大型LNG储罐翻滚事故放空气扩散后果模拟  

Simulation on diffusion consequence of vent gas in rollover accident of large LNG storage tank

作　　者：王鹏[1,2] 王全国[1,2] 党文义[1,2] 韩中枢[1,2] 

机构地区：[1]中国石化青岛安全工程研究院,山东青岛266071 [2]化学品安全控制国家重点实验室,山东青岛266071

出　　处：《中国安全生产科学技术》2014年第11期174-179,共6页Journal of Safety Science and Technology

摘　　要：发生翻滚事故时,大型LNG储罐内压力急剧升高,为防止储罐超压破裂,大量的天然气通过安全阀放空,而天然气具有易燃易爆的特点,可能在LNG接收站的装置区及罐区发生爆炸。利用计算流体力学的方法对不同风速、风向下放空气的扩散过程进行了模拟,得到CH4的浓度分布情况。结果表明:大气风速对放空气的扩散过程具有影响,当风速逐渐增大时,降落到地面的CH4逐渐增多,而当风速超过7m/s时,随着风速的增大,降落到地面的CH4开始减少。随着风速的增大,50%LEL影响范围逐渐减小。各种风速条件下,装置区和罐区CH4的浓度均未达到50%LEL,因此LNG储罐发生翻滚事故时,放空气不会形成爆炸性气氛。When occurring rollover accident,the pressure in the large LNG storage tank will rise sharply.In order to prevent the storage tank from overpressure and rupture,a large number of natural gas vent through the safe valve mounted on the top of tank,which may lead to explosion in the unit area and tank zones of LNG receiving station due to the flammable and explosive characteristics of natural gas.Based on the computational fluid dynamics（CFD） technology,the diffusion processes of vent gas under different wind velocities and wind directions were simulated,and the concentration distributions of CH4 were obtained.The results showed that the wind speed had an influence on the diffusion process of vent gas.The amount of CH4 falling to the ground increased as the wind speed increased.If the wind speed exceeded 7m / s,the amount of CH4 fall to ground decreased as the wind speeds increased.50% LEL scope of CH4 decreased as the wind speed increased.Under various wind speed conditions,both the concentration of CH4 in the storage tank area and the device area did not reach 50% LEL,therefore the vent gas in rollover accident of large LNG storage tank would not form explosive atmosphere.

关 键 词：LNG 大型储罐 翻滚事故 放空 扩散 

分 类 号：X937[环境科学与工程—安全科学]