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1、Task3(3.2)determinationofsulfurcontent-LightingDeterminationofsulfurcontent-Lighting1.Thepurposeoftheexperiment(1)Grasptheprincipleandsignificanceofthemeasurementofsulfurcontentsinoilproducts(2)Masterhowtotestsulfurcontentsinoilproductsbylampmethodandrelatedconditions(3)Knowinstrumentstructuresforth
2、elampmethod,mastertheoperationmethodofinstrumentspalm2.MethodOverviewThepetroleumproductisburnedinthelampofthetester,andthesulfideinitgeneratesSO2.TheSO2generatedisabsorbedwithanexcesssodiumcarbonateaqueoussolution.Afterthereaction,theremainingsodiumcarbonateistitratedwithahydrochloricacidstandardso
3、lution,thesulfurcontentinthesampleiscalculatedaccordingtotheamountconsumedbythehydrochloricacidstandardsolution.3.InstrumentsandReagents(1)InstrumentThesulfurcontentrecognizerforthelampmethod:shouldthetechnicalrequirementsofGB/T380,includingsuctionbottle:500mLor1000mLburetteof25ml,25mL;suctiontubeof
4、2mL,5mLand10mL,;washbottle,waterpumporvacuumpump,glassbead:shortglassrodwithadiameterof5-6mmandlengthof8-10mm,andcottonyarnwick.(2)ReagentsAnalytical:reagentto0.3%sodiumcarbonateaqueoussolutionhydrochloricacidandanalyticalreagentto0.05mol/Lhydrochloricacidstandardsolutionindicator：0.2%bromocresolgre
5、enethanolsolutionand0.2%methylredethanolsolutionwith95%ethanol95%ethanol(analyticalpurity);standardn-heptane;gasoline:boilingpointrange80-120C,sulfurcontentnotmorethan0.005%;petroleumether:chemicallypure,60-90C.4.Preparation:(1)Recognizerpreparation.Carefullywashtheabsorber,dropletcollectorandfluewi
6、thdistilledwater.Washanddrythelampandwickwithpetroleumether(2)Smoke-freesampleprocessing.Takesomelowboilingpointsampleswithsulfurcontentsoflessthan0.05%likeaviationgasoline,Inject4to5mLintoacleananddrylamp(nottobeweighedinadvance).Plugthelampwithawick-wearingtube.LeveltheupperedgeofthewicktubeIgnite
7、andadjusttheflameto56mminheight.Thenputoutthelamp.Coverthelampwiththelampshade.Weighonananalyticalbalance(to0.0004g)4.Preparation:(3)Treatmentofsmokingsamples.Petroleumproductsburningaloneinalampandproducingsmoke(e.g.dieselhightemperaturecrackingproductsorcatalyticcrackingproducts).Inject1-2mlintoac
8、leananddrylampwhichisweighedinadvancetogetherwiththewickandlampshade.Weighthesample(to0.004g).Infusethelampwithstandardnormalheptane,95%ethanolorgasolineat1:1ratio.Itcanbe3:1(volumeratio)ifnecessarytoensurethatthemixedsolutionisburningwithoutsmokeinthelamp.Thetotalvolumeofthesamplemixedwithstandardn
9、-heptane,95%ethanolorgasolineis45mL.(4)Fillingofabsorptionsolution.Pourglassbeadswhicharecarefullywashedwithdistilledwaterintothelargecontaineroftheabsorbertoits2/3height.Accuratelyinject10ml0.3%sodiumcarbonatesolutionwithasuctiontubeAdd10mldistilledwaterwithameasuringcylinderConnectrelevantelements
10、ofthesulfurrecognizer5.Experimentalprocedure(1)Airinjectionandtestingconditionadjustment.Aftertherecognizerisappropriatelyconnected,openthepumpswitch.Maketheairpassevenlyandslowlythroughtheabsorber.TakeoffthelampshadeIgnitethelamp.Putitundertheflue.Theedgeofthewicktubeshouldnotbehigherthanthelowered
11、geoftheflueby8mm.Whenlightingthelamp,useanon-sulfurflame.Theflameofeachlampshallbeadjustedto68mm(theinnerwickmaybestirredbyaneedle).Theairflowvelocityshouldbekepteveninallabsorbers,sothattheflamedoesnotgenerateblacksmoke.(2)Dilutedsampleprocessing.Ifthesampleisdilutedbystandardn-heptane,95%ethanolor
