Experimental investigation of hematite oxygen carrier decorated with NiO for chemical-looping combustion of coal

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• 作者：Ding-qian CHEN ; Lai-hong SHEN ; ^{lhshen@seu.edu.cn} ; Jun XIAO ; Tao SONG ; Hai-ming GU ; Si-wen ZHANG
• 关键词：chemical-looping combustion ; hematite ; oxygen carrier ; CO2 capture ; decoration
• 刊名：Journal of Fuel Chemistry and Technology
• 出版年：2012
• 期刊代码：7_18725813
• 类别：ce
• 出版时间：March, 2012
• 卷：40
• 期：3
• 页码：267-272
• 文件大小：234 K

摘要

Experiments on chemical-looping combustion of coal were conducted in a 1 kW_th interconnected fluidized-bed reactor using a natural hematite as an oxygen carrier and Shenhua bituminous coal and Huaibei anthracite as fuel. An evaluation of a hematite oxygen carrier decorated with NiO by mechanical mixing and impregnation methods was also performed. The results indicate that coal gasification rate is a time-limiting step that is employed in the chemical-looping combustion of coal, and the coal type has a great impact on the CO₂ capture efficiency. When the fuel reactor temperature is 970掳C and using hematite as an oxygen carrier, the CO₂ capture efficiency for Shenhua bituminous coal is 81.7%, whereas the one for Huaibei anthracite is 65%. Hematite shows stable reactivity during a process of long-term operation, and it should be a good candidate as an oxygen carrier for the chemical-looping combustion of coal. It is an effective way of improving the reactivity of the hematite oxygen carrier as well as the CO₂ capture efficiency by mechanical mixing with the NiO/Al₂O₃ oxygen carrier. Impregnating NiO on hematite exhibits a negative effect of the reaction performance between the product of coal gasification and the oxygen carrier due to the poor microstructure after calcination. Further investigations on the method and process of impregnation should be conducted.