PREFERREDSTARTUPCONDITIONSOFNAFION®MEMBRANES杜邦离子膜首选的开车条件STARTUPCONDITIONSFORNEWMEMBRANES新膜开车条件•Goal:MaintainUniformConductivityDuringStartup目的:使离子膜在开车期间形成均一的导电性•IdealConditions:理想的条件–CurrentDensity:Gradualriseto>4.0kA/m2电流密度逐步升到4.0kA/m2以上–Temperature:温度>70oC(最佳>75oC)–CatholyteStrength:阴极液浓度28-30%NaOH–FeedbrineStrength:入槽盐水浓度210-300gpl(最佳300gpl)–AnolyteStrength:出槽盐水浓度170-230gpl(PH>2)–Uniformtemperature,concentrationsandcurrentthroughoutthecell确信电槽内部有均一的温度、浓度及电流.NewMembraneStartedProperly新膜恰当地开车ChannelsDevelopUniformly,CreatingUniformCurrentDistributionMembrane离子膜•Goal:MaintainUniformConductivityDuringStartup离子膜内部通道均匀地形成,这样电流今后可均匀地分布目的:使离子膜在开车期间形成均一的导电性能.NewMembraneBeforeFirstStartup新膜第一次开车之前IonConductingChannelsNeedtobeEstablished•Whencurrentisturnedonforthefirsttime,theionflowwillfollowthepathofleastresistancethroughthemembrane.第一次通电,离子将会从离子膜电阻最小的部位通过.•Dangeristhatsomechannelswillhavehigherresistancethanothers.危险的是部分离子通道形成较高的电阻.Membrane离子膜离子传输通道需形成NewMembraneStartedBadly新膜不好地开车SomeChannelsDevelopFirstandBecomeOverloaded,CausingLocalOverheating•Whencurrentisturnedonforthefirsttime,theionflowwillfollowthepathofleastresistancethroughthemembrane.(见上页)•Dangeristhatsomechannelswillhavehigherresistancethanothers.(见上页)•Ifsomechannelscarrymoreoftheloadwhileotherareasarestilllessconductive,theycanbecomedamagedbyexcessivecurrent.当部分通道承受过多的电流而其它部位的导电性又差,这些通道会因过多的电流而损坏.Membrane离子膜有些通道首先形成并且(因离子过多而)超载,导致局部过热.WhyAreTheseConditionsImportant?为什么这些开车条件很重要•Whencurrentisturnedonforthefirsttime,theionflowwillfollowthepathofleastresistancethroughthemembrane.第一次通电,离子将会从离子膜电阻最小的部位通过.•Dangeristhatsomechannelswillhavehigherresistancethanothers.危险的是部分离子通道形成较高的电阻.•Ifsomechannelscarrymoreoftheloadwhileotherareasarestilllessconductive,theycanbecomedamagedbyexcessivecurrent.当部分通道承受过多的电流而其它部位的导电性又差,这些通道会因过多的电流而损坏.•PermanentdamagecanresultinlowerCEandhighervoltage.(这些部分通道)永久性地损坏将导致(该离子膜)电效低和槽压高.VoidDamageDuetoHarshStartup因不当地开车导致(离子膜)空洞损坏Voids空洞CathodeSurfaceView(350X)离子膜阴极表面图(放大350倍)CrossSectionView(750X)离子膜横截面图(放大750倍)WhyAreTheseConditionsImportant?•Whencurrentisturnedonforthefirsttime,theionflowwillfollowthepathofleastresistancethroughthemembrane.(见上页)•Dangeristhatsomechannelswillhavehigherresistancethanothers.(见上页)•Ifsomechannelscarrymoreoftheloadwhileotherareasarestilllessconductive,theycanbecomedamagedbyexcessivecurrent.(见上页)•PermanentdamagecanresultinlowerCEandhighervoltage.(见上页)•Itmaybepossibletorecover,byreducingcurrent,andloweringelectrolyteconcentrations.(特定条件下离子膜性能)也许可以恢复,通过降低电流及降低电解液浓度.ConductivityatStartup(离子膜)开车时的传导性•Goal:Makemembranehighlyconductive,sostartupcurrentdoesnotexceedthemembrane’sresistanceatanypointinthemembrane.目的:使离子膜有高的传导性,所以开车时的电流不要超过离子膜任何部位的电阻.•Toincreaseconductivity:增加(离子膜的)传导性(的方法)–Raisetemperature提高(电解液的)温度...
