稻壳气化过程中碳微观结构及气化活性演变历程研究

Evolution of carbon microstructure and gasification activity during rice husk gasification

为探究高倍率循环流化床气化过程中生物质中碳微观结构及气化活性演变规律,在实验室固定床反应装置上对稻壳进行了高循环倍率气化过程模拟,并对稻壳热解焦及其不同次数循环气化后样品的孔隙结构、碳微观结构及气化活性进行了研究。结果表明,随着循环次数的增加,焦的比表面积呈现先增大后减小的趋势,但不同次数循环后焦的BET比表面积均明显高于稻壳热解焦。随着循环气化过程的进行,焦中碳的I_(D1)/I_(G)不断减小,即焦中碳结构有序程度不断提高,而A_(D3+D4)相对含量则先减小后稍有增加,但与热解焦相比均有所减小。在实验条件下不同次数循环后焦的气化活性均优于其热解焦,且随着循环次数的增加,焦的CO_(2)气化反应活性不断提高。

In order to investigate the evolution of carbon microstructure and gasification activity during circulating fluidized bed gasification,the simulated circulating gasification of a rice husk was carried out in a laboratory fixed bed reactor,and the pore structure,carbon microstructure and gasification activity of char during gasification were investigated.The results show that the BET surface area of char increases firstly and then decreases with an increase in gasification cycle times,and the surface areas of rice husk chars obtained from circulating gasification process are much higher than that of original char.The I_(D1)/I_(G) values of char decrease monotonously with an increase in gasification cycle times,indicating that the graphitization degree of carbon structure in char increases.Meanwhile,the relative content of A_(D3+D4) of char decreases firstly and then increases slightly with the progress of circulating gasification,and the relative contents of AD3+D4 of all chars obtained from a circulating gasification process are lower than that of original char.Moreover,the gasification activity of char increases gradually with an increase in gasification cycle times,and the gasification activity of all chars obtained from a circulating gasification process are higher than that of original char.