添加CO2对Fischer-Tropsch合成反应的影响  

Effect of CO_2 Addition on Fischer-Tropsch Synthesis

作　　者：刘颖[1] 郝栩[1] 相宏伟[1] 徐元源[1] 钟炳[1] 李永旺[1] 

机构地区：[1]中国科学院山西煤炭化学研究所煤转化国家重点实验室

出　　处：《石油化工》2008年第5期450-455,共6页Petrochemical Technology

基　　金：国家杰出青年科学基金项目(20625620);国家自然科学基金项目(20590361);国家科技部“973”计划前期研究专项基金项目(2007CB216401)

摘　　要：采用无梯度反应器,在Fe-Mn催化剂、不同氢碳比和反应温度下,考察了反应体系中添加CO2对Fischer-Tropsch合成反应的影响。实验结果表明,添加CO2可加快水煤气逆变换反应的速率,CO2的选择性降低。当反应体系总压不变时,在不同氢碳比和反应温度下,添加CO2降低了合成气的分压,CO转化率降低,含氧化合物的生成速率也呈下降趋势。添加CO2降低了表面氢物种的浓度,低碳烃的烯烷比增大。乙烯的再吸附及二次反应性能强于丙烯、丁烯等的再吸附及二次反应性能;随氢碳比的增大,乙烯二次加氢反应显著增强。无论添加CO2与否,乙烯选择性均随氢碳比的增大而降低,而其他轻质烃的选择性则随氢碳比的增大而增加。在本实验条件范围内,水煤气变换反应仍远离平衡。Effect of CO2 addition on Fischer-Tropsch （F-T） synthesis was studied on an Fe-Mn catalyst in a spinning basket reactor at different n （ H2 ） ： n （ CO ） and reaction temperatures. CO2 addition would lead to speeding of reverse reaction of water gas shift （WGS） and a drop of CO2 selectivity. CO2 addition would bring down partial pressure of syngas and suppress CO conversion. The formation rate for oxygen compounds decreases when CO2 is added to the feed gas. It also decreases surface hydrogen concentration. As a result paraffin formation is inhibited, mole ratio of olefin to paraffin is lifted. Ethylene is one of the most active species in the complicated F-T synthesis. It shows unique characteristic of re-adsorption and than that of propylene and butylene. Therefore, no secondary hydrogenation which are much stronger matter whether CO2 is added to the feed gas or not, selectivity of ethylene decreases with increasing of n （ H2 ） ： n （ CO）, which is contrary to selectivities of other light hydrocarbons. WGS reaction is still far from thermodynamic equilibrium under wide F-T synthesis conditions.

关 键 词：FISCHER-TROPSCH合成 水煤气变换 铁-锰催化剂 二氧化碳 一氧化碳 

分 类 号：TQ031.2[化学工程]