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Underground coal gasification (UCG) is an industrial process which converts coal into product gas. UCG is an ''in-situ'' gasification process carried out in non-mined coal seams using injection of oxidants, and bringing the product gas to surface through production wells drilled from the surface.〔(Coal Gas ), www.clarke-energy.com, retrieved 12.12.2013〕 The predominant product gases are methane, hydrogen, carbon monoxide and carbon dioxide. Ratios vary depending upon formation pressure, depth of coal and oxidant balance. Gas output may be combusted for electricity production. Alternatively gas can be used to produce synthetic natural gas or hydrogen and carbon monoxide can be used as a chemical feedstock for the production of fuels (e.g. diesel), fertilizer, explosives and other products. The technique can be applied to coal resources that are otherwise unprofitable or technically complicated to extract by traditional mining methods. UCG offers an alternative to conventional coal mining methods for some resources. It has been linked to a number of concerns from environmental campaigners.〔(), BBC - Coal gasification: The clean energy of the future?, retrieved 12.07.2014〕 ==History== The earliest recorded mention of the idea of underground coal gasification was in 1868, when Sir William Siemens in his address to the Chemical Society of London suggested the underground gasification of waste and slack coal in the mine.〔 〕〔 〕 Russian chemist Dmitri Mendeleyev further developed Siemens' idea over the next couple of decades.〔〔 〕 In 1909–1910, American, Canadian, and British patents were granted to American engineer Anson G. Betts for "a method of using unmined coal".〔〔 The first experimental work on UCG was planned to start in 1912 in Durham, the United Kingdom, under the leadership of Nobel Prize winner Sir William Ramsay. However, he was unable to commence the UCG field work before the beginning of the World War I, and the project was abandoned.〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「underground coal gasification」の詳細全文を読む スポンサード リンク
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