Research Of Methane Detection Technology Based On Laser Spectral Absorption

With the development of science and technology,the green economy has gradually become the main direction.But the leakage of methane can cause environmental pollution,even lead to the industrial safety accident.,which is very unfavorable to the development of green economy.We must take appropriate measures to solve the problems caused by methane leakage.Therefore,it is necessary for people to monitor methane gas.This paper focus on the real-time monitoring of methane concentration.By analyzing the gas concentration detection method,we find TDLAS(Tunable Diode Laser Absorption Spectroscopy)is beneficial to methane detection.So we select the wavelength modulation technology to develop the real-time monitoring system of methane concentration.After analyzing Lambert-Beer's law,we begin to study TDLAS theory for gas concentration detection,especially the wavelength modulation technology and harmonic detection technology.And we use the mathematical model from the research to simulate the process of methane detection based on wavelength modulation on LabVIEW,then debug the system to obtain the best parameters of the monitoring system.At the same time,the simulation results verify the correctness of the theoretical analysis.According to gas detection model and corresponding parameters,we design DFB laser module,data processing and display module,optical chamber and flameproof.By realizing the function of each independent module,we build the flame-proof real-time monitoring system of methane concentrations.Finally,selecting different concentration of methane gas to calibrate the real-time monitoring system.And we use the designed experiment to determine the system performance indicators,such as show error,repeatability,response time,zero drift and span drift,and then by evaluating the system,we find out the existing defect of the design in the current system and put forward the corresponding solutions to eliminate unreasonable design for improving the performance of the monitoringsystem.By analyzing the existing performance indicators,we ensure the monitoring system meet the demand of the original design,which can realize real-time monitoring methane concentrations.