Kinetic models of catalytic cracking of oil fractions in single-stage and multistage reactors with fluidized beds and interpretation of experimental data of catalytic cracking performed in these reactors

Abstract

This article presents kinetic models for the catalytic cracking of oil fractions in single-stage and multistage fluidized countercurrent flow-type reactors. The models are based on the evaluation of the hydrodynamic conditions in the fluidized beds, using theoretical equations and concrete experimental data. The derivation of theoretical equations assumes that in the fluidized beds of the two flow-type reactors all the ingredients of the systems are in a backmix flow. On the basis of these models and experimental data we have calculated the values of the apparent reaction rate constants which permit the quantitative evaluation of the influence of the following: (1) the number of fluidized stages in the reactor, (2) the temperature of the process, (3) the fractional composition and nature of the oil fractions, (4) the dilution of the reacting substance (oil fractions) with the products of its conversion, (5) the mean diameter of the particles of catalyst, and (6) the extent of irreversible deactivation of the activity of the catalyst by poison. It is shown that the kinetic models and calculated values of the apparent reaction rate constants allow: (7) the determination of the weight of catalyst necessary to achieve a specified degree of conversion of the oil fractions in the reactor, (8) the evaluation of the reproducibility of the results of the process, and (9) the appreciation of how the efficiency of the reactor changes when its geometrical dimensions increase.