Research And Design Of Real Time Monitoring System For Methane Concentration Based On TDLAS

In recent years,human’s activities have infiltrated in many field of production,with the rapid development in science and industrial economy. However,many problems arisen in the development should be solved, especially the pollution of environment and industrial safety production which has been the focus of social attention. Methane is mainly caused by greenhouse gases in the environmental pollution, and the methane gas brings serious threat to coal mine safety mining.So,as a consequence, it is very important to monitor methane in real time.In this paper, aiming at the shortcomings of the traditional methane gas detection technology, we introduced the non contact optical gas detection technology developed rapidly in recent years, which is called Tunable Diode Laser Absorption Spectroscopy(TDLAS),and designed a real-time methane concentration monitoring system based on TDLAS technology. The monitoring system is based on LambertBeer’s Law, combining with related theory of TDLAS technology for gas detection,studying the key technology of TDLAS gas detection. Including frequency modulation spectroscopy technology, harmonic detection technology, and two important factors of the light source and the air chamber which has a great influence on the structure and gas detection results, we put forward the source selection,designed scheme and the chamber structure determination. And in the Matlab software platform, the influence of TDLAS technology principle and modulation parameters to gas detection is simulated, in order to provide reference for the design of the monitoring system parameter setting. Then on the bases of the analysis and research to the theory the overall design of the monitoring system is completed,including the hardware design and software design. Finally, on this platform of the monitoring system, choose different concentrations of methane gas for testing and calibration, and the test results at normal temperature and temperature are researched,then temperature compensation technology is added, which makes the testing error decrease obviously. Experimental results show that this methane monitoring system basically achieves real-time detection of methane gas concentration.