文档名：Ag表面对SF6初级分解产物氧化反应的影响作用研究
摘要：运行经验显示SF6在气体绝缘开关设备(GIS)中的热稳定性低于预期,GIS内部的金属表面可能对SF6初级分解与次级反应具有显著的影响作用,但作用机理尚不明晰.该文基于密度泛函理论获得了O2在Ag表面的解离-吸附构型,并建立了低氟硫化物与Ag表面O原子的反应模型,初步揭示了GIS过热故障状态下SF6初级分解产物在Ag表面的氧化反应机理;基于过渡态理论和反应动力学理论,计算获取了界面反应的能垒和反应速率常数,并与气相反应对比,分别确定了三种低氟硫化物的氧化反应路径及其主要场所,并分析了Ag表面对反应的促进/抑制作用机制.结果显示,Ag表面可显著促进SOF4与SOF3的产生,但不利于SF2的表面氧化反应.
Abstract：OperationalexperienceshowsthatthethermalstabilityofSF6inthegas-insulatedequipmentislowerthanexpected,andthemetalsurfaceinsidetheequipmentmayhaveasignificanteffectonSF6primarydecompositionandsecondaryreactions,butthemechanismisnotyetclear.First,itisnecessarytostudyhowtheO2moleculedissociatesandprovidesthereactionsystemwithOatoms,whichrequireshighenergy;second,itneedstorevealthereasonsforthesignificantlylowerstabilityofSF6thanexpectedintheactualfaultstate;third,itisnecessarytoinvestigateindepththemechanismofthemetalsurfaceinsidetheGISonthegenerationprocessofimportantcharacteristicproducts.AmongthemetalmaterialsusedinGIS,silverisusuallyplatedontheinternalcontacts,electricalconnectionsandotherlocationstolowerthecontactresistivitywherethelocalover-thermalfaultsoccasionallyoccur.Inthiscase,theAgsurfaceisindirectcontactwithSF6gasandotherimpuritygases,whilethemechanismoftheinterfacialinteractionisnotknownandneedstobestudied.First,theadsorptionconfigurationofO2ontheAgsurfaceisobtainedbasedondensityfunctionaltheory,andthereactionmodeloflow-fluorinesulfideswiththeOatomonAgsurfaceisestablished,whichinitiallyrevealsthemechanismofoxidationreactionofSF6primarydecompositionproductsontheAgsurfaceunderGISover-thermalfaultstate;Second,basedontransitionstatetheoryandreactionkinetictheory,theenergybarrierandreactionrateconstantofinterfacialreactionarecalculatedandcomparedwiththecorrespondinggas-phasereaction,respectively.Last,themainreactionsitesoftheoxidationreactionpathsofthethreelow-fluorinesulfidesareidentifiedseparately,andthepromotion/inhibitorymechanismofthereactionbytheAginterfaceisanalyzed.(1)ThepresenceoftheAginterfaceenablestheSOF4generationreaction,whichisotherwisedifficulttooccurinthegas-phasespaceatbothroomtemperatureandsuperheatedstate,toproceedatroomtemperature,anditsreactionrateisfurtherenhancedwithincreasingtemperature,whichcanbecompletedinstantaneouslywithalowhalf-lifeof5.05×10-9hat400℃.Comparedwiththegas-phasereaction,theenergybarrierofthisreactionisreducedby71.45%underthecatalysisoftheAgsurface.(2)TheAgsurfacealsosignificantlyreducestheactivationenergyrequiredtogenerateSOF3,allowingittobegeneratedrapidlyatroomtemperature;thegas-phaseformationreactionofSOF3issensitivetotemperature,whichmakesithaveafasterreactionrateunderover-thermalconditions.BoththeAgsurfaceandthegas-phasespaceareimportantreactionsitesfortheformationofSOF3.(3)UnlikeSOF4andSOF3,theAgsurfacedoesnothaveapromotioneffectonthegenerationofSOF2.Itraisestheenergybarrierofthereactionandsignificantlyreducestherateconstantofthereaction.Accordingly,itisjudgedthatSOF2ismainlygeneratedthroughthedirectreactionbetweenSF2andO2inthegasphasespace.ThemainreasonmaybethesmallmolecularmassofSF2andthestrongadsorptioneffectofAgsurfaceonit,whichleadstothedifficultyfortheproducttoleavefromthesurfaceafterSF2interactingwithsurfaceOatoms.Thus,thegenerationofSOF2gasmoleculesisinhibited.Theresultsofthispaperrevealthemechanismofgas-solidreactionsinvolvinglow-fluorinesulfides,oxygen-silversurfaces.ThecatalyticeffectofAgonseveralofthesereactionsisfound,thusexplainingpreviousdoubtsaboutthecauseofSF6stabilityfailure.Theresearchmethodologyestablishedinthispaperisexpectedtobeaninspirationingas-solidreactionstudies.
作者：李昊天 曾福平 颜伊鸣 朱可馨 姚强 唐炬 Author：LiHaotian ZengFuping YanYiming ZhuKexin YaoQiang TangJu
作者单位：武汉大学电气与自动化学院武汉430072国网重庆市电力公司电力科学研究院重庆401123
刊名：电工技术学报
Journal：TransactionsofChinaElectrotechnicalSociety
年，卷(期)：2024, 39(9)
分类号：TM855
关键词：气体绝缘开关设备 六氟化硫 过热分解 银表面 氧化反应
Keywords：Gasinsulatedswitchgear SF6 thermaldecomposition silversurface oxidation
机标分类号：O641TM595TM85
在线出版日期：2024年5月13日
基金项目：国家自然科学基金，湖北省杰出青年基金资助项目Ag表面对SF6初级分解产物氧化反应的影响作用研究[
期刊论文] 电工技术学报--2024, 39(9)李昊天 曾福平 颜伊鸣 朱可馨 姚强 唐炬运行经验显示SF6在气体绝缘开关设备(GIS)中的热稳定性低于预期,GIS内部的金属表面可能对SF6初级分解与次级反应具有显著的影响作用,但作用机理尚不明晰.该文基于密度泛函理论获得了O2在Ag表面的解离-吸附构型,并...参考文献和引证文献
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