大型储罐内LNG翻滚机理和预防措施

对于连续生产运营的LNG接收站，LNG储罐一般不会完全倒空储存LNG。由于不同产地、不同批次的LNG密度不同，在充装密度、温度都不同的新LNG一段时间后，LNG在储罐内将产生分层，时间较长时容易产生翻滚，从而对LNG储罐的安全造成极大的威胁，也会增加处理翻滚产生的蒸发气的费用。分析了储罐内LNG液体翻滚的机理及其危害，研究了消除LNG分层、预防翻滚的对策。结论指出：利用储罐设计时提供的顶部卸料管和底部卸料管，在储罐投入运营后，当接卸的LNG密度与储罐内的LNG密度不同时，采用合理的卸料方式，不同密度的LNG将自动混合，不会产生明显的分层，进而极大地降低了翻滚发生的概率。

LNG STIRRING MECHANISM AND COUNTERMEASURES IN LARGE LNG STORAGE TANKS

In those LNG receiving terminal stations under continuous operation, LNG storage tanks will storage LNG without necessary to be emptied. Due to different sources at different times, the filled LNG in the storage tank will be stratified by various temperature and different density and even stirred after some time, which will directly threaten the safety of the storage tank, and meanwhile increase the cost on dealing with the BOG (boiling of gas) by LNG stirring. After thorough analysis on the mechanism and hazards of the LNG stirring, this paper discusses how to prevent LNG in the storage tanks from being stratified and stirred. The basic data of solution was provided when the tank was designed (e.g. loading tubes were designed respectively at the top and bottom of the tank); after the tank put into operation, a reasonable loading solution (e.g. LNG was filled from the ship either through the top or the bottom of the tank) was adopted to make different density LNG mixed without being so variously stratified that the rate of stirring could be decreased to a large degree.