LNG储罐分层高度对翻滚的影响

Influence of Stratification Heights on Rollover in LNG Storage Tanks

针对LNG储配站常用的3×10~4m^3LNG储罐,建立了分层高度为2 m、3 m、4 m、5 m、6 m的LNG分层翻滚模型,利用Fluent软件进行LNG翻滚的模拟,得到结论:不同分层高度下,LNG储罐发生翻滚的现象有所不同,分层高度越小,翻滚开始的时间越早;分层高度越大,分界面越难以被破坏,翻滚开始时间滞后。分层高度影响LNG储罐翻滚持续时间,分层高度越大,翻滚持续时间越长,翻滚产生的潜在威胁越大。分层高度越大,翻滚过程中最大分界面速度越大,越具有破坏性,更容易发生安全事故;分层高度对翻滚过程中最大分界面速度出现的时间也有影响,分层高度越大,最大分界面速度出现的时间越滞后。建议:尽量避免物性参数(密度、温度)相差很大的LNG充装进同一储罐;在运行过程中密切监视储罐内LNG物性参数的变化,尽量避免形成大的分层。

For the 3×104 m3 LNG storage tank commonly used in LNG storage and distribution stations,a LNG stratification and rollover model with stratification heights of 2 m,3 m,4 m,5 m and 6 m is established,and the simulation of LNG rollover is carried out using Fluent software.It is concluded that under different stratification heights,the rollover phenomenon in LNG storage tanks is different.The smaller the stratification height,the earlier the rollover starting time.The higher the stratification height,the more difficult it is to destroy the interface,and the degree of rollover will lag.Different stratification heights affect the rollover time after stratification in LNG storage tanks.The higher the stratification height,the longer the rollover duration,and the greater the potential threat of rollover.The higher the stratification height,the greater the maximum interface velocity during the rollover process,the more destructive and more prone to safety accidents.The stratification height also affects the time when the maximum interface velocity appears during the rollover process.The higher the stratification height,the more logged the time when the maximum interface speed appears.Suggestions:Try to avoid filling the LNG with large difference in physical properties(density and temperature)into the same storage tank;closely monitor the changes of physical parameters of LNG in the storage tank during operation,and try to avoid the formation of large stratification.