Heat current model of solid granule cooling processes in moving packed beds and its applications

Abstract

The moving packed bed is commonly used for cooling high-temperature solid granules. Its effective and concise modelling is important for reducing the complexity of system analyses. This study defines the inlet temperature-based thermal resistance of solid granule cooling processes considering the porosity of the packed layer and constructs a heat current model of a practical moving packed bed. The corresponding governing equations are established by applying the Kirchhoff’s law in circuitous philosophy to reflect the overall heat transfer law in the entire moving packed bed with a low computational complexity. On this basis, the cooling process in a cement grate cooler is studied and the results simulated by the proposed model agree with those obtained using the finite difference method and experimental data. Meanwhile, the distribution of heat transfer rates in the cement grate cooler shows that the first stage, the following four stages, and the last four stages undertake 47.87%, 48.49%, and 3.93% of the total heat load, respectively. Moreover, the inlet temperature-based thermal resistance in the last four cooling stages accounts for 70.98% of the total thermal resistance, which can guide improvements in the cooling performance.