长输管道腐蚀防护系统安全性动态评价方法研究

发布时间：2018-01-20 19:36

  本文关键词： 长输管道 腐蚀防护系统 动态评价方法 支持向量机 集对理论 权重计算方法　出处：《西安科技大学》2017年博士论文　论文类型：学位论文

【摘要】：长输管道由于腐蚀引起的事故危害性特别严重,故针对管道腐蚀相关的安全管理和维护变得越来越重要。管道的腐蚀与防护是长输管道完整性管理的核心组成部份,对其系统的安全性评价是实现管道完整性管理的基础。目前国内有关基于客观数据分析和融合的管道腐蚀防护系统适用性综合安全评价方法还处于起步阶段。加之,系统的动态性特点,以及静态评价方法的局限性,其相关的评价方法研究都具有相对主观性较强,时效性、适应性和有效性考虑不足等片面性的情况。因此、论文系统研究了运用客观数据分析和融合为基础的管道腐蚀防护系统安全性分级、综合和动态评价方法及理论应用,这对管道腐蚀防护系统的安全性评价及完整性管理的决策具有重要的理论和现实指导意义。通过对管道腐蚀类型分类,以及相关电化学腐蚀机理的分析,结合长输管道常见腐蚀因素,建立了长输管道腐蚀防护失效事故树,为构造长输管道腐蚀防护系统评价指标体系提供了依据标准。根据长输管道外腐蚀突出的特点,结合现场测量、理化性质和检测数据分析,进行了土壤腐蚀、杂散电流腐蚀、阴极保护、防腐层保护的权重集研究,实现长输管道的安全性分级和动态评价。对于土壤腐蚀评价,以往土壤腐蚀等级评价中不同方法所偏重的突出影响因素不同,对不同地域条件下方法的适应性和有效性考虑不足,存在着评价的可靠性不高、时效性较差等问题。由于不同地域条件下土壤腐蚀多因素影响也不同的动态性特点,以及检测数据存在冗余性、异常性,研究提出了粗糙集-决策树-支持向量机(RS-DT-SVM)组合方法的土壤腐蚀等级动态评价。根据检验效果分析来看,RS-DT-SVM在多因素控制系统的评价等级分析中具有相对优越性。对于杂散电流腐蚀评价,利用拉普拉斯方程建立杂散电流腐蚀状态数学模型,并结合Comsol有限元软件进行了数据仿真实验研究,验证了杂散电流与土壤电阻率成反比,与管地电势之间成正比的关系,为杂散电流腐蚀强度评价提供了相应的理论依据。结合国内外相关标准,给出了其与土壤电位梯度,管地位偏移的关系和评价指标范围。对于阴极保护评价,利用阴极保护准则作为间接测量的方法进行了有效性的分析评价,提出了一种计算阴极保护系统平均IR降的判定方法,该方法比现有的测量平均IR降的方法简单。利用此平均IR降加上各区段管道测试桩测量的通电电位,可估计管道实际通电电位是否符合阴保准则,为管道阴极保护系统完整性管理及评价提供参考依据。对于防腐层保护评价,针对不同防腐层采用检测方法不同。依据国内外相关标准和准则,得到了防腐层开挖和非开挖情况下的分级指标体系和评价方法。针对静态评价方法的不足研究了防腐层劣化趋势的动态评价,构建了一种集对(SPA)状态评价和马尔科夫链趋势分析于一体的防腐层安全性动态评价方法。该方法通过检测大数据的实例验证,能对防腐层的安全水平进行动态评价,提高了防腐层劣化趋势评价能力,为管道维护提供了决策性的理论依据。对于分级评价方法,为减少主观因素,增加客观因素分析的针对性,结合各指标因素的特点,综合利用实际客观的检测数据,根据粗糙集和熵权计算法的应用特点,将两种方法组合进行权重的计算和验证,提高了系统权重计算确定时的应用性和可靠性。然后再利用集对理论聚类分析方法,根据各自指标因素特征,建立具有针对性的联系度应用模型来进行分级评价,提高了分级评价的适用性,为评价指标体系权重分析和分级评价提供指导。针对现有长输管道综合评价方法应用有效性不足,适用性差的问题,提出利用集对理论多元联系数的分析思想,将腐蚀和防护指标体系与评价等级组成集对,并根据指标特征建立有针对性的腐蚀态势和防护态势的四元联系度关系式,从而可考虑到指标之间的联系,达到对管道的腐蚀态势和防护性态势两方面联系的综合评价。该方法可反映出各管段的腐蚀和防护分级,找出重点的腐蚀防护区域,为综合掌握管道腐蚀与防护态势的危险等级提供了技术依据,提高了长输管道综合评价的适用性和合理性。为了能合理描述系统动态性的特点,运用集对理论的集对势进行了管道腐蚀与防护趋势优劣性的动态评价,提出了相关动态评价方法,发挥了综合评价的意义,为管道腐蚀防护系统安全性评价提供了技术指导。采用实际现场检测数据,包括土壤腐蚀数据48组,管道腐蚀防护系统综合数据6组,共计54组,通过2个一级指标因素,4个二级指标因素,20个三级指标因素对上述各评价方法进行了验证,其开挖结果表明各评价方法具有一定的实用性和有效性。应用论文中的安全性评价方法,可根据实际环境的特点,动态的适应性评价系统的安全性能,这对长输管道腐蚀防护系统的安全性评价研究具有重要的现实意义。
[Abstract]:Long pipeline accidents caused due to corrosion damage is particularly serious, so the safety management for pipeline corrosion related and maintenance becomes more and more important. The corrosion and protection of pipeline is the core of pipeline integrity management part, to evaluate the safety of the system is based on the implementation of pipeline integrity management at home and abroad on. The objective data analysis system of corrosion protection and fusion pipeline applicable comprehensive safety evaluation method is still in the initial stage. Based on the coupled with the system dynamic characteristic, and the limitations of the static evaluation method, the evaluation methods of research have relatively strong subjectivity, timeliness, lack of adaptability and effectiveness of one-sided consideration. Therefore, this dissertation has systematically studied the use of objective data analysis and fusion based pipeline corrosion safety protection system of classification, comprehensive and dynamic evaluation method The theory and application, has important theoretical and practical significance of the pipeline corrosion protection system safety assessment and integrity management decision. Through the classification of pipeline corrosion types, and analysis of electrochemical corrosion mechanism, combining with the common corrosion factors of pipeline, a failure fault tree of pipeline corrosion protection, provide the standard for constructing the evaluation index system of long distance pipeline corrosion protection system. According to the characteristics of pipeline corrosion prominent, combined with field measurement, analysis of properties and test data, the soil corrosion, stray current corrosion, cathodic protection, corrosion protection layer set of weights, realize the safety classification of long distance the pipeline and dynamic evaluation for soil corrosion factors, to highlight the impact of different methods of soil corrosion grade evaluation on different conditions of the domain under different methods Lack of adaptability and effectiveness, there are the evaluation of reliability is not high, the problem of poor timeliness. The dynamic characteristic of soil corrosion factors due to different geographical conditions have different effects, redundancy, and detection of abnormal data, the research proposed the rough set and decision tree support vector machine (RS-DT-SVM) evaluation of soil corrosivity dynamic combination method. According to the test result analysis, RS-DT-SVM has the relative superiority in the evaluation level of multi factor analysis of control system. The evaluation for stray current corrosion, stray current corrosion using the mathematical model established the Laplasse equation, and the simulation experiment data combined