Study On TDLAS Detection Of Gas Leakage In High Pressure Pipeline

With the rapid economic and social development and the protection of the environment,natural gas is gradually replacing coal as a new energy,which not only provides the convenience of production and life,but also bring the corresponding risks.The use of natural gas is mainly through the pipeline for transportation,due to pipe lax,corrosion perforation,man-made management failure and other factors,combined with natural gas in the main component of methane,if not timely and accurate detection found that prolonged leakage prone to fire and explosion in the early stages of leakage,a huge loss of major accidents and casualties may have national economy.Therefore,for the problem of high-pressure gas pipeline leak trace,expand the theoretical and technical research on the safety and security of life and property of the gas pipeline,which has a very important practical significance.This article is to study and analyze the law and TDLAS technology and gas pipeline leak detection performance spectrum of the spread according to the theory of basic knowledge of fluid dynamics and kinematics.Firstly,the research status of several common gas detection technologies and TDLAS technology is compared,the theoretical basis and absorption principle of TDLAS technology for gas detection are analyzed.The detection lines of methane gas are studied and determined,and the principle of harmonic detection technology is introduced.And the second harmonic is selected.Secondly,according to knowledge of fluid mechanics,the basic equations of gas flow in the gas pipeline are put forward.The steady and dynamic leakage model of the pipeline gas is studied and discussed.Two states of the gas flow in the pipeline and the ratio of the pore diameters leak judgment based on the model.Thirdly,the diffusion model of natural gas is established,the factors affecting the diffusion and the diffusion coefficient are determined.At the same time,the dangerous area of the pipeline gas leakage and diffusion is calculated and analyzed,and the quantitative analysis is provided for the later emergency rescue.Finally,the performance test of TDLAS system,including the overall design and construction of TDLAS system,and the use of second harmonic signal strength to calculate the concentration of leaking gas,the system from the minimum detection limit,repeatability and stability,response time three Performance analysis,according to the experimental data show that TDLAS system to meet the trace gas leakage of high accuracy,high sensitivity of the detection requirements.In this paper,the TDLAS system is used to detect the micro-leakage of high-pressure pipeline gas,from the theoretical analysis to the establishment of the leakage diffusion model,and the system performance testing.Compared with other optical detection technology,TDLAS technology in the detection of trace gas leakage with high sensitivity,high selectivity and high reliability advantages,making non-contact detection technology has a new idea and reference for the late long-distance transmission.The trace leakage test of gas pipeline and the improvement of system performance provide important reference value and guiding significance.