基于可靠性的输气管道设计系数研究与影响因素分析

发布时间：2018-02-15 11:09

本文关键词： 输气管道设计系数试压止裂韧性可靠性理论　出处：《长江大学》2017年硕士论文　论文类型：学位论文

【摘要】：设计系数是衡量输气管道输送能力和承压能力的关键指标。设计系数越高,管壁承受的压力越大,管道的输气量也越大。虽然,国外一些国家已经在部分一级地区的输气管道上采用了0.72以上的设计系数,但由于受客观技术条件所限,目前我国一级地区的大多数输气管道仍然采用0.72的设计系数。近年来,国内在管线钢冶金、制管、施工、焊接及质量控制等方面都取得了长足进步,管线钢的实物质量达到甚至超过国际先进水平。此外,我国管道风险管理和完整性管理水平也有了显著提高。提高我国输气管道一级地区设计系数已具备良好的条件和基础。因此,基于可靠性理论对我国一级地区输气管道设计系数及其影响因素进行深入研究具有广泛的工程背景和现实意义。本文通过调研国内外相关文献以及工程实践资料,从失效事故率、风险管理、应力腐蚀开裂、试压技术方面分析了提高一级地区输气管道设计系数的可行性;并结合工程实例分析了提高设计系数对含缺陷管道临界极限尺寸、管道刺穿抗力以及管道止裂韧性产生的影响;运用应力—强度干涉理论和一次二阶矩法,结合中俄东线管道工程实例验证了将输气管道一级地区设计系数提高至0.8的可行性。本文得到的主要结论如下:(1)设计系数的提高对管道事故率有一定影响,但管道失效事故的发生并非取决于设计系数。管道风险管理水平的提高才是管道失效事故率降低的根本原因。因此提高一级地区输气管道设计系数是可行的;(2)通过钢管实际屈服应力理论分析和调研实物钢管的屈服强度表明管道屈服时的环向应力大于110%SMYS。以西气东输三线伊宁—霍尔果斯段为例进行压力—容积水压试验,发现压力—容积曲线在环向应力达到100.5%SMYS时未出现向下偏转,说明在该压力下试压是安全的。调研管道爆破压力的相关资料发现不同钢级的直缝和螺旋缝钢管爆破时环向应力均大于120%SMYS。因此,可考虑通过提高运行压力的方式提高设计系数;(3)将管道的设计系数从0.72提高到0.8,含腐蚀缺陷管道的临界极限尺寸出现一定程度的降低;在输气管道的运行压力、钢级、管径、撞击长度和撞击宽度均相同的情况下,将设计系数从0.72提高到0.8,会使管道刺穿抗力降低;以西气东输三线一级地区为例,分别采用Battle双曲线法、BTC加Leis修正式和BTC加修正系数方法计算0.72、0.8设计系数下管径1219mm、X80管道止裂韧性值,结果表明随着设计系数的提高,对于输气管道止裂韧性值的要求也有一定程度的增加;(4)中俄东线一级地区0.72设计系数下无缺陷管道和含体积型缺陷管道的可靠度均大于API579的目标可靠度。在此基础上,根据API579推荐的目标可靠度计算得到一级地区无缺陷管道的设计系数最大允许值为1。在考虑含体积型缺陷的情况下,DNV RP-F101方法较PCORRC方法更为保守,因此计算结果安全性更高。对于一级地区根据DNV RP-F101,通过增加压力的方法计算得到的设计系数最大允许值为0.808;通过降低壁厚的方法计算得到的设计系数最大允许值为0.796,为将设计系数提高至0.8,可通过控制单个参数的方法使其满足安全要求。
[Abstract]:The design of transmission coefficient is a measure of key indicators of gas pipeline transportation capacity and the bearing capacity of the design. The coefficient of the tube wall, the greater the pressure, the greater the amount of gas pipeline. Although, some foreign countries have in part a in gas transmission pipeline is designed by coefficient of more than 0.72, but due to the technical conditions are limited, most of the current level of China gas pipeline design is still used a coefficient of 0.72. In recent years, the domestic steel pipe manufacturing, metallurgy, construction, welding and quality control has made considerable progress, the physical quality of pipeline steel reached or exceeded the international advanced level. In addition, China's pipeline risk management and integrity management level has been improved significantly. To improve our level of gas pipeline design area coefficient has been a good foundation and conditions. Therefore, the reliability theory of a region of China based on The design of gas pipeline and its influencing factors of coefficient of in-depth study has extensive engineering background and practical significance. This paper through the research of domestic and international relevant literature and engineering practice, the failure rate, risk management, stress corrosion cracking, pressure test technology feasibility analysis provided a high level of transmission coefficient of gas pipeline design area; and combined with the engineering example analysis to improve the size of the design coefficient on the critical limit of defective pipelines, pipeline piercing resistance and pipeline crack arrest toughness impact; using the stress strength interference theory and a two order moment method, combined with the Sino Russian East pipeline engineering examples to verify the feasibility of the gas pipeline to improve the design level to 0.8 area coefficient the main conclusions are as follows: (1) the increasing design coefficient has a certain effect on the pipeline accident rate, but the pipeline failure accidents does not depend on the design The coefficient of pipeline. Raising the level of risk management is the fundamental cause of the accident rate is reduced. Therefore the pipeline failure to improve one area of gas pipeline design coefficient is feasible; (2) the actual steel yield strength theory analysis and research of real steel yield showed the pipeline circumferential stress is greater than 110%SMYS. the West three east line Yining - Huoerguosi section as an example for the pressure volume pressure test, pressure volume curve in the circumferential stress downward deflection does not appear to 100.5%SMYS, indicating the pressure under the pressure test is safe. Research the pipe burst pressure of different grade of steel straight and spiral seam pipe when blasting circumferential stress is greater than 120%SMYS. so, can be considered to improve the design coefficient by improving operating pressure; (3) the design of the pipeline coefficient increased from 0.72 to 0.8, pipeline with corrosion defects The critical limit size decreased in a certain degree; the operation pressure, the gas pipeline steel grade, diameter, length and width are impact impact under the condition of the same design coefficient increased from 0.72 to 0.8, will make the pipe piercing resistance is reduced; the west east gas pipeline three line level land area as an example, respectively. The Battle hyperbola method, BTC plus Leis and BTC plus modified correction coefficient calculation method 0.72,0.8 design coefficient of diameter 1219mm, X80 pipeline anti crack toughness value, the results show that with the increasing design coefficient, also increased to a certain degree for gas pipeline crack arrest toughness requirements; (4) the reliability of defect free a pipeline in eastern Russia in 0.72 and design coefficient with volume defects of pipeline are larger than the API579 of the target reliability. On this basis, according to the API579 recommended target reliability design and calculation of a defect free area coefficient and get the maximum To allow the value of 1. in considering the volume defects under the condition of DNV RP-F101 method is more conservative than the PCORRC method, so the calculating result is more secure. The level of area according to DNV RP-F101, obtained by increasing pressure calculation design coefficient of the maximum allowable value for 0.808; through the method of reducing the wall thickness calculation the design of the coefficient of the maximum allowable value for 0.796, for the design coefficient increased to 0.8, the control method of single parameter to meet the safety requirements.

【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE973.1

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