Abstract

Dimethyl Ether(DME) is currently used as propellant of spray can, while it could be a clean and economical alternative fuel if it is produced in a large quantity at low cost. The properties of DME are similar to those of LPG and it can be used for various sectors; household, transportation, power generation, etc. DME can be produced from various resources as natural gas, coal or coal bed methane through synthesis gas. Various utilization technologies for DME are being developed.

An innovative process of direct synthesis of DME from synthesis gas has been developed. Newly developed catalyst in a slurry phase reactor gave a high conversion and high selectivity of DME. After pilot plant (5 tons/day) testing, for further technical development to commercialization, demonstration plant (100 tons/day) project has started in 2002 with the Japanese government support.

In 2003 and 2004, three continuous test operations of two to three months duration have been successfully conducted. Various process parameters targeted for ATR and DME synthesis were achieved under very stable condition. Based on the obtained data, scale-up studies to a commercial scale plant are underway.

Introduction

Dimethyl ether (DME) is an innovative clean fuel, as its properties are similar to those of LPG (liquid petroleum gas).Nowadays, DME is used mainly as a propellant for spray cans. Approximately 150,000 tons/year are produced worldwide by a dehydration reaction of methanol. In order to use DME as a fuel, it must be produced at low cost in large quantities.

As methanol, itself, is produced from synthesis gas (hydrogen and carbon monoxide), it would be more efficient to produce DME directly from synthesis gas. We have carried out the technical development of DME direct synthesis process from synthesis gas for the past 15 years.

In the fundamental research, a new efficient catalyst and slurry phase process for DME synthesis were developed (1).

On these fundamental results, five years development project using a 5 tons/day pilot plant was successfully conducted since 1997 with funds provided by the Ministry of Economy, Trade and Industry (2). At this stage, a reformer technology to give adequate synthesis gas was also started to be developed.

In 2002, five years development project using 100 tons/day demonstration plant has started by DME Development Co., Ltd. which is a consortium of nine Japanese companies and one French company with funds provided by the Ministry of Economy, Trade and Industry (3).

In addition to the production technologies, how to transport and utilize DME is extensively investigated in Japan, because DME could be a promising option to diversify energy resources in the future.

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