Part 2 CCT Overview
Multi-purpose Coal Utilization Technologies (Liquefaction Technologies)

4A4. Dimethyl Ether Production Technology (DME)
Research and development: DME Development Co., Ltd., JFE Holdings Co., Ltd., Taiyo Nippon Sanso Corporation,Toyota Tsusho Corp., Hitachi Ltd., Marubeni Corp., Idemitsu Kosan Co., Ltd., INPEX Corporation, TOTAL S.A. (France),
LNG Japan Co., Ltd., and Japan Petroleum Exploration Co., Ltd. (JAPEX).
Project type: National Grant project of "Development of Technology for Environmental Load Reducing Fuel Conversion" of theAgency for Natural Resources and Energy of the Ministry of Economy, Trade and Industry
Period: 2002-2006 (5 years)

Technology overview

1. Background and process overview
Dimethyl ether (DME) is a clean energy source and as it

produced by dehydrating methanol. Approximately ten thousand

generates no sulfur oxide or soot during combustion its

tons per year are produced in Japan, and 150 thousand tons per

environmental impact is low. Owing to its non-toxicity and easy

year worldwide. DME’s main use is as a spray propellant. Givenliquefaction properties, DME is easy to handle and therefore canthe above-described superior properties, if DME were to become

be used as a domestic-sector fuel (substitute for LPG),

widely available in large volumes at a reasonable price, DME

transportation fuel (diesel vehicles, fuel cell vehicles), power plant

could be used as a fuel in a wide variety of fields.

fuel (thermal plants, cogeneration plants, stationary fuel cells),
and as a raw material for chemical products. Currently DME is
2. Development objectives and technology to be developed
The objective of this study is the development of a process toChemical reaction:(1) 3CO+3H2 CH3OCH3+CO2(2) CO+2H2 CH3OH(3) 2CH3OH CH3OCH3+H2O

directly synthesize DME from syngas (mixture of H2 and CO),(Chemical reaction (1)).
Existing technology produces DME through the dehydration ofmethanol, (Chemical reaction (3)). The scale of the plant in actual
operation, however, is rather small, and scaling-up is an issue to100

produce DME as a commercial fuel. In addition, the equilibrium

H2+CO conversion [%]conversion of the methanol synthesis reaction (Chemical reaction(2)) is relatively small, as show in Figure 1. On the other hand,because the methanol synthesis equilibrium limitation can beavoided in the direct DME synthesis reaction (1), a higher
conversion rate can be achieved.
The reaction formulae relating to the direct synthesis of DME areprovided below. The equilibrium conversions for methanol
synthesis and direct DME synthesis are given in Figure 1. Since(1) 3CO + 3H26040(2) CO + 2H220

direct synthesis produces the maximum conversion with a syngas

CH3OCH3 + CO280

CH3OH

composition of H2/CO=1, the process is suitable for the syngas
produced from coal gasification (H2/CO=0.5-1). The targets of the0.0

development study include the following:

0.5

1.0

1.5

2.0

2.5

H2/CO ratio [-]1. DME production rate: 100 tons/day or greater, syngas total
conversion: 95% or greater, DME selectivity: 90% or greater,

Fig. 1 Equilibrium conversion (280 C, 5Mpa)
O

DME purity: 99% or greater
2. Establishing scale-up technology
3. Optimizing entire system
4. Establishing stable plant operation

63

3.0

Clean Coal Technologies in Japan

3. Progress and development results
The development of the direct synthesis process has been led byconstructed with the aid of METI. This demonstration plant wasJFE. The first step was the search for a direct synthesis catalyst.

completed in November 2003 and is scheduled to have six long-The second step was a small bench plant (5 kg/day). The third

term continuous operation runs over 2 to 5 months from the end

step was a 5 ton/day pilot plant (Photo 1) constructed with the aidof 2003 to 2006. The total production of the demonstration plantof the Ministry of Economy, Trade and Industry (METI). The fourth

has reached approximately 19,000 tons.

step was a 100 ton/day demonstration plant (Photo 2) also

Photo 1 Five ton/day pilot plant

Photo 2 One-hundred ton/day demonstration plant

4. Issues and feasibility of practical application
DME is already utilized as a fuel on a small-scale in an inland

the future, however, they are expected to switch to coal, whicharea of China. In Japan, activities toward the practical application

has larger reserves than natural gas, as the feedstock. Usingof DME as a fuel are being undertaken by: DME International

natural gas, the CO2 obtained from the CO2 separation column isCo., Ltd., which was established by the same ten companies thatreturned to the syngas generation furnace; if coal were to beestablished the DME Development Co., Ltd., aiming to study theused, however, the CO2 would be released into the atmosphere.

commercialization of DME; Japan DME Co., Ltd., which wasWhen long-term CO2 storage technology is established in theestablished by Mitsubishi Gas Chemical Co., Inc., Mitsubishi

future, the coal-based process will be able to provide purified

Heavy Industries, Ltd., JGC, and Itochu Corp.; and Mitsui & Co.,

CO2 without any additional equipment. In the West, DME has

Ltd. and Toyo Engineering Corp., which adopted the methanol

drawn attention in a wide range of fields as a new fuel. There,

dehydration process. These activities aim to supply DME producthowever, it is expected to be mainly used in diesel vehicles toin 2006. All of them plan to use natural gas as the feedstock,

fully leverage the fact that DME combustion generates no soot.

because natural gas requires only a small initial investment. InPurge gas

CO2CO235m3 N/hNon-reacted gas

Natural gasDME

5t /dCoal mine methane
CoalOxygen
SteamLiquid/gas separator

Reaction condition
250-280OC
3-7Mpa750m3 N /hCO, CO2, H2Synthesis gas generation furnace

Gas purification column

MethanolDME synthesis reactor

CO2 separation column

DME purification column

0.8t /dFig. 2 Typical process flow diagram of DME direct synthesis from a coal or natural gas plant

References

1) Tsunao Kamijo et al., Lecture papers of The 8th Coal Utilization Technology Congress, Tokyo, pp.194-205, 1998.
2) Yotaro Ohno et al., Preprint for the lectures of the 30th Petroleum and Petrochemical Discussion Meeting, Tokyo, pp. 26-29, 2000.
3) Yotaro Ohno: Japan DME Forum Workshop, Tokyo, pp.113-122, 2002.
64