Y分子筛处理方式对催化剂及费托蜡加氢裂化性能的影响

Effect of treatment methods of Y zeolite on catalysts and their hydrocracking performance for Fischer-Tropsch wax

选择Ni/W为加氢金属组分,金属改性Y和Al2O3作为载体,制备不同金属溶液处理加氢裂化催化剂,采用加氢金属溶液调节NH4Y分子筛的物化性质,考察金属预处理方式对催化剂物性结构及加氢裂化反应性能的影响。结果表明,经金属溶液处理后,催化剂活性和柴油选择性比非金属溶液处理的催化剂均有显著提高。NH4Y分子筛经过偏钨酸铵溶液处理后,W6+进入分子筛孔道或笼内,与酸性位形成较强的离子键,降低催化剂的B酸,同时使金属离子与酸性位点间的距离适当减小,使得费托蜡加氢裂化在高转化率下得到较好的柴油选择性。

Using Ni/W as metal component for hydrogenation, Y zeolite modified with metals and Al2O3 as the supports, the hydrocracking catalysts were prepared by treating with metal solutions. The effects of metallic pretreatment methods on physical properties, structure and hydrocracking performance of the cata- lysts were investigated by adjusting the properties of NH4Y treated with hydrogenation metal solutions. The experimental results indicated that the activity of the catalysts treated with metallic solution and the selectivity to diesel were significantly higher than those of non-treated ones. After NH4Y zeolite was treated in metatungstate solution, tungsten ions W^6 ＋ got into the channels or cages of the zeolite, in which they were connected with acidic sites to form relatively strong ionic bonds that contributed to the reduction of catalyst acidity and the appropriate reduction of the distance between metal ion and acid site, thereby leading to favorable the selectivity to diesel at high conversion rate for hydrocracking of Fischer-Tropsch wax.