| Long-distance natural gas pipeline is prone to leak because of its long distance transport,harsh environment it passes through and difficulty of supervision.Natural gas leakage accidents always threaten the safety of lives and property.Risk analysis is very effective in preventing and dealing with leakage accidents in time,because it can predict the consequences and estimate the risk level of accidents.A risk analysis method is proposed for pipeline whose property and environmental parameters are changing,by means of numerical simulation and physical models.This paper takes a pipeline whose length is 150 km as an example to illustrate the method.The main contents of this paper are as follows:(1)Calculation model of pipeline failure probability is proposed,and the pipeline segment method is proposed as well.The pipeline which is as example is divided into several segments and the failure probability of each segment is obtained.(2)Each gas leakage model is analysed and compared by example calculation.The optimal model is selected and leakage rate of each segment is obtained.(3)Three accident scenarios are established by analyzing the actual situation of pipeline accidents,and the spread of gas in each scenariois simulated by FLUENT.The gas diffusion law and the spread data of each segment are obtained for the following consequence analysis.(4)The quantitative consequences are calculated through combining physical and damage models of fire and explosion,based on the data obtained by numerical simulation.Seriously injured radius,death radius and probability of death around leak point are obtained.(5)Calculation model of multi-consequence accident risk is proposed,and the comprehensive individual risk and social risk of gas leakage accident are calculated.The risk level is obtained through comparing with the acceptable risks. |
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