Simulation investigation of heating rate and temperature uniformity in fluidized bed.

• A CFD-DEM study of gas–solid heat transfer process in fluidized bed is presented. • Bed temperature and heat flux distribution are provided at particle-scale. • Heating rate and temperature uniformity in the bed are quantitatively analysed. • Tracer particle study under thermal condition is developed. In this paper, the hydrodynamics and gas–solid heat transfer characteristics during bed material heating process are investigated using the CFD-DEM approach, and the heating rate and bed temperature uniformity are quantitatively analysed. After model validation, gas–solid heat transfer characteristics in a typical case is analysed. On this basis, the effects of operating conditions is further discussed. The results show that overheating phenomenon at bed bottom is weakened obviously by solid internal circulation behavior in fluidized bed. As time marches, bed temperature uniformity is effectively improved with increasing mean bed temperature. Specially, a temperature drop at particle scale is captured by tracer particle method. A simplified energy balance model is developed to explain the relationship between bulk heating rate and operating conditions, and qualitatively consistent between simulation results and model analytical solutions is captured. Furthermore, the temperature uniformity under different operating conditions is qualitatively discussed by standard deviation of particle temperature. [ABSTRACT FROM AUTHOR]