Catalytic Cracking of VGOs Derived from Hydroprocessing (Part 1) Properties of VGO Fractions and Their Catalytic Cracking Characteristics

Abstract

Pretreatment of FCC feedstock was carried out in a bench-scale hydroprocessing unit under various conditions with fresh or spent Ni-Mo/Al2O3 catalyst, which was followed by catalytic cracking experiments in a Micro Activity Test (MAT) unit. The severity of the pretreatment had a significant effect on the properties of FCC feedstock and catalytic cracking conversion. Under the pressure of 3.9 MPa and at temperature of higher than 400°C, thermal cracking proceeded more favorably and VGO fraction contained more nitrogen and polyaromatics than at 7.8 MPa, where hydrodenitrogenation was more pronounced. Excessive hydrocracking at 3.9 MPa was found to lead to decreased catalytic cracking conversion. A correlation was established between MAT conversion and chemical composition of the feedstock, including nitrogen and polyaromatics plus resin contents. Reaction kinetics of desulfurization, denitrogenation and hydrocracking were also studied, considering correction for catalyst deactivation. © 1994, The Japan Petroleum Institute. All rights reserved.