高压输气管道泄漏危险性分析及后果模拟

发布时间：2018-10-12 08:42

【摘要】：高压输气管道输送天然气是较安全、较经济的运输方式。与其它管道一样,高压输气管道运行过程中受到多种内外因素的干扰,从而导致高压输气管道发生泄漏。由于天然气易燃、易爆及毒性的特征,泄漏一旦发生并且扩散到大气中,遇到点火源便可能发生剧烈燃烧或爆炸,可能造成人员伤亡和严重的财产损失,带来恶劣的政治及社会影响。因此,对可能发生的天然气管道泄漏事故进行定性、定量的危险性分析及泄漏后果模拟,以达到风险最小、效益最大的目标。本文通过识别和确认高压输气管道运行过程中涉及的风险进行系统的,分析高压输气管道的危险有害因素,找到与高压输气管道泄漏事故紧密联系的危险因素,为故障树分析做铺垫。为查找高压输气管道运行过程中导致泄漏的原因,采用故障树分析法进行定性分析,求出高压输气管道泄漏故障树的最小割集,得到能够引起高压输气管道泄漏的主要危害因素有第三方破坏、腐蚀、管材缺陷和自然灾害。由于高压输气管道中的具体实验数据及现场数据不足,因此采用模糊故障树分析法对高压输气管道系统进行分析。以高压输气管道主要风险因素故障树为模型,事件发生的概率采用三角模糊数表示,计算管道泄漏概率,并通过模糊重要度法对主要危险因素故障树基本事件进行排序。高压输气管道泄漏后泄漏量是灾害后果计算的基础,根据射流理论进行分析,运用流体力学理论,建立与实际状况相符合泄漏模型。系统地研究了高压输气管线泄漏小孔模型、大孔模型及管道模型,并得出三种模型的使用范围,并确定大孔模型适用于任何泄漏孔径。在系统地介绍各种泄漏扩散模型的基础上,选择高斯烟团模型模拟高压输气管道泄漏扩散过程,利用MATLAB对高斯烟团模型进行模拟,得出扩散区域与风速、泄漏孔径之间的关系。高压输气管道泄漏后可能发生火灾和爆炸等危害后果。在科学选取灾害模型——喷射火火灾模型、火球火灾模型和蒸气云爆炸模型的前提上,对高压输气管道泄漏后可能发生的事故进行喷射火热辐射伤害计算、火球热辐射伤害计算及蒸气云爆炸冲击波伤害进行计算,得出事故的影响范围和伤亡半径。采用与天然气泄漏扩散相似的固体火焰模型对喷射火灾产生的热辐射伤害进行计算；在对火球火灾的伤害半径的计算中,引进积分的思想对火球燃烧过程中的伤害效应进行累加求解,进一步提高了计算的精度；天然气泄漏遇延迟点火源会引发蒸气云爆炸,对其伤害程度计算的主流模型即为TNT当量模型,通过求取燃料等效TNT质量来确定蒸气云爆炸的伤害范围,计算过程简单易懂,有利于在实际灾害分析中的推广。
[Abstract]:High pressure gas transmission pipeline is a safe and economical way to transport natural gas. Like other pipelines, high pressure gas pipelines are disturbed by many internal and external factors during operation, which leads to leakage of high pressure gas pipelines. Because of the flammable, explosive and toxic characteristics of natural gas, once a leak occurs and spreads into the atmosphere, it may ignite or explode violently in the presence of a ignition source, which may result in casualties and serious property losses. Bring bad political and social influence. Therefore, the possible gas pipeline leakage accident is analyzed qualitatively and quantitatively, and the result of leakage is simulated in order to achieve the goal of minimum risk and maximum benefit. By identifying and confirming the risks involved in the operation of high pressure gas transmission pipeline, this paper systematically analyzes the dangerous and harmful factors of high pressure gas transmission pipeline, and finds out the risk factors closely related to the leakage accident of high pressure gas pipeline. Pave the way for fault tree analysis. In order to find out the cause of leakage during the operation of high pressure gas transmission pipeline, the fault tree analysis method is used to qualitatively analyze, and the minimum cut set of leakage fault tree of high pressure gas transmission pipeline is obtained. The main harmful factors which can cause leakage of high pressure gas transmission pipeline are third party damage, corrosion, pipe defect and natural disaster. Due to the shortage of experimental data and field data in high pressure gas transmission pipeline, fuzzy fault tree analysis method is used to analyze the high pressure gas transmission pipeline system. Based on the fault tree of main risk factors in high pressure gas transmission pipeline, the probability of occurrence is expressed by triangular fuzzy number, the leakage probability of pipeline is calculated, and the basic events of main risk factor fault tree are sorted by fuzzy importance method. The leakage amount after leakage in high pressure gas transmission pipeline is the basis of disaster consequence calculation. Based on the analysis of jet theory and the application of fluid dynamics theory, the leakage model is established in accordance with the actual situation. The leak pore model, large hole model and pipeline model of high pressure gas pipeline are studied systematically. The application range of the three models is obtained, and it is determined that the large pore model is suitable for any leak aperture. On the basis of systematically introducing various leakage and diffusion models, Gao Si smoke cluster model was selected to simulate the leakage and diffusion process of high pressure gas transmission pipeline, and then the Gao Si smoke cluster model was simulated by MATLAB, and the relationship between diffusion region and wind speed and leakage aperture was obtained. Fire and explosion may occur after leakage of high pressure gas transmission pipeline. Based on the scientific selection of disaster models, such as fire model of jet fire, fireball fire model and vapor cloud explosion model, the possible accidents after leakage of high pressure gas transmission pipeline are calculated. The thermal radiation damage of the fireball and the shock wave damage of the vapor cloud explosion are calculated, and the influence range and the casualty radius of the accident are obtained. The thermal radiation damage caused by jet fire is calculated by using a solid flame model similar to that of natural gas leakage and diffusion, and the damage radius of fireball fire is calculated. The concept of integral is introduced to solve the damage effect in the process of fireball combustion, and the accuracy of calculation is further improved. The mainstream model for calculating the damage degree is the TNT equivalent model. The damage range of the vapor cloud explosion is determined by obtaining the equivalent TNT mass of the fuel. The calculation process is simple and easy to understand, which is beneficial to the popularization of the actual disaster analysis.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE88

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