高压管道气体微量泄漏的TDLAS技术检测研究

发布时间：2018-05-05 20:26

本文选题：TDLAS系统 + 二次谐波信号　；参考：《华北科技学院》2017年硕士论文

【摘要】：伴随着经济社会的快速发展和对环境的保护,天然气正逐渐代替煤炭成为新能源,这不仅提供了生产和生活的便利,同时也带来了相应的风险。天然气的使用主要是通过管道进行输送,由于管道连接不严、腐蚀穿孔、人为管理失效等因素,加之天然气中的主要成分为甲烷,在泄漏初期如果不能及时和准确的检测发现,长时间泄漏就容易发生着火和爆炸,可能产生人员伤亡的重大事故和国民经济的巨大损失。因此,针对高压管道气体微量泄漏的问题,展开理论和技术上的研究,对输气管道和生命财产的安全和保障,具有非常重大的现实意义。本文是运用光谱学基础知识、流体动力学、运动学来研究和分析输气管道泄漏扩散的规律和TDLAS技术以及检测性能。首先综合比较几种气体常见检测技术和TDLAS技术的研究现状,分析TDLAS技术用于气体检测的理论基础和吸收原理,重点研究和确定了甲烷气体的检测谱线,介绍了谐波检测技术的原理和二次谐波的选择;其次,根据流体力学知识,提出了输气管道内气体流动的基本方程,研究并讨论了管道气体稳态和动态的泄漏模型,研究出管道内气体流动的两种状态以及将孔径比作为不同泄漏模型的判定依据;再次,建立了天然气的扩散模型,确定了影响扩散的因素和扩散系数,同时对实际的管道气体泄漏扩散的危险区域进行计算和分析,为后期应急救援提供定量分析依据;最后,对TDLAS系统进行性能测试,包括总体设计和搭建TDLAS系统,并利用二次谐波信号强度来计算泄漏气体的浓度,对系统从最低检测极限、重复性和稳定性、响应时间三方面进行性能分析,根据实验得到的数据说明TDLAS系统满足对微量泄漏气体高准确性、高灵敏性的检测要求。本文是利用TDLAS系统对高压管道气体微量泄漏进行检测,从理论分析到泄漏扩散模型的建立,以及系统的性能检测。相比于其他光学检测技术,TDLAS技术在检测微量泄漏气体方面具有高灵敏度、高选择性和高可靠性的优势,使得非接触式检测技术有了一个新的思路和借鉴,为今后长距离输气管道的微量泄漏检测试验和系统性能的改进提供了重要的参考价值和指导意义。
[Abstract]:With the rapid development of economy and society and the protection of the environment, natural gas is gradually replacing coal as a new energy source, which not only provides the convenience of production and living, but also brings the corresponding risks. The use of natural gas is mainly carried out through pipelines. Due to the factors such as lax connection of pipelines, corrosion and perforation, artificial management failure, and the main component of natural gas is methane, if it cannot be detected in time and accurately at the early stage of leakage, Long time leakage is prone to fire and explosion, which may cause casualties of serious accidents and great loss of national economy. Therefore, to solve the problem of trace gas leakage in high pressure pipeline, it is of great practical significance to carry out theoretical and technical research on the safety and security of gas pipeline and life and property. In this paper, the basic knowledge of spectroscopy, fluid dynamics and kinematics are used to study and analyze the laws of leakage and diffusion of gas pipeline, TDLAS technology and the detection performance. Firstly, the research status of several common gas detection techniques and TDLAS technology is compared, the theoretical basis and absorption principle of TDLAS technology for gas detection are analyzed, and the detection spectrum line of methane gas is studied and determined emphatically. The principle of harmonic detection technology and the choice of second harmonic are introduced. Secondly, according to the knowledge of fluid mechanics, the basic equations of gas flow in gas pipeline are proposed, and the steady and dynamic leakage models of gas in pipeline are studied and discussed. Two states of gas flow in pipeline are studied and the pore size ratio is taken as the basis for judging different leakage models. Thirdly, the diffusion model of natural gas is established, and the factors affecting the diffusion and the diffusion coefficient are determined. At the same time, the dangerous area of pipeline gas leakage and diffusion is calculated and analyzed to provide quantitative analysis basis for later emergency rescue. Finally, the performance of TDLAS system is tested, including the overall design and construction of TDLAS system. The second harmonic signal intensity is used to calculate the concentration of leakage gas, and the performance of the system is analyzed from three aspects: the lowest detection limit, the repeatability, the stability and the response time. According to the experimental data, the TDLAS system meets the requirements of high accuracy and high sensitivity for detecting trace leakage gas. In this paper, TDLAS system is used to detect trace gas leakage in high pressure pipeline, from the theoretical analysis to the establishment of leakage diffusion model, and the performance detection of the system. Compared with other optical detection techniques, TDLAS has the advantages of high sensitivity, high selectivity and high reliability in the detection of trace leakage gas, which makes the non-contact detection technology have a new idea and reference. It provides important reference value and guiding significance for micro leak detection test and improvement of system performance of long distance gas pipeline in the future.
【学位授予单位】：华北科技学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE88;TN249

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