Modeling and Kinetic Study of an Ebullat

The present work was devoted to investigate the kinetic behavior of an industrial-scale ebullated bed reactor, licensed by Axens Co., in Lukoil refinery at Bourgas, Bulgaria. Another objective of the present work is to formulate a steady state mathematical model to predict the profile of products along the reactor, and to investigate effects of the operating variables (e.g., operating temperature, weight hour space velocity (WHSV), and reaction time) on the kinetic parameters, and performance of the industrial ebullated bed reactor. A five-lump kinetic model was utilized to describe the catalytic hydrocracking of heavy oil and to formulate the reaction rate equations of the main components of heavy oil. The formulated model was validated by comparing its outcome with experimental measurements of fractions of VR, VGO, and N at the effluent of industrial reactor against residence time. Results revealed an opposite relationship of the effectiveness factor with both temperature and WHSV. Results showed that the activation and deactivation energies were approximately equal, indicating that catalyst deactivation has no appreciable effect on the hydrocracking reactions in the ebullated bed reactor. The hydrocracking reactions of vacuum residue to lower molecular weight components are preferentially obtained in the following descending order: VGO; middle distillates; naphtha; gases. WHSV has a negative effect on the yield of the industrial reactor while the trend was different with the operating temperature. Outcomes of the formulated model were compared with the data reported in the literature.