Effect of endothermic reaction mechanisms on the coupled heat and mass transfers in a porous packed bed with Soret and Dufour effects

Taking the influences of chemical reaction mechanisms into account, a mathematical model has been developed to simulate the coupled heat and mass transfer as well as endothermic reactions in a non-thermal equilibrium packed bed with Soret and Dufour effects, which was numerically solved and validated by comparing with experimental data. It was found that the chemical reaction mechanisms have a great influence on the calculated solutions, and the cross-diffusion effects on the reactive characteristics of the packed beds are diverse under different chemical reaction mechanism. For the heat transfer controlled mechanism, the maximum reductions of the concentration of gas product and the solid fractional conversion induced by the Soret and Dufour effects are 25.1% and 14.4% respectively at superficial velocity 53.3 cm s−1 and the Nusselt number 4.1. However for the mass transfer controlled model, the calculated solid fractional conversions are higher than that obtained by neglecting the cross-diffusion effects and the increase being less than 16% at superficial velocity 11.9 cm s−1 and the Sherwood number 47.1. The differences induced by the Soret and Dufour effects are demonstrated numerically to increase gradually with the Nusselt number or the Sherwood number.