Research On Online Detection Of Anode Gas Composition In Aluminum Electrolysis Cell

Qin Jianmin, Zeng ShuipingUsing CO2 air-sensitive electronic-ceramic sensor and data collection system of micro-controller to measure anode gas composition, and calculating the current efficiency in aluminum electrolysis is a new method, which can realize online determination of the current efficiency in aluminum production.The paper brought forward an online detection system of the anode gas composition in aluminum electrolysis. The system mainly consists of the electronic-ceramic capacitive-type sensor for CO2, the single chip system with the MSP430F149 CPU and the data processing software on PC.The electronic-ceramic capacitive-type sensor for COi is based on the nanometer and semiconductor theories. According to the mechanism of the gas surface absorbing actions and the mechanism of grain boundary effect of semiconductors, the capacitance of the sensor can be changed with the variation of CO2 concentration. This sensor is made from BaTiO3 and CuO powder in nanometer grade. The process of manufacture is described as mixing BaTiO3 and CuO powder adequately, then pressing the mixture into wafer with thickness 0.6mm and radius 8mm, and finally sintering the wafer at 500癈 for 5 hours. The Ag electrode and Pt down-lead were set to the sensor.The Micro-controller system used MSP430F149 of TI Company as CPU, which has an in-system programmable and intelligent data acquisition system. The system has four parts, which are data collecting subsystem, data storage subsystem, data displaying subsystem and data uploading subsystem. The system's anti-interference has also been considered for the special cases of Al-electrolysis industry. The driver program of system is compiled by Clanguage. After being debugged, the system can collect spot data using sensor and calculate the content of CO2. The measured results can be stored and displayed. The system can also upload the data to PC in order to analyze data conveniently.PC software was programmed with C++ builder 5.0 for further dealing with the data. The interface of software is friendly; the received data can be stored and displayed; the relative curve based on received data can be conveniently shown on the screen.