formation of soft particles in drop-in...

FormationofSoftParticlesinDrop-in

RichardA.Alim

Master´sThesisProject

KTHRoyalInstituteofTechnology

EngineeringSciencesinChemistry,Biotechnology,andHealth

FormationofSoftParticlesinDrop-in

RichardA.Alim

Supervisor:

HenrikHittig

Examiner:

LarsJ.Pettersson

Abstract

Asthemissiontothedecreaseglobalwarmingandphaseouthighlypollutingenvironmentalpracticesglobally,regulationsincludingEuro6andpoliciesgeneratedbytheUnitedNationsFrameworkConventiononClimateChange(UNFCCC)arepushingcompaniestobemoreinnovativewhenitcomestotheirenergysources.Theseregulationsinvolvemanyfactorsrelatedtothecleanlinessofthefuelandproducedemissions,forexample,propertiesofthefuelssuchassulfurcontent,ashcontent,watercontent,andresultingemissionvaluesofCarbondioxide(CO2)andNitrogenOxides(NOx).Furthermore,Swedenhassetachallengingtargetofafossil-fuel-independentvehiclefleetby2030andnonetgreenhouse-gasemissionsby2050.

Onewaytocutdownonthepollutingpropertiesinthefuel,aswellasweakeningthedependenceonfossilfuelbasedfuelincludesutilizinghigherblendingratiosofbiofuelsinthetransportsector.Thistransitiontobiofuelscomeswithmanychallengestothetransportindustryduetohigherconcentrationsofthesenewfuelsleadstocloggingofthefiltersintheengine,aswellas,internaldieselinjectordeposits(IDIDs)thatproduceinjectorfouling.Thiscloggingofthefiltersleadstolowerperformancebytheengineswhichleadstohigherrepairtimes(uptime)andlesstimeontheroadtotransportgoods.Theformationofthesesoftparticlesattherootofthecloggingissueisapivotalissuebecausetheprecisemechanismsbehindtheirformationarehighlyunknown.Scania,aleaderintheSwedishautomotiveindustry,isveryinterestedinfiguringoutwhatmechanismsarethemostinfluentialintheformationoftheseparticlesintheengine.UnderstandingthekeymechanismswouldallowScaniatomakeappropriateadjustmentstothefuelortheenginestoensuremoretimeontheroadandlessmaintenance.

Therearemanyconditionsknowntobepossiblecausesoftheformationofsoftparticlesinenginessuchaswatercontent,ashcontent,andtemperature.Aftergeneratingsoftparticlesusingamodifiedacceleratedmethod,particleswereanalyzedusinginfraredtechnology(RTX-FTIR)andaScanningElectricMicroscope(SEM-EDX).Manydifferentexperimentswereperformedtobeabletomakeaconclusionastowhichmechanismsweremostinfluentialincludingtemperature,time,water,air,andoil.Thecombinationofagingbiofuels(B100,B10,HVO)withmetals,andwaterproducedthelargestamountofparticlesfollowedbyagingthebiofuelswithagedoil,metals,andwater.Agingthefuelswithagedoilincreasedparticles,meanwhiletheadditionofwaterpreventedparticleproductionpossiblyduetoadditives.B100producedthehighestamountofparticleswhenagedwithCopper,B10withBrass,andHVOwithIron.

NomenclatureAbbreviationCommonName

HVO Hydrotreatedvegetableoil

FAME Fattyacidmethylester

ISO TheInternationalOrganizationforStandardization

ULSD UltraLowSulfurDiesel

CEN EuropeanCommitteeforStandardization

CR Commonrail

B0 Nobiodieselpresent

B10 10%concentrationofbiodieselinfuel

B100 100%biodiesel:nopetrodieselpresent

DCA DepositControlAdditive

PIBSI Polyisobutylenesuccinimides

SG Sterylglycoles

SMG SaturatedMonoglycerides

VF VacuumFiltration

TableofContentsNomenclature.........................................................................................................................................4

Introduction............................................................................................................................................1

LiteratureStudy.......................................................................................................................................1

Whatarebiofuels?..............................................................................................................................1

CommonBiofuelCompositions...........................................................................................................2

FuelSelection......................................................................................................................................3

UltraLowSulfurDiesel(ULSD)........................................................................................................4

HydrotreatedVegetableOil(HVO)..................................................................................................7

FattyAcidMethylEster(FAME)......................................................................................................7

FiltrationSystemintheCommonRailEngine...................................................................................10

FilterClogging....................................................................................................................................11

Sieving...........................................................................................................................................11

Bridging.........................................................................................................................................11

Agglomeration...............................................................................................................................12

DieselInjectorClogging.....................................................................................................................12

InternalDieselInjectorDeposits...................................................................................................12

NozzleGeometry...........................................................................................................................13

FuelComposition...........................................................................................................................13

Temperature.................................................................................................................................13

ContaminantsinFuel........................................................................................................................13

Particlesinfuel..............................................................................................................................14

Water............................................................................................................................................14

Air..................................................................................................................................................15

PresenceofMetals........................................................................................................................15

SterylGlucosides(SG)&SaturatedMonoglycerides(SMG)..........................................................16

FuelAdditives................................................................................................................................18

TestMethods....................................................................................................................................19

AcceleratedMethod......................................................................................................................19

AcceleratedOxidationTest...........................................................................................................19

DaimlerOxidationTest..................................................................................................................20

RancimatEN15751.......................................................................................................................20

PetroOXYEN16091.......................................................................................................................20

ColdSoakFiltrationTest(ASTMD2500)........................................................................................21

FiltrationMethods.............................................................................................................................21

SimpleFiltration............................................................................................................................21

VacuumFiltration..........................................................................................................................22

TechniquestoMeasureSoftParticles...............................................................................................22

FilterAnalysis................................................................................................................................22

SmearMethod...............................................................................................................................22

ManualCollectionMethod............................................................................................................22

Centrifugation...............................................................................................................................23

AnalyticalMethods...........................................................................................................................23

OpticalMicroscopy........................................................................................................................23

ElectronMicroscopy......................................................................................................................23

X-rayenergy-dispersivespectroscopy(EDX).................................................................................24

Fourier-transformInfraredSpectroscopywithAttenuatedTotalReflection(FTIR-ATR)..............24

Experimental.........................................................................................................................................24

Materials...........................................................................................................................................24

Metals............................................................................................................................................25

Water............................................................................................................................................25

Oil..................................................................................................................................................25

Procedure..........................................................................................................................................25

AppliedMethods...................................................................................................................................27

AcceleratedMethodsforOxidationofFuelOils...........................................................................27

ColdSoakFiltrationTest................................................................................................................27

VacuumFiltration..........................................................................................................................27

AppliedTechniquestoMeasureSoftParticles..................................................................................28

FilterAnalysis................................................................................................................................28

ManualCollectionMethod............................................................................................................28

AnalyticalTechniques........................................................................................................................28

Fourier-transformInfraredSpectroscopywithAttenuatedTotalReflection(FTIR-ATR)..............28

ScanningElectronMicroscopy(SEM)............................................................................................28

Results...................................................................................................................................................29

AgingofB100withFreshOil(MAM1)...............................................................................................29

AgingofBiofuels(MAM2).................................................................................................................29

AgingofBiofuelswithFreshOil(MAM3)..........................................................................................31

AgingofBiofuelswithAgedOil(MAM4)...........................................................................................32

AgingofHVOwithAgedOilforanExtendedPeriod(MAM5)..........................................................33

AgingofBiofuelswithAgedOilandWater(MAM6).........................................................................34

AgingofBiofuelswithAgedOilandMetals(MAM7)........................................................................35

AgingofBiofuelswithAgedOil,MetalsandWater(MAM8)............................................................36

AgingwithAgedOilandMetals(MAM9)..........................................................................................38

Discussion..............................................................................................................................................39

Conclusion.............................................................................................................................................44

Futurerecommendations......................................................................................................................44

Appendices............................................................................................................................................45

IRSpectra..........................................................................................................................................45

Filter´sPost-Treatment.....................................................................................................................45

AgedFuelwithFreshOil(MAM3).................................................................................................45

AgedFuelwithAgedOil(MAM4)..................................................................................................45

AgedHVOwithAgedOil(MAM5).................................................................................................45

