61.石炭熱分解時の窒素の行方に及ぼす脱鉱物質と触媒添加の影響

抄録

Demineralization of a Chinese lignite with HCl washing decreases remarkably conversion of coal nitrogen to N_2 during pyrolysis, whereas it increases the conversion to char-N. Contrarily, the fate of the nitrogen in an Australian bituminous coal is not changed significantly with NaOH treatment followed by H_2SO_4 washing, though the ash content is decreased drastically by the treatment. The X-ray diffraction measurements of high temperature ashes reveal that iron and calcium species inherently present in the lignite can be removed by HCl washing. The addition of a nanophase iron oxide catalyst with mean particle size of 3nm into coal promotes the formation of N_2 from all the coals examined with the corresponding decrease of residual nitrogen in the chars, but the catalytic effect depends strongly on the coal type.