摘要
为研究CO_(2)对铁基催化剂费托合成反应的影响,利用搅拌釜反应器和沉淀铁费托合成催化剂,在合成气分压不变条件下,研究了CO_(2)分压变化对费托合成反应的影响。试验表明:相较于水煤气变换反应,费托合成反应对CO_(2)更为敏感,较低CO_(2)分压即可带来费托合成反应速率的明显下降,而水煤气变换反应则在低CO_(2)分压时基本保持稳定。当CO_(2)分压超过0.58 MPa后,其对水煤气变换反应正反应产生较强的抑制作用,使得CO_(2)生成速率显著下降,而此时CO反应速率趋于平稳,更多的CO发生费托合成反应,造成水生成速率的大幅提升。H_(2)转化率随CO_(2)分压的增加先轻微下降后缓慢提升,在CO_(2)分压0.4 MPa附近出现最小值。CO_(2)的加入使得反应停留时间缩短,同时引起催化剂表面吸附的H_(2)和CO摩尔比下降,导致低碳烃产物选择性和烯烃烷烃摩尔比增大。费托合成产物中的含氧化合物以甲醇、乙醇、乙酸等低碳醇类、酸类为主,约占含氧化合物总质量分数的95%以上,随着CO_(2)分压的增加,产物水中的含氧化合物含量先降低后增加。
To investigated the effect of CO_(2) on the Fischer-Tropsch Synthesis(FTS)reaction of iron catalyst,the effect of the partial pressure change of CO_(2) on FTS was studied in a stirred tank reactor with precipitated-iron based catalyst under the condition of unchanged partial pressure of syngas.The results showed that FTS reaction rate decreased significantly at low CO_(2) partial pressure,while water-gas shift(WGS)reaction rate was basically stable,which meant the FTS reaction was more sensitive to CO_(2) than WGS reaction.When the partial pressure of CO_(2) exceeded 0.58 MPa,it began to have a strong negative effect on the forward WGS reaction,resulting in a significant decrease of CO_(2) generation rate.At the same time,CO reaction rate tended to level off,which meant more CO took reaction in FTS,causing a substantial increase of water generation rate.With the increase of CO_(2) partial pressure,H_(2) conversion rate first decreased slightly and then increased slowly,and the minimum value occurred when CO_(2) partial pressure was about 0.4 MPa.The addition of CO_(2) shortened the residence time and decreased the ratio of H_(2)/CO adsorbed on the catalyst surface,leading to an increase of both the selectivity of low-carbon hydrocarbon products and the olefin/paraffin ratio.The oxygenates in FTS products were mainly low-carbon alcohols and acids such as methanol,ethanol and acetic acid,which accounted for more than 95%of the total oxygenates.With the increase of CO_(2) partial pressure,the oxygenates content in the product water first decreased and then increased.
作者
张奉波
樊晶
孟祥堃
门卓武
Zhang Fengbo;Fan Jing;Meng Xiangkun;Men Zhuowu(National Institute of Clean-and-Low-Carbon Energy,Beijing 102211,China;China Chemical Technology Research Institute,Beijing 102402,China)
出处
《煤化工》
CAS
2024年第4期88-91,96,共5页
Coal Chemical Industry
关键词
费托合成
CO_(2)
水煤气变换
反应速率
转化率
选择性
Fischer-Tropsch synthesis
CO_(2)
water-gas shift reaction
reaction rate
conversion rate
selectivity
