Correlations for Predicting the Effect of Feedstock Properties on Catalytic Cracking Kinetic Parameters

Abstract

The rate and the catalyst decay constants used in the three-lump kinetic model proposed by Weekman (Ind. Eng. Chem. Prod. Res. Dev. 1968, 7, 90−95) for the catalytic cracking reactions were correlated as a function of the total sulfur and nitrogen contents and carbon distribution evaluated by the n−d−M method (ASTM D-3238-82 Method, 1982) using information reported in the literature about the cracking of 16 different feedstocks. The correlations developed in this work are more accurate than those previously reported. Catalytic cracking in a microactivity reactor of six gas oils was used to determine the effect of feedstock properties on FCC product selectivities. It was found that the sulfur content has a strong influence on kinetic constants and the effect of nitrogen is lower. Good predictions of gasoline yields were obtained from the kinetic model, with an average absolute deviation of less than 1.5% with respect to experimental data.