Theory And Application Of Energy-saving And Quality-improving And Optimization For SiC Industrial Synthesis New Technology By Multi-thermal-source Furnace

The new technology of industrial synthesizing SiC by Multi-thermal-source Furnace comes into mature through small-scale tests in the lab, pilot-plant tests and the commercial tests,and is used widely in SiC industry, especially in Qinghai and Ningxia Province. Several furnace cores are used in Multi-thermal-source Furnace, while single a furnace core is used in traditional Acheson Furnace, thus the heat inner Multi-thermal-source Furnace is scattered, the temperature field is even, and the area fit for SiC growth is larger. Therefore the product increases and the energy is saved. By the means of numerical method, the character of SiC synthesis furnace's temperature field and how did the process conditions affect the temperature field were studied. The temperature zone fit for SiC synthesized can be improved, thus the product can be increased, the quality can be improved and the energy can be saved essentially.The temperature inner SiC synthesis furnace was measured by the designed experiment. And the relation between temperature of furnace core surface and power supply system was studied. Then temperature inner the furnace was predicted based on the measured temperature. Temperature measuring experiment is the foundation of numerical calculation. The mathematical model of Multi-thermal-source Furnace was founded after heat transfer analysis. The solution of temperature field differential equation is determined by Monodromy nonambiguity conditions, so the physical condition, geometrical condition, time condition and boundary condition were studied individually on the character of SiC synthesis furnace. The differential equation can be solved by finite element technique, and the calculation process was done by the finite element technique software ANSYS. The temperature field of SiC synthesis furnace is two-dimensional, transient, and of inner heat source, so random a plane vertical to lengthwise direction can represent the whole furnace. To point, line and plane individually, the temperature, temperature gradient and heat flow rate per unit area were researched. SiC ingot cylinder growing process and the product character were also studied. It was found that superposotion and shielding of the heat field are the fundamental reason for the energy- conservation, production increasing, and quality improving for multi-heat-source furnace. The temperature field of Multi-thermal-source Furnace affected by furnace body parameters and power supplying parameters were studied banded together with industrial practice. And the optimal parameters such as insulating layer thickness, surface loading, power-on time, sizes of furnace core and distance of furnace cores were obtained after the yield and energy per furnace and the product's quality were integrated considered. Multi-thermal-source Furnaces were designed with furnace cores in order based on the optimal furnace body structure parameters. And the temperature fields of Multi-thermal-source Furnaces with the furnace core number varied were simulated on the same power supplying conditions. Then the relation between SiC yield per furnace and furnace core number was found, and one decision model of furnace core number was built. In order to find the common regulation, the abstract models of SiC ingot cylinder produced by Multi-thermal-source Furnaces were designed referred to the character of SiC product and the rules of heat and mass transfer. Another decision model of furnace core number was built after the abstract models were studied. The two decision models are accordant and complementary.