AgedFuelwithAgedOil,andWater(MAM6)...............................................................................46

AgedFuelwithAgedOil,andMetal(MAM7)................................................................................46

AgingofFuelswithAgedOil,MetalsandWater(MAM8)............................................................47

AgingofFuelswithMetalsandWater(MAM9)............................................................................47

References.............................................................................................................................................49

IntroductionRenewablefuelsarebecomingmoreprominentgloballylargelyduetorecentpushesfromgloballeaderstodecreasethedependenceonfossil-fuelbasedenergysourcesincludingtheincreasedregulationofacceptableamountsofemissionsfromthetransportsectorsuchasEuro6andpoliciesgeneratedbytheUnitedNationsFrameworkConventiononClimateChange(UNFCCC).TheUNFCChasmadeparticularprogressinbringinggloballeaderstogethertoagreeontheparamountParisClimateChangeAgreementattheParisClimateConference(COP21)in2015,whichwastheaimstokeeptheglobaltemperaturebelowthecritical2°Cinthelongterm,amongotherimportantpolicies[1].Oneofthewaystoaccomplishthisgoalofreducingthesocietalecologicalfootprintistodevelopmorecleantechnologythatcanallowforindependencefromfossilfuels,andthisiswherethetransportindustryhasstartedtakinginitiativeduetoincreasingpressures.Swedenhasbeenaleaderinfurtheringtheclimatechangeinitiativeintakingastrongstancebysettingademandingmilestoneofafossil-fuel-independentvehiclefleetby2030andnonetgreenhouse-gasemissionsby2050[2].Thiscanbeaccomplishedbyimplementinghigherusageofrenewablefuelsinthetransportsector.Thechallengingtaskofproducinglessfossilfuel-dependentsystemshasbecomecentraltotheworkthattheSwedishautomotivecompany,ScaniaAB,isinvolvedinwhenitcomestotheenginesintheirtrucksandbuses.Scaniahasbeenlongatworktomaketheirdieselenginesmoreenvironmentallyfriendlybyrunningtheirsemi-trucksonabiodieselandregulardieselblend.Inparticular,therearebiofuelsthatcanbeusedincurrentenginesintheirpureordilutedformswhichareknownasdrop-infuels.Moreover,theyareinterestedinthedrop-infuelbiofuelmarketduetotheabilityofthisclassofbiofuelstoruninanenginewithoutanymodificationsrequired.Thegoaltoincreasetheblendingofbiofuelsinworkingdieselenginescanbechallengingduetothemanyissuesthatariseincludingseverecorrosion,carbondepositionandwearingofenginepartsofthefuelsupplysystemcomponents[3].Understandingthemechanismsbehinddepositsonthefiltersandfuelinjectorsiscrucialtoimplementinganeffectivesolution.Thegoalofthisreportistogainadeeperunderstandingintothemainmechanismsbehindthedepositformationsformedfromtheuseofbiofuels(alsoknownasdrop-infuels)orinordertodevelopanewmethodtogeneratesoftparticlesinalabsetting.Thiswouldallowforfurtherinvestigationintopossiblesolutionstopreventtheformationoftheaforementionedparticles,whetherthatbeviaalteringthecompositionofthebiodieselormakingadjustmentstooperatingconditionsoftheengines.

LiteratureStudy

Whatarebiofuels?Biodieselisafuelsubstitutethatismadefromvegetableoilsoranimalfats.Vegetableoilscommonlyusedincookingarefartooviscoustobeusedinadieselengineduetothepresenceofglycerine[4].Therefore,inordertousecertainbiofuelsincurrentengines,certainprocessesarerequiredincludingesterification,hydrotreating,andgasificationasshowninTable1.Currentbiofuelsaremainlyproducedfrommainstreamcommodityoilcrops,principallyoilpalm,soybean,andrapeseed,whilesomeoftheminoroilcropscanbeusedtoproducebiofuelsmorelocally[5].Furthermore,themainbiofuelsusedbyvehiclesinSwedenare(inorder),HVO(hydrotreatedvegetableoil),FAME(fattyacidmethylester),

ethanol,andbiogas[6].ScaniahaslongbeenworkingonsolvingthisissuebyblendinganincreasingamountofbiofuelssuchasFattyacidMethylEsters(FAME)andhydrogenatedvegetableoil(HVO)withregulardiesel.Thisreportisinterestedincharacterizingthemechanismsbywhichthesoftparticlesareformed,includingbutnotlimitedto,hightemperaturesincombustion,watercontent,anddegradationofbiofuels.Furthermore,thisinformationwillbeusedinordertoattempttogeneratesoftparticlesinalaboratorywiththeintenttolearnwhichfactors,infact,playaroleintheformationoftheparticlessincethereisverylimitedresearchonthistopic.

Table1:Differenttechnologiesforbiobaseddieselfuels[7]

CommonBiofuelCompositionsBiofuelsfromdifferentsourcesarecomposedofvaryingcompositionsofcommontypesofvegetableoilsincludingPalmitic,StearicandsoonasTable2shows[8].

Table2:Fattyacidchainscommoninbiofuels[8]

Name ChemicalFormula Carbons:DoublebondsPalmitic R=-(CH2)14–CH3 16:0Stearic R=-(CH2)16–CH3 18:0Oleic R=-(CH2)7CH=CH(CH2)7CH3 18:1Linoleic R=-(CH2)7CH=CH-CH2-CH=CH(CH2)4-CH3 18:2Linolenic R=-(CH2)7CH=CH-CH2-CH=CH-CH2-CH=CH-CH2-

CH318:3

Eicoseneacid R=-(CH2)9CH=CH(CH2)7-CH3 20:1ErucicAcid R=-(CH2)11CH=CH(CH2)7-CH3 22:1

whereRisthelongchainsofcarbonsandhydrogenatoms,sometimesreferredtoasfattyacidchains

Furthermore,Table3onthefollowingpageshowsthecompositionsofvariousoilsandfatsusingthecomponentsmentionedabove[1].

Table3:FattyAcidcompositionofVariousOilsandFats[1]

OilorFat 14:0 16:0 18:0 18:1 18:2 18:3 20:0 22:1Soybean 6-10 2-5 20-30 50-60 5-11 Corn 1-2 8-12 2-5 19-49 34-62 Trace Peanut 8-9 2-3 50-65 20-30 Olive 9-10 2-3 73-84 10-12 Trace Cottonseed 0-2 20-25 1-2 23-35 40-50 Trace HilinoleicSafflower

5.9 1.5 8.8 83.8

HiOleicSafflower

4.8 1.4 74.1 19.7 13.2

HiOleicRapeseed

4.3 1.3 59.9 21.1 13.2

HiErucicRapeseed

3.0 0.8 13.1 14.1 9.7 7.4 50.7

Butter 7-10 24-26 10-13 28-31 1-2.5 0.2-0.5 Lard 1-2 28-30 12-18 40-50 7-13 0-1 Tallow 3-6 24-32 20-25 37-43 2-3 LinseedOil 4-7 2-4 25-40 35-40 25-60 YellowGrease

2.43 23.24 12.96 44.32 6.97 0.67

Inthecaseofthisreport,thebiofuelthatisutilizedwasproducedusingrapeseed.

FuelSelectionTherearemanydifferenttypesoffuelsusedgloballydependingontheregion,however,thankstotheemphasisonincreasinglyenvironmentallyfriendlyalternativestherehasbeenapushfortheuseofUltraLowSulfurDiesel(ULSD)andfortheincreaseduseofrenewablefuels(HVO,FAME,etc.).Moreover,therehasbeenapushforcleanerfuelsgloballysotherehavebeenincreasingregulationsintroducedbytheInternationalOrganizationforStandardization(ISO)includingISOEN590andEN15940fordieselfuelwhichwillbediscussedlaterinthisreport.FuelpropertiesareshownbelowinTable4,whereEN590isregulardiesel,andGTLisGas-to-liquidproducedfromFischer-Tropschsynthesis[7].ThisreportwillcoverGTLfromFischer-Tropschsynthesisasitisnotinthescopeofinterest.HVOandFAMEcanbeproducedfromthesamefeedstock,buthavevastlydifferentprocessingtechniques[9].ThetransesterificationprocesstoproduceFAMEcanbeaccomplishedatamuchcheapercostwhencomparedwiththehydrotreatmentprocesstoproduceHVO,however,HVOismuchpurerthanFAMEcontainingnoconstituentsthatwouldleadtodepositsinfuelinjectors[10].HVOwillrequireahigherinvestmentbygovernmentsinordertointroduceitasamorecommoneverydayfuel,aswellas,expansionduetolimitedaccessrelativetoFAME.

