Study On Detection Of Hydrogen Sulfide Gas Concentration Based On Spectral Absorption Principle

In the process of oil and gas exploitation,highly toxic and corrosive hydrogen sulfide gas will be produced.In addition,China’s high-sulfur oil and gas fields are mostly located in southwest region.The leaked toxic and harmful gases are difficult to diffuse in time because of the complex geographical environment,which seriously threatens the safety of people’s lives and property.Therefore,real-time and rapid detection of hydrogen sulfide gas is of great significance to the development of country and society.In this paper,the concentration of hydrogen sulfide gas is detected based on the principle of spectral absorption,and a new method is proposed based on the traditional spectral absorption method.In the detection system,filter,double chamber differential and harmonic detection technology are added,and the performance of the whole system is improved.The application of double-chamber reduces the influence of the drift of the system,especially the fluctuation of the light source.The filter and the extraction of the harmonic signal are completed by the lock-in amplifier,and the relevant clutter and interference are filtered at the same time,only the harmonic signal related to the gas concentration is retained.The absorption intensity of hydrogen sulfide gas is strong when the wavelength is 1.578μm,and it is contained in the low loss region of quartz crystal,so 1.578μm is selected as the input wavelength of the detection system.However,there are absorption wavelengths of impurity gases near the 1.578μm wavelength,which interfere with the absorption of hydrogen sulfide gas.When the interference is too large,the output value can not be accurately obtained.Therefore,the interference of impurity gases on the absorption intensity of hydrogen sulfide gas is summed up as the interference of impurity gases on the absorption coefficient of hydrogen sulfide gas.A random signal is added to the system to test the output response of the system,and the mean value of the output results is obtained under the interference of impurity gases.The simulation results show that the system can detect the concentration of hydrogen sulfide effectively even if the interference of impurity gas is added,and the error is within the acceptable range,which proves that the method is correct and feasible.Fiber optic sensor has strong anti-interference ability,can realize long-distance transmission,and has broad application prospects.It provides a good theoretical basis for the realization of remote monitoring.