基于CFD的LNG储罐泄漏扩散研究

Study on Leakage Diffusion of LNG Storage Tank Based on CFD

为评估不同围堰和围墙高度对LNG储罐泄漏扩散的影响,以某LNG应急气源站为例,LNG储罐工作压力为10 kPa,工作温度为-162℃,溢出持续时间为10 min,设计溢出质量流量为8.0 kg/s,溢出源在储罐顶部,储罐外壁与圆形围堰之间的距离为15.40 m,圆形围堰与南侧、西侧、北侧围墙的最近距离分别为30.49、33.64、30.93 m。采用FLACS软件的液体溢出模块进行数值计算,计算结果表明:LNG储存区围堰和围墙的高度均为3.5 m、扩散时间为830 s时,蒸气云扩散范围将有50%越过储存区南侧的围墙。LNG储存区的围堰增高至6.0 m、围墙增高至4.0 m,扩散时间为830 s时,蒸气云扩散范围被有效控制在围墙内,并且蒸气云量也大大降低。LNG储存区围堰高度为6.0 m、围墙高度为4.0 m,扩散时间延长至1 350 s时,蒸气云扩散范围少部分越过储存区南侧的围墙。该站围堰高度设计为6.0 m、围墙高度设计为4.0 m,能够满足LNG储存区的生产安全要求。

In order to evaluate the influence of different dike and wall heights on the leakage diffusion of LNG storage tanks, taking an LNG emergency gas source station as an example, the working pressure of LNG storage tank is 10 kPa, the working temperature is-162 ℃,the overflow duration is 10 min, the designed overflow mass flow is 8.0 kg/s, and the overflow source is on the top of the storage tank, the distance between the outer wall of the storage tank and the circular dike is 15.40 m, and the closest distances between the circular dike and the south, west and north walls are 30.49 m, 33.64 m and 30.93 m, respectively, the liquid overflow module of FLACS software is used for numerical calculation. The calculation results show that when the heights of the dike and the wall of the LNG storage area are both 3.5 m, and the diffusion time is 830 s, 50% of the vapor cloud diffuses cross the wall on the south side of the storage area. When the dike of the LNG storage area is raised to 6.0 m and the wall is raised to 4.0 m, and the diffusion time is 830 s, the vapor cloud diffusion range is effectively controlled within the wall, and the vapor cloud amount is greatly reduced. When the height of the dike in the LNG storage area is 6.0 m, the height of the wall is 4.0 m, and the diffusion time is extended to 1 350 s, a small part of the vapor cloud diffuses cross the wall on the south side of the storage area. The dike height of the station is designed to be 6.0 m, and the wall height is designed to be 4.0 m, which can meet the production safety requirements of the LNG storage area.