In Japan, Coal Industry Policy has been focused, for many years, on industrial reactivation of her nation-wide coal mining regions and reclamation of devastated mining sites, etc. However, after fall in 1973, When the first oil crisis hit Japan, such new concepts as more expanded use of coal and increase of coal import from abroad came to be adopted, year after year, as an energy security policy. The post-eighth Coal Policy issued in 1991 had characters as so-called a final readjustment strategy and also as a part of Japan's energy policy. In this up-dated coal policy, two major targets were postulated such as follows; (1) stabilized coal demand and supply in the Asian Pacific region should be taken into consideration in addition to the traditional stabilized coal supply to Japan and (2) global environment issues should be considered as well as domestic pollution matters in Japan. To support this new strategy, new flexible targets have been highlighted and further development of advanced coal utilization technology has been accelerated in Japan.
Ash formation mechanisms are summerized for combustion and gasification processes in this review. The effects of elements such as Na, S, Fe, Si, Al and the corresponding compounds contained in ash on the ash melting, sintering or agglomeration and slagging are discussed. Some attentions are emphasized in investigating the ash behaviors in combustion and gasification processes.
Saturate fractions (Sa) were fractionated from the hexane soluble products by the repetitive butylation of Yubari and Taiheiyo coals using zinc and butyl iodide under mild conditions (130°C, under atmospheric pressure), and then fractionated further by gel permeation chromatography (GPC) to investigate the structural features and biological markers. Yields of Sa for Yubari and Taiheiyo coals were 3 .1 and 5.2 wt% (based on original coals), respectively. Five groups of peaks were present in gas chromatograms of GPC fractions of both Sa, and were consisted of the components as follows: first [Kovats index (KI), 1400-1600], cyclohexane derivatives; second (KI, 1600-1800), cyclohexane and dicyclic ones; third (KI, 1880-2120), di- and tricyclic ones; fourth (KI, 2121-2350), triand tetracyclic ones; fifth (KI, 2350-3620), tetra-and pentacyclic ones . Fifteen biological markers were identified in Yubari Sa, and among them eleven were new components identified in Yubari coal. Because of high yields of solvent soluble products and the mild reaction conditions, many biological markers trapped into coal matrix came to solubilize into Sa. Some components in Sa seemed to be also butylated, since there were some compounds with the MS fragment of m/e57 and their molecular weight were increased with 56n (n=1, 2).
Dimethyl ether (DME) synthesis from synthesis gas was conducted under pressurized conditionsover catalysts prepared by various methods. Among the Pd/SiO2, Pd/Al2O3, modified Pd/Al2O3 and hybrid (physically mixed) catalysts containing Pd/SiO2 or Cu-Zn-Al (O) and γA -Al2-O3, the hybrid catalyst showed much higher activity and selectivity for DME formation under relatively mild reaction conditions. It was clarified that the combination of methanol synthesis on the Pd or Cu-Zn-Al catalyst and the successive dehydration of methanol to DME occurred smoothly on either supported catalyst or the hybrid catalyst.