Technical Study On Multi-component Gas Detection Technology Based On Photoacoustic Spectroscopy

With the continuous progress of gas detection technology,it has been widely used in industry,medicine,environment and other fields.Traditional gas detection methods are often unable to meet the increasingly stringent requirements of detection accuracy and speed.As a branch of gas detection technology,photoacoustic spectrum gas detection is characterized by high sensitivity and fast response speed,which can be used for qualitative and quantitative analysis of mixed gases.Based on the theory of gas infrared absorption spectrum,the theory of gas detection in photoacoustic spectrum is expounded,and the mathematical relationship between gas concentration and photoacoustic signal is deduced.The finite element software and Octave were used to simulate the photoacoustic cell,and the influence of the structure and size of the photoacoustic cell on its internal sound field,quality factor,resonant frequency,cell constant and other main performance indexes was studied.According to the simulation results,the design of the photoacoustic cell was completed.The influence of different types of light sources and acoustic sensors on the performance of photoacoustic spectrum gas detection system is analyzed,And the two components are selected.The noise source and category of photoacoustic spectrum gas detection system are analyzed,and discusses the principle of correlation detection and denoising,uses the Lock-in amplifier to remove the non-correlated noise in the environment.Uses circuit simulation software to build the model of Lock in amplifier,and studies the influence of element parameters on the denoising ability and response speed of the phase-locked amplifier.The method of multi-component gas detection based on photoacoustic spectroscopy is discussed.Compares and analyzes different multi-component gas detection methods,and finally chooses the detection method based on RBF neural networkAiming at the environmental factors,the influence of temperature and pressure on the parameters and performance of the photoacoustic spectrum gas detection system is studied,and the mathematical relationship between temperature and pressure and the main parameters of the system is established.The multi-component gas detection method based on photoacoustic spectroscopy was simulated,and the detection of CH3 Cl and H2 O mixed gas was completed.Finally,the factors affecting the sensitivity of the system were analyzed.The multi-component gas detection method based on RBF neural network effectively simplifies the system parameter calibration of the traditional photoacoustic spectrum multi-component gas detection method and has high precision.The designed multi-component gas detection system can meet the requirements of accuracy and detection speed,and the overall cost is low,which has certain practical value.