Research On Risk Evaluation Of Municipal Underground Gas Pipeline

In recent years our country pays more attention to energy safety and environmental problems. As a kind of clean energy, natural gas being used increasingly. With the development of the gas transport projects, such as transport gas from west to east, transport gas from south of Russia to China, import LNG, gas transport to land from sea, the using of gas in city will be more prevalent. City is the center of population and economy, the substance in municipal underground gas pipeline has the character of flammability, explosion and toxicity. The consequence will be very serious when the underground gas pipeline is failure. Any accident about underground gas pipeline will take amount of people's life and cost a lot of money and will hurt society deeply. So it is quite significant to perform the risk assessment and ensure safe operation of the municipal underground gas pipeline.In this dissertation, the research focus on risk analysis and assessment of underground gas pipeline, the research contents are as follows:(1) Describe the basic principle of risk management and risk assessment. The integrated matter-arrangement of risk management has been given from the viewpoint of system engineering. The risk analysis, risk assessment and risk control of municipal underground gas pipeline have been detailed according to the matter-arrangement framework.(2) The fault tree of municipal underground gas pipeline is erected with the deduction method according to the risk assessment basic theory. The maximum cut sets of this fault tree are got through the Boolean algebra simplifying method. Through qualitative analysis of the fault tree structure importance, the conclusion is drawn that the main factors resulting in municipal underground gas pipeline failing are third destruction, corrosion, misplacement and design bug. The technical measures and administrative measures are proposed to prolong life span of municipal underground gas pipeline.(3) Discuss principle of the choice of indexes of risk assessment of municipal underground gas pipeline. Based on the analysis of fault tree, established the factor system of assessment of municipal underground gas pipeline. According to the method of index risk assessment, mark the factors which influence the safety of municipal underground gas pipeline.(4) In the risk assessment of the underground gas pipeline, many factors have the character of uncertainty. In order to describe these fuzzy factors exactly, the concept of fuzzy knowledge is introduced and the fuzzy comprehensive evaluation is applied to estimating the risk of the underground gas pipeline. The application process of the fuzzy comprehensive evaluation method is applied to an example of municipal underground gas pipeline is given.