Influence Of Alkali Carbonates On Gasification Reactivity Of Coal With CO₂

Coal gasification has an important function on high efficient and clean utilization of coal resource. Compared with other coal gasification technologies, coal catalytic gasification technology has the advantages of lower reaction temperature, higher reaction speed, more simple technology and regulable components of gaseous production.Pingshuo and Lingwu raw coal, which has the same carbon content, were used in this text. The single or mixture of binary Li2CO3, K2CO3 and Na2CO3 were selected as catalysts of coal gasification during TGA temperature programme experiment. The main conclusions are as fllowing:1) The TGA analysis show that Li2CO3,K2CO3 and Na2CO3 all have favorable catalytic activity to Pingshuo and Lingwu raw coal, and make increase the speed and reduce the final temperature of gasification reaction. The final temperatures of gasification reaction reduce about 300℃and 400℃respectively for Pingshuo and Lingwu raw coal when 10% catalysts was loaded. The order of catalytic activity to Pingshuo raw coal gasification is Li2CO3 > K2CO3 > Na2CO3.2) Binary catalysts show also better catalytic activity to Pingshuo and Lingwu raw coal gasification than that of single alkali carbonate, the better ratio of binary catalysts were selected. The best mole ratio of Li2CO3 and K2CO3 is 9:1, 1:7 and 7:1 to Pingshuo coal, and is 7:1 and 3:1 to Lingwu coal. The best mole ratio of Li2CO3 and Na2CO3 is 9:1 to Pingshuo and Lingwu coal. Comparing the single and binary catalysts, the latter present the higher catalytic activity. Not that the activity of arbitrary binary catalyst were superior to single catalyst.3) the loading quantity of catalysts have an remarkable influence to the coal gasification. With the increase of catalytic dose the catalytic activity increase also. But the catalyst cannot give full play when the quantity too large and cause of materials waste. The best loading quantity of the catalysts in coal is 10% to Pingshuo and Lingwu coal.4) According to the products analysis of Pingshuo coal gasification reaction, the catalysts has definite effect on the release amount of H2,CH4,C2-C4. and it has an remarkable influence on the release of CO, which the initial release temperature is reduced about 300℃in accordance with the result of TG study.