Simulation Of Temperature Field In Polysilicon Reduction Furnace

The modified Siemens method is the production process adopted by most domestic and foreign enterprises.In the actual production process,the reduction energy consumption generated by the reaction in the polysilicon reduction furnace accounts for about 60% of the total energy consumption of polysilicon production,and in the reduction furnace reaction process.The main loss of energy consumption is the small amount of heat carried out by the exhaust gas after the deposition reaction,the heat lost by the convective heat transfer of the mixture gas in the furnace,and the radiation heat transfer of the silicon rod and the wall surface of the reduction furnace cylinder,wherein the silicon rod and the reduction The radiation heat transfer energy loss of the wall surface of the furnace tube accounts for 75%-90% of the total energy consumption of the reduction furnace.It can be seen that how to reduce the energy loss of the radiation heat transfer is the key to reduce the total energy consumption in the production process.In this paper,the drawings of 12 pairs and 24 pairs of silicon rod reduction furnaces provided by polysilicon manufacturers are used to establish a model,and the two models of the established reduction furnaces are numerically simulated by Fluent.The effects of different silicon rod diameters on the temperature field and flow field in the furnace and the transfer of radiant energy in the reduction furnace,the changes of the temperature field and flow field in the furnace under different parameters are also obtained.The furnace type has higher utilization efficiency and more energy saving for radiant energy.These studies can provide a theoretical basis for the stability,energy saving and consumption reduction of polysilicon reduction,the improvement and improvement of polysilicon quality and the pursuit of high silicon rod log reduction furnace for industrial production.The simulation results show:1)In the 12 pairs of silicon rods and 24 pairs of silicon rod reduction furnaces,as the inlet flow rate increases,the average temperature of the furnace temperature field will be higher,and the material gas flow rate near the silicon rod will be faster,which will promote new and old materials.The replacement is beneficial to the progress of the vapor deposition reaction on the surface of the silicon rod.2)As the diameter of the silicon rod increases,the total volume of the silicon rod increases the proportion of the volume in the furnace,the space for gas flow decreases,and the flow rate of the material gas increases.At the same time,the increase in the diameter of the silicon rod also causes the reaction area of the silicon rod to pass.The hot area is increased,so that the optimum reaction temperature is better in the furnace,and the temperature field distribution in the furnace is more uniform.3)Compared with the two furnace types,the arrangement of the inlet and outlet ports of the 24 pairs of silicon rod reduction furnaces is more symmetrical than that of the 12 pairs of silicon rod reduction furnaces,which can fully make the material gas and the silicon rods in full contact with each other,and the overall flow path presents a "fountain" image.4)The arrangement of the three-row silicon rods of the 24 pairs of silicon rod reduction furnaces,compared with the two-row arrangement of the 12 pairs of silicon rods,can make the radiant energy between the silicon rods of each circle can be used interchangeably,effectively reducing the wall clamping The heat taken away by the heat pipe can better improve the utilization efficiency of the radiant energy in the furnace.Therefore,it is concluded that the 24 pairs of silicon rod reduction furnaces are more energy efficient than the 12 pairs of silicon rod reduction furnaces.5)The lower the emissivity of the inner wall of the reduction furnace,the smaller the radiant energy of the silicon rod in the reduction furnace,which can effectively reduce the power consumption of the reduction process.