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1、传质论文：降膜式脱挥器中粘性流体脱挥特性的研究【中文摘要】本文立足于低能耗、低成本和高效率,设计了降膜式脱挥器的实验装置。首先,实验中以丙烯腈作为挥发性单体,聚丙烯腈的二甲基亚砜溶液作为高黏介质,对聚合物溶液中残余单体的检测方法进行了试验研究。采用顶空—气相色谱法,对聚合物含量、平衡时间、平衡温度及顶空体积对测定结果的影响进行了分析,通过改进优化顶空进样条件,解决了工业中传统测量方法误差大的缺点。其次,采用粘度范围2.150Pa.s~236Pa.s的聚丙烯腈和二甲基亚砜的溶液,利用可视化技术研究了孔式降膜元件中流体的流动、成膜及更新等性能。第三,考察聚合物溶液的粘度、单体初始含
2、量、温度和真空度对脱挥效果的影响,为工业化降膜脱挥提供依据。第四,在渗透理论和质量守恒原理的基础上,建立降膜式脱挥器的传质模型,推导出聚丙烯腈-二甲基亚砜溶液脱除丙烯腈单体的效率的表达式,脱挥效率的实验值与计算值的相对标准偏差在±4%以内。【英文摘要】Basedonthelowenergyconsumption,lowcostandhighefficiency,thefallingstranddevolatilizer(FSD)experimentdevicewasdesignedinthispaper.Firstly,itintroducedamethodofdetermin
3、ationofresidualacrrylonitrileinpolyacrylonitrilesolutionbyheadspacegaschromatographyandatthesametime,theeffectsofcontentofpolymerinsolution,equilibriumtime,equilibriumtemperatureandheadspacesamplevolumeonthedeterminationresultswereanalyzed.Throughtheimprovementofoptimizationconditions,solvin
4、gtheproblemofbigerroroftraditionalmeasuringmethodinindustry.Secondly,thehydrodynamicsperformanceofholeelementshasbeeninvestigated.PAN/DMSOsolutionswithviscosityrangefrom2.150~236Pa.swereselectedasexperimentalmedia.Theperformanceonfluidflowing,filmforming,andsurfacerenewalofsingleelement,whic
5、hchangedwiththeviscosity,operationconditionsanddiameter,hasbeenstudiedbyusingvisualtechnique.Thirdly,Theinfluenceoftheliquidviscosity,temperature,vacuumdegree,andinitialANcontentintheliquidonANremovalefficiencywasinvestigated.Theexperimentalresultsindicatedthattheremovalefficiencyincreasedwi
6、thincreasingvacuumdegreeandtemperatureanddecreasedwithincreasingliquidviscosity.ItwasalsoobservedthatANremovalefficiencyisn’trelatedtotheinitialANcontentdirectly.Finally,Amasstransfermodelfordevolatilizationprocessofhighlyviscousmediainfallingstranddevolatilizer(FSD)wasdevelopedbasedonpenetr
7、ationtheoryandmassconservation.Itwasfoundthatbubblingplayedanimportantroleinthedevolatilizationandnitrogenhadthelargesteffectonthepolymer-solventbehavior,thenonthebasisofexperiment,thecorrelationofremovalefficiencyofANinPAN—DMSOviscoussolutionwaspr
