Quantitative Risk Assessment Technology Of Town Gas Pipeline

Gas pipeline is an important ingredient of urban system,providing great convenience to production and human life.However,the natural gas is inflammable and explosive,once it leaks,fire and explosion occur easily,and it may even cause a chain reaction of domino accident,inducing extremely serious influence.Quantitative risk assessment of gas pipeline is proposed to reduce accident risk,and it is of great significance to eliminate hidden dangers,minimize the loss,and provide technical reference for the safe operation of gas pipeline.The main research contents and conclusions of this paper are shown below:(1)Based on Pipeline Incident Database(statistics of EGIG in Europe,PHMSA in the United States,UPOKA in the United Kingdom,AER in Canada)and accidents of gas pipeline in China.Four failure modes of urban gas pipeline in China are determined: corrosion,third-party damage,wrong operation and design factors.(2)According to the theory of fluid mechanics,the basic governing equations of the gas in the pipe are established,and the gas leakage rate model,the Gaussian plume model of continuous diffusion and the Gaussian puff model of instantaneous diffusion are applied.The gas leakage and diffusion can induce the phenomenon such as fireball,jet fire and gas cloud explosion.The size of damage area impacted by fireball and jet fire is estimated by thermal radiation damage criterion and the range of damage area caused by gas cloud explosion is evaluated by shock wave damage criterion.(3)The research status of domino effect is reviewed,and the accident spreading factors and equipment damage probability in domino scenario are determined.A domino analysis method based on Bayesian network is proposed.By drawing the Bayesian network of multi-level accident expansion and selecting the multi-level domino effect in turn,the key equipment of accident expansion in the domino scene can be quickly found,and two different kinds of protection means based on the precaution method can be adopted for control.(4)The determination criteria of acceptable risk standards at home and abroad are analyzed and compared.Adopting a proper one from mentioned above,namely the ALARP principle,to establish risk acceptance criteria for the urban gas pipelines from personal risks,social risks,economic losses,and environmental pollution.This paper studies the quantitative risk assessment method of gas pipelines including analysis of incentives to evaluate the possibility of accidents,quantitatively calculating the severity of consequences,and establishing risk acceptable standards.This method can provide a theoretical reference for the safe operation and risk assessment of gas pipelines.For those methods discussed in the previous contents,the Bayesian network locate the key equipment for multi-level expansion of accidents in the domino effect,and the method for establishing risk acceptance standards can also be used in the risk management in the chemical industry.