Study On Cobalt Base Catalysts For Producting-The Light Olefins From Synthesis Gas

Fischer-Tropsch synthesis (FTS) is a process which synthesis gas (CO and H2) is converted into aliphatic hydrocarbons and oxygenates via surface polymerization. As Fischer-Tropsch synthesis using coal, natural gas and other resources, through steam reforming or gasification processes producing clean fuels, it has attracted much attention because of the shortage of oil resources. The distribution of FTS products is mixture and fellows Anderson-Schultz-Flory (ASF) distribution. Therefore the study of catalyst to improve selectivity of light olefins has gradually been in a hot research. In this study, we prepared five different morphology Co3O4 (particle, sheet, rod, sphere, cube) catalyst to investigate the effects of catalyst morphology on selectivity of light olefins (C2-C4-). The physicochemical property of catalyst was characterized by XRD, TPR, SEM, TEM, and XPS. The Mn promoter on the activity of catalyst and selectivity of light olefins were also studied. On the other hand, a series of cobalt catalysts supported on Q50 with different Mn content were prepared by impregnation method to investigate the effects of promoter, support and impregnation method on properties of obtained catalyst.Five different morphology Co3O4 were prepared by hydrothermal synthesis to analyze the effects of phase composition, crystal size, crystal surfaces on FTS reaction. The results show that particle Co3O4 and sheet Co3O4 have a better activity for smaller grain diameter and higher reduction degree, and sphere Co3O4 and cube Co3O4 have better selectivity of C2=?C4=The Mn/C03O4 catalysts with different Mn content were prepared by impregnation method to study on Mn promoter on FTS performance. The results indicated that the Mn promoter induce both structural and electronic promotion effects, decreased the H2 chemisorption and C5+selectivity. The selectivity of C2=?C4= was 48.44% and O/P was 3.75 for 10%Mn/Co3O4.A series of xMn/Co3O4/Q50 catalyst were prepared by impregnation method to investigate the effects of FTS performance. The result showed that pore size of support could significantly affect the pace times of FT production preventing the secondary hydrogenation.