金属分散位置对加氢裂化催化剂性能的影响

摘要

以Y分子筛、β分子筛和无定形硅铝基质材料为载体组分,通过将金属组分负载在不同载体组分的表面制备了金属分散位置不同的催化剂,考察了载体酸中心与金属中心的位置分布对催化剂孔结构、酸性和加氢裂化反应活性的影响.结果表明,与金属组分均匀分散于无定形硅铝和分子筛上相比,将金属组分全部负载于无定形硅铝材料上时催化剂的比表面积损失较小,催化剂中分子筛的酸性降低程度低;金属组分活性中心距离载体强酸中心较近时,有利于反应物分子由酸中心向加氢中心扩散,催化剂的加氢反应活性较高,反应转化率、轻油选择性及化工原料收率均较高,但液体收率较低.%Hydrocracking catalysts with different metal distribution were prepared by impregnation method,where the metals were loaded ① on mixture of Y,β zeolite and amorphous silica-alumina,or ② on SiAl first and then mechanically mixed with Y and β zeolite mixture,respectively.The effect of metal and acidity distribution on the pore structures,acidity,and hydrocracking performance of the catalyst prepared by two different methods was investigated.The results show that the surface area and acidity are slightly lowered by the second way,compared with the first method.It is proved that shorter distance between metal and acidic center is favorable to the diffusion of reactant from acidic center to metal center,resulting in higher conversion rate,light oil selectivity and the yield of chemical raw materials,while the liquid yield is relatively lower.