Various kinds of waste paper with different ash content were solubilized by hot compressed water (HCW) in mini-batch reactor for the purpose of examining an optimum operating condition to yield a higher conversion rate of water-solubilized carbon. When the operating conditions of reaction temperature and time were varied, a maximum value of conversion rate of water-solubilized carbon reached around 50wt% and it was found formic, acetic and lactic acids were mainly produced. Waste paper with higher calcium carbonate content was favorable in producing much more amount of organic acids. As an example, the conversion rate of water-solubilized carbon of about 50wt% and acetic acid of 14700mg/L were obtained, when a flier, 26.3wt% ash content and 10wt% calcium carbonate content, was treated under the condition of 325°C and 120s. Ad-dition of hydrogen peroxide improved decomposition behavior of waste paper. In the case of using 5.2wt% hydrogen peroxide water solution as a hydrolysis medium, conversion rate of water-solubilized carbon reached about 43wt% and total organic acids of 13500mg/L was yielded in the treatment of the same flier despite of a milder condition of 275°C and 5min. Moreover, adherence of char to the inner wall of the reactor was markedly decreased.

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Fulvic acid becomes the most valuable humic substance because of the water-solubility and the physi-ological action. However, a little amount of fuvic acid is extracted in general from a variety of natural humic resources. Therefore, in this work, its preparation was examined by hot compressed water treatment of Xinjiang (China) weathered coal. The resulting water-soluble product was proved to be a sort of fulvic acid. The yield of the produced fulvic acid by this procedure was at most 26 [wt%]. The formed fulvic acid showed a higher content of oxygen and carboxyl group than those of the extracted one from the original weathered coal. Furthermore, the phenolic hydroxyl group content was higher than that of products of the ozone oxidation of humic acid from the same weathered coal, reported previously.

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Natural gas is regarded as an environmentally friendly energy and one of the cleanest forms of fossil fuel energy. Therefore. the development and promotion of natural gas has been very active around the world. Although natural gas reserves are widely distributed all over the world, most of these reserves are located in undeveloped areas, far away from consuming cities. A lot of investment will be necessary such as pipeline construction, liquefaction facilities and storage tanks, to bring these reserves to market. Only large scale gas fields have been tapped so far, because they are relatively easy to commercialize, but small or middle scale gas fields have been left undeveloped, due to the economy of scale difficulties.
This paper discusses the possibility of natural gas utilization among the Asian-region developing countries, which own undeveloped small or middle scale gas fields.

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