焦油组分重整过程中关键反应的机理研究
Mechanism investigation of key reactions during tar component reforming process
杜文亚 1于震宇 2郭锐 2孙超 2邵正日 3谢华清2
作者信息
- 1. 重庆赛迪热工环保工程技术有限公司,重庆 401120
- 2. 东北大学 冶金学院,辽宁 沈阳 110819
- 3. 营口理工学院 辽宁省储能与能源利用技术重点实验室,辽宁 营口 115014
- 折叠
摘要
采用密度泛函理论计算方法,对焦油重整过程中主要发生的C-C键裂解反应、CH4 重整反应和水煤气转化反应的机理和能量变化进行探究.结果表明:在C-C键裂解反应中,C3H8 首先吸附于催化剂表面形成吸附态C3H8*,进一步裂解生成CH3*和CH2CH3*,裂解反应放热,但是反应能垒较大,较难进行;在CH4 重整反应中,CH4*发生顺序脱氢反应生成CH3*,CH2*,CH*,相比于继续脱氢,CH*更倾向于与OH*发生重整反应生成CHO*,CHO*脱氢生成CO*,各步骤产生的H*结合生成H2*,CH2*裂解生成CH*的反应为CH4 重整反应的限速步骤;在水煤气转化反应中,H2O*分解后生成的OH*更倾向于与CO*结合生成COOH*,而不是直接与H*生成H2*,COOH*脱去H,生成COO*,该反应为限速步骤.
Abstract
Density functional theory calculations were employed to investigate the mechanisms and energy changes involved in C-C bond cracking,CH4 reforming,and water gas shift reactions in the tar reforming process.The findings reveal that,in the C-C bond cracking reaction,C3H8 initially adsorbs onto the catalyst surface to form adsorbed C3H8*,subsequently undergoing cleavage to produce CH3*and CH2CH3*.While the cracking reaction is exothermic,it is hindered by a significant energy barrier and difficult to carry out.In the CH4 reforming reaction,CH4*undergoes sequential dehydrogenation reactions,producing CH3*,CH2*,and CH*.Comparatively,CH*has a greater tendency to react with OH* to form CHO*,which further undergoes dehydrogenation to form CO*.Additionally,H*generated in each step combines to form H2*.Throughout the CH4 reforming process,the rate-limiting step is the cracking of CH2*to CH*.In the water gas shift reaction,the OH*species formed from H2O*decomposition prefers to combine with CO*to generate COOH*rather than directly reacting with H*to produce H2*.COOH*removes H and generates COO*,which is the rate limiting step.
关键词
焦油/重整/密度泛函理论/基元反应Key words
tar/reforming/density functional theory/elementary reaction引用本文复制引用
基金项目
辽宁省储能与能源利用技术重点实验室基金项目(CNWK202305)
出版年
2024
国家科技期刊平台
NSTL
维普
万方数据