The developed countries except for the USA, have ratified the Kyoto protocol as of February 16th, 2005. Under the protocol, Japan must carry out the promised reduction in greenhouse gas emissions of 6.0 percent from 1990 levels during 2008-2012. The target value for final energy consumption by Japan in 2012 was 12.7×10¹⁸J/Year. However, using an L-model of logistic approximation, we have estimated that the final energy consumption in 2012 will be 17.0×10¹⁸J/Year. If it is possible to decrease the export amount and increase the oil price, the final energy consumption should be below the target value 12.7×10¹⁸J/Year.

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For the purpose of establishing recycle technology to reduce environmental load, technical and practical development of supercritical water is required. An area of high impact on above purpose is in the recycling of sulfur-containing wastes that are produced in gas clean-up facilities of coal gasification processes. For this purpose, pseudo-first order rate constants were evaluated for thiosulfate ion and thiocyanic ion decomposi-tion in subcritical water and in supercritical water (SCW). Experiments were conducted to decompose so-dium thiosulfate and sodium thiocyanate at 340-400°C and at 25MPa. Thiosulfate ion could be decomposed 100% in 10s reaction time to sulfite, sulfate, and sulfide ions in SCW. Thiocyanic ion could be decomposed 20% in 30s in SCW. When thiosulfate ion was added to sodium thiocyanate solution, however, decomposition rate increased to about 30%. Main reaction pathways and kinetics were determined with a flow reactor. The results show that thiosulfate ion can be completely decomposed in SCW, but that decomposition of thiocyanic ion in SCW requires different conditions, additives, or oxidants.

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Transesterification of soybean oil was carried out with methanol over calcium oxide at methanol re-fluxing temperature, in order to study the application of heterogeneous catalytic process to biodiesel produc-tion. The catalyst samples were prepared by calcination of the precipitated calcium carbonate at 900°C in the prescribed atmosphere, an ambient air or a helium gas flow. Calcium oxide prepared in an ambient air catalyzed the transesterification of soybean oil, but yield of the fatty acid methyl esters was only 10% for 4h. The calcination in a helium gas flow markedly intensified the activity of calcium oxide, as the obtained catalyst sample completed the transesterification for 2h. The obtained oil after completing the transesterification had appropriate properties for diesel fuel oil. The active catalyst prepared in a helium gas flow has a higher base strength (15.0<H_<18.4) than the dull one in an ambient air (9.3<H_<15.0). Addition-ally, the base Quantity was 5times larger for the active catalyst. The dull catalyst could be activated by calcination at 300°C in a helium gas flow. The poisoning species in an ambient air was elucidated through the activity test for a series of the catalyst sample obtained by conditioning the partial pressure of CO₂ and moisture in the calcining atmosphere.

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