Economically viable global coal reserves are expected to total about one trillion tons, about half of which is comprised of lowgrade coal such as sub-bituminous coal and brown coal. Coal has a larger ratio of reserves to production (R/P) than that of oil and natural gas. For full-scale effective utilization of coal, however, the effective use of low-grade coal is critical. Lowgrade coal contains a large amount of water but has an autoignition property in a dry state compared with bituminous coal and other higher grade coals. Consequently, brown coal liquefaction technology development progressed aiming to contribute to a stable supply of energy in Japan by converting the difficult-to-use low-grade coal into an easy-handling and useful product, or by producing clean transportation fuels such as gasoline and kerosene from the low-grade coal.

As shown in the figure, the BCL process has four stages: the slurry dewatering stage where the water is efficiently removed from lowgrade coal; the liquefaction stage where liquefied oil production yield is increased by using a highly active limonite catalyst and the bottoms recycling technology; the simultaneous hydrogenation stage where the heteroatoms (sulfur-laden compounds, nitrogenladen compounds, etc.) in the coal-liquefied oil are removed to obtain high quality gasoline, kerosene, and other light fractions; and the solvent deashing stage where the ash in coal and the added catalysts are efficiently discharged from the process system.

In Asian countries, economic growth steadily increases energy

demand, and countries possessing low-grade coal resources, such

as Indonesia, anticipate commercialization of the technology.