(8.1)-任务1汽油安定性英文版

Task1GasolineStabilityI.SignificanceofAssessingGasolineStability

stabilityreferstothepropertythatmaintainsthequalityofpetroleumproductsduringtransport,storageandapplication.Gasolinewithpoorstabilitymayhaveoxidationreactionsduringtransport,storageandapplication.Itiseasytogenerateacidicsubstances,stickygelatinoussubstancesandinsolublesediments,darkenoilproducts,leadtoandecreaseinoctanevalue,corrodemetaldevices,causeenginemalfunctionandincreaseoilconsumption.II.FactorsAffectingGasolineStability

Thestabilityofoilproducts,firstlydependsonthechemicalcompositionoftheoilitself,especiallytheamountofunsaturatedhydrocarbonsandnon-hydrocarbonsubstances.Nextistheconditionsofoiltransport,storageandapplication,suchaslight,heating,airoxidation,metalcatalysis,etc.Theimportanceofqualitycontrolinpetroleumproducts.Astrongnationrequiressupremequality.Agoodandrapideconomicandsocialdevelopmentcannotleave.Mustbeagoodwordhighquality.Ⅲ.MethodofevaluatinggasolinestabilityTheindicatorsandtestmethodsforevaluatingthestabilityofgasolineandaviationpistonenginefuelsareshowninTable8-1.1.Solventgelcontent(1)SolventgelcontentThestickyandnon-volatilebrowncolloidalsubstanceformedduringthestorageanduseofgasolineiscalledcolloid.Dependingonthesolubility,colloidscanbeseparatedintoinsolublecolloid,solublecolloidandadhesivecolloid,whicharecalledtotalcolloids.Solvent-washedgummainlyreferstothesecondkindofcolloid.Inaddition,thecolloidproducedduringthetestprocessisalsoincluded.Solventwashinggumcontentreferstothepartofautomobilegasolineevaporationresidueinsolubleinn-heptanemeasuredundertestconditions,expressedinmg/100mL.Theactualcolloidreferstotheevaporationresidueofoilproductssuchasaviationpistonenginefuelmeasuredunderthetestconditions,andthepartthathasnotbeenwashedbyn-heptane,expressedinmg/100mL.Solventwashedgumcontenttisanimportantindextoindicatetheantioxidantstabilityofenginefuel,usingtoassessthetendencyofgeneratingcolloidsintheengineandintakepipe,andontheintakevalve.Tendencytoproducecolloid,Itisalsoanimportantindexofenginefuelstoragecontroltojudgewhetherthefuelcanbecontinuouslyusedandkept(Table8-1).Therefore,theexistentgumshouldbetestedregularly.(2)OverviewofMethodofdeterminationsolventgumcontenttestaccordingtoGB/T8019-2008"fuelgumcontentdeterminationMethodinjectionevaporationMethod.Thisstandardisapplicabletothedeterminationofthesolventwashinggumcontentandactualgumofvehiclegasoline,vehicleethanolgasoline,aviationpistonenginefuelandjetfuel."AsshowninTable8-1,thedeviceisdividedintothreeparts:airintakesystem(airorsteam,includingsteamsuperheater),measurementsystem(includinggasflowmeterandthermometer)andevaporationbath(metalblockbathorelectricheatingliquidbath).Whenmeasuring,the50mlsampleiscontrolledattemperature(150~160℃),airflowrate(airflowisrequiredforvehiclegasoline,andtheflowrateis1000ml/s)andevaporationtime(30min)undertheconditionsofevaporation,andweighingthemassoftheresiduebeforeandaftertheextractionofn-heptane,theresultsarereportedinmg/100mL,whicharecalledtheunwashedgumcontentofvehiclegasolineandthesolvent-washedgumcontent.Thepurposeofthetestonmotorgasolineistodeterminetheoxideformedbythesamplebeforeandunderthetestconditions.Sincenon-volatileoilsoradditivesareoftenintentionallyaddedtotheproductionofmotorgasoline,itisnecessarytousen-heptanetoextractthemfromtheevaporationresidue.X1=（mC－mD＋mX－mZ）×2000mg/(100mL•g)（8-1）X2=（mB－mD＋mX－mY）×2000mg/(100mL•g)（8-2）ThetestmethodfordeterminingactualcolloidisalsoGB/T509-1988"DeterminationofActualColloidofEngineFuel".Atpresent,thismethodisonlyusedforthedeterminationofactualgumofjetfuel.2.Inductionperiod

