Investigation on the pretreatment and cleaning technologies ofAustralian brown coal

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In this project, we researched the environmental problems in Australian brown coal mine and efficient techniques for the dewatering of brown coals and the treatment of wastewaters from dewatering processes. Project members visited brown coal mine in Victoria, Latrobe Valley and discussed with the brown coal researchers. Australian members were invited to the International Conference related to coal utilization. This project was introduced in the Work Shop held just after the conference and many Australian and Japanese researchers discussed together about the brown coal utilization. 5 members have stayed at Australian brown coal research institutes for 1 - 2 months to carry out detail surveys of brown coal mine and recent technologies related to brown coal dewatering. Following results were obtained1)Release of trace elements during combustion and treatment of wastewater in the open cut brown coal mine will be serious problems.2)Organic residue with high ash content is the byproduct of the preparation of coal for the export to Japan and Korea. The power plant is now working utilizing the organic residue for coal preparation.3)MTE (Mechanical Thermal Expression) is focused on as an efficient dewatering process. The relationship between the process conditions and wastewater properties was clarified.4)An Australian PhD student has stayed at Kyoto for two weeks and performed the hydrothermal gasification of wastewater for MTE process using Ni/C catalyst developed by the head investigators. The possibility for treating MTE wastewater was presented.5)It was found that the efficiency for whole process should be considered to determine the operating conditions for realizing the hydrothermal gasification process with MTE process.6)Release behavior of alkali metals, arsenic compounds, and selenium compounds was examined.7)Hydrogen bondings related to the aggregate structure of brown coal were simulated by using MM method and MD method.