COMPREHENSIVE HEAT-TRANSFER MODEL FOR ROTARY DESORBERS

A model that describes the heat transfer processes within a rotary des orber is presented. This model has several advantages over previous mo dels. The method for calculating the wall-to-bed heat transfer rate in cludes the effects of moisture in the feed solids and allows for evapo ration from the bed before the bulk bed temperature reaches the satura tion temperature of the moisture. The method for calculating radiative heat transfer in the desorber accounts for the real nature of the par ticipating gas and the amounts of CO2 and H2O in the gas phase from bo th combustion and evaporation. Results from experiments performed usin g a pilot-scale desorber are discussed, and the model is validated by comparing the predicted bed temperature profiles and evaporation rates to those found experimentally. A preliminary attempt to account for t he effects of a non-uniform bed on the evaporation rate from the bed i s also presented along with several parametric studies.