Design And Development Of Gas Concentration Field Detection System Based On TDLAS Technology

On-line detection of the distribution of the combustion product gas concentration in the cross section of the boiler in the power station boiler is of great significance for accurately grasping the combustion status in the furnace,accurately controlling the wind-to-coal ratio and optimizing the combustion performance.The tunable semiconductor laser spectral absorption technology(TDLAS)technology is a non-contact gas detection technology based on the principle of laser spectral absorption.It has the characteristics of high sensitivity,strong anti-interference ability,and fast response speed.The most promising method for measuring problems.Based on the two-dimensional gas concentration field detection platform built in the laboratory,this paper develops a gas concentration field measurement system based on TDLAS technology,which lays a foundation for applying this technology to the measurement of actual boilers.First of all,considering that the furnace of the power station has a large space and complicated combustion conditions,the traditional detection method is relatively sparse compared to the effective measurement light path of the measurement object,and it cannot guarantee that the gas distribution reconstruction result with higher accuracy can be obtained.Scanning TDLAS detection system platform,on which mechanical scanning mechanism is used to drive four laser emitting devices to automatically scan the laser receiver,and 80 light paths are arranged in the detection area,which greatly increases the number of effective light paths.Then,a measurement software system is designed and developed for the experimental platform.The laser scanning part adopts PLC-based programming control to achieve a relatively accurate automatic control function.The acquisition and calculation part uses a LabVIEW-based development environment.The calculation method for measuring the gas concentration on the optical path and the two-dimensional concentration distribution inversion algorithm are compiled and integrated into the software.The signal acquisition,numerical calculation,and reconstruction results are displayed as One function.Finally,the detection system developed by this project was used to reconstruct and image the two-dimensional distribution state of the CO2 gas concentration field under different working conditions A series of measurement experiments were performed with the concentration and distribution area of the CO2 gas as independent variables.The comparison and error analysis verify the feasibility of the gas concentration detection system based on TDLAS technology in the application of two-dimensional gas distribution detection.