水热处理对Mo-Ni/Al_2O_3催化剂活性结构和催化硫醚化反应性能的影响

Effect of Hydro-Thermal Treatment on Active Phases and Catalytic Thioetherification Performance of Mo-Ni/Al_2O_3 Catalyst

采用水热处理的方法对Mo-Ni/Al_2O_3催化剂的微观孔结构性质和负载金属的结构性质进行调变,并考察调变后催化剂在硫醚化反应中的催化性能。结果表明,水热处理可增加催化剂的平均孔径,有利于产物中形成的大分子异构硫醚的扩散,维持催化剂的稳定性;还可以降低负载金属与载体间的作用,提高负载金属的硫化度,增加Ni-Mo-S活性中心数目。然而,这些对催化剂结构性质的促进作用,不仅提高了硫醚化反应过程的硫醚化反应和二烯烃选择加氢反应性能,还大大促进了烯烃的加氢饱和反应,造成反应产物辛烷值的损失。

Mo-Ni/Al_2O_3 catalysts were hydro-thermally treated to investigate the properties of the microscopic pore structure and the active metals supported on the carriers.Meanwhile,the catalytic performance of the Mo-Ni/Al_2O_3 catalysts were also tested for the thioetherification process in a conventional fixed bed reactor.The results showed that the hydro-thermal treatment could increase the average pore diameter, which contributed to molecular diffusion of isomerized thiother products,and promote catalytic stability.The hydro-thermal treatment of the catalysts could decrease the interaction of the metals and carriers,which could improve the sulfidation degree of the metals and increase the amount of Ni-Mo-S active sites.However,the results was also proved that as the sulfidation degree of the metals supported on the carriers was raised,not only the catalytic performance of thioetherification reaction and selective hydrogenation of diene were improved,but also hydrogenation of olefin was enhanced,which caused the dramatic loss of product octane value.