COMPARISON OF FORMULAE FOR DETERMINING HEAT TRANSFER COEFFICIENT OF PACKED BEDS.

Abstract

Heat transfer coefficient for packed beds have been evaluated using different corelations available in the literature assuming same process parameters with respect to temperature of the gas, temperature of the solid, void fraction of the bed, etc. The values calculated vary depending upon the equation used. As such, when these equations are used in a model for heat transfer in a fixed bed, for the same conditions, different temperature profiles are obtained. Equations that give close values for the heat transfer coefficient give rise to similar temperature profiles in packed beds. Equations predicting relatively lower heat transfer coefficients used in a model for describing the induration of pellets in a pot grate gave closer results to experimentally observed bed temperatures.