Research On Electric-thermal Field Simulation And New Energy Balance System Of High-density Anode Aluminum Electrolyzer

As the core component of aluminum electrolyzer,the quality and consumption of carbon anode directly affect the economic and technical indexes.Based on the preparation of high-density anode by impregnation roasting process,this paper establishes a coupled electric-thermal field calculation model of high-density anode aluminum electrolyzer based on ANSYS software in a 200 k A series aluminum electrolyzer in an aluminum plant in Baotou,and verifies the accuracy of the model.By comparing and analyzing the impact of the change of various factors on the electricthermal field of the electrolyzer with a 7.54% increase in bulk density of high-density anode,the new energy balance system of high-density anode aluminum electrolyzer was studied and optimized according to the thermal field test results,and finally the economic benefits were analyzed.The main research contents and conclusions are as follows.(1)The average temperature of high-density anode carbon block increased by 8.73 ℃,and the maximum thermal stress increased by 0.1MPa,but the deformation variable decreased by 0.077 mm,which can effectively reduce the generation of cracks and carbon slag and reduce carbon consumption.The average temperature of the side shell decreased by 28.59 ℃,of which 65.8% and 26.1% were caused by the change of carbon block properties and the decrease of electrolyte resistivity,respectively,and the maximum thermal stress and deformation of the side shell decreased by 3 MPa and 0.028 mm,respectively,and the reduction of deformation could ensure the stability of the inner chamber shape.The total voltage of the high-density anode aluminum electrolyzer was reduced by a total of 50.12 m V,of which 22.38 m V and 26.64 m V were reduced under the conditions of carbon block physical property change and electrolyte resistivity reduction,and their effects accounted for 45.64% and 54.36%,respectively.(2)The temperature of the structure above the carbon anode increases,such as the steel claw,guide rod,covering material,etc.,especially for the higher flow rate of flue gas,and its temperature increase leads to a significant increase in the upper heat dissipation.On the contrary,the side and bottom tank shell heat dissipation decreases,and the energy balance system of the electrolyzer changes from the traditional heat dissipation type of the common anode to the enhanced upper heat dissipation type.(3)According to the comparison of experimental test and simulation calculation results,the current on-time of the new high-density anode is at least 3.38 h shorter than that of the common anode,and it is still shortening with the increase of anode bulk density,and can be shortened by 4.26 h after increasing 10%,which is conducive to reducing the adverse effects of carbon block heating and current on-time on the operation of aluminum electrolytic cells,and reducing DC power consumption.(4)After analyzing the results of the hot field test,after increasing the covering material of the high-density anode aluminum electrolyzer from80 mm to 120 mm,the energy consumption of the aluminum electrolysis reaction is increased by 0.84%,the current efficiency is increased by 2.02%,and the DC power consumption is reduced by 315 k W-h/t-Al,which is a very obvious energy saving effect compared with the common anode aluminum electrolyzer.Theoretically,if the voltage is reduced by 50.12 m V and the current efficiency remains unchanged,the DC power consumption can be reduced by up to 473 k W-h/t-Al.Based on a 100,000-ton capacity of an aluminum plant,the direct economic benefit of highdensity anode can be at least 11.37 million yuan per year,with an average direct benefit of 224.3 yuan per high-density anode prepared.