Table4:TypicalpropertiesofHVO,EuropeanEN590:2004dieselfuel,GTLandFAME[1]

UltraLowSulfurDiesel(ULSD)

Alongwiththepressurestoshifttomoreenvironmentallyfriendlyfuelsglobally,thespreadofdieselwithlowamountsofsulfurhavebecomemoreprominent.Themotivationtomovetolowersulfurcontentinfuelsislargelybasedupontheneedtoreducepoisoningoftheexhaustaftertreatmentcatalysts,reducedieselengine'sharmfulemissions,toimproveairqualitybydecreasingtheemissionsofsulfuroxides(SOx),NitrogenOxides(NOx),andparticulatematter.Onemainfocusfortheuseofultra-lowsulfurdiesel(ULSD)istominimizethepossiblepoisoningintheexhaustaftertreatmentsystemscausedbysulfur,whichincludethedieselparticularfilter(DPF),NOxreductionsystemandSelectiveCatalyticReduction(SCR)[11][12].Theexhaustaftertreatmentsfiltersarebecomingincreasinglyimportantinthechallengetokeepupwiththeemissionsstandardsthatgrowmoreandmorestringenteveryyearinthetransportindustry.Onesimplerwayforthetransportindustrytodecreasethechallengeofmeetingthehighemissionstandardsistoshiftthefocusfromdevelopingexpensiveaftertreatmentsystems(suchastheadditionofasulfurtrapcatalyst)todemandinghigherqualityfuel[11].Forexample,Zhangetal.studiedtheeffectofSO2poisoningontheSCRreactionactivityofaCu-SAPO-34catalysttoidentifytwomechanismsofwhichtheSCRcatalystwasinhibited;formationof(NH4)2SO4whichcanleadtoblockingoftheactivesites,aswellas,identifyingthetrendthatSO2absorptioncompeteswithNOxabsorptionontheCusites.Theconcentrationofsulfurinfuelshasalsobecomeakeyissueuponthefindingsthatcombustionofregulardieselfuelproducesamountsofsulfurdioxide,SO2,andNOx,nitrogenoxides.Moreover,whenSO2dissolvesintothewaterthisproducesthephenomenonknownasacidrainwhichcontributestoenvironmentaldamage.Whentheacidrunsintoriversand

streamsitcanleadtoincreasedacidity,whichhasanimmediateeffectonbiodiversity.Furthermore,itcanreactwithmetalssuchaslimestone,aswellas,damagingthewaxlayerontreeswhichmakesitmoredifficulttoabsorbnecessaryminerals[13][14].Meanwhile,NOxcontributestothegreenhouseeffect.Astheamountsofvehiclesrunningondieselincreasesontheroadeveryyear,itbecomesnecessarytoreducetheamountofPMproducedtoensuresufficientairquality.Sootisthemainculpritofdieselnoxiousblackexhaustfumes,consequently,itisoneofthemajorcontributorstoairpollution[15].Moreover,thePMproducedareharmfulduetotheirabilitytopenetratedeeplyintothelungs.Startingin2004thestandardEN590reducedtheallowableamountofsulfurindieselfuelfrom50ppmto10ppmforroadvehicles[16].Inaddition,itallowsfortheblendingofupto7%volumeofbiofuelswithconventionaldieselfuel.AllofthestandardsareprovidedinTable5.Thisstandardhasbeenextendedtooff-roaddieselenginesandlargeengines,cappingthematalimitof15ppmsulfur.

Table5:Generallyapplicablerequirementsandstandardizedtestmethodsforautomotivedieselfuel[16]

Property Unit Limits TestMethod

Minimum Maximum

Cetanenumber 51.0 - ENISO5165EN15195EN16144!EN16715

Cetaneindex 46.0 ENISO4264

Densityat15°C kg/m3 820.0 845.0 ENISO3675ENISO12185

Polycyclicaromatichydrocarbons

%(m/m) - 8 EN12916

Sulfurcontent mg/kg - 10 ENISO20846eENISO20884ENISO13032

Manganesecontent mg/dm3 - 2 EN16576

Flashpoint °C Above55.0 - ENISO2719

Carbonresidueg(on10%distillationresidue)

%(m/m) - 0.3 ENISO10370

Ashcontent %(m/m) - 0.010 ENISO6245

Watercontent %(m/m) - 0.020 ENISO12937

Totalcontamination mg/kg - 24 EN12662

Copperstripcorrosion(3hat50°C)

Rating Class1 ENISO2160

Fattyacidmethylester(FAME)content

%(V/V) - 7.0 EN14078

Oxidationstability h -20

ENISO12205EN15751

Lubricity,wearscardiameter(WSD)at60°C"

µm - 460 ENISO12156-1

Viscosityat40°C mm2/s 2,000 4,500 ENISO3104

Distillation%(V/V)recoveredat250°C%(V/V)recoveredat350°C95%(V/V)recoveredat

%(V/V)%(V/V)°C

<65360

ENISO3405ENISO3924

HydrotreatedVegetableOil(HVO)Hydrotreatingofvegetableoilisamodernwaytoproduceveryhigh-qualitybiobaseddieselfuelswithoutcompromisingfuellogistics,engines,exhaustaftertreatmentdevices,orexhaustemissions.Additionally,theyarecommonlycomposedofamixtureofparaffinichydrocarbons[17].HVOcomeswithmanyperkssuchasthepossibilitytoadjustthecoldpropertiesofthefuelbyadjustingtheseverityoftheprocess,orbyadditionalcatalyticprocessing,aswellas,thefuelhavingahighcetanenumber.Itisagreatalternativeforbiofuel,butcomeswithdisadvantageswhichincludeexpensiveproductionandthatitisproducedfromsimilarfeedstocksasbiodiesel[18].Infact,HVOhasmanyadvantagesatcoldtemperatures:fasterandeasiercoldstart,lesscoldstartsmoke,lessenginenoiseafteracoldstart[10].TheprocessrequiredtoproduceHVOinvolvessaturatingtriglyceridesunderhydrogenpressureandconvertingthemintofreefattyacidsandpropane.Subsequently,threesimultaneousreactionsoccurproducinglong-chainhydrocarbons,water,carbonmonoxide,andcarbondioxide[19].AdiagramdescribingthestepsinvolvedinofthehydrotreatmentcanbeseenInFigure1.

TheEuropeanCommitteeforStandardization(CEN)hasapprovedtheEN15940standardforparaffinicdieselspecifyingthequalityandpropertiesofadvanceddieselwhichiseithersyntheticorproducedfromrenewablerawmaterialsthroughhydrotreatment.Dieselfuelsthatcomplywiththestandardcanbeusedinexistingengineseitherassuchorasbefore,asblendcomponentsinconventionaldiesel[20].

WhileHVOmaycomewithmanyadvantages,thehighcostofproductionofthisbiofuelhavebeenplayedalargepartinthelimiteduseofitinthetransportsector.ThehighproductioncostscanbeattributedtohydrogenationandloweryieldsatHVOproduction[21].ThisfuelnotonlycostssignificantlymorethanotherbiodieselalternativessuchasFAME,butisalsoproducedfromthesamefeedstockwhichcausesstrainonthealreadylimitedresources.

