Dynamic Monitoring And Simulation Analysis Of Aluminum Electrolytic Cell's Ledge Based On Temperature Field Analysis

Aluminum Electrolytic Cell(AEC)is one of the most important production equipment in aluminum electrolytic industry,whose operation conditions could affect production capacity and economic benefit of factories directly.However,due to the technology limitation,leakage,the common breakdowns of AEC,could lead to economic loss and even serious accidents like fire and explosion that pose huge threat on workers' personal safety.Currently,the industry is short of on-line detection and control technology about slot's fault in the process of aluminum electrolysis.When the fault occurs,the factories have to stop the production process to repair the AEC.In view of this technical problem,this paper puts forward on-line detection technology to AEC management,and carry out fault monitoring and control through modern technologies.AEC consists of carbon anode,carbon cathode,tank shell,side carbon block,groove chamber,insulating brick,anti-seepage material and calcium silicate plate,etc.An important sign marking AEC into the normal production stage is a stable electrolyte crust layer attaching to the inside tank wall,which is called groove chamber and which could prevent leakage by protecting side lining materials from erosion of liquid aluminum and electrolyte.As the thinnest part of the tank,the variation of ledge thickness can be used to estimate whether there is leakage in the side of AEC.Hence,the dynamic supervision system of ledge should be constructed to monitor any possible breakdown of ACE on line for normal production of electrolytic cell.Namely,when the ledge thickness reaches its critical value,the system could trigger the alarm automatically and remind workers to take measures timely to eliminate the breakdown of ACE.This paper has focused on the following aspects to construct the dynamic monitoring system:(1)For strong magnetic field,high hydrogen fluoride,heavy dust,high temperature of aluminum electrolytic workshop,this paper analyzes the characteristics of various temperature sensors in data collection,and uses fiber bragg grating sensor to collect the surface temperature data of tank shell.As a kind of wavelength modulation type sensor,it is not interfered by the special environment of electrolytic workshop,and can accurately collect the data of the temperature about tank shell,which has high reliability.(2)Modeling and simulation of AEC is based on ANSYS software.Combining with the aluminum electrolysis production process and the internal structure,the temperature distribution of AEC is analyzed detailedly to determine the location and number of temperature measurement point on tank shell.Not only this method grasps the changes of tank shell temperature,but also greatly reduces the enterprise's capital output.(3)After analyzing the characteristics of wired data transmission and wireless data transmission,ZigBee,a modern Internet of things technology,has been adopted to transmit tank shell's surface temperature wirelessly.The features of ZigBee,namely huge data loading capacity,fast response speed,high reliability,strong anti-electromagnetic interference ability and anti-hydrogen fluoride corrosion,enhance the accuracy and reliability of the data transmission system by avoiding typical problems of wired transmission,for instance,maintenance inconvenience,electromagnetic interference and line corrosion.(4)Taking temperature as the main reference variables,the variation of ledge thickness and relevant temperature value is researched by changing heat parameters,and then the relation between them is found out.With the detected data of the tank shell,the ledge thickness can be reflected in real time.So the working condition of AEC could be detected,namely normal or abnormal,in line with ledge thickness and its characteristic value of the leakage about AEC.(5)Feasibility of the forward experimental scheme is verified by a empirical analysis based on 400 KA series aluminum electrolytic cell in Zunyi aluminum co.LTD..Data of ledge thickness and the relevant tank shell temperature were collected respectively by A bar and portable infrared thermometer.Then these two sets of data which obtained by experiment and simulation were compared to prove the consistency of results and to verify the accuracy and feasibility of the proposed scheme.