(65f) Predicting Temperature Distributions in Rotary Calciners By Thermo-Mechanical DEM
Calcination is a process whereby particles are thermally treated, usually in rotary drums, to bring about a desired chemical and/or physical transformation. Developing a better process understanding of calcination can significantly improve the quality of the end product as well as save energy and material costs. However, there is a lack of predictive models, for example, to predict the average temperature of particles during calcination process as well as upon scale-up from laboratory scale to manufacturing scale. Discrete element method (DEM) based simulations were used to study the distribution of temperature of particles in rotary calciners at low temperature. Various physical, mechanical, and thermal properties of particles were considered in the simulations and in the analysis. In addition, the effect of operating conditions such as size of calciner, material fill level, and speed of rotation on the heat transfer were investigated. Based on the DEM simulations, timescales relevant to the heat transfer process were identified and a relationship between these timescales was developed that can be used to predict the average temperature of particles. It was also found that the distribution of temperature of particles depends on these relevant timescales. The characteristic of the temperature distribution with respect to the relevant timescales will be also included in the presentation.