The Study Of Promoter On Iron-Based Catalyst For CO₂Hydrgenation

C02hydrogenation can make the waste to profitable, which is an important way to cut down carbon emission. CO2hydrogenation to hydrocarbon is one of the most effective methods to remit the shortage of current energy supply. Iron-based catalyst is considered to be the most promising catalyst for CO2hydrogenation. We studyed the catalyst promoter and SiO2content in order to improve the iron-based catalyst activity, stability and selectivity to C5+product. This research is to advance the iron-based catalyst of CO2hydrogenation to hydrocarbon into industrial application.This paper focuses on the effect of Zn, K, Cu, Al and Ca additives, and the content of SiO2in iron-based catalyst on CO2hydrogenation reaction properties.The low temperature N2adsorption, X ray diffraction (XRD) have been used to know the physic-chemical properties and research the relationship between catalyst structure and its reaction performance. The results are as follows:1. CO2hydrogenation with ZnKCu/FeSi catalyst was investigated. The catalytic synthesis process has been optimized by testing the promoters’content, reaction temperature, dilution effect of inert gas and the catalyst use-pattern. With the Zn:K:Cu=6:2:2catalyst, the260℃reaction temperature,4%inert gas, catalyst loading by using one tube serie, there is a appropriate activity, the best selectivity of C5+hydrocarbon.2. CO2hydrogenation of AlKCa/FeSi catalyst was investigated. The single additive and three additives added catalyst were tested. The specific surface area of single additive catalysts is lower than FeSi precursor. Ca promoter has a strong function to expand the pore size. The optimal amount is7%for Al, and5%for K. Ca promoter is indispensable, although the adding amount is as low as0.25%.3. The SiO2content in the catalyst has been changed to control the interaction of metal-supporter. When the SiO2content is20%, the specific area is the largest. When the content is15%, it has the smallest pore size. With the increase of SiO2content, the catalyst crystallinity decreased.The phase of iron oxide is existed in the catalysts with y-Fe2O3. The influence of SiO2content on the reaction performance of AlKCa/FeSi catalyst (Al:K:Ca=2:3:0.25) were studied. For the SiO2content of5-15%, the activity of catalysts is changed little. When the content is20%, the activity of the catalyst decreased significantly. The change of the content of SiO2had little influence on the distribution of C1-C5hydrocarbons in catalytic products, but a greater impact on the C2-C5olefin product ratio. With the SiO2content is10%, olefin ratio of the product is highest.