Numerical Simulation And Optimization On Coupled Multi-field In The Reclaimed Copper Reverberatory Furnace

Reverberatory furnace is a key equipment for production of reclaimed copper. But its application is greatly limited due to the problems, such as low thermal efficiency, low recovery rate, unstable product quality, short life of the furnace. In this paper, based on the numerical simulation method, the thermal process of the furnace in a reclaimed copper plant in Hunan was studied systematically in order to optimize the parameters of structure and operation.Based on FLUENT6.3 the physical model of calculation region was built and the appropriate unstructured grid was established through the grid independence study. Meanwhile, the heat balance data measured from the running furnace were used as the boundary conditions of the model. The standardκ-εmodel, species transport model and P1 radiation model was chosed to carry out couple numerical computation of flow filed, temperature filed, concentration field and heat release filed. The main conclusions are as follows:(1) As for the furnace with a direct-current (DC) burner there is a back flow zone, which can intensify the circulation and the mixture between the fuel and air and stabilize the combustion in the furnace effectively. The temperature maximum in the furnace is 2279K and appear at the region about 1.0 meter from the burner. The temperature level at the bottom of the furnace is about 1400K. As a whole, the problems in the furnace with DC burner are the excess air coefficient, larger temperature distribution, lower thermal efficiency. A small amount of fuel components appear at the flue exit, which indicates that the organization of combustion is not enough good.(2) The simulation results are basically consistent with the data measured from the running furnace, where the relative error is less than 7%. These indicate that the model for simulating combustion process in the reverberatory furnace is reliable.(3) The numerical simulation results of rotary burner and different mounting angle show that the combustion performance of rotary burner is better than DC burner which optimum installation angle is 45°.(4) The numerical simulation results of different excess air coefficient and the oxygen concentration show that when the excess air coefficient is 1.05 the combustion is better, the temperature distribution is more even and high temperature zone is mainly distributed in the melt department. As decreasing of the oxygen concentration of the combustion-aid air, the flame surface increases while the maximum combustion temperature decreases. The average temperature in the furnace rises and the temperature distribution becomes more even, more fuel-efficient. For example, it can save 46.99% fuel when the oxygen concentration of combustion air is 5% and the preheat temperature is 1073K.