Detection of hydrogen sulfide in coal mine based on laser absorption spectrometry

In order to accurately forecast the hydrogen sulfide content in underground coal mine and prevent the harm caused by the excessive hydrogen sulfide content, a portable hydrogen sulfide detector was designed and developed based on technology of Tunable Diode Laser Absorption Spectroscopy (TDLAS). The instrument adopted the Distributed Feedback Laser (DFB) with the central wavelength of 1 590 nm, combined with the multi-reflection Herriott long optical path gas absorption pool, which can meet the real-time detection of hydrogen sulfide from 0 mg/L to 200 mg/L in the underground coal mine. The relative error of the detector measured by offline calibration and laboratory test was ±2%, and the fastest response time system was 0.5 s; through the laboratory measurement of the gas composition of 120205 upper corner of coal face and goaf in Dawan Coal Mine of Liupanshui. The results show that the portable hydrogen sulfide detector is stable and reliable, and can meet the requirements of hydrogen sulfide early warning in underground coal mine.