快速热解温度下的淮南煤焦与水蒸汽气化反应的研究  

Effects of Pyrolysis Temperature on Steam Gasification of Huainan Char

作　　者：许慎启[1] 周志杰[1] 杨帆[1] 于广锁[1] 于遵宏[1] 

机构地区：[1]华东理工大学煤气化教育部重点实验室,上海200237

出　　处：《高校化学工程学报》2008年第6期947-953,共7页Journal of Chemical Engineering of Chinese Universities

基　　金：国家重点基础研究发展规划(973计划)(2004BC217704);长江学者和创新团队发展计划资助(IRT0620);教育部新世纪优秀人才支持计划(NCET-06-0416)

摘　　要：考察了淮南煤在不同温度下快速热解制得的煤焦与水蒸汽的气化反应,研究发现煤焦的气化反应速率不仅与转化率有关也与气化反应时间有关,对不同热解温度煤焦在x=0.2、t=2min附近时,化学反应速率存在极值或转折点(Q),即反应速率开始急剧减少的点。用未反应芯缩核模型和随机孔模型对实验数据拟合,结果表明随机孔模型对实验数据的拟合更为准确,并将拟合得到的结构参数ψ与煤焦气化反应活性之间的关系进行分析,发现同一种煤焦ψ相近,但ψ与煤焦的气化反应活性不存在必然的联系。用SEM和XRD考察了不同热解终温下的煤焦表面孔隙结构与微晶结构的变化及其对煤焦气化反应活性的影响,不同热解温度下制得的煤焦,其形态结构存在很大的差异,热解温度越高,煤焦表面壳状凸起越多,化学反应性降低。此外,随着热解温度的升高,煤焦的微晶结构趋于石墨化,化学稳定性增强。The purpose of this study is to investigate the steam gasification reaction of Huainan coal chars prepared with different pyrolysis temperatures. The experiments show that the gasification rate is not only related to the conversion ratio x, but also related to the reaction time t, and the gasification rate increases with increasing conversion rate and reaction time at first, and then decreases promptly after reaching a peak or a turning point Q locating around x=0.3, t=2 min. The experimental data fitting was conducted by using the random pore model and the unreacted-core shrinking model, respectively, and the results show that the random pore model fits the data better. The initial pore structure parameters ψ0 of the chars pyrolyzed at different temperatures were obtained from the fitting curves of the data, and it was found that the variation of ψ0 is small for the same char under different reaction temperatures. Since the surface morphology and the crystallite structure of the char affect its reactive activity, the SEM and XRD were used to investigate the difference of the chars pyrolyzed with different temperatures. The results show that the higher the pyrolysis temperature is, the more the shell-like protrusions on the char surface are formed, and the lower gasification activity the char can have. Moreover, accompanying with the increase of pyrolysis temperature, the char crystallite structure tends to be graphitized and the chemical stability of the char increases.

关 键 词：高温热解 水蒸汽气化 随机孔模型 未反应芯缩核模型 

分 类 号：TQ546.2[化学工程—煤化学工程]