中缅天然气大落差管道安全清管方案研究

发布时间：2017-12-28 07:30

本文关键词：中缅天然气大落差管道安全清管方案研究　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：中缅天然气管道途经地区山体高耸、地势险峻,管道在修建过程中常依地势而建,因而形成了许多大落差管道。出于安全考虑,中缅天然气管道自投产后在大落差管道地区并未实施清管作业,因为在大落差管道的下坡段,清管器和液弹会在重力和压差作用下加速向下流动,当到达管道底部时,由于流动方向的改变,清管器和液弹会对管道底部形成间歇性的冲击应力并伴随强烈的震动。同时,在此清管冲击过程中大落差管道还将受到内压、土壤、温度等载荷,这些载荷的共同作用对大落差管道的危害性极大,轻则引起管道结构的严重变形,重则引起结构失稳、破坏,严重威胁天然气管道的安全运行。针对这一问题,本文以龙陵输气站—弥渡输气站间的两段典型大落差管道为研究对象,采用理论和数值模拟相结合的方法,研究了大落差管道在不同清管载荷作用下管道的应力、应变大小并进行安全性校核,提出了相应的防护措施并制定了安全清管方案。具体的研究内容如下:(1)为了获取清管过程中清管器、液弹以及管道相关基础参数,基于OLGA软件建立了大落差管道清管多相流仿真模型,将模拟结果与现场数据进行对比验证了模型的准确性,对其在设计输量范围内可能存在的6种清管工况进行模拟,得到清管载荷计算所涉及到的关键参数变化范围,主要包括:积液量大小及分布、清管器和液弹运行速度、液弹持液率。(2)大落差管道受力的理论分析是进行载荷加载的前提条件。为了为后续有限元模型参数及边界条件设置提供理论依据,模拟计算大落差管道在清管载荷作用下的应力应变行为。针对大落差管道埋地状态这一特性,对大落差管道所受载荷类型进行了分类,建立了考虑清管器、液弹冲击、管道内压、温度、土壤载荷的计算模型,并选择了基于应力的失效判定准则对大落差管道的安全性进行校核。(3)以OLGA软件模拟得到的积液量分布为前提,针对清管过程中是否包含液弹的情况,将大落差管道分为无积液段和有积液段,采用ABAQUS、CAESARⅡ两种有限元软件相结合的方法,建立了需要进行清管载荷受力分析的两段大落差天然气管道模型,分别对大落差天然气管道在上述6种清管工况产生的清管载荷进行分析,探求在不同载荷作用下管道的应力、应变大小,并进行安全性校核,筛选安全的清管工况。(4)针对中缅天然气大落差管道在清管过程中的安全问题,结合前文清管多相流分析结果和大落差管道清管载荷分析结果,提出降低大落差管道清管风险的措施,并制定安全的清管方案,为中缅天然气大落差管道在清管工况下的安全运行提供一定的技术保障。本文有针对性开展清管载荷研究,进而制定安全清管方案,不仅可为中缅管道的安全运营提供科学建议,亦可为其它山区大落差管道清管提供思路和借鉴。
[Abstract]:The mountains of China and Myanmar natural gas pipelines are towering and steep, and the pipelines are often built in the course of construction, so many large drop pipelines have been formed. For security reasons, not the implementation of pigging operation in big drop pipeline area since after the China Burma gas pipeline, because the downhill section in big drop pipeline, pigging and liquid slug in under the action of gravity acceleration downward flow and pressure difference, when reaching the bottom of the pipe, due to the change of flow direction, pigging device and liquid slug will form the bottom of the pipe on the intermittent impact stress is accompanied by a strong shock. At the same time, the Qing big drop pipeline in the process of impact will be affected by the loads of internal pressure, soil, temperature, harmfulness of the joint action of these loads of big drop pipeline greatly, the light is caused by severe deformation of pipeline structure, weight is caused by structural instability and failure, seriously affect the safe operation of natural gas pipeline. To solve this problem, this paper takes Midu power station Longling two typical big drop pipeline between the gas station as the research object, adopting the methods of theory combined with numerical simulation, studied the big drop pipeline security check in different pipeline pigging load stress, strain and size, put forward the corresponding the protective measures and formulate the safety clearance programme. The specific contents are as follows: (1) in order to obtain the pigging process in pigging liquid slug and pipeline and related basic parameters, based on the OLGA software to set up a big drop pipeline pigging multiphase flow simulation model, the simulation results and field data are compared to verify the accuracy of the model, the design throughput range in the 6 possible pigging simulation, get the key parameter ranges, pigging load calculation involved include: the amount of effusion size and distribution, and pigging liquid slug velocity, liquid slug liquid holdup. (2) the theoretical analysis of the force of the large drop pipe is the precondition for loading load. In order to provide theoretical basis for subsequent finite element model parameters and boundary conditions setting, stress and strain behavior of large drop pipeline under pigging load is simulated. According to the characteristics of underground big drop pipeline, classify the load type on the big drop pipeline, considering the pipe cleaner, liquid slug impact, pipeline internal pressure, temperature, soil load calculation model, and select the failure criterion based on stress safety of big drop pipeline check. (3) with OLGA software to simulate the fluid volume distribution is obtained as the premise, according to whether the pigging process contains liquid bomb, the big drop pipeline is divided into segments and effusion fluid, method of using two kinds of finite element software ABAQUS, CAESAR II combined with the established two section needs to be clear the gap of natural gas pipeline stress analysis of pipe load model of the big drop in the 6 natural gas pipeline pigging of pigging load analysis, explore the different loads of pipeline stress and strain size, and security check, security screening pigging. (4) according to the China Burma gas big drop pipeline safety problems in the pigging process, combined with the above pigging multiphase flow analysis and big drop pipeline pigging load analysis results, put forward to reduce the big drop pipeline pigging risk measures, and develop safety pigging project, provide technical support for in Burma gas big drop pipeline safe operation in pigging conditions. This paper carry out pigging load on, and establish the safety clearance programme to provide scientific advice for the safe operation of the pipeline can not only China, but also for other mountain big drop pipeline pigging to provide ideas and reference.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE832.36

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