Preparation And Catalytic Performance Of Cobalt Based Catalysts For Fischer-Tropsch Synthesis

Fischer-Tropsch synthesis?FTS?was a method to convert syngas,which derived from coal,natural gas and biomass,into clean liquid fuel and high-valued industrial chemicals.It had been acknowledged as one of the most efficient technology to resolve the shortage of the liquid fuel.Cobalt-based catalysts were considered to be the most promising catalysts for Fischer-Tropsch synthesis,due to its high catalytic activity and chain growth capacity,difficult to carbon deposition and deactivation,low activity for water-gas shift reaction.In this paper,cobalt-based catalysts for Fischer-Tropsch synthesis were prepared by incipient wetness impregnation.The optimal catalysts which around the CO conversion and C₅-C₁₁ hydrocarbon gasoline selectivity,were used to prepare the composite catalysts.Their catalytic performances were evaluated in a fixed bed reactor.The properties of the catalysts were characterized by BET,XRD,TPR,TPD,FT-IR,and so on.This paper includes the following aspects:?1?The effects of oxide support such as SiO₂,carbon support such as CNTs,silica molecular sieve support such as MCM-41,SBA-15,acid molecular sieve support such as H?,HY,HZSM-5,mordenite on Co-based Fischer-Tropsch catalysts were investigated.The results showed that Co/SBA-15 catalyst had the highest CO conversion and Co/HZSM-5 catalyst had the highest selectivity of C₅-C₁₁ hydrocarbons.The Co/SBA-15 catalyst of CO conversion was 92.6%.The Co/HZSM-5 catalyst of the selectivity of C₅-C₁₁ hydrocarbons was 48.3%.The optimal catalysts which around the CO conversion and C₅-C₁₁ hydrocarbon gasoline selectivity,were the Co/SBA-15 catalyst and the Co/HZSM-5 catalyst.?2?The effect of different silica-alumina ratio on Co/HZSM-5 catalysts was investigated.The result showed that Co/HZSM-5?SiO₂/Al₂O₃=200?achieved the highest CO conversion and selectivity of C₅-C₁₁ hydrocarbons.The CO conversion was 84.1% and the selectivity of C₅-C₁₁ hydrocarbons was 52.8%.The effect of calcination temperature on Co/HZSM-5 catalysts was investigated.The result showed that the Co/HZSM-5 catalyst which under the calcination temperature of 400 oC,had the highest CO conversion and selectivity of C₅-C₁₁ hydrocarbons.The CO conversion was 84.1% and the selectivity of C₅-C₁₁ hydrocarbons was 52.8%.?3?Based on the previous study,the optimal catalysts were used to prepare the composite catalysts.The effect of different HZSM-5 silica-alumina ratio on Co/?SBA-15+HZSM-5?catalysts was investigated.The result showed that the Co/SZ-200-4 catalyst had the highest CO conversion and selectivity of C₅-C₁₁ hydrocarbons.The effect of different mass ratio of SBA-15 and HZSM-5 on Co/?SBA-15+HZSM-5?catalysts was investigated.The result showed that the Co/SZ-200-4 catalyst had the highest CO conversion and selectivity of C₅-C₁₁ hydrocarbons.The CO conversion was 93.0% and the selectivity of C₅-C₁₁ hydrocarbons was 51.8%.?4?Compare to the Co/HZSM-5-200 and Co/SBA-15 catalyst,the Co/SZ-200-4 catalyst had the highest C₅-C₁₁ hydrocarbons yield.The C₅-C₁₁ hydrocarbons yield was 48.2%.