Research on distributed laser methane detection system and temperature compensation technology

The detection accuracy of gas concentration is not high and the workload of sensor maintenance is large, which are the important problems in coal mine gas disaster prevention and control at present. To solve these problems, a distributed laser methane detection system based on fiber transmission was designed and its temperature compensation scheme was studied. The method of multichannel system design using tunable laserl absorption technology and optical multiplexing technology was described, and then the relationship between ambient temperature change and absorption spectrum of methane was analyzed. On this basis, a multi-variable adaptive temperature compensation algorithm based on experimental data was proposed, which realized the accurate detection of gas concentration in large space and complex temperature field. The test results show that the system can realize the accurate detection of 64 measuring points in the range of 10 km. After temperature compensation, the measurement range of methane volume fraction is 0 to 100.00% and the measurement error is less than ±2.00% in the temperature range from 0 ℃ to 40.0 ℃. The system is suitable for coal mine ventilation roadway, coal mining face and other dangerous places. It has the characteristics of high measurement accuracy, wide information coverage, passive air chamber, intrinsically safety and low cost, and can provide accurate basic data for coal mine gas outburst warning and gas extraction.