结构助剂SiO2、Al2O3对铁基催化剂浆态床F-T合成性能的影响

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状Fe/Cu/K/SiO2和Fe/Cu/K/Al2O3催化剂，研究SiO2和Al2O3作为结构助剂对铁基催化剂吸附行为、炭化行为及F-T合成反应性能的影响。表征结果表明,与Al2O3相比较，SiO2抑制了H2的吸附，但促进了CO的吸附，有利于催化剂的炭化。催化剂在260℃、1.5MPa、H2/CO=0.67和2000h-1下的浆态床F-T合成反应评价表明，Fe/Cu/K/SiO2催化剂具有较高的F-T合成活性、高的水煤气变换反应（WGS）活性，且其烃产物选择性明显向高炭数方向偏移，而Fe/Cu/K/Al2O3催化剂则表现出较低的F-T合成活性、低的水煤气变换反应（WGS）活性和高的轻质烃选择性。但Fe/Cu/K/Al2O3催化剂比Fe/Cu/K/SiO2催化剂具有更好的运行稳定性。

Effect of SiO2 and Al2O3 on performances of iron-based catalysts for slurry Fischer-Tropsch synthesis

Two spherical iron-based catalysts (Fe/Cu/K/SiO2 and Fe/Cu/K/Al2O3) were prepared by the combination of coprecipitation and spray drying method for the application of slurry Fischer-Tropsch synthesis (FTS). The effects of SiO2 and Al2O3 on the reduction and the carburization behaviors of iron-based catalysts were studied using temperature-programmed desorption (TPD) in H2 and CO, isothermal reduction in syngas, and Mssbauer-effect spectroscopy (MES). The results indicate that SiO2 suppresses the H2 adsorption, facilitates the CO adsorption, and the carburization as compared with Al2O3. The FTS performances of the catalysts were evaluated in a slurry reactor under the industrial relevant reaction conditions of 260℃, 1.5MPa, H2/CO = 0.67, and a space velocity of 2000h-1. This indicates that SiO2-supported catalyst has higher FTS activity, higher water-gas shift reaction (WGS) reactivity, and higher selectivities to heavy hydrocarbons. Furthermore, the run stability of Al2O3 supported, iron-based catalyst is better than SiO2 supported catalyst.