高比表面积双孔SiO2负载钴基催化剂费托合成反应性能研究

Fischer-Tropsch synthesis performance of cobalt-based catalysts supported on bimodal porous SiO_(2)with high specific surface area

载体的结构可以显著影响钴基费托合成催化剂的活性和产物选择性。大孔结构载体可以改善反应物和产物的传质情况,提升CO转化活性和C5+产物选择性;高比表面积载体有利于使负载的金属分散,提高催化剂的金属利用效率和稳定性。然而,要获得同时具备高比表面积和大孔结构特征的载体相对困难。本研究采用结构导向水解法,合成了一种比表面积达1103.2 m^(2)/g的介孔(2.9 nm)-大孔(63.8 nm)双孔二氧化硅(BP-SiO_(2))载体,研究了其负载钴催化剂的费托合成反应性能。结果表明,相对规整介孔SBA-15分子筛负载的钴催化剂Co/SBA-15,210℃反应时,催化剂Co/BP-SiO_(2)的CO转化率提高33.3%,CH4选择性降低30.1%,C_(5+)选择性增加到80.0%,稳定性显著增强。

The structure of the supports can significantly affect the Fischer-Tropsch catalyst activity and selectivity.The porous structure can improve the mass transfer of reactants,enhance the CO conversion activity and C5+product selectivity;the high specific surface area is beneficial to disperse the loaded metal,improve the catalyst metal utilization efficiency and catalyst stability.However,it is relatively difficult for supports to obtain high specific surface area and macropore structure characteristics simultaneously.A mesoporous(2.9 nm)-macroporous(63.8 nm)bi-porous silica(BP-SiO_(2))support with a high specific surface area of 1103.2 m^(2)/g was synthesized by the structure-directed hydrolysis method,and its catalytic performance for Fischer-Tropsch synthesis was investigated.The results showed that compared to the Co/SBA-15 catalyst with equivalent mesopore diameter,the catalyst Co/BP-SiO_(2)showed CO conversion rate nearly increased by 33.3%,CH_(4)selectivity reduced by 30.1%,improved C_(5+)selectivity and stability.