(1)Inductionperiod.Inductionperiodisthetimewhenoilproductsareinastablestateunderspecifiedacceleratedoxidationconditions(min).Inductionperiodisanimportantindextoevaluatetheantioxidantstabilityofgasoline.Itindicatesthetendencyofgasolinetooxidizeandformcolloidsinlong-termstorage.Alongerinductionperiodmeanssmallertendencytoformcolloids,betterantioxidantstability,morestableoilproducts,andlongerstorageperiod.Automobilegasolinerequiresthattheinductionperiodshouldbenotlessthan480minutes.(2)OverviewofdeterminationmethodsGB/T8018-1987"Determinationofoxidationstabilityofgasoline(inductionperiodmethod)"issuitablefordeterminationofoxidationstabilityofgasolineunderacceleratedconditions.SeeFigure8-2andFigure8-3forthetester.Theteststepsareasfollows:(1)removetheoriginalairintheoxygenbombatatemperatureof15~25℃,puttheglasssamplebottleintothebomb,add50mLofsample,coverthesamplebottle,closetheoxygenbombtightly,oxygenispasseduntilthegaugepressureis689~703kPa,andthenthegasisreleasedslowly(notlessthan15s)ataconstantspeedtoflushouttheoriginalairinthebomb.(2)testtheleakageofoxygenuntilthegaugepressureis689~703kPa,observethepressuredrop,therapidlychangingpressuredrop(generallynotmorethan41.4kpa)causedbythedissolutionofoxygeninthesampleatthebeginningisnotconsidered.Ifthepressuredropdoesnotexceed6.89kPainthenext10min,itwillberegardedasnoleakageandcanbetestedwithoutre-boosting.(3)Duringtheinductionperiodofthedetermination,puttheoxygenbombcontainingthesampleintoaviolentboilingwaterbath(avoidshaking!),Recordtheteststarttimeatthistime.Maintainthewaterbathtemperaturebetween98~102℃.Duringthetest,observethetemperatureontime(readto0.1℃)andcalculatetheaveragetemperatureto0.1℃asthetesttemperature.Continuouslyrecordthepressureintheoxygenbomb.Ifanindicatorpressuregaugeisused,recordthepressurereadingevery15minorless.Continuethetestuntiltheturningpoint,andrecordtheoilatthetesttemperaturefromthetimetheoxygenbombisputintothewaterbathuntiltheturningpoint.Testshouldbenoted:Ifthetestbeginswithin30min,theleakincreases(with15minstablepressuredropgreatlyexceeds13.8kPatojudge),thetestisinvalid;ifthetestareaoftheatmosphericpressureisconsistentlylowerthan101.3kPa,itisallowedtoaddahigherboilingpointoftheliquidtothewater(suchasglycol),sothatthewaterbathtemperatureismaintainedbetween98~102℃.(4)disassembleandcleantheinstrumentFirstcooltheoxygenbomb,thenslowlyrelease(notlessthan15seachtime)thepressureinsidetheoxygenbomb,cleantheoxygenbombandthesamplebottle,inpreparationforthenexttest.(5)CalculationIfthetesttemperatureisnotequalto100℃,themeasuredinductionperiodneedstobecorrectedwithequation(8-3)andequation(8-4).（8-3）（8-4）Ⅳ.MainFactorsAffectingthedetermination1.Solventgelcontent(1)WeighingconditioncontrolWeighingthebeakercontainingthesampleandthebeakercontainingresiduesafterthetestshallbecarriedoutstrictlyaccordingtooperationrules.Thatistosay,afterdryinginthespecifiedmanner,puttheminacoolingcontainernearthebalanceandwaitforatleast2hours,then,weighthebeakersagain.(2)Theeffectofheatingtemperatureonthetestresult.Generallyspeaking,underthetestconditionthatthereexistsoxygenintheair,colloidswillbegeneratedatamorerapidspeedasthetemperaturebecomeshigher.Therefore,ifthecontrolledwaterbathtemperatureexceedsthestandard,thetestresultwillbehigher.Whenthetemperatureistoolow,matrixcomponentsinoilproductscannotbeevaporatedcompletely,whichleadstoalargertestresult.(3)Thesamplecontainershouldbeaglassinstrument.Forthesamesample,ametalcontainerhasacatalyticeffectontheformationofcolloids.Thus,itsresultislargerthanthatofaglasscontainer.Itisrequiredtouseglasswareassamplecontainerswhentheexistentgumistested,insteadofsteelorcoppercontainers.(4)Thepurificationdegreeoftheairflow.Usuallyusingasteelcylindertosupplyairpresentsabettereffect.Whenairissuppliedbyanaircompressor,lubricatingoilintheequipmentiseasilyentangledintheairsupply.Ifthepurificationprocessdoesn'tworkwell,andthiskindofoilisdifficulttoevaporateatthetesttemperature,thetestresultwillbelarger.Whenanindustrialairductisusedasasourceofairflow,purificationalsoneedsmuchattentionsoastoavoidbringingwater,oilandrustintoth