基于水力工况的天然气干线管网供气可靠性研究
发布时间：2019-02-22 11:35
【摘要】：天然气是一种集清洁、高效两大优点于一身的新型化石能源,是新世纪世界能源结构不断优化的重要方式,而在众多输送方式中,管道必然是大规模输送天然气的最佳选择。我国天然气资源遍布南北,天然气市场尚不集中,管道沿线地理环境复杂、生态敏感性高、用户需求多样,因此我国的天然气管线承担了最大的输送任务和压力,但管网系统的冗余度却最小。综合种种因素,使得我国天然气管网成为世界上最复杂、输送任务最艰巨的输气管网系统。天然气管网作为天然气输送的关键因素,其作用不言而喻,气田的制造以及供气的好坏与管网的质量也有直接关系,天然气管网系统需要极高的安全性和极稳定的输气能力。因此,将系统可靠性融入管网规划、设计、运行维护全过程,实现对管网系统可靠性及单元间相互作用规律的全面、深入掌控,是我国天然气管网发展的必然要求。本文针对天然气输送管网系统,在对管网系统进行故障工况下的水力工况分析的基础上,研究天然气管网系统的供气可靠性。 天然气管网系统的可靠性综合评价,应当首先研究管网故障工况下的拓扑结构,根据故障工况下的拓扑结构,结合水力计算基本模型,计算故障工况下的流量分布情况,最后根据计算得到的流量结果计算可靠度指标。 研究管网故障工况下的拓扑结构时,第一步是建立平面管网的关联矩阵和可以反映阀门信息的混合关联矩阵,采用矩阵法将平面管网转化为阀门网络模型,根据阀门网络模型及其关联矩阵,可以直观地搜索出关断区域,进而制定故障元件对应的关阀方案,通过搜索故障隔离时平面管网的所有连通子图,重构故障管网。 根据天然气在管道内流动的相关性质,建立天然气管网水力计算的基本模型,根据节点方程法,结合图论基本知识,利用MATLAB软件编制了管网的水力计算程序。基于水力计算的基本模型和故障管网拓扑结构,建立管网系统故障工况水力分析模型。运用TGNET软件对故障工况下的水力计算结果进行模拟,验证计算结果的准确性。 最后基于状态空间法建立可靠度基本模型,此可靠度模型是功能质量指标,包括设计负荷可靠度指标和限额供气可靠度指标,这两个指标是用来综合评价系统的可靠性。此外,还提出将应力-强度干涉理论的思想引入供气可靠性评价当中,将市场需求量视为应力,管网供气量视为强度,将两者的概率分布相干涉,可用蒙特卡洛法计算管网的供气可靠度。 综上,天然气管网系统的综合可靠性评价通过重构故障管网、故障工况下的水力计算和供气可靠度指标的计算完成。
[Abstract]:Natural gas is a new fossil energy with the advantages of cleanliness and high efficiency. It is an important way to optimize the energy structure of the world in the new century. Among the many transportation modes, pipeline is the best choice for large-scale transportation of natural gas. The natural gas resources of our country are all over the north and south, the natural gas market is not concentrated, the geographical environment along the pipeline is complex, the ecological sensitivity is high, and the user's demand is diverse. Therefore, the natural gas pipeline in our country undertakes the biggest transportation task and pressure. But the redundancy of pipe network system is the least. Combined with all kinds of factors, natural gas pipeline network in China has become the most complicated and arduous gas transmission network system in the world. As the key factor of natural gas transportation, the role of natural gas pipeline network is self-evident, and the quality of gas field manufacturing and gas supply is also directly related to the quality of the pipeline network. The natural gas pipeline network system needs very high security and extremely stable gas transmission capacity. Therefore, it is necessary to integrate the system reliability into the whole process of pipe network planning, design, operation and maintenance, and to realize the comprehensive and thorough control of the reliability of the pipeline system and the interaction between units, which is the inevitable requirement of the development of natural gas pipeline network in China. In this paper, the reliability of natural gas pipeline network system is studied on the basis of analyzing the hydraulic condition of the network system under the malfunction condition. In the comprehensive evaluation of the reliability of natural gas pipeline network system, the topology structure under the fault condition of the pipeline network should be studied first. According to the topology structure under the fault condition and the basic hydraulic calculation model, the flow distribution under the fault condition should be calculated. Finally, the reliability index is calculated according to the calculated flow results. The first step is to establish the correlation matrix of the plane pipe network and the hybrid correlation matrix which can reflect the valve information. The matrix method is used to transform the plane pipe network into the valve network model. According to the valve network model and its correlation matrix, it is possible to directly search the exit and break area, and then to formulate the closing valve scheme corresponding to the fault components, and to reconstruct the fault network by searching all the connected subgraphs of the plane pipe network when the fault is isolated. According to the related properties of natural gas flowing in pipeline, the basic model of hydraulic calculation of natural gas pipeline network is established. According to the nodal equation method and the basic knowledge of graph theory, the hydraulic calculation program of pipeline network is compiled by using MATLAB software. Based on the basic model of hydraulic calculation and the topological structure of the fault pipe network, the hydraulic analysis model of the fault condition of the pipe network system is established. The TGNET software is used to simulate the hydraulic calculation results under the fault condition, and the accuracy of the calculation results is verified. Finally, the basic reliability model is established based on the state space method. The reliability model is the function quality index, including the design load reliability index and the quota gas supply reliability index, which are used to comprehensively evaluate the reliability of the system. In addition, the idea of stress-strength interference theory is introduced into the reliability evaluation of gas supply. The market demand is regarded as stress, the gas supply in pipe network is regarded as intensity, and the probability distribution of both is interfered. The reliability of gas supply can be calculated by Monte Carlo method. To sum up, the comprehensive reliability evaluation of natural gas network system is accomplished by reconstructing the fault network, calculating the hydraulic calculation under the fault condition and calculating the reliability index of the gas supply.
