Research Of Risk Assessment On Long-distance Pipelines System For Natural Gas

Nowadays, long-distance pipelines for natural gas have stepped into a rapid development era in China. Until the end of 2006, long-distance pipelines for natural gas have been thirty-two thousand kilometers. Natural gas pipeline safety and steady transportation is the essential factor determining the economy benefits of natural gas pipeline companies. Due to the dangers of fire and explosion, natural gas pipeline will bring destructive effect on human life and natural environment once pipeline leaks happen. So it is the most important issue concerned by pipeline operators how natural gas pipeline smoothly and safely manage to complete the transportation mission with specified volume, time, operating conditions and good quality. Applying risk evaluation on gas pipeline system is an effective method to acquire the pipeline safety management and smooth running. By risk identification and risk grouping to the application, all the risk factors affecting the system safety can be found out and risk point value can be arranged using of science evaluation method. It can guide governor to ascertain out rational risk shortening measures, ensure systematic nature safety, cut down economic losses and increase performance of enterprises. On the base of the results about the research findings risk theory on gas pipeline system at home and abroad, three assessment methods-qualitative, half-quantitative, and quantitative-were adopted to evaluate the gas pipelines and gas transmission station. By analyzing the failure factors and accident statistics, consulting the currently national standard and industry criterion, safety check list was brought. Combining practical situation in China, the expert assessment model of the long-distance gas pipelines and gas transmission station were established. The index system of risk Assessment, weighing and point value can be gotten, which deal with design, purchase for raw and processed materials, construction, supervise, code criteria, scheme of put into production, pressure test, pilot run, landform, environmental condition, climatic condition, natural disaster, and so on. This method has the merits such as systematicness, integrality, easily grasping and extending. But it has stronger subjectivity. To make up this one point, the method of fuzzy synthetic evaluation was adopted. The fuzzy poly-assessment model for long-distance gas pipelines, gas transmission station and the judging standards were given. The research findings were applied on Shanshan-Urumqi long-distance pipelines for natural gas, which were tested to fit the pipeline practical situation, and showed high eliability. These all can provide the scientific theory basis to the accident prevention.