Digital Twin Of Alumunum Eectrolysis Cell—Measurement And Analysis Of Anode Current

Aluminum electrolysis cell is the main equipment of primary aluminum production.Modern aluminum reduction cell contains dozens of anodes whose current signals can reflect the local conditions of the cell.The accurate measurement of anode current of aluminum electrolytic cell can master the activity of anode in the process of electrolysis,so as to facilitate the adjustment of electrolysis conditions,and provide a basis for the diagnosis and decision-making of cell faults,and the optimization control of production process.It is of great significance to improve production efficiency and product quality,and control energy consumption and environmental pollution.In this paper,the fiber optical current sensor is used to measure the anode current,the column bus current,the redistribution of anode current before and after anode change,and the change of anode current after stop feeding in a 500 k A aluminum reduction cell.The current distribution and fluctuation are evaluated by means of average value and standard difference.The influence degree of different factors on regional current was studied by multifactor variance analysis.Using regression analysis to study the trend of current change and quantitative evaluation.According to the conductor structure of an aluminum electrolysis cell,an equivalent circuit model of a 500 k A aluminum electrolytic cell was established based on Matlab/Simulink software,and the anode current of different bus configuration,anode changing and stopping feeder was simulated and analyzed by using this model.The analysis of measured data shows that the anode current of aluminum reduction cell obeys normal distribution.And anode changing operation will lead to the decrease of current in the anode changing region and the increase of current in adjacent areas,and the two adjacent regions will share nearly 80% of the current reduction.The lack of material will lead to local anode effects,which makes the anode current fluctuate greatly,and the fluctuation has a certain periodicity.The simulation results show that the bus configuration of the 500 k A electrolytsis cell can provide a uniform distribution of anode current and column bus current.When the upstream cell is shut down,the current of the column busbar at the aluminum outlet and flue end is relatively high,but it has no significant impact on the distribution of current between the anodes due to the configuration of the cathode busbar and the good current sharing effect of the horizontal busbar.The decrease of anode-cathode distance caused by the horizontal current formed by anode changing has a much greater impact on the anode current than the balancing effect of the busbar.The changes in electrolyte resistance and equilibrium potential caused by the concentration of alumina jointly determine the change mode of anode current.When the concentration of alumina is 1.8%,the anode current is the highest.