Temperature Monitoring System For Aluminum Reduction Cell Shell Based On Cell Status Diagnosis

Aluminum reduction is the only industrial method to produce metal aluminum in the world today.As the main equipment of aluminum electrolysis,pre-baked anode aluminum reduction consumes huge energy,and the average power consumption range is 13000～15000 kWh/t-Al.Aluminum electrolysis is a complex multi-factor and multi-parameter controlled comprehensive reaction process,which is easily affected by various factors in the production process.If the control of these parameters is not handled properly,the energy balance of reduction cell may be destroyed,and then the phenomenon of malformation of reduction cell may occur.The temperature of the cell is the most intuitive expression of energy balance and energy distribution inside aluminum reduction,by monitoring it can provide judgment basis for the production status of aluminum reduction cell and ensure a safe production environment.In addition,energy loss of reduction cell can be calculated according to cell shell temperature,and further energy saving research can be carried out.This paper investigates and compares the current high temperature measurement methods in China,and expounds the advantages of fiber Bragg grating sensing temperature measurement technology in aluminum electrolysis production.Presented a design scheme of real-time temperature monitoring system for aluminum electrolytic cell shell based on fiber Bragg grating(FBG)temperature measurement technology.Then the framework of the diagnosis system of aluminum reduction cell status serving for the prevention and treatment of aluminum reduction cell defects was constructed,according to the industrial control parameters of aluminum reduction cell and the expert system.(1)A temperature acquisition subsystem with fiber grating temperature sensor,optical splitter and fiber grating sensing analyzer as the main structure was built.The fiber Bragg grating temperature sensors was repackaged,and the methods of sensors’installation and layout were determined,and the temperature measurement system of the fiber optic sensing temperature was calibrated.According to the TCP Modbus communication protocol,the specific communication address configuration of each temperature sensor is completed.(2)The architecture of the aluminum reduction cell condition diagnosis expert system with the database,expert knowledge base,consulting system,interpretation subsystem and knowledge acquisition subsystem as the main structure was established.The system is mainly for the prevention and control of cold and hot cell in the production of aluminum reduction,and the auxiliary electrolysis workshop staff completes the prevention and treatment of the disease trough.(3)Through dynamic temperature monitoring,it is determined that the temperature measurement accuracy of the aluminum reduction cell temperature monitoring system between 20～320℃ can be controlled within±5℃ error range,meeting the temperature measurement requirements of aluminum electrolysis industry.The response rate of the temperature monitoring system is verified.The data acquisition frequency is adjustable from 1 to 1000 ms.The continuous temperature measurement stability of the system in the range of 200～300 ℃ is satisfactory,which meets the requirements of continuous temperature monitoring in the aluminum electrolysis industry.