Catalytic pyrolysis of heavy oils: 8-lump kinetic model

Abstract

A new 8-lump kinetic model is proposed to describe the heavy oil catalytic pyrolysis process. The kinetic model contains 17 kinetic constants and one for catalyst deactivation. This paper also presents a new catalyst deactivation model, a function of feed properties and operating conditions, in which the deactivation constant doesn’t vary with reaction temperature. Kinetic constants and apparent activation energies were determined by the least square regression analysis of the experimental data, obtained in a confined fluidized bed reactor at temperatures of 600, 630, 660 and 700 °C. Most of the apparent activation energies are higher than 100 kJ/mol, between the apparent activation energies for catalytic cracking and those for thermal cracking. The predicted results indicate that catalytic pyrolysis of heavy oils had better be conducted at high temperature and short residence time of oil gas, and heavy oils with the aromaticity higher than 30% had better not be considered as the feeds of catalytic pyrolysis.