Tunable Diode Laser Absorption Spectrometer Coal Mine Methane Detection System Based on DSP

Tunable diode laser absorption spectroscopy (TDLAS) technology is a new detective method developed with the combination of a tunable diode laser source and a long absorption path. It has the characteristic of high sensitivity, high precision and rapid response. Based on TDLAS and high performance microcontroller (DSP), the system is developed to monitor the coal mine methane. The second harmonic detection is used to lower the detection limit further that is below 0.086 mg/m³. The results show that the intensity of second harmonic signal is in proportion to the methane concentration. It has an obvious advantage not only in sensitivity but also in stability and can achieve the real-time measurement of methane concentration. It has been used abroad for detection of methane in some industrial fields.