## Numerical simulation of gas-solid flow in a cement precalciner using adaptive mesh refinement

- Poncharoen Chanamai, Faculty of Engineering, Kasetsart University, Bangkok, Thailand
- Supasit Rodkwan, Faculty of Engineering, Kasetsart University, Bangkok, Thailand, Corresponding author; E-mail: fengcerm@gmail.com

#### Abstract

A burning process is very critical in the clinker production of cement industry. The process consists of precalcination in precalciner and combustion in the combustion chamber. During precalcination, the amount of 97% calcium carbonate (CaCO3) chemically decomposes into calcium oxide (CaO) and carbon dioxide (CO2), resulting in lower energy consumption at the precalciner. Therefore, this research focuses on numerical simulation of gas-solid flow in a cement precalciner using adaptive mesh refinement. The geometrical models of both gas and solid phases were carried out for subsequent mathematical analysis. The Eulerian scheme with a turbulent model and Lagrangian scheme with discrete phase model (DPM) were then applied for gas and solid phases, respectively, through the computational fluid dynamics (CFD), using the adaptive mesh refinement (AMR). Various parameters, such as temperature, streamline, velocity vector and trajectory of pulverised coal/raw meal were numerically obtained. In the gas phase, the temperature profiles were found, the streamlines of tertiary air, raw meal air, and kiln gas were shown, as well as the velocity vectors of various layers were illustrated. In the solid phase, the trajectories of pulverised coal, raw meal, and a mixture of pulverised coal/raw meal were presented. In the gas-solid phase, both the streamline and trajectory of a mixture of air, pulverised coal, and raw meal were given. With a measurement access limitation in the cement plant, the model validation can be mainly carried out through temperature measurement in the gas phase which shows a good correlation within 6% discrepancy. Consequently, the developed AMR model, in this research, can be further used to improve precalcination efficiency and precalciner design.

**Keywords:** *AMR, cement, CFD, DPM, numerical simulation*

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