Impact of adding CO2 in stirred-tank reactor on Fischer-Tropsch synthesis
To investigated the effect of CO2 on the Fischer-Tropsch Synthesis(FTS)reaction of iron catalyst,the effect of the partial pressure change of CO2 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 CO2 partial pressure,while water-gas shift(WGS)reaction rate was basically stable,which meant the FTS reaction was more sensitive to CO2 than WGS reaction.When the partial pressure of CO2 exceeded 0.58 MPa,it began to have a strong negative effect on the forward WGS reaction,resulting in a significant decrease of CO2 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 CO2 partial pressure,H2 conversion rate first decreased slightly and then increased slowly,and the minimum value occurred when CO2 partial pressure was about 0.4 MPa.The addition of CO2 shortened the residence time and decreased the ratio of H2/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 CO2 partial pressure,the oxygenates content in the product water first decreased and then increased.
NETL
NSTL
万方数据
