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采用连续共沉淀与喷雾干燥成型技术相结合的方法制备了微球形Fe- Cu- K- SiO2催化剂,并考察了焙烧温度对催化剂的结构和织构性质的影响.结果表明,催化剂具有较好的织构和结构热稳定性,粘结剂SiO2起到了分散和稳定α-Fe2O3晶相的作用.随着焙烧温度的升高,催化剂的比表面积逐渐减小,α-Fe2O3晶粒逐渐增大,催化剂体相中的Cu和K原子向表面富集,且Cu向表面的迁移更明显;同时,催化剂中的α-Fe2O3和CuO相发生了一定程度的离析,Cu的助剂作用减弱,使催化剂在合成气气氛下难于还原碳化.催化剂在n(H2)/n(CO)=0.67,GHSV=2.0L/(g·h),p=1.5MPa和θ=250℃下的浆态床F T合成反应评价结果表明,升高焙烧温度,催化剂的初活性和最高活性下降,但运行稳定性提高,而且有效地抑制了CH4的生成,明显促进了烃产物向高碳数方向移动.反应600h后卸载下的催化剂的形貌观测表明,催化剂的磨损主要是由化学磨损引起的,提高焙烧温度可明显改善其抗磨损性能,焙烧温度高于400℃时,催化剂具有较好的抗磨损性能.
The microspherical Fe-Cu-K-SiO2 catalyst was prepared by a combination of continuous coprecipitation and spray-drying. The effects of calcination temperature on the structure and texture properties of the catalyst were investigated. The results show that the catalyst has good Texture and thermal stability of the structure, the binder SiO2 played the role of dispersion and stable α-Fe2O3 crystal phase.With the calcination temperature increases, the specific surface area of the catalyst decreases gradually, α-Fe2O3 grains gradually increase, The Cu and K atoms in the bulk of the catalyst are enriched to the surface and the migration of Cu to the surface is more obvious. At the same time, the α-Fe2O3 and CuO phases in the catalyst are segregated to a certain degree, the effect of the Cu promoter is weakened, It is difficult to reduce carbonization under a syngas atmosphere Catalyst Slurry bed FT synthesis at n (H2) / n (CO) = 0.67, GHSV = 2.0 L / (g · h), p = 1.5 MPa and θ = The results of the reaction evaluation showed that the calcination temperature, the initial activity and the maximum activity of the catalyst decreased, but the operation stability was improved, and the generation of CH4 was effectively suppressed, and the hydrocarbon product was obviously promoted to the high carbon direction. After 600 hours of reaction, the catalyst was unloaded The morphology of the catalyst under the observation shows that the catalyst wear is mainly caused by Science caused by wear, can significantly increase the firing temperature to improve its wear resistance, the firing temperature is higher than 400 ℃, the catalyst having a good wear resistance.