焙烧温度对Mo-Ni/SiO_2-Al_2O_3-Y加氢裂化催化剂反应性能的影响

Effect of calcination temperature on hydrocracking performance of Mo-Ni/SiO_2-Al_2O_3-Y catalyst

以碱式碳酸镍和硝酸镍为镍源（前者占镍源总质量的2/3）,三氧化钼为钼源,采用等体积浸渍法制备了Mo-Ni/SiO2-Al2O3-Y加氢裂化催化剂,并对其性质进行了表征。以正十二烷为模型化合物,在反应压力为4 MPa,氢气/原料油（体积比）为1 200,空速为2.0 h-1,反应温度为320℃的条件下,对催化剂的加氢裂化性能进行了评价。结果表明,当焙烧温度低于480℃时,金属物种在催化剂表面高度分散;高于500℃时,MoO3物种出现一定程度的聚集。随着焙烧温度升高,催化剂的孔容和比表面积均降低,孔径分布向小孔径方向略有迁移。当焙烧温度为480℃时,正十二烷转化率和C4~C8选择性均达到最大值,二者分别为62.3%,85.6%。

Hydrocracking catalyst Mo - Ni/SiO2 -Al2O3 -Y was prepared by equal volume impregna- tion method with basic nickel carbonate and nickel nitrate （the former was 2/3 of total mass） as nickel sources, molybdenum trioxide as molybdenum source,and its property was characterized. The hy- drocracking properties of catalyst were evaluated with n - dodecane as model compound under the conditions of reaction pressure 4 MPa, H2/raw mate- rial（ volume ratio） 1 200,weight hourly space veloc- ity 2.0 h-1 and reaction temperature 320 ℃. The results showed that the metal species were highly dispersed on the surface of the catalyst at calcinationtemperature below 480℃, and MoO3 active compo- nent aggregated over 500 ℃. With the increase of calcination temperature, the pore volume and specif- ic surface decreased, the pore size distribution slightly migrated in the direction of small pore size. When the calcination temperature was 480℃, the n - dodecane conversion rate and selectivity of C4 - Cs components reached the maximum value,62.3% and 85.6% respectively.