LNG加气站槽车卸车直供过程泄漏后果分析*

为研究LNG加气站槽车直接供液过程泄漏后果严重程度，采用HAZOP辨识槽车供液和储罐供液典型泄漏场景，基于PHAST分析不同泄漏场景下LNG液池半径、蒸汽云扩散距离及积聚时长、爆炸超压和池火热辐射影响范围，定量评价槽车供液可能造成的事故后果扩大程度。结果表明:槽车供液泄漏事故的LNG液池最大半径、蒸汽云最大扩散距离、爆炸超压最大影响半径和池火热辐射最大半径，分别为储罐供液的5.7,1.7,2.3,7.9倍；槽车在无人值守条件下泄漏形成的LNG液池最大半径和蒸汽云积聚时长，分别为有人值守下的1.85,56倍；日供液量较大加气站不宜采用槽车直接为汽车供液模式，而应采用先卸车入罐、再储罐供液的模式；应落实槽车卸车轮班值守制度，并与周边社区建立有效的应急联动方案。

Quantitative analysis on leakage consequences during unloading and direct refueling process of tank truck at LNG refueling station

Using LNG tank trucks to directly refuel the vehicles for a long time had become a common supply guarantee measure for the LNG refueling stations with a large daily refueling load and the insufficient storage tank for meeting the turnover demand.However,it would cause the extended unloading time and the increased leakage risk.Taking a typical LNG three level refueling station as the research object,the HAZOP method was used to identify the typical leakage scenarios in the processes of tank truck refueling and storage tank refueling.The LNG liquid pool radius,vapor cloud diffusion distance and accumulation time,explosion overpressure and influence range of pool fire thermal radiation under different leakage scenarios were analyzed based on PHAST,and the extent of accident consequences expansion caused by tank truck refueling was quantitatively evaluated.The results showed that the maximum radius of LNG liquid pool,the maximum diffusion distance of vapor cloud,the maximum influence radius of explosion overpressure and the maximum radius of pool fire thermal radiation in the leakage accident of tank truck refueling were respectively 5.7 times,1.7 times,2.3 times and 7.9 times of those with the storage tank refueling.The maximum radius of the LNG liquid pool and the accumulation time of vapor cloud formed by the leakage of tank truck under unattended conditions were respectively 1.85 times and 56 times of those under manned conditions.It showed that the gas refueling station with a large daily refueling amount should not use tank trucks to directly refuel the vehicles,but should adopt the mode of unloading the truck into the tank and then using the tank refueling.A shift duty system for the tank truck unloading should be implemented,and an effective emergency linkage plan should be established with the surrounding communities.