| Iron and steel industry is an important pillar industry in China’s economic system,and its production mainly depends on submerged arc furnace.Submerged arc furnace smelting is the core smelting process of ferroalloy industry.It is characterized by industrial electric furnace with huge power consumption and wide application range.The traditional smelting process of AC submerged arc furnace is based on reduction reaction.The three electrode AC arc in the submerged arc furnace forms arc heat and resistance heat between the arc and the furnace charge,so that the furnace charge can carry out a series of chemical reduction under the action of high temperature to obtain the required ferroalloy.The overall process is to convert electric energy into chemical energy.However,the reactions in the furnace are complex and changeable,difficult to observe and sample,and the electrodes are mainly controlled by manual experience.Therefore,in order to better understand the performance of the submerged arc furnace,realize the visualization of the production process of the submerged arc furnace,improve the production efficiency of the submerged arc furnace,and reduce the energy consumption in the smelting process of the submerged arc furnace,this topic conducts research from two aspects:revealing the distribution law of the internal field of the submerged arc furnace and the electrode control system of the submerged arc furnace.First,according to the actual situation of the submerged arc furnace in the production process,a three-dimensional model of the submerged arc furnace is established.Based on Maxwell’s equation,Ohm’s law,fluid control equation and heat transfer mechanism,the electric field,magnetic field,flow field and temperature field in the furnace are numerically simulated,and the temperature field distribution in the furnace under different electrode parameters is compared.The results show that the influence of skin effect on the current density is mainly concentrated on the electrode surface,and the maximum value is 35000A/m~2;Joule heat is mainly concentrated at the electrode bottom of the material layer;The maximum magnetic flux density is about0.02T at the polar circle of the electrode;Fluid flow in molten pool is affected by Lorentz force and gravity,and Lorentz force is more obvious in slag layer;The maximum temperature in the furnace reaches 2500℃and is located at the bottom of the electrode,which is gradually transferred from the material layer to the slag layer.With the increase of electrode diameter,the temperature in the furnace decreases,and the deeper the electrode is inserted,the temperature in the furnace also decreases.On this basis,the electrode lifting control system of submerged arc furnace based on PLC is designed.The position of the electrode in the furnace is measured by the photoelectric encoder,which is converted into a signal that can be recognized by PLC and then sent to PLC.The PLC then controls the electrode lifting and carries out simulation.The system calculates the difference value of electrode position by measuring the electrode position,and controls the electrode rise and fall according to the difference value to achieve the optimal position of the electrode,so that the temperature in the furnace is stable and efficient,and the smelting efficiency of the submerged arc furnace is greatly improved.The research of this topic reveals the distribution law of each physical field in the furnace,realizes the automatic control of the AC electrode system,improves the production efficiency and product quality,reduces energy consumption,and provides effective optimization guidance for the design and production of ferroalloy smelting in submerged arc furnace in reality,which has certain reference value. |
