Studies On Catalysts For Catalytic Cracking Of Coker Gas Oil

At present, seeking a suitable way of processing coker gas oil, a kind of inferior fluid catalytic cracking blending feedstock, is a difficult problem that refiners have to face. It is one of the most economical and effective approaches of optimizing blending ratio that using nitrogen-resistant catalysts or additives.In order to meet the requirements for enhancing activity and improving coke selectivity of catalysts, several aspects such as acidity of catalysts, special surface area and pore volume of matrixes and composite catalysts were investigated. The catalytic cracking performances of catalysts were evaluated by a micro-activity test unit with coker gas oil as feedstock.It was discovered that: modified by impregnating lanthanum or with the active Al2 O3 matrix,the number of acid sites of catalysts increased; using SiO2 /La2 O3 composite oxide matrix, the acid sites distribution of catalysts was optimized; with kaolin matrix modified by (NH4 )2 SO4, the special surface area and pore volume of catalysts improved. Compared with the general catalytic cracking catalyst, the conversion of the composite catalyst increased 7.3 percent points; the gasoline, light oil and liquid yields increased 3.9, 3.2 and 6.6 percent points respectively; the coke selectivity decreased 1.4 percent points. So, composite catalyst exhibited higher cracking activity, better product distribution. Especially, coke selectivity of catalyst improved remarkably.