Research On Reliability And Explosion Risk Assessment Of Natural Gas Transportation Single Span Pipe

With the rapid development of science and technology and industry,natural gas energy has gradually become an indispensable part in industry,transportation and other fields.The rapid promotion of natural gas energy is also faced with many potential problems,such as the safety of natural gas(NG)pipe,which has attracted people's attention.Once the NG pipe leaks and forms flammable vapor cloud,it will bring huge casualties and economic losses to the society.In this paper,the reliability,stress and explosion accident consequence of NG transportation simple supported pipe under the action of uneven settlement of foundation are analyzed,and the risk assessment and prevention and control of such explosion accident are studied.The main research contents are as follows:(1)Reliability analysis of NG pipe under uneven settlement of foundation.In this paper,the stress of single span NG pipe under the action of uneven foundation settlement is analyzed,and the limit state equation is established.The reliability analysis model of NG single span pipe structure under non-uniform settlement of foundation is established with Monte Carlo method.The influence of pipe outer diameter,pipe wall thickness,pipe working pressure and support spacing on pipe structure reliability is analyzed,which is NG.provide the basis for risk assessment of leakage and explosion accident of single span pipe.(2)Finite element analysis of NG single span pipe based on fluid structure coupling.The finite element analysis model of NG single span pipe is established,and the fluid simulation results are imported into static as conditional load Structural module carries out mechanical analysis,analyzes the stress distribution of NG pipe under different fluid velocity,different pipe working pressure and uneven settlement of foundation,and obtains the maximum equivalent stress distribution under different settlement conditions,which provides the basis for risk assessment of NG single span pipe leakage and explosion accident.(3)Numerical calculation and propagation law analysis of explosion shock wave of NG pipe with or without explosion-proof wall.The LS-DYNA software is used to establish the explosion model of NG single span pipe with or without blast wall.The propagation characteristics of explosion shock wave and the influence of different height explosion-proof wall on shock wave are analyzed.Based on the numerical simulation results,the nonlinear fitting of shock wave overpressure attenuation curve is carried out.(4)Risk assessment model construction and case analysis of NG pipe explosion accident.From the perspective of probability and consequence severity of leakage and explosion accident of NG single span pipe,the risk assessment model of leakage and explosion accident of simple supported NG pipe was constructed,and the relevant calculation formula of explosion accident probability and consequence loss was obtained.The model was applied to a case of NG transportation simple supported pipe in Guangzhou Industrial Park The risk is evaluated,and the targeted risk prevention and control measures are put forward from a reasonable point of view.