The Thermo-Electric Field Model And Application Research In Low Voltage Aluminium Reduction Cells

Aluminum electrolytic is a high-energy consumption industry, how to seek a low-power high-efficiency mode of production has been the pursuit of aluminum electrolytic industry. By reducing the cell voltage to reduce the energy consumption of aluminum electrolytic is an important means of energy-efficient aluminum industry. However, the lower cell voltage will reduce the current efficiency and destroy the thermal equilibrium.Therefore, carrying out the research of thermo-electric field in low voltage aluminum reduction cell is of great significance.The most effective way to reduce the cell voltage is to drop the polar distance. The research object is based on175kA series pre-baked aluminum reduction cell of Chongqing Tiantai aluminium limited company, the effect of different cathode structure on current distribution in metal pad of aluminum reduction cells was talked about. On the basis of the thermal equilibrium calculations of a300KA series aluminum reduction cell,calculated the heat ratio parts of aluminum reduction cell at different voltages,and specific thermal insulation Program was proposed in the end of this dissertation. The main research content and results obtained as follows:(1) The quarter cell electric calculation model of175kA series aluminum reduction cell of Chongqing Tiantai was established based on simulation software ANSYS. And made a detailed calculation and analysis to the potential and current distribution on each of the conductive structure. The results in line with the actual. It provided a clear thought for comprehensive understanding electric field distribution and the optimization of the partial structure of aluminum reduction cell.(2) The effect of different conditions on current distribution in metal pad of aluminum reduction cells was talked about by changing the shape of collector bars and installing insulation boards in metal pad based on175kA pre-baked aluminum reduction cell in Chongqing Tiantai electric model. The result show that advanced collector bars can significantly reduce the maximum and average values of horizontal current density along y axis in the metal pad under anode carbon block,the values of horizontal current density reduced from(-500-1300)A/m2to (-500-250)A/m2.Insulation boards can effectively restrain the current offset to the side of the anode carbon block.By combining advanced collector bars with insulation boards,it can not only control the current in metal pad under anode carbon black but the value and distribution of horizontal current density can also be controlled effectively.It provided theory basis for the actual production of aluminum reduction.(3) The influence of thermal field in different process conditions was researched and analyzed. The result show that polar distance and early crystallization point temperature have a big influence on thermal field. Electrolyte height has a little influence on thermal field. Further, anode changing will destroy the heat balance of aluminum reduction cell in a short period of time especially anode changing occurred in the four corners.It can be weakened by anode preheating.(4) Energy expenditure of different heat loss part and heat ratio parts of aluminum reduction cell were calculated On the basis of the thermal equilibrium calculations of a300KA series aluminum reduction cell. The energy balance error below3%. Taking into account that in aluminum reduction cell energy expenditure, non-heat loss part is difficult to control, new thermal equilibrium was mainly maintained by reducing heat dissipation after voltage reduced. On the basis of the energy balance calculation results,calculated the heat ratio parts of aluminum reduction cell at different voltages, according to the heat income and expenditure principle of aluminum reduction cell. Finally, specific thermal insulation Program was proposed. Pictures47,Tables20,References88.