Research On Monitoring Online Method Of Cathode Distribution Current In Aluminum Electrolyic Cell

At present,the measurement and research of the cathode current of aluminum electrolytic cell is still in the initial stage,and the equidistant voltage drop method or special Ammeter are often used to measure,which cannot content the actual needs of industrial production field.Compared with the common cathode current detection methods,the noncontact Hall cathode current measurement method has the advantages of high measurement accuracy,preferable stability,and achievable online monitoring.The cathode current detection of aluminum electrolytic cell plays an increasingly prominent role in maintaining the stable production of aluminum electrolytic cell,monitoring the condition of aluminum electrolytic cell,preventing early bottom failure and improving current efficiency.Firstly,based on the theory of electromagnetic field distribution around rectangular conductor and the characteristics of electromagnetic field distribution of aluminum electrolytic cell,the purpose of measurement of cathode current is achieved by measuring the electromagnetic field around the cathode rectangular conductor.According to the actual position of the cathode at the bottom of the aluminum electrolytic cell,the electromagnetic field interferences near cathode rectangular conductor are analyzed,and the differential Hall multi-sensor current detection scheme which can compensate the temperature and eliminate the influence of the interference electromagnetic field is determined.The calculation method of the cathode current for the actual position is given at last.Then,the software and hardware design of data acquisition system for cathode current of aluminum electrolytic cell is completed.According to the actual situation of inconvenient power supply at the bottom of the aluminum electrolytic cell,the thermoelectric generator based on the temperature of the aluminum electrolytic cell shell and the supply module based on the voltage difference of the cathode bus are developed.The WSH138 linear Hall multisensor module is designed for standardized installation,protection and electromagnetic field differential measurement.And the TP300 data acquisition card is used for cathode current data acquisition.The development of cathode current monitoring network platform based on TLINK of IOT,which can realize data management,daily monitoring and abnormal alarm of cathode current.The data acquisition system is tested in the laboratory,and the sensor used in the actual test is calibrated.Finally,through the field installation test of 410 k A potline in an electrolytic aluminum plant,the data of cathode current of 4024 th cell are collected.The current data are analyzed statistically,and the distribution of cathode current data is analyzed according to the actual production conditions according to the actual location.The results are in accordance with the actual operation state of the 4024 th cell.Finally,the reasons for the influence of the uniformity of cathode current distribution in each stage of the aluminum electrolytic cell are analyzed.