longer the smog capitol? (Because they are smarter than we are!!. We have enough coal in this country to last 600 yearsd - if we are smart enough to use it - until a satisfactory fuel cell can be developed(Fusion also). We have to get started NOW or our kids and kids kids are really going to suffer. I have worked with some awfully smart people and they can do just about anything - if we apply some intelligent leadership to do it. If there is anything that I* can do to help, let me know.
Posted by: J Hoelz, P.E. Ret | 02 June 2008 at 05:44 AM
I understand, that...
1.The high temperature, high pressure gas reformers operated within half a degree of meltdown... and the inevitable happened! Horrors! Holes in the Inconel!
2.Because the price of crude oil was so low at the time, it was uneconomic to repair the plant.
3.It also seems like a huge waste of resource to immediately turn half the feedstock into water and this was considered to be something of a scandal.
4.Also, the Maui gas field is winding down and the days of plentiful, cheap natural gas are numbered.
Posted by: Michael Glover | 24 December 2009 at 01:13 AM