NON-DARCIAN FLOW, HEAT AND MASS-TRANSFER IN CATALYTIC PACKED-BED REACTORS

Traditional models of transport in packed beds assume that the velocity across the reactor is uniform, even along the solid surfaces. Because of the velocity-slip assumption, corresponding convection studies for inert beds rely on a temperature-slip boundary condition to predict experimental data. For reacting beds, the transport process is more complex; however, the analysis is simplified using the temperature-slip heat transfer coefficients determined under non-reacting conditions. Since the heat transfer rates differ between reacting and inert beds, considerable discrepancies often exist between predicted results and experimental measurements. Furthermore, using the boundary conditions from inert beds precludes the determination of the actual wall heat transfer for catalytic reactions. The present non-Darcian analysis assumes a porosity variation near the wall and solves the governing momentum equation satisfying that noslip boundary condition. The corresponding heat transfer solutions use the wall-temperature boundary condition and hence can predict cooling rates when chemical reactions are included. The analysis yields results that agree with existing experimental data. © 1989.