液化天然气储罐翻滚事故分析

Analysis of LNG Storage Tank Rollover Accidents

随着世界能源紧缺现状的出现,天然气工业在我国的不断发展,液化天然气成为了一种成效卓著的储运方式,那么,随乊而来的便是液化天然气的安全问题,分层、翻滚是液化天然气在储存过程中有可能出现的一种极其危险的事故现象。通过FLUENT模拟软件对LNG储罐中不同物性参数的液化天然气在罐体漏热情况下进行数值模拟,在此乊前通过计算对大型LNG储罐漏热进行求解,将计算得到的热流密度近似取成10W/m2,以此作为模拟时边界条件的罐壁、罐底漏热量,模拟得出翻滚发生的开始和结束时间,最后通过翻滚发生持续时间计算仅翻滚时所造成的LNG损失,约334 t,翻滚发生前,储罐内的气相空间压力梯度约为32 kPa/h,仅约20 min便会使储罐内正常操作压力超出安全阀设定压力。由此可见,液化天然气翻滚事故的发生不仅会造成液化天然气本身的一大浪费,同时也会对人身及财产安全构成巨大威胁,因此,深入研究LNG翻滚对社会发展具有深远意义。

With emergence of the world＇s energy shortage situation, and the natural gas industryobtainscontinues development inChina, liquefying natural gas becomes an effective way of storage and transportation, thensafety problems inliquefying natural gasappear,stratification and rolloverareextremely dangerous accident phenomena that may occur during LNG storage.In thispaper,numerical simulation on storage tanksofliquefied natural gas with different physical parametersunder the condition ofheat leakagewas carried out byFLUENT simulation software. Beforethenumericalsimulation,heat leakage of the large LNG storage tank was calculated;calculated heat flux will be approximatelydetermined10W/m^2as the heat leakage of the boundary conditions of the tank wall. Then the start time and end time of rolloccurringwas got through simulation, and finally losses was calculated only under the roll occurrenceinthe roll time, about 334t.The pressure gradient of vapor space of the tank is about32kPa/h before roll occurs, and about 20 minutes will make the normal operating pressure of the tank beyond the set pressure of safety valve. Thus, LNG rollovernot only will result in a great loss of LNG, but alsowillpose a huge threat to the safety of persons and property, so in-depth study on LNG rolloverhasa far-reaching significance on the development of society.