FattyAcidMethylEster(FAME)FAMEiscomposedofaglycerinemoleculeconnectedwiththreelonghydrocarbons,whichcannotbeusedasafuelinitsoriginalformduetoitshighviscosity.Inthiscase,theFAMEissourcedfromrapeseedoilalthoughitcancomefrommanydifferentsourcesaspreviously

Figure1:Reactionschemeforhydroprocessingatriglyceride,e.g.triolein,bysaturation,fattyacidformation,andthreeroutestohydrocarbonformation[19]

mentionedinthisreport.Therefore,inordertoutilizevegetablefuelsindieselengines,aprocesscalledtransesterificationisrequired.Transesterificationisanalcoholysisprocessthatconvertstriglyceridesfromvegetableoiltofattyacidmethyl/ethylestersbydisplacingalcoholfromanesterbyanotheralcohol[3].Afterthetransesterificationprocessiscomplete,thethreelonghydrocarbonmoleculesareeffectivelyseparatedasisshowninFigure2.Methanoliscommonlyusedintheprocesstobreakupthetriglycerides,aswellas,astrongbaseorastrongacidthatcanbeusedasacatalyst[22].:

Figure2:Thetransesterificationprocesstoproducebiodieselandglycerol[22]

AsthereactioninFigure2displays,methanolisreactedwithtriglycerideinthepresenceofacatalysttoproducerawbiofuelandglycerol.Furthermore,usingmethanolinthetransesterificationprocessallowsfortheglyceroltoberemovedsimultaneously[22].However,acleaningstepisrequiredinordertoobtainaviableformofthebiodiesel.OneofthecurrentissuesinusingFAMEintheautomotiveindustryistherateatwhichitdeterioratesrelativetoULSD.Deteriorationofthefuelincreaseswiththenumberofdoublebondspresentinthefeedstock;therefore,higherchanceofoxidationdeterioration[23].ThenumberofbondspresentinthreedifferentcommonFAMEsourcesaredisplayedinFigure3includingSoybeanMethylEster(SME),RapeseedOilMethylEster(RME)andPalmOilMethylEster(PME)wherethepurplerepresentsnonbondedcarbons,redrepresentssingle-bondedandyellowrepresentsdouble-bondedcarbons[23].

TriglycerideMethanolGlycerol Esters

Figure3:NumberofbondsperdifferentFAMEsources[23]

TheincreaseduseofFAMEhasintroducedmanyissuesduetocontaminantswhichwillbediscussedlaterinthisreport.Moreover,togetanideaofthenovelproblemsthatmustbemitigatedFigure4showsasummaryofthemanyshortcomingsthatcanarise.Duetothemanypossiblesourcesofcontamination,itisverydifficulttonarrowdownwhichcontaminantsarethemostpotenttoengineperformance.Moreover,figure4displaysmanyoftheissuesknowntocausedeposits.

Figure4:IssuesintroducedduetohigherconcentrationsofFAME[23]

FiltrationSystemintheCommonRailEngineThecommonrailfuelsystemutilizestwofiltersintheengineinordertoprotectthevariouscomponents,theprimaryandsecondfilterasisdisplayedinthediagramdisplayedin[24].

Figure5:Adiagramofthelayoutofadieseltruckengine[24]

Theprimaryfilteriscommonlylocatedonthesuctionsideofthefueltransferpumpandallowsfortheprotectionofthepumpwhilesimultaneouslytakingadvantageofeasierfuelwaterseparationconditionsbeforethepumpemulsifiesthefuel/watermixture[24].Moreover,uponcloggingoftheinlet-sidefilerresultsinthepressurelossofthesuctionofthefuelpump,inotherwords,morepressuredropleadstolessthansufficientfuelsupplyandlimitsenginesperformancedirectly[25].Efficiencyratingsfortheprimaryfiltersaredependentuponvehicle,engine,andoperatingenvironmentprimaryfiltersrangingfrom7µmto25µm.

Thesecondaryfilterislocatedbetweenthetransferandhigh-pressureinjectionpump.Thesefiltersprovideprotectionforthehigh-pressurefuelpumpandsensitivefuelinjectioncomponentsfromparticlesthatcancausewearanderosiondamage[24].Secondfiltersinhigh-pressurecommonrailfuelsystemsgenerallyhaveefficiencyratingsof4-5µm.

Theprimaryandsecondaryfiltersarebothparadigmstoanefficientrunningengineandcanbeafflictedbysimilarrootcauses.Thepre-filterandmainfiltercanbothbecloggedbytheaggregationofsoftparticles,however,theyoccurinslightlydifferentways.Thepre-filtercanbecomecloggedwithlargesoftparticlesthatdepositonitssurface,effectivelylimitingtheflowoffueltotheengine.Meanwhile,themainfiltercanbeaffectedbythesmallersoftparticlesintwoways:agglomerationandpresenceinthefuelinjector.Moreover,smallerporesizerestrictionsforfuelfiltersduetotighterclearancesinHPCR(High-PressureCommonRail)injectors,coupledwithcontaminantsfrombiodieselandcarboxylatesaltsinfuel,havebeenidentifiedasaccelerantsofdieselfuelfilterplugging[26].Itshouldbenotedthatthe

sizeofthesesoftparticleslieintherangeof5to15µm,whereastheaverageeyecanonlydetectobjectsassmallas40µmasisshownin[27].Thesephenomenawillbediscussedinfurtherdetailinthenextsections.

Figure6:Generalsizesofcommonthings[27]

FilterCloggingUsingablendofbiodieselandregulardieselincurrentenginesintroducesnovelissuesintothepowersystemsbyproducingsoftparticleswhichclogtheenginefilters.UnderstandingthemainmechanismbywhichsoftparticlesareformediscrucialbecauseitwouldallowScaniatooptimizetheperformanceoftheirtrucksbyadjustingthecompositionofthebiofuelsorengineparameters,forexample,toadjustformorehumidregionssuchasLatinAmerica.Onestudyfoundthatfiltercloggingduetobiofuelsispossiblyrelatedtosolubilityincompatibilityandthatdepositsmaybetheresultofheavyoxidationoffuelcomponentssuchaslubricantadditivesduringcombustionofthefuel[28].Theaccumulationofsoftparticlescanleadtopluggingofthepre-filter(Stage1)viamanymechanisms,including,sieving,bridging,andagglomerationwhicharerepresentedinFigure7[29].SievingSievingcanresultincloggingduetothefactthatasoftparticlecanenteramicrochannelwhosesizeissmallerthanthediameteroftheparticleatrest.Inotherwords,whenapressuredifferenceisappliedbothvolumeandshapeofadeformableobjectchangeduetolocalmechanicalstresses.Thisshapechangeleadstoblockageofchannels,i.ecloggingofthefilter[29].BridgingBridgingcanformintheinstancesthatconvergingflowandhighparticleconcentrationoccurs,generatingalayerofparticles,typicallybetween2and10,thatspanacrosstheentirechannel.Thisoccurslargelyduetostericeffectsthroughtheformationofanarchofparticlesacrossthewidthofthechannel,resultingincloggingofthefilter[29].

AgglomerationAgglomerationistheendresultofcloggingduetosuccessivedepositionofcolloidalparticles.Thisphenomenoncanoccurinthebulkofsuspensionoronafluidinterface[30].Short-rangeattractivevanderWaalsforceisthemaindrivingforcebehindtheformationofcloggingfromagglomeration,inotherwords,thehigherfrequencyofcollisionsofparticlesleadstohigherratesofdepositformationsonthefilters.Furthermore,globallythereisavarietyofweatherconditionsandaltitudeswhereScaniatruckstravelandtransportcargo,soknowledgeoftheprominentmechanismcanbeusedtoreduceuptimeofthevehicles

Figure7:PhenomenathatcancauseStage1andStage2filtersclogging[29]

DieselInjectorCloggingAnadditionalissuethatarisesfromtheformationofsoftparticlesisthegenerationofparticleswhicharesmallerthanthefiltersizeitself.Thisbecomesespeciallytroublesomebecausesomeparticlesmayfindtheirwaythroughtheprimaryandsecondaryfilter,whichleadstodepositsonthefuelinjector.Thisproblemispotenttotheoperationofanenginesincedepositsintheinjectorreducethehydraulicdiameter,indoingso,reducesthehydraulicflowinthenozzle.Thustheamountofinjectedfuelisdecreasedandsprayqualityisdecreased.Manystudieshavebeenperformedwhichhavenotonlyidentifiedcommoninternaldieselinjectiondeposits(IDID´s),butalsoidentifiedthemaincausesbehindinjectordepositsincludednozzlegeometry,fuelcomposition,andtemperature[31][32].InternalDieselInjectorDepositsInfact,thereare6differenttypesofinternaldieselinjectiondepositsthathavebeenidentifiedwhichareallproductsofthecontaminants.Thesixtypesof(IDID´s)include

carboxylatesalts,polymericamides,inorganicsalts,agedfueldeposit,lacquer-basedorcarbonaceous[32].Furthermore,IDID´saremoreoftenthannotacomplexmixtureofmultiplesortswhichcanmakepinpointingthetruecauseofcloggingincreasinglydifficult.

