大型LNG全容储罐干燥置换氮气用量计算方法-61c9f0d6.pdf

工程设计

DOI：10.3969/j.issn.1001-2206.2024.01.013

大型LNG全容储罐干燥置换氮气用量计算方法

张宝和，张元杰，卞琦，孙波，李作伟

海洋石油工程股份有限公司，天津300461

摘要：大型LNG全容储罐的压力测试都采用水压进行，试压结束后必须对LNG储罐进行干燥置换。工程中

较多采用氮气持续吹扫的方法进行干燥置换，会造成成本高、氮气用量大、工期较长等影响，另外其理论计算

方面的不完善也会使LNG全容储罐干燥置换的相关计算产生误差。为合理节省且准确预估干燥置换氮气用量，

结合项目实际情况分别介绍及分析持续吹扫式和压涨式两种干燥置换方法，同时考虑氧含量及露点等参数影

响，推导出氮气用量计算公式并编制相关计算软件，与现场具体施工情况进行对比分析表明：最终得出的干燥

置换综合计算方法能够较为快速准确地计算氮气用量及作业工期，可为大型LNG全容储罐干燥置换相关的理论

计算及施工作业提供参考。

关键词：LNG储罐；干燥置换；用氮量；氧含量；露点

CalculationmethodsofnitrogenconsumptionfordryreplacementoflargeLNG

fullcapacitystoragetanks

ZHANGBaohe,ZHANGYuanjie,BIANQi,SUNBo,LIZuowei

OffshoreOilEngineeringCo.,Ltd.,Tianjin300461,China

Abstract：ThepressuretestofthelargeLNGstoragetankisperformedbyhydraulicpressure.Afterthetest,theLNGstoragetank

needstobedriedandreplaced.Inengineering,themethodofcontinuousnitrogenblowingisoftenusedfordryingandreplacement,

whichcanresultinhighcosts,highnitrogenconsumption,andlongconstructionperiods.Inaddition,theimperfecttheoretical

calculationcanalsoleadtoerrorsinthecalculationofLNGtankdryingandreplacement.Toreasonablysaveandaccuratelyestimatethe

amountofnitrogenusedfordryingandreplacement,twomethodsofLNGtankdryingandreplacement,continuousblowingandpressure

expansion,areintroducedandanalyzedbasedontheactualprojectsituation.Atthesametime,theinfluenceofparameterssuchas

oxygencontentanddewpointisconsideredtoderiveaformulaforcalculatingnitrogenusageanddeveloprelevantcalculationsoftware.

Comparativeanalysiswiththespecificconstructionsituationonsiteshowsthattheproposedcomprehensivecalculationmethodfor

dryingandreplacementcanquicklyandaccuratelycalculatenitrogenusageandoperationperiod.Themethodalsocanguidethe

theoreticalcalculationandconstructionworkrelatedtoLNGtankdryingandreplacement.

Keywords：LNGstoragetank;dryreplacement;nitrogenconsumption;oxygencontent;dewpoints

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