天然气输送管道泄漏事故危害定量分析

Quantitative Risk Analysis on the Leakage of Compressed Natural Gas Pipeline

针对某天然气工程中高压输送管道可能发生的天然气泄漏的爆炸危险性进行分析。利用质量流速模型计算出泄漏流量。根据泄漏流量和天然气的燃烧下限浓度,通过高斯扩散模式定量计算在大气为中性,风速为5m/s,且位于市区的条件下,天然气在大气中的轴向、径向和切向的扩散距离,从而计算该天然气-空气混合云团的体积。对该体积预混云团的爆炸危害进行评估,计算形成蒸气云爆炸的参数,并应用Matlab软件计算出该管道泄漏引起蒸气云爆炸事故的个人风险曲线,其结果可为新管线的规划、建设及现有管线的调整提供决策依据。

The leakage explosion risk of compressed natural gas（CNG）pipeline under high-pressure is analyzed.The leakage flow is calculated by using mass flow model.By using Gauss diffusion model,the maximum diffusion ranges in three dimensions under the conditions of neutral steady atmosphere with 5m/s wind velocity in urban are obtained,from which the volume of mixed cloud of NG with air can be calculated based on leakage flow and flammable low limit of density.The parameters of vapor cloud explosion（VCE）are calculated by evaluating the explosion hazard of the mixed cloud.Eventually,the individual risk curve caused by VCE due to pipeline leakage is estimated with Mat lab method.The proposed method of quantitative risk assessment may be useful to the risk management during the planning and building stages of a new pipeline,and the modification of a buried pipeline.