NozzleGeometryDuetotheimportanceofgeometryintheprocess,itisveryimportanttohaveanaccuratemeasureofthegeometry.Macianet.aldescribesonemethodthatutilizesformingamoldofthenozzletipusingsiliconduetoitsmaterialproperties.Tanget.alinvestigatedtheimpactofenhancedcavitationontheformationofdepositionsbyvaryingthegeometriesofthesprayholesand,thuscavitationtendency.Onegeometry(Type2)utilizedahydro-grinded(respectivelyrounded)sprayholeinlettoreducecavitationinthenozzleorifice.Whiletheotherwasassumedtoresultinaminorcokingincomparisontothepreviousgeometry(Type2).Upontestinginamedium-dutytruckengineOm906usingCycle1.itwasfoundthattheType2geometryreducedinpoweroutputby6%,whilethetype1nozzleindicatednosignificantcokinglevel[34].Additionally,anotherstudyexaminedseveralgeometricalparametersandtheirinfluencesincludingoutletholediameter.Conicityfactor(Cf),andtheinletholeradiuswhichiscontrolledbythelevelof“hydrogrinding”.Argueyrolleset.al.foundthatlargeroutletholediameterandthereforelargerhydraulicflowleadtolargerdeposits.whilekeepingthefuelflowratelosslow[35].

FuelCompositionThenumberofdepositformationsincreaseswithalargerconcentrationofbiofuelinafuelmixtureasmanystudieshavefound[36].Birgeret.alperformedastudytoinvestigatetheeffectofdifferentfuelsfromvegetableoilthathadbeenprocessedviathetransesterificationprocessincludingB0(RF06),B30(30%V/V)andB100.DepositsweremeasuredbyadropinIndicatedMeanEffectivePressure(IMEP).Moreover,theresultsindicatedthatboththeB30andB100blendsofoff-specificationbiodieselacceleratedthedepositformation.

TemperatureManystudieshavebeendoneandcometotheconclusionthathighertemperaturesleadtomoredepositsintheengine,aswellas,studiesthathaveshownthatcoldtemperaturesleadtodepositsintheengine.Whenthebiofuelissubjectedtohighertemperatures,oxidationofthefuelincreasessubstantially.Itshouldbenoted,inadieselenginethetemperatureusedisathighestaround80°Canditisonlysubjectedtothistemperatureforashortwhile.Oxidationduetohightemperaturesismoreafocustoensurethelongevityofthecontaminantsthataccumulateovertime.Argueyrollesetal.statethatnozzletemperatureshigherthan300°Ccanresultinsignificantcoking.Furthermore,Galleet.alrecommendsavoidingtemperaturesover280°Cinthenozzletiptopreventcloggingandcarbonizing.Meanwhile,undercoldtemperatures,organicparticlessuchasSterylGlucosides(SG)precipitateoutofthefuelleadingtocloggingissues.However,thisspecificissuewillbediscussedinthefollowingsection.

ContaminantsinFuelTherearemanysortsofcontaminationthatcanoccurinafluidpowersystem:gaseous(e.gair),liquid(e.g.water),andsolidcontaminantsasFigure8belowdemonstrates.Furthermore,

solidcontaminationcanbesubdividedintothreedifferentgroups:extremelyhard,hardandsoft.Contaminationiscommonlyintroducedthroughtheuseofuncleantanks,dirtaddedduringmaintenancecycles,tankopentotheenvironmentandmissingorlow-qualityairbreathersintanks[27].Forthisreport,thefocuswillbeonsoftparticles.Thesesoftorganicparticlescanbuildupwithintheengineduetotheiraccumulationintheenginefromnaturalcauses,aswellas,duetooxidationofthebiofuel.Softorganicparticlescanbesoft,stickyorslimywhichquicklyleadstobuild-upwithinthefiltersintheengine[24].Therootcausesfortheirformationwillbediscussedinthissection.

Figure8:Differenttypesofcontaminationinafluidsystem[24]

ParticlesinfuelParticulatecontaminantsincluderoaddust,enginerustorwearparticles,andanyotherhardparticlesthatcancauseenginedamage[24].Theseparticlesarecommonlyrigidinnatureandthereforecancausealargeamountofdamagetotheengine,however,thetrueextentofdamageisdependentonparticlesize,shape,rigidity,concentrationandcomposition.Thefirstlineofdefenseagainstthesedestructiveparticlesistheprimaryfilter,whichisdesignedtocapturetheseparticlesinthefuelinordertoreducedamagetoimportantcomponentsofthesystem[25].Therearetwocommonsourcesofparticulatecontaminationincludingdieselfuelcleanlinesslevelsofavailablefuel,andthetankvent.Asthisreporthasdiscussedearlier,therearecertainrequirementsforthecleanlinessofthefuelwhereitcanonlyincludeamaximumofcertainknowntroublesomecomponents[16].Asforcontaminantsthatareintroducedviathetankvent,theyincludeambientairwhichcancontributedustandotherharmfulcomponentsintothetank.Theproblemsthatcomewiththeambientairinthetankspecificallywillbediscussedlaterinthisreport.

WaterWatercanenterasystemasfree,dissolvedandemulsifiedwaterinthefuel.Waterfoundindieselfuelscancauseenginepartcorrosionanderosion,fuellubricitydeterioration,fuel

pumpcavitation,fuelinjectordepositbuild-upandfuelfilterplugging[24].Inaddition,itcanalsopromotefuelinstabilityandbacteriagrowthatthefuel/waterinterface.Freeandemulsifiedwatercontentindieselfuelscanleaduptocloggingofthefilterssinceitpromotesbiologicalgrowthinstoragetanks,whichcanleadtocorrosionofmetals(copper,iron,steel,andothers)andformationofsludgeandslime[38].Meanwhile,dissolvedwaterleadstofasteroiloxidation,reducedfatiguelife,anddemolitionofester-basedfluidsandadditives[27].Itshouldbenoted,thatwaterinthetankisnotabnormalbecausewatercanalsobetransferredintothevehicle´sfueltankasthelevelofdissolvedwaterinthefuelequilibrateswiththerelativehumidityoftheoutsidesurroundings.Moreover,Thompsonetal.foundthatsaturationmoistureinbiodieselrangedfrom0.10to0.17%wtinthetemperaturerangeof4°to35°C,whichwas15-25timeshigherthanthatofstandarddiesel.Thispropertyleadstothepossibilityifwatercollectingatthebottomofthetank,whichleadstobiggerproblemsmentionedearliersuchasbiologicalgrowth.Fanget.alusedtheD2274standardmethodtoageB20inthepresenceofasmallamountofwaterandfoundthatitincreasedtherateforboththehydroxylandthecarbonylbands.Ultimatelysuggestingthemechanismsoccursasshowninequation2[40].Theproposedmechanismissuchthattheestersreactwithwatertoformcarboxylicacidandmethanol.

AirAsmentionedpreviously,ambientairmayenterthegastankwheneverthetankventisopenedwhichcanleadtomanyissuesincludingoiloxidation,varnishformation,cavitation,noise,andchangeofviscosity[27].Pre-maturedegradationofthebiofuelisakeyissuewhentheairisintroducedsincetheoxygencomponentwillreactwithoil.Thisisduetothepresenceofdoublebondsinthemoleculeinducesahighlevelofreactivitywithoxygenwhenitmakesdirectcontactwithair.Moreover,Altaieet.alfoundthatwhencomparingfueltankstoragethatwasclosedtotankstoragethatwasexposedtoambientair,thelaterdegradedatafasterrate[41].Decreaseinpumpefficiencyandeventuallydamagetopumpsiscausedbytheformationandcollapseofgaseousoilcavities(i.e.cavitation).

