Detection Of Hazardous Gas Leaks Based On TDLAS Technology

A variety of trace hazardous gas leak detection can be obtained by hydrogen sulfide sensor model developed,which also applies to methanethiol,dimethyl sulfide,ammonia,methane and other trace hazardous gas leak detection and only need to replace the corresponding laser and photoelectric detectors.Hydrogen sulfide is a highly toxic,fatal and odor pollution gas,and it's well known to people as its rotten eggs at low concentrations.The main source is as the by-product of natural gas and oil purification,and it also exists in the stagnant pool,animal waste or abandoned coal pile.Detection of its concentration is of great significance to the safety mining of petroleum mine.Hydrogen sulfide can also be used as a raw material for the production of hydrogen which will not only be able to remove a toxic gas and produce a kind of energy gas.In addition,hydrogen sulfide is essential for the treatment of many physiological or pathological diseases.Therefore,concentration detection of trace hydrogen sulfide gas has important significance for environmental monitoring,safety production,biochemistry and medicine field.In this paper,the significance of gas concentration detection is introduced based on the background of trace hydrogen sulfide gas detection method.A new method was introduced for the on-line monitoring of trace dangerous gas leakage by using the laser hydrogen sulfide gas detection sensor.The full text is mainly about the calibration free wavelength modulation spectroscopy technology and the development of the software,hardware and sensor performance evaluation of hydrogen sulfide gas sensor.The main work has been discussed as follows:(1)Through the HITRAN database simulation,the strongest characteristic absorption peak of hydrogen sulfide was identified at 1578.128nm in near infrared region which avoids the spectral interference of carbon dioxide and water in the air.According to the above,the distributed feedback(DFB)laser whose center emission wavelength at 1578nm was employed as the laser source.Other selected hardware included:digital phase-locked amplifier,laser controller.InGaAs photoelectric detector,homemade calibration gas pool,off-axis parabolic mirror and angle reflector.Simultaneously,a kind of equipment which could be configured with the required concentration ratio is made.(2)LabView PC waveform data display program and lower machine Arm and FPGA program were written for the built hardware system,and Devin DGUS touch screen interface design and programming was carried out.(3)By using the gas splitter to the gas calibration pool,the different concentrations of hydrogen sulfide standard gas were used to complete the calibration of the sensor.At the same time,the linearity,response time,stability and detection limit of the sensor were evaluated.