The Research Of Quantitative Risk Evaluation Index System For City Gas Pipeline Network

Through analyzing the needs of integrity management for city gas network in the system of city gas transmission and distribution, combining development history and the present research status of risk assessment at home and abroad, contrasting and analyzing the quantitative risk assessment, semi-quantitative risk assessment and qualitative risk assessment, summed up the commonly evaluation method used at home and abroad, and determined the method for which this research subject need.Based on the city gas network estimating index system that designated by pipeline risk management manual, applied analysis method of fault tree, identified the danger factor of city gas network minutely, analyzed the consequences model of pipeline failure, built the quantitative risk evaluation index system of city gas pipeline network, amended every occurrence index probability value, combined with the engineering practice to proof the newly established evaluation index system scientifically, choose a pipeline existed in the Ba Zhou Ji Zhong Kun Lun gas of Petro China city pipeline network system for the risk evaluation, and provide the decision analysis.The study results of this paper provide theoretical guidance for the safety of city gas management, determining risk factors, forecasting probabilistic of accident and security scheme of accident emergency. Analyzed and calculated the accident consequences model of city pipeline network system, elaborated calculation method emphatically of the individual risk, social risk and property losses, and introduced the risk accept risks standards present situation of domestic and foreign.This paper narrated the domestic and foreign present situation and meaning of city gas pipeline network of quantitative risk assessment in the first chapter. In chapter2, this paper expounded the basic concept, research the cause of accident and data, contrasted analysis all kinds of calculation method for the basic affair occurrence probability, and determined the fuzzy mathematics and experts investigation for this topic research methods.In chapter3, used the analysis method of fault tree to identify risk factors each kind of the city gas network system, statistics the shortest path to set and cut set, calculated the probability value of the major failure modes and the basic even. The fourth chapter, built accident consequences model for researching quantitative analysis personal risk, social risk and property damage after the accident happened. Chapter5introduced the correction probability method of the top events and basic events, constructed the city gas pipeline network quantitative risk evaluation index system that based on correcting the probability of the bottom index factors. The sixth chapter, built the application model of quantitative risk evaluation system, and studied the evaluating steps and process applicability in this thesis. Chapter7combined with established evaluation system and the method, chose a pipeline existed in the Ba Zhou Ji Zhong Kun Lun gas of Petro China city pipeline network system for the risk analysis, quantitative calculation and the risk level determination, finally put forward the measures for reform.In chapter8, proposed the aspect for further research according to the fault of this paper.Through studied the change from the qualitative risk assessment to quantitative risk assessment in the city gas pipeline, and further increased the reliability and accuracy of risk evaluation, and provided the foundation of theory and practice to the next comprehensive implementation city gas transmission and distribution system integrity management.