PresenceofMetalsThepresenceofmetalshasaverydampeningeffectontheperformanceofadieselenginesincetheycausedecreasedoxidationstabilityinbiofuels.Whiletheeffectofzinconbiofuelsiswellknown,othermetalsproducesimilareffectsincludingsodium,calcium,copper,andiron.TheissueofmetalsarisesduetothefundamentalsofthedegradationofbiofuelsbecauseitleadstotheformationofLongChainFattyAcids(LCFA)andShortChainFattyAcids(SCFA).TheSCFAareveryreactiveandreactwiththemetalionspresentformingmetalsoaps,whichcontributetothecloggingofthefilter.Risberget.alfoundthatsodium,calcium,copper,andironsaltssignificantlyfoulednozzleholes[42].Infact,atrendwasidentifiedthathigherchargeofthemetalcationinthecarboxylicsaltincreasedthefuelflowloss.Whilethe

Equation1:Esterhydrolysisbyreactionwithdissolvedwater[40]

Ester Water GlycerolCarboxylicAcid

concentrationofzincinmarketdieselfuelsisratherlow,usuallybelow0.1ppm,zinccanbeintroducedfromfuelsystemcomponentsandlubricantsystems[43].Despitetheselowconcentrationsofzinc,theissueofconcentrationarisesduetoaccumulationovertime.Thedebilitatingeffectofzincondieselengineshasbeenwelldocumented,andmanyreportshaveconcludedthatithasthiseffectataslittleconcentrationas1ppm[31],[42],[43].Fangetal.researchedtheeffectofmetalsonB100usingsmallamountsofferricacetylacetonate(withironFeconcentrationat16or40ppm)usingtheD2274standardmethodofagingthefueltoobservenewbandinthecarbonylregionat1640cm-1[40].Thisnewbandwasidentifiedasacarboxylateformation,makingthecaseforareactionbetweenironandcarboxylatefunctionalgroups.

SterylGlucosides(SG)&SaturatedMonoglycerides(SMG)Plant-basedbiofuelsarecomposedoffreesterols,sterylestersandacetylatedsterylglucosides(ASGs).Moreover,duringthetransesterificationprocess,theASGsareconvertedtoSterylGlucosidesduetothepresenceofmethanol[44].Furthermore,manystudieshavefoundthatthepresenceofSGleadstofiltercloggingparticularlyincoldtemperatures[45],[46].ThefiltercloggingduetoSGislargelyduetothelowsolubilityofSGinbiodieselandhighmeltingpoint,leadingtosoftparticlesinthefuel.Furthermore,concentrationaslowas20ppmleadstofilterclogging[46],[47].

Monoglycerides(SMG)arepartiallyconvertedfatsandoilswithinthebiodiesel[48].Furthermore,Itcanhavetwoforms,saturatedandunsaturated;wheretheformercansignificantlyraisethecloudpointofthebiodieselwhilethelatterdoesnot[49].SimilartoSG,studieshaveshownthatSMGisacommonsourceoffilterplugging.TherearestandardsthatareaimingatthedecreasingconcentrationofSGandSMG´sintransportfuelsincludingENSS-EN14214,however,thisfocusfallsmainlyonfuelproducers.ThestandardsandestablishedtestmethodsforeachparameterofFAMEbiofuelareshowninTable6.Thisisnotaverypotentsourceofcontaminationduetothefactthattheconcentrationsaregenerallyextremelylow,andthereforenotalargefocusonfiltrationclogging[1].Fanget.alperformedanexperimentgravimetricallywherea20-gyellowgreasebiodieselsamplewasmixedwith2%EHN,0.1%organo-sulfonicacid(C12SO3H)and100ppmferricacetylacetone.Whereupon,a20%aqueousglycerinewasaddeddropwise[40].Afterfirstheatingthesampleat120°Cfor4hoursandthen110°Cforthenext16hourswithaconstantairflowrateof15cc/min,itwasfoundthatanincreasedbuild-upofdepositsoccurredwhentheglycerin/waterconcentrationreachesabout600ppm.

Table6:GenerallyapplicablerequirementsandtestmethodsperSS-EN14214[78]

FuelAdditivesFueladditivescanservemanypurposesinafuelincludingimprovinghandlingpropertiesandstabilityofthefuel,improvecombustionpropertiesofthefuel,provideengineprotectionandcleanliness,increasetheeconomicuseofthefuelandtoestablishorenhancethebrandimageofthefuel[50].Furthermore,dependingonthetransportsystemavarietyofthepreviouslymentionedfeaturesmayberequired.TherearemanyadditivesthatareinvolvedintheblendingofdieselfuelsincludingDepositControlAdditives(DCA)´s,CetaneNumberImprovers,ColdFlowImprovers,andStabilityImprovers.DepositControlAdditivesDepositcontroladditiveshavebecomeveryusefulinreducingclottingofthefilters,whichcanhelpmitigatetheissueofpowerlossengineperformanceduetosoftparticlesthatformindieselengines.DieselDCApreventstheformationofdepositsininjectornozzlespartlybyprovidingafilmonmetalsurfacesandpartlybypreventingagglomerationofdepositprecursors[51].Thisispossibleduetoitsstructurewhichconsistsofapolarheadwhichhasanaffinityforthemetalsurfaceinthefuelsystemandahydrocarbontailwhichallowsfuelsolubility.Theimportanceofthisadditiveindieselfuelblendingisreflectedinthecompositionoffuelssuchthat40-50%ofalladditivesusedareinfactDCA´s[52].ThereisoneparticularDCAthathasbeenavastlysuperioradditiveoverthelastthirtyyearsknownaspolyisobutylenesuccinimides(PIBSI)[53].ThechemicalstructureofPIBSIisdisplayedinFigure9.TherehasbeendebateastowhetherPIBSIcouldleadtoinjectordepositswheresomestudiesfoundthatbymixingandheatingPIBSIwithacidiccompoundscouldgenerateamidesandproducematerialwithasimilarFT-IRspectrumtodepositsanalyzedfromaninjector[54],[55].Consequently,afollow-upstudywasperformedwhichconcludedthatwhilethematerialproducedlookedsimilar,therewasnoconclusiveevidencethatPIBSIwouldproducedeposits[56].

CetaneNumberImproversCetanenumberimproversarecrucialinfuelstoprovideacost-effectiveincreaseindieselcetanequalityandarepredominantlyalkylnitrates,ofwhich2-ethylhexylnitrate(2-EHN)hasbeenthemostcommonforover80years[51].Ahighcetanenumberisveryimportantforafuelbecauseitdetermineshowfastafuelwillignite,therefore,thehigherthecetanenumberthemorereducedtheignitiondelay.Theydonotonlyincreasethecombustionprocessensuringearlyanduniformignitionofthefuel,butalsopreventprematurecombustionandexcessivepressureincreaseinthecombustioncycle.Alkylnitratesareveryeffectiveduetotheexcessoxygenthattheyintroduceintothefuelupondecomposition,whichisverybeneficialforthe

Figure9:TheChemicalStructureofPIBSI

combustionofthefuel[50].Thoughtheseadditivescanbeveryeffectiveinimprovingthequalityofthefuel,theyalsocatalyzefueloxidationduetotheirstrongtendencytodecomposeathightemperaturesleadingtomorefreeradicalsinthefuel.Equation2showsthedecompositionreactionofanalkylnitrate[28].Equation2:AlkylNitrateDecomposition

𝑅𝑂𝑁𝑂$%&𝑅𝑂 ∙ +𝑁𝑂$

Fangelal.agedfuelswithdifferentconcentrationsofsulfuraccordingtoASTMD2274(SeeAcceleratedMethod)andfoundthattheadditionofalkylnitratesleadtolargeconcentrationsofcarbonylandhydroxylfunctionalgroups[28].

ColdFlowImproversColdflowimprovershelpnegatetheformationoflargewaxcrystalsthatbegintooccurlargelydueton-paraffinsastemperaturedrops,whichoftenleadtoblockingofthefuelfiltersandfeedlinesthatcanultimatelycauseengineshutdown.Co-precipitationoftheseadditiveswithwaxcrystalsreducesthenumberoflargecrystallatticesandinsteadproducesmanysmallcrystalseffectivelyallowingforbetterflow[51].

