カルボニル鉄酸ナトリウムを触媒とする石炭の水蒸気ガス化 炭種の影響

Abstract

The catalytic steam gasification of eleven different rank coals was carried out using sodium hydridotetracarbonylferrate (Na [HFe (CO) 4]) (Na: 0.68-2.05 wt%, Fe: 1.67-5.0wt%) as a catalyst in order to investigate characteristics of the catalyst. Reactions were conducted in a semi flow type fixed bed reactor or in a thermobalance under a steam argon atmosphere at 700-850°C.Steam gasification of all the coal used were significantly enhanced by impreg-nating the ferrate to coal.The profile of the gasification rate against carbon burn-off for catalyzed runs differs considerably by the coal used, when small amount of the catalyst was loaded. With increasing the amount of the ferrate, the initial rate of gasification was elevated and the profile of the rate against burn-off drastically changes from the pattern that the rate of gasification decreased with an increase in burn-off to the opposite pattern that gasification rate increases with an increase in burn-off. Similar tendency was observed when reaction temperature was elevated at the lower catalyst level.The coal with the ferrate was treated under argon at 800t for 60 min and then gasified by steam. The gasification rate decreased in comparison with the non-treated coal wtih the same catalyst.When a selected coal was deashed and loaded with the ferrate, gasification profile changed into the pattern that show great increase in the gasification rate with an increase in burn-off.These results showed that the gasification rate was lowered by deactivation of the catalyst with ash in coal, deactivation of coal char at higher temperature, and the evaporation of alkali metal from coal char surface, during steam char reaction.