磷对MoCoNi/Al2O3催化剂性能及活性结构的影响

摘要

采用饱和浸溃法分别制得含磷及不含磷的MoCoNi/Al2O3渣油加氢催化剂,采用科威特常压渣油为原料对催化剂性能进行评价,并通过TPR、DRS等方法对催化剂结构进行表征,研究磷对MoCoNi/Al2O3催化剂反应性能及活性结构的影响.结果表明:与MOCoNi/Al2O3催化剂相比,添加磷的MOCoNiP/Al2O3催化剂在渣油加氢反应中具有更高的杂质脱除能力,而且催化剂加氢活性的提升改善了加氢后产品作为催化裂化原料的整体性能;添加磷的MOCoNiP/Al2O3催化剂活性组分的低温还原性提高,增加了八面体配位钼物种的数量,从而提高了催化剂活性;添加磷的MoCoNiP/Al2O3催化剂的孔体积和比表面积有所损失,不利于催化剂容金属能力的提升,但反应后催化剂表面的积炭量没有发生变化,说明催化剂的抗积炭性能得到了保持.%MoCoNi/A12O3 and MoCoNiP/Al2 O3 hydrotreating catalysts were prepared by saturation impregnation method respectively.The effect of phosphorus on the catalytic performance and active component structure of the catalysts was studied using Kuwait atmospheric residue as feedstock and characterizing by DRS,TPR and other techniques.Results showed that as compared with MoCoNi/Al2O3 catalyst, MoCoNiP/Al2O3 catalyst exhibited improved hydrotreating activity,and furthermore,its higher hydrogenation activity led to obtain a totally improved quality product for FCC feedstock.For MoCoNiP/Al2 O3 catalyst, due to the increase of Mo(O)species in octahedral structure, the reduction ability of active components at low temperature was enhanced and the catalyst activity was promoted.The pore volume and surface area of the phosphorus modified catalyst were reduced in some extent,which was unfavorable to the metal tolerance performance of catalyst.However,the coke deposits on the catalysts with or without phosphorus were the same, indicating that the two catalysts had similar ability to restrain coke formation.