NKK Tests Low-Emission Vehicle Fueled by Dimethyl Ether
NKK's bench plant for DME synthesis research
NKK has successfully completed driving tests of a diesel truck fueled by dimethyl ether (DME), a new source of clean energy, produced at the company's small bench plant using proprietary direct synthesis technology. NKK purchased a commercially available diesel truck for the tests. As part of its commitment to global environmental responsibility while meeting the emerging demand for a stable energy supply, NKK began working to develop DME direct synthesis technology in 1989 using untapped natural resources such as low-grade coal and coal-bed methane.The company is nearing the practical application of DME through the basic technologies it has established at its 50kg-per-day bench plant. About 8,000 tons of DME (CH3OCH3) is used annually in Japan, mainly as an aerosol propellant for cosmetic products. DME is a chemically stable colorless gas with a boiling point of -25°C at atmospheric pressure. It is very safe and easy to handle and can be liquefied at room temperature by compressing it to about six atmospheres. The liquefied DME can be transported and stored just like LPG. DME is a clean burning gas with a greater calorific value than methane, and is just as safe to use as methane. It also features a higher cetane number(compression ignition quality) than diesel oil. In light of these advantages, DME is expected to find a wide range of uses as a household gas and as a fuel for transportation and power generation if a technology can be developed to produce it inexpensively in large quantities. In the NKK diesel truck test-drives, small mechanical alterations were made to the fuel injection system of the diesel engine because DME has a lower viscosity than diesel oil, while the engine itself was not altered. NKK made test-drives at its Tsurumi Works and the truck underwent about100 hours of total driving time. The positive results of the test-drives included:
These results demonstrate the potential that DME holds as a clean fuel for the low-pollution vehicles of the future. With a research grant for the promotion of coal utilization technology from the Agency of Natural Resources and Energy under the Ministry of International Trade and Industry (MITI), NKK will continue R&D on direct synthesis technology for the low-cost mass production of DME. In the project, NKK is working toward practical applications of DME in collaboration with the Center for Coal Utilization of Japan, Taiheiyo Coal Mining Co.,Ltd. and Sumitomo Metal Industries, Ltd. The five-year research project that runs from fiscal1997 through 2001 calls for the construction of a five ton-per-day pilot plant in Kushiro in northern Japan to evaluate the whole system. 
NKK's DME-fueled diesel truck responded well in tests.
|
