Effects of Shear Zone and Non-uniform Gas Flow on Heat Exchange in Moving Bed

Abstract

A mathematical model is developed to describe heat-exchanging condition in moving bed. The model takes account of the radial distribution of such process variables as descending velocity of solid particle, flow rate of gas, temperature of gas, temperature of solid particle, and pressure of gas.
The heat exchange characteristics in the counter-current or co-current moving beds and in the moving bed heated internally or externally are clarified by numerical computation of the obtained model.
Thickness of a shear zone formed near the wall and the temperature distribution in the counter-current moving beds are observed in the experiments.
The dimensionless radius of the plug flow region, ro/R is independent of the Froud number and is proportional to (dp/D)^-0.2.
The radial distribution of the thermal flow ratio, or the temperature, can be appreciably affected by the preferential gas flow near the cooled wall and by the shear zone established. In case of the counter-current moving bed, the temperature difference between the plug flow region and the shear zone increases with the thickness of the shear zone.