Catalyst grading technology for promoting the diesel hydrocracking to naphtha

This paper reports the application of multi-component hydrocracking catalyst grading technology in diesel hydrocracking system to increase naphtha, and studies the influence of catalyst systems with different number of graded beds on the reaction process of diesel hydrocracking. Three hydrocracking catalysts with different physicochemical properties as gradation components, the diesel hydrocracking reaction on catalyst systems of one-component, two-component and three-component graded beds with different loading sequences are carried out and evaluated, respectively. The catalytic mechanism of the multi-component grading system is analyzed. The results show that, with the increase of the number of grading beds, the space velocity of reaction on each catalyst increases, which can effectively control the overreaction process; along the flow direction of feedstock, the loading sequences of catalysts with acidity decreasing and pore properties increasing can satisfy the demand of different catalytic activity for the conversion of reactant with changing composition to naphtha, which has a guiding role in the conversion of feedstock to target products. Therefore, the conversion of diesel, the selectivity and yield of naphtha all increase significantly on the multi-component catalyst system. The research on the grading technology of multi-component catalysts is of great significance to the promotion and application of catalyst systems in various catalytic fields.