Detailed simulation of a commercial radial fixed bed reactor for isomerization of C8 aromatics

Abstract

Numerical simulations of C8 aromatics isomerization in radial reactors are important for understanding fluid flow, heat and mass transfer, complex reactions, and operational optimization. To investigate these aspects, we develop a three-dimensional porous media model integrated with modified reaction kinetics. This model accurately accounts for the actual reactor structure while parametrizing Ergun's equation to describe the pressure drop of the fluid passing through the scallop and center pipe. The catalyst seal exhibited an inverted U-shaped velocity distribution, resulting in a dead zone in the upper-right corner and an approximately 50 % reduction in catalyst utilization rate. Under 381 ℃ and 0.71 MPa conditions, the reactor exhibited an axial distribution uniformity value of 0.183, a pressure drop of 18.61 kPa, and an isomerization activity of 23.83 %. The calculated product profiles closely match the actual production data. Our validated and credible model provides valuable guidance for industrial radial reactors.