A synthetic diesel fuel production technique using the FT synthesis catalytic reaction is the core technology for the production of liquid fuels from synthetic gas components. To be cost-effective when compared to petroleum-based light diesel oil, it is considered indispensable to further develop FT synthesis by introducing new types of technologies in the future. In the case of GTL, the raw-material gas components of FT synthesis are being diversified for different technologies, such as small to large scale natural gas fields, unprofitable natural gas fields, the gasification of biomass, and the gasification of coal. It is therefore expected that highly efficient FT synthesis technologies appropriate to the characteristics of respective raw materials will be developed.
FT technology is composed of technical fields such as catalysis development, reactor development, and plant development. Fig. 2 shows the BTL Integrated System being developed by AIST. Compared with conventional gasification, gas refining, and the FT synthesis process, this system shows merit, such as improved energy efficiency by Hot Gas Cleaning using activated carbon, and the significant increase in the yield of light diesel oil by combining directly with FT synthesis, hydrocracking, and catalytic isomerization.
DME has similar properties to LPG and is expected to become a new clean fuel that can be utilized in the public sector, transport sector, and as fuel for power generation, due to its ease of transport and storage. DME can be produced not only from fossil resources such as coal, petroleum and natural gas, but also from synthetic gas generated by the gasification of biomass. It can contribute to the diversification of primary energy resources, the reduction of carbon dioxide emissions and due to its super clean composition (sulfur and odor-free), it is expected to become the ultra low polluting diesel fuel in the future.
DME is currently produced by a dehydration reaction of methanol on the scale of several tens of tons per day. However in order to use DME as a fuel, it is necessary to produce it on a larger scale and at a lower cost. The raw material, methanol, can also be produced from synthetic gas, and so the development of a technique is being sought to produce DME directly from synthetic gas instead of from methanol. A DME direct synthetic reaction is very promising from the viewpoint of production cost because it is possible to obtain a higher yield rate at lower pressure if compared to a conventional methanol producing installation.