大型LNG接收站泄漏事故灾害效应分析与预测

Analysis and prediction on the disaster effect of leakage accidents at large LNG receiving stations

LNG接收站的储运介质主要是液化天然气,由于其具有易泄漏、易挥发扩散等特性,泄漏形成的可燃蒸气云团有可能引发火灾爆炸等严重后果,分析并预测接收站LNG泄漏事故产生的灾害效应,可以为LNG接收站选址、布局设计和事故灾害预防提供参考。为此,利用FLACS软件,根据国内某大型LNG接收站的现场布局建立LNG泄漏扩散三维预测模型,采用相对偏差率对不同风速、风向和围堰高度条件下的LNG泄漏扩散行为进行分析与评价,预测了接收站LNG泄漏事故产生的灾害效应。研究结果表明:①在300 s的扩散时间内,LNG泄漏扩散呈现重力沉降特点;②定量分析了泄漏点位置对国内某拥有5个储罐的大型接收站LNG泄漏与扩散效应的影响,确定3号储罐泄漏造成的灾害效应影响最大;③围堰高度对LNG气云爆炸灾害效应的影响最大,其次为风速和风向,而风向对LNG气云窒息灾害效应的影响最大,其次为围堰高度和风速;④发生泄漏事故意外点火爆炸,热辐射死亡最大半径为170.1 m,三度烧伤最大半径为213.7 m,二度烧伤最大半径为261.7 m,一度烧伤最大半径为370.1 m,其气云团覆盖的范围基本是死亡区,人员重伤死亡。

Liquefied natural gas(LNG)is a major storage and transportation medium at LNG receiving stations.LNG leaks,volatilizes and diffuses easily,and the flammable vapor cloud derived from its leakage may lead to serious consequences,e.g.fire and explosion.Therefore,analyzing and predicting the disaster effect of LNG leakage at LNG receiving stations can provide reference for the site selection,layout design and disaster prevention of LNG receiving stations.In this paper,a 3D prediction model for LNG leakage and diffusion was established based on the field layout of one domestic large LNG receiving station by using the Flacs.Then,the LNG leakage and diffusion behaviors at different wind speeds,wind directions and cofferdam heights were analyzed and evaluated by virtue of relative deviation ratios.Finally,the disaster effect of LNG leakage at the LNG receiving station was predicted.And the following research results were obtained.First,in the diffusion time interval of 300 s,LNG leakage and diffusion presents the characteristics of gravity settling.Second,the effects of leakage positions at the LNG receiving station on the LNG leakage and diffusion are quantitatively analyzed,and it is determined that the disaster effect caused by the leakage of No.3 tank is the maximum.Third,as for the disaster effect of LNG cloud explosion,cofferdam height is the most influential factor,and wind speed and wind direction take the second place.As for the disaster effect of LNG cloud choke,however,wind direction is the most influential factor,and cofferdam height and wind speed take the second place.In the accident of leakage explosion,the maximum death radius of thermal radiation is 170.1m,the maximum radius of third-degree burn is 213.7m,the maximum radius of second-degree burn is 261.7m,and the maximum radius of first-degree burn is 370.1m.The area covered by the vapor cloud is basically a death zone,where people are seriously injured and dead.