A compact gas monitoring system for methane based on photoacoustic spectroscopy

A compact system for methane monitoring based on Photoacoustic Spectroscopy has been designed. In this paper, we theoretically derived the photoacoustic pressure and the first-order longitudinal resonant frequency of different photoacoustic cells. Based on theoretical analysis, we improved the acoustic signal amplification capability of the photoacoustic (PA) cell by optimizing the radius and length of the resonator and buffer through the simulation. A compact optimized H-type PA cell was designed, whose total volume was 60*30*30 mm 3 . The performance of this system was evaluated through Methane detection. Experimental results show good linearity, and the linear fitting R square is 0.9993. The minimum detectable limit of CH 4 is calculated to be 4 ppm with an integration time of 10 s.