Effect of Coal Particle Size on the Temperature and Pressure of Low Temperature Carbonization Square Furnace: A Combined Computational and Industrial Practice Study

Three-dimensional computational fluid dynamics according to the actual size of carbonization square furnace was performed, the standard k-ε model, the finite-rate/eddy-dissipation model and the P1 radiation model were adopted to simulate the flow of gases, the combustion of gas mixture and the heat transfer process, a mathematical model for square furnace was established when the porous medium model was selected for approximate replacement of coal seams in the furnace. The temperature and pressure fields with eight particle sizes of coal were also investigated and compared to five groups of conditions in the actual industrial production. The results showed that furnace witnessed dropped temperature, increased pressure, and gradually accelerated decline in the volume percentage of the carbonization zone with decreasing particle size of coal. However, the trends of flow field distribution were similar under different particle sizes, the maximum temperature and pressure presented an approximately linear decline and an approximately exponential growth, respectively. The temperature difference at the same height gradually narrowed with the gradual increase in the coal seam height under the same particle size. Moreover, the comparison between the numerical simulation results and industrial practice revealed a temperature and pressure error both lower than 6.25% and 12.8%, respectively.