Axial heat transfer in packed beds. Gas flow through beds between 20 and 650°C

Abstract

The experimental measurements and theoretical models described in part I are extended to the case of gas flow through the bed. Temperature profile measurements are given for cocurrent gas and axial heat flows through the bed over a temperature range 20–650°C and a particle Reynolds number up to 5. These results are analysed in terms of both a continuous (diffusion) model and a new discrete (mixing cell) model. The latter provides more quantitative information on the heat transfer mechanisms involved since, unlike the former, separate account is taken of solid conduction-radiation, solid contact resistance, as well as solid-gas convection and bulk gas flow convection. The suitability of the discrete model is verified by comparison with both the present experimental cocurrent results at low and high temperatures and with previously published countercurrent low temperature measurements using a range of packing materials.