60.石炭チャーガス化時のアルカリ金属放出挙動と触媒効果

抄録

Four kinds of alkali compounds and kaolinite were added to acid-treated Yallourn coal. The alkali-loaded coal was pyrolyzed in N_2 and gasified in CO_2 atmosphere. The effects of temperature, gasifying atmosphere, mineral matter and carbon conversion on volatilization of alkalis and gasification rate were examined. The organically bound sodium in coal was appreciably stable below 840℃ in N_2, whereas the sodium retained in char was easily released with the progress of char gasification. The alkali volatilization both in the pyrolysis stage of coal and in the gasification stage of char were suppressed by the addition of kaolinite. The catalytic effectiveness of alkali metal on the gasification rate was affected by the addition of kaolinite and coal particle size. The char gasification rate was extraordinally enhanced by the addition of Na_2SiO_3.