StabilityImproversStabilityimproveradditivesarecommonlyaddedinblendingofdieselfuelduetotheirabilitytoinhibittheformationofsludge,deposits,anddarkeningofcolorthatoccursnaturallyindieselfuelswhenstoredoveralongperiodoftime[51].Onetypeofstabilityimproverusedisknownasanantioxidant,whichcanimprovedthefuelstabilitybysuppressingthepropagationprocessbyreactingwithfreeradicals,aswellas,bydispersingsedimentagglomeratetopreventfilterblocking[50].Withthetrendofwantingtoblendhigherconcentrationsofbiodiesel,thesestabilizersgrowevermoreimportant.

TestMethodsAcceleratedMethodAgingofthefuelcanbeaccomplishedusingtheASTMD2274-14standardwhichisaStandardTestMethodforOxidationStabilityofDistillateFuelOil.Inthiscase,thisstandardwasusedasabasecaseandthentheexperimentsweremanipulatedbasedontheresultsthattheyproduced.Accordingtothisstandard,asampleofthe350-cm3volumeoffilteredmiddledistillatefuelisagedat95°Cfor16hourswhileoxygenisbubbledthroughthesampleat3dm3/h[57].Thismethodexposesthefuelforalongperiodoftimetohighlyoxidizingconditions.Furthermore,theinherentpotentialofthematerialbeingtestedtoformdepositsundertheseconditionsismeasured[58].Thisstudyisinterestedinisolatingparameterstoinvestigatetheindividualeffectofeach,thereforeithasbeeninitiallymodifiedsothata350-mlvolumeofabiofuelsampleisagedatdifferenttemperaturesforvaryingtimesopentotheenvironmentinafumehood.

AcceleratedOxidationTestTheOilStabilityIndex(OSI)canbecalculatedusingthestandardtestforDeterminationofOxidationStabilityonFatandOilDerivatives-namelyFattyAcidMethylEsters(FAME)asdescribedinSS-EN14112:2016[59].Thisstandardmeasuresthelengthoftimeat110°Cin

airbeforevolatileoxidationproductsbegantoform[58].Moreover,itcanpredicthowlongamaterialcanwithstandoxidativeconditions.

DaimlerOxidationTestThisisamodifiedmethodthatutilizesrefluxandisbaseduponCECL-48-A-00.Afuelsampleisheatedatatemperatureof160Cunderconstantmixing,whiletheoxidationiscatalyzedusingareactivemetal(Fe(III)acetyl-acetone,100mg/kg).Airisfedintothesystemat10cm3/hthroughouttheoxidationprocess.Generally,250gofunusedmotoroilistestedandtheconcentrationofbiofuelconcentrationcanbevariedthoughaconcentrationof5%isrecommended.Thismethodisveryeffectiveforoxidationtestingduetothere-circulationoftheproductswithlowerboilingpoints.

RancimatEN15751EN15751isastandardtestmethodusedInEuropeforthedeterminationoftheoxidationstabilityoffuelsfordieselengines,bymeasuringtheinductionperiodofthefuelupto48hours.Thismethodcanbeusedtotestthestabilityofpurefattyacidmethylester(FAME)orinblendsbetween2and7%volumeFAME.Inthisprocess,astreamofpurifiedairispassedthroughthesamplewhichhasbeenheatedat110°C,whereuponoxidationvolatilecompoundsareformed.Thesevolatilecompoundsarepassedtogetherwithairintoaflaskcontainingdemineralizedordistilledwater,whichisequippedwithaconductivityelectrode.Usingthiselectrode,theconductivityismonitoredcloselyandupondetectionofrapidincreasedconductivityduetothedissociationofvolatilecarboxylicacidsproducingduringtheoxidationprocessandabsorbedinwater[60].EN590specificationforFAMEblends(2-7%-vol)isminimum20hoursandinEN15751(2009)forneatFAMEminimum8hours[61].

Figure10:MeasurementprincipleoftheRancimatmethod[61]

PetroOXYEN16091SS-EN16091isastandardmethodusedinEuropeforthedeterminationoftheoxidationstabilityofmiddledistillatefuels,fattyacidmethylester(FAME)fuelandofrespectiveblends,bymeasuringtheinductionperiodtothespecifiedbreakpointinareactionvesselchargedwiththesampleandoxygen.Theprocessmeasuresthestabilityofafuelbymeasuringthepressurechangesofoxygenovertimeinavesselpressurizedto700kPaasthesampleis

heatedat140°C,asthepressureinthevesseldropsastheoxygenisconsumedduringoxidationofthesample.Theinductiontimeisthetimeittakesfortheoxygentoreachbreakpoint(i.e.whentheoxygenpressurecollapses).Furthermore,themorestableafuelisthehighertheinductiontime.

ColdSoakFiltrationTest(ASTMD2500)ASTMD2500standardisastandardmethodtotestforcloudpointofpetroleumproductsandliquidfuels.Moreover,itiscommonlyusedtotesttheperformanceofbiofuelsincoldtemperaturesviaafuelscloudpoint.ColdSoakFiltrationisagreatwaytoprecipitateoutformedsoftparticlesinoursamplesthathavealreadybeentreated(suchasusingthemodifiedacceleratedmethod)sincethecoldtemperatureprecipitatesouttherelevantsoftparticlesformed.PerASTMD2500,asampleiscooledatatemperatureof4.5°Cforanextendedperiodoftimefollowedbywarm-upbetween20to22°Ctoobserveanyformationofprecipitates[62],[63].

FiltrationMethodsTherearetwocommonfiltrationmethodsincludingsimplefiltrationandvacuumfiltrationwhichcanbeutilizedasaseparationtechniquedependingonthepropertiesofthesample,however,itshouldbenotedthatnotallparticlesmaybecollectedonthefilterifsomeofthecomponentsareinfactsolubleinthemixture.Thissolubilityleadstotheparticlespossiblypassingthroughthefilter,ratherthanremainingonthefiltertobelateranalyzedasdesired[28].

SimpleFiltrationThisisthemostcommonmethodoffiltrationandisusedtoremoveaninsolublesolidmaterialfromasolution[64].Thistypeoffiltrationreliesongravitytoproduceenoughforcetopullasolutionthroughafilter,whichisnotalwaysenoughrequiringsomeseparationprocessestousevacuumfiltration.

Figure11:MeasurementprincipleofPetroOXYmethod[62]

VacuumFiltrationTheindustrystandardASTMD-6217entitledStandardTestMethodforParticulateContaminationinMiddleDistillateFuelsbyLaboratoryFiltrationcanbeappliedasaneffectivefiltrationmethod.Accordingtothisstandard,whenperformingvacuumfiltration1Loffuelisfilteredthroughoneormoresetof0.8microns(µm)membranefilters,whicharesubsequentlywashedwithasolvent,driedandweighed[65].Theparticularcontaminationismeasuredbythedifferenceinweightbetweenthetreatedfiltersandcontrolfilters.Duetothehighviscosityoftheoils,avacuumsystemisrequiredwhichcanbeaccomplishedusingawateraspiratedoramechanicalvacuumpumpasisshowninFigure12[66].

TechniquestoMeasureSoftParticlesFilterAnalysisUponvacuumfiltration,particleswillaccumulatedirectlyonthefilterthatcanbedirectlyanalyzed.TheparticlesthencanbeanalyzedontopofthefilterusingFTIR&SEM-EDX.TheOnlydrawbackisthatthenifthelayerofparticlesisnotthickenough,thefiltermaterialwillshowupintheanalysis[67].

SmearMethodWhenusingtheFTIR-ATRanalyticalmethod,itisoftendesiredtoexaminethesoftparticlesformedonthefilterwithoutanalyzingthefilteritself.Onemethodtoaccomplishthisistousethesmearmethodwhereasampleoftheformeddepositsistransferredtothesensorviaplacingitnearandspreadingitaroundwhileapplyingslightpressure.Thecrystalisverysmallsoaminusculeamountofparticlesarerequiredforanalysis.

ManualCollectionMethodThismethodcanbeusedwhenafuelhasproducedalargenumberofstickyparticlesinthebeaker.Therefore,whenthisphenomenonoccursitispossibletouseaspatulaorscoopulatotransfertheparticlesfromthebeakertothehopperduringVFordirectlytoexamineontheFTIRcrystal.

