GAS-TO-PARTICLE HEAT TRANSFER IN THE DRAFT TUBE OF A SPOUTED BED

Abstract

The gas-to-particle heat transfer coefficients in the spout region of draft tube spouting beds of 2.6 mm glass beads were determined during continuous operation with particle fed through the base. For this purpose, detailed profiles of the gas temperature were measured in both spout and annular regions, as well as the temperature of the particles in the annulus. Fluid dynamic data were used to determine the volumetric solids concentration in the spout region. The effects of the spouting air flow rate, the particles feed rate, the height of the bed and the solids volumetric concentration, β _v , on the heat transfer coefficients were also determined. The data obtained was compared with the predictions of equations for spouted beds and vertical pneumatic conveying.

Keywords:

• Continuous feed
• Hydrodynamics
• Solids volumetric concentration

ACKNOWLEDGMENTS

The authors are indebted to CAPES, CNPq, FINEP and FAPESP for the financial support, which are gratefully acknowledged.