12、gasoline,whenthemixedsolutioniscompletelyburnedout,Re-inject12mLstandardn-heptane,95%ethanolorgasolineintothelamp.Afterthecombustionofthesampleorthedilutedsamplehascompleted,putoutthelamp.Coveritwiththelampshade.After35minutes,closetheflowpump(3)Combustionquantityofthesample.Fortheundilutedsample,we
13、ighthelamponananalyticalbalance(to0.0004g)aftercombustion.Calculatethedifferencebetweenthequalityofthelampcontainingthesamplebeforethetestanditscounterpartaftercombustion.Fordilutedsample,Whenthecombustionfinishesagain,calculatethethedifferencebetweenthequalityofthelampcontainingthesampleandthequali
14、tyofthecleananddrylampwithoutthesample.5.Experimentalprocedure(4)Absorptionliquidcollection.Takeaparttherecognizerandwashthedropletcollector,flueandupperpartoftheabsorberwithdistilledwaterinthewashingbottle.Collectabovementioneddistilledwatertotheabsorbercontaining0.3%sodiumcarbonatesolutionforsulfu
15、rabsorption.(5)Titrationoperation.Connecttheglasstubeoftheabsorberwitharubbertube.Bloworextracttheabsorptionsolutionwithanearballorapump.Titratewith0.05mol/Lhydrochloricacidstandardsolution.Firstly,titratetheblanksample(theabsorptionsolutionwithsubstancesaftercombustingstandardn-heptane,95%ethanolor
16、gasoline),untilitturnsredastheblanktest.Titrateeachabsorptionsolutioncontainingsamplecombustionsubstances.Whenthesolutionpresentsthesameredcolorasthetitrationblanktest,itreachesthetitrationendpoint.6Dataprocessingandreporting(1)CalculatetheamountofsulfurcontentsinthesampleX%m/m,accordingtothefollowi
17、ngequationWherein:V-thevolumeofhydrochloricacidstandardsolutionconsumedfortitrationofblanktestsolution,ml;V1-thevolumeofhydrochloricacidstandardsolutionconsumedbytitratingandabsorbingthesolutionofcombustionproductsofthesample,ml;K-thecorrectioncoefficientconvertedinto0.05mol/lhydrochloricacidsolutio
18、n,I.e.theratiooftheactualconcentrationofhydrochloricacidto0.05mol/l;M-combustionamountofsample,m;0.0008-themassofsulfurequivalentto1mlof0.05mol/lhydrochloricacidsolution,g/ml;7.precisionThedifferencebetweentworesultsparallelstested,shouldnotexceedthevaluesinthefollowingtable.PrecisionofSurfaceSulfur
19、ContentSulfurcontent/%allowabledifference/%0 10.006016%oftheminimummeasuredvalue8.ImportantNotice:(1)Ifthecombustiondegreeofthesampleiscomplete,themeasurementresultwillbelow;Therefore,theexperimentalmethodspecifiestheheightoftheflameduringcombustion,thespeedofairflow,theflamecannotcarrysmokeduringco
20、mbustion,usestandardn-heptane(orethanol,gasoline,etc.)todiluteviscousoilproducts,etc.,thepurposeistoensurethatthesampleiscompletelyburnedout.(2)TestmaterialsandenvironmentalconditionsIfthereissulfur-containingcomponentinthematerialsusedorambientair,itisboundtoaffectthemeasurementresults.Thestandards
21、tipulatesthatitisnotallowedtousematchesandothersulfur-containingignitiondevicestoignite;(3)whetherthevolumeofsodiumcarbonatesolutionaddedby3)Absorptionliquiddosageisaccurateandconsistent,andwhetherthereisanylossintheoperationprocessalsoaffectsthedeterminationresults.(4)Endpointjudgment.Stirtheabsorptionsolutionwhiletitrating.Comparethecolorwithitscounterpartoftheblanktestwhenitreachestheendpoint