摘要
采用热重分析仪(TGA)来探究胜利褐煤的灰分和气化温度对其焦样CO2气化反应性及结构的影响。将胜利褐煤(SL)经HCl-HF酸洗处理制得脱灰褐煤(DSL),然后在管式炉中制取焦样。通过扫描电子显微镜(SEM)、傅立叶红外光谱仪(FTIR)、氮气吸附脱附仪(BET)分析脱灰前后煤样的结构和性质差异。结果表明:胜利褐煤富含含氧官能团,酸洗处理不会破坏胜利褐煤中的主要官能团,但在一定程度上脱除了侧链和小分子。脱灰褐煤煤基质表面矿物质颗粒显著减少,比表面积增加,孔结构也更加发达。但等温气化时脱灰褐煤的气化反应性却低于胜利褐煤的气化反应性,故猜测两种煤焦在不同温度下气化时有着不同的控制机理,为此提出两种气化反应性指数R 0.5和R 0.9,结果证实:胜利褐煤气化反应性在低温阶段由煤样中碱金属和碱土金属元素(AAEM)的催化作用主导,在高温阶段由煤样的孔结构扩散作用控制。另外,采用了分布活化能模型(DAEM)和随机孔模型(RPM)对气化反应性进行动力学分析,DAEM的拟合程度略好于RPM的拟合程度。
The effects of the temperature and the ash content on the CO2 gasification reactivity and the structural characteristics of the Shengli lignite(SL)char were investigated through the thermogravimetric analyzer.The demineralized lignite(DSL)was obtained by using the HCl-HF acid-washing treatment for the SL raw coal.Then the coal char was prepared in a tube furnace.The morphology and structural features of the two coal simples were analyzed through the scanning electron microscope,Fourier infrared spectroscopy,and nitrogen absorption-desorption.The results show that the SL possesses a large number of oxygen-containing functional groups,and the acid-washing pretreatment partly removes the side chains and small molecules.The mineral particles on the surface of the DSL coal matrix are dramatically decreased,while the specific surface area increases and the pore structure become more advanced.By contrast,it is observed that the gasification reactivity of the DSL is lower than that of the SL during the isothermal gasification.It is hypothesized that there are different control mechanisms during the coal gasification process.Therefore,two gasification reactivity indexes,namely R 0.5 and R 0.9,were introduced,and the results confirm that the gasification reactivity of SL is dominated by the catalytic function of alkali and alkaline earth elements at relatively low temperatures and controlled by the diffusion within the pores at relatively high temperatures.In addition,the distributed activation energy model and random pore model were used for dynamic analysis.The fitting by using the DAEM is slightly better than that by using the RPM.
作者
李润
周敏
王姗
LI Run;ZHOU Min;WANG Shan(School of Chemical Engineering and Technology,China University of Mining and Technology,221100 Xuzhou,China)
出处
《煤炭转化》
CAS
CSCD
北大核心
2020年第6期26-32,共7页
Coal Conversion
基金
国家重点研发计划资助项目(2016YFE0102500-11-01).
关键词
灰分
温度
气化反应性
焦样结构
动力学分析
ash
temperature
gasification reactivity
char structure
kinetics analysis
