Studies On Synthesis Of Olefins From Syngas

In this paper,the most crucial problems for the preparation of catalysts for synthesis of low-carbon olefins in syngas are discussed.With cordierite as the carrier,iron-based catalyst as the main body,the effect of different metal molybdenum and nickel on the catalyst performance of different catalysts is studied.The characteristics of the phase,morphology,and electron binding energy of different catalysts are investigated,and the mass ratio between different substances in the process of preparing the catalyst,the modification of the aluminum sol of the carrier cordierite,the influence of the amount of the additive on the catalyst performance etc.are studied.The reaction factors,temperature,syngas ratio and space velocity were discussed to obtain the best catalytic activity.The details are as follows:1.Fe-Mo based loaded with cordierite catalyst was prepared by impregnation method.The structure and morphology of the catalyst were characterized by SEM、FT-IR、XRD、EDX and XPS methods.It was found that the catalyst played an active role in iron and molybdenum,in the form of iron oxide and molybdenum oxide respectively.The catalytic performance for syngas was investigated under optimum reaction conditions:H2/CO=2,WHSV= 2.0 L/g cat-h,450℃.The results showed that the selectivity of ethylene and conversion of carbon monoxide was up to 46.3%and 63.5%,respectively.2.On the basis of the above catalyst,it was found that the catalyst had good catalytic effect by the addition of potassium promoter to improve the electronic structure of the catalyst and modified the cordierite by the aluminum sol.The structure and morphology of the catalyst were analyzed by SEM,TEM,EDX,XRD and XPS.The addition of the potassium promoter had an effect on the structure of the catalyst.It was more favorable for the iron material to exist in the form of low valence,which was beneficial to the formation of the active state in the literature.3.The results showed that the optimal composition of catalysts for ethylene production was:the weight ratio of Fe-Mo was 1:1,which promoted with 0.12wt%K and Al sol modified cordierite.The results showed that the best operational conditions were H2/CO＝1 at 450℃and gas hourly space velocity(GHSV)of 1200 mL/g cat-h.The K promoter with Al sol modified Fe-Mo/cordierite catalyst showed high CO conversion(51.4%)and ethylene selectivity(25.2%).4.A series of Fe-Ni based loaded with cordierite catalysts were prepared by impregnation method.It was found that Fe-Ni based catalyst had an obviously effects on the synthesis of C2 hydrocarbon.The catalytic performance for syngas was investigated under reaction conditions of H2/CO= 2,GHSV= 2800 mL/g cat-h,and 450 ℃.The results showed the selective of C2 hydrocarbon and conversion of carbon monoxide was up to 37.7%and 58.5%,respectively,and the ethylene selectivity up to 26.6%.