(263g) Thermal Treatment of Granular Materials in a Rotary Drum Equipped with Baffles

Rotary drums play a vital role in the thermal treatment of granular materials in processes such as calcination and drying. A rotary drum equipped with baffles/flights is of interest as studies show that baffles can effectively decrease the required processing time and improve the uniformity of the final product. However, much uncertainty still exists about how baffles impact the rate of heat transfer in rotary drums for different operating conditions and particle properties. In order to understand how baffles affect heat transfer of granule materials in rotary drums, a series of simulations for different operating conditions and particle properties were carried out using the discrete element method (DEM). A number of different operating conditions were considered including: fill level, drum size, baffle size, and number of baffles. Different thermal properties of the particles were considered by varying the thermal conductivity and the effect of particle size was also considered. The simulation result show that the heat transfer initially improves significantly by increasing the number and size of the baffles and the decreasing the fill level. However, it should be noted that adding an excessive number of baffles can decrease the rate heat transfer of granule materials in rotary drums. Moreover, we observed, there is an optimum number and size of baffles for a given fill level. By introducing a new scaling parameter we were able to categorize all the simulation result for different operating conditions and material properties and introduce an optimum condition for adding baffles to the rotary drum. The results of the study have advanced our understanding of thermal treatment of granular materials in a rotary drum equipped with baffles.