Figure12:SchematicofFiltrationSystem[66]

CentrifugationCentrifugationisacommonmethodtoseparatetwoentitieswhicharecomprisedofdifferentdensities,andgenerallyinsoluble.Justlikeitisusedtoseparateglycerolfrombiofuel,itcansimilarlybeusedtoseparatethehigherdensityparticleswhichareformedduringagingfromthelessdensefuel[68].

AnalyticalMethodsOpticalMicroscopyTheopticalmicroscopeisutilizedfortheobservationofparticlesfromabout150to0.8µminsize.Particleslargerthan150µmcanbeobservedusingasimplemagnifyingglass,whileparticlessmallerthanthisrangerequiretheuseofelectronmicroscopy[69].Thelimitedmagnificationcanbealimitingfactorinusingthisrelativetomoreadvancedmethodssuchaselectronmicroscopy,however,alargeissueliesinthecommonoccurrenceofdistortionthatoccursonpointsoftheimageswhentheOPwithtransmittedlightisusedatveryhighmagnifications[70].ThoughtherearemethodsthatcanbeusedtocurbthislimitingissueincludingSpatiallymodulatedillumination(SMI),Spectralprecisiondistancemicroscopy(SPDM),Stimulatedtransmissionemissiondepletion(STED)and3Dsuper-resolutionmicroscopy.

ElectronMicroscopyElectronmicroscopyprovidesaprecisemethodtoobserveandmeasureparticlesincludingmethodssuchasScanningElectronMicroscopy(SEM),andTransmissionElectronMicroscopy(TEM).Thesemethodsareallcommonlyusedinindustry,however,theselectionofthemethodisveryspecifictoparametersofinterestssuchasmorphology,size,andcomposition.ScanningElectronMicroscopyTheScanningElectron(SEM)Microscopyexaminesmicroscopicstructurebyscanningthesurfaceofmaterials,indoingsoitusesafocusedelectronbeam(5-50keV)thatscansoverthesurfaceareaofaspecimen[69].Itisverycommonlyusedtoanalyzethesurfaceofmaterialsduetoitsabilitytoanalyzematerialsofverysmallscaleassmallastheorderoftensofmicrometersat103×magnificationandtheorderofmicrometersat104×magnification[71].SEMproducesanimagebyutilizingsecondaryorbackscatteredelectronsignals,wherethesecondaryelectronsaregeneratednearthesurfaceofthesampleandthebackscatteredelectronsarethosereflecteduponstrikingtheatomscomposingthesample.Thescanningelectronimagereflectsthefinetopographicalstructureupondetectionoftheseelectrons[72].Whenanalyzingorganicmaterialsalow-pressurevacuumisrequired,meanwhileformetalsandinorganicmaterialsahigh-pressurevacuumisoftenutilized.Inordertoproduceanimage,theSEMbeamisfocusedtoafinepointandscanslinebylineoversamplesurfaceinarectangularrasterpattern.Additionally,amuchloweracceleratingvoltageisrequiredasitdoesnotneedtopenetratethespecimen[73].SEMisalsoconsiderablyfasterrelativetoTEMandproducesmore3-dimensionaldetails,inlargepartduetoitsabilitytomagnifysamplesupto100.000xatresolutionsof15-20nmcomparedto0.3-0.5nmfortheTEM[69].

TransmissionElectronMicroscopyInatransmissionelectronmicroscope,animageisproducedviaelectronsthatareacceleratedfromaninitialsourceontoacondenserlens.Subsequently,thebeamtravelsnearorcloseto,normalincidence.Thesetransmittedbeamsarethenfocusedbyanobjectivetoformanimagewhichisfurthermagnifiedbyintermediateandprojectorlensesontoaphosphorscreenorelectroncamera[74].TEMisoftenusedtoobserveparticlesinthesizerange0.001to5µm[75].Moreover,usesabroadstaticbeamtoproduceanimage,unliketheSEMbeamwhichrequiredfinepointfocustoscanline-by-line.AlargedisadvantageofusingTEMisthatathinspecimenisrequired,aswellas,alargeacceleratingvoltageinordertopenetratetheaforementionedsample[73].

X-rayenergy-dispersivespectroscopy(EDX)Energy-dispersivespectrometer(EDX)isanadditionaltoolthatcanbeusedtoperformacompositionalanalysisofasamplewhenaddedtotheSEMmicroscope.X-rayspectroscopydeterminespresenceandquantitiesofchemicalelementsbydetectingcharacteristicX-raysthatareemittedfromatomsirradiatedbyahigh-energybeam.InthecaseofEDX,thecompositionofasampleiscalculatedfromthex-rayenergybasedonthecharacteristicx-raysemittedfromsampleatoms[71].Fourier-transformInfraredSpectroscopywithAttenuatedTotalReflection(FTIR-ATR)Fourier-TransformInfraredSpectroscopyisaverypowerfultooltounderstandthecompositionofasamplebyprovidingoverallstructuralinformation.Thisisaccomplishedviathemeasurementofthewavelengthandintensityoftheabsorptionofnear-infraredlightbyasample.Infraredradiationistransmittedthroughasample,wherepartoftheradiationisabsorbedwhiletherestistransmittedthrough.Asensorusesthisinformationtogeneratestructureinformationaboutfunctionalgroupspresentinthesample[76].Oneoftheadvantagesofthisanalyticalmethodisthatitrequiresaverysmallamountofthesampletoobtainveryaccurateresults[77].Inthiscase,aSpectrum100wasusedwithaDATR1DiamondZincSelenidecrystal.Additionally,ithastheAttenuatedTotalReflectance(ATR)featurewhichallowsforfastersamplingwithnopreparation,highreproducibility,andminimaloperator-inducedvariations[76].OnedisadvantagetousingFTIRisthatonlypeaksfromfunctiongroupsareproduced,thereforeahigherqualityanalysiscanbeachievedwhenusedincombinationwiththeSEMmicroscopewithEDXanalysis.

Experimental

MaterialsTodevelopamethodtoproducesoftparticlesinalaboratoryusingB10,B100,andHVO.Thebiodieselusedwasprimarilyproducedfromrapeseedoil,largelyduetoit´sabundanceinSweden.Inaddition,previouslynotedcausesofsoftparticlesinadieselenginewereaddedto350-mlsamplesofthefuelsincludingwater,metals,freshoilandheavilyoxidizedoil.Thesesamplesweresetonrespectiveheatplatesandsubjectedtoheatingforaselectedamountoftimetodegradethefuelandproducethedesiredsoftparticles.Asummaryofalltheexperimentscompletedincludingtheparameterstested,temperatures,andadditivesusedisdisplayedinTable8.

MetalsInthecasesofthemetalsused,therewerealltubesof42mmlength,butthespecificpropertiesareshowninTable7.Themetalpieceswereplacedinthecornerofthebeaker,soasnottodisturbthemixingofthestirbar.

Table7:Propertiesofthemetalsusedintheagingofthefuels

Metal Type Dimension(lengthxdiameterxwidth)

Brass CuZnPb 42mmx10mmx1mm

Copper CopperC106(CW024A) 42mmx6mmx1mmIron E235SS 42mmx12mmx2mm

WaterInthecaseofModifiedAcceleratedMethods6through8,wherethefuelswereexposedtowaterduringaging,waterwasinitiallyaddedtothebeakerandthenfilledwiththebiofuelandsoon.Additionally,a3%concentration(10.5g)wasaddedtwiceaday(morningandevening),soastopreventtheevaporationofthewaterdespitekeepingthetemperaturebelowtheboilingpointofwater.Inthecaseofthisreport,onlypurifiedMilliQwasusedtoreducecontaminationfromotherpossibleions.

OilInthecaseofoil(freshandheavilyoxidized),aconcentrationof1%wasusedwhichequatesto3.5ml.Fortheheavilyoxidizedoilwithanoxidationnumberof12.8fromamotorcellrunatScania,itwasassumedtobeasimilardensity,thereforethesameweightwasused.Agedoilwasusedtosimulatetheeffectofagedoilthattendstomixwiththefuelintheenginesystem.

ProcedureTheexperimentalmethodwasbasedupontheASTMD2274-14standardwhichisaStandardTestMethodforOxidationStabilityofDistillateFuelOil.Theset