with Comsol finite element software, verify the stray the current and the soil resistivity is inversely proportional to the relationship between pipe and ground potential is proportional to the corresponding theory, provides for the stray current corrosion strength evaluation On the basis of. Combined with relevant standards at home and abroad, and gives the soil potential gradient, pipe position offset relationship and range of evaluation index. Evaluation for cathodic protection, using cathodic protection standards as the indirect measurement method of effectiveness evaluation, put forward a calculation of the average IR cathodic protection system drop determination method, method the method is better than the existing IR measuring the average drop. By using this simple average IR with each section of pipe testing on potential pile measurement, can be estimated through the electric potential is consistent with the actual pipeline cathodic protection criteria for cathodic protection system of pipeline integrity management and provide reference for evaluation. Evaluation of anticorrosion coatings. In view of the different coatings using different detection methods. Based on the domestic and foreign relevant standards and norms, the anticorrosion layer excavation and non hierarchical index system and evaluation method under the condition of excavation in the static. Dynamic evaluation evaluation method to study the state of lack of coating deterioration trend, construct a set of (SPA) coating safety dynamic evaluation method of condition evaluation and trend analysis of Markov chain in one. The detection method by examples of big data validation, can dynamically evaluate the safety level of the anticorrosion layer, improve the corrosion evaluation of deterioration trend, the theoretical basis for decision-making for pipeline maintenance. The classification evaluation method, to reduce the subjective factors and objective factors for analysis, combined with the characteristics of each index, the detection data of actual objective comprehensive utilization, application characteristics calculation method based on rough set theory and entropy the two methods combined calculation and verification of weight, improve system reliability and weight calculation application determined. Then the set theory of cluster analysis method, according to their respective Factors of characteristics, to establish a connection for the application of the model for grade evaluation, improve the applicability of classification evaluation, provide guidance for the evaluation of the evaluation index system of weights analysis and classification. In view of the existing comprehensive evaluation method of long distance pipeline application effectiveness, the problem of poor applicability, the analysis thought of set theory multi contact number, the corrosion and protection of the index system and the evaluation grade set of components, and according to the characteristics of the establishment of the index of the corrosion situation and protection situation of four yuan of relation, which can take into account the link between indicators, comprehensive evaluation of two aspects to the corrosion situation of the pipeline and the protection of the contact situation. This method can reflect the pipe corrosion and protection grade, find the key regional corrosion protection, comprehensive grasp the dangerous situation of pipeline corrosion and protection grade of the offer The technical basis, improve the comprehensive evaluation of long distance pipeline and the applicability and rationality. In order to reasonably describe the characteristics of the dynamic system, the use of Set Pair Theory in the dynamic evaluation of pipeline corrosion and protection trends of potential advantages and disadvantages, puts forward relevant dynamic evaluation method, comprehensive evaluation of the significance of play, provided technical guidance for pipeline corrosion protection system safety evaluation. The testing data of the actual scene, including the soil corrosion data of 48 groups, pipeline corrosion protection system of comprehensive data of 6 groups, a total of 54 groups, the 2 level indicators, 4 level two indexes, 20 level three indexes to verify the various factors the evaluation method, the excavation results show that the evaluation method is practical and effective. The safety evaluation methods applied in this thesis, according to the characteristics of the actual environment, the dynamic adaptability evaluation system. It is of great practical significance to study the safety evaluation of long distance pipeline corrosion protection system.

【学位授予单位】：西安科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TE988.2
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本文编号：1449287