【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】：TE832
本文编号：2428182
[Abstract]:Natural gas is a new fossil energy with the advantages of cleanliness and high efficiency. It is an important way to optimize the energy structure of the world in the new century. Among the many transportation modes, pipeline is the best choice for large-scale transportation of natural gas. The natural gas resources of our country are all over the north and south, the natural gas market is not concentrated, the geographical environment along the pipeline is complex, the ecological sensitivity is high, and the user's demand is diverse. Therefore, the natural gas pipeline in our country undertakes the biggest transportation task and pressure. But the redundancy of pipe network system is the least. Combined with all kinds of factors, natural gas pipeline network in China has become the most complicated and arduous gas transmission network system in the world. As the key factor of natural gas transportation, the role of natural gas pipeline network is self-evident, and the quality of gas field manufacturing and gas supply is also directly related to the quality of the pipeline network. The natural gas pipeline network system needs very high security and extremely stable gas transmission capacity. Therefore, it is necessary to integrate the system reliability into the whole process of pipe network planning, design, operation and maintenance, and to realize the comprehensive and thorough control of the reliability of the pipeline system and the interaction between units, which is the inevitable requirement of the development of natural gas pipeline network in China. In this paper, the reliability of natural gas pipeline network system is studied on the basis of analyzing the hydraulic condition of the network system under the malfunction condition. In the comprehensive evaluation of the reliability of natural gas pipeline network system, the topology structure under the fault condition of the pipeline network should be studied first. According to the topology structure under the fault condition and the basic hydraulic calculation model, the flow distribution under the fault condition should be calculated. Finally, the reliability index is calculated according to the calculated flow results. The first step is to establish the correlation matrix of the plane pipe network and the hybrid correlation matrix which can reflect the valve information. The matrix method is used to transform the plane pipe network into the valve network model. According to the valve network model and its correlation matrix, it is possible to directly search the exit and break area, and then to formulate the closing valve scheme corresponding to the fault components, and to reconstruct the fault network by searching all the connected subgraphs of the plane pipe network when the fault is isolated. According to the related properties of natural gas flowing in pipeline, the basic model of hydraulic calculation of natural gas pipeline network is established. According to the nodal equation method and the basic knowledge of graph theory, the hydraulic calculation program of pipeline network is compiled by using MATLAB software. Based on the basic model of hydraulic calculation and the topological structure of the fault pipe network, the hydraulic analysis model of the fault condition of the pipe network system is established. The TGNET software is used to simulate the hydraulic calculation results under the fault condition, and the accuracy of the calculation results is verified. Finally, the basic reliability model is established based on the state space method. The reliability model is the function quality index, including the design load reliability index and the quota gas supply reliability index, which are used to comprehensively evaluate the reliability of the system. In addition, the idea of stress-strength interference theory is introduced into the reliability evaluation of gas supply. The market demand is regarded as stress, the gas supply in pipe network is regarded as intensity, and the probability distribution of both is interfered. The reliability of gas supply can be calculated by Monte Carlo method. To sum up, the comprehensive reliability evaluation of natural gas network system is accomplished by reconstructing the fault network, calculating the hydraulic calculation under the fault condition and calculating the reliability index of the gas supply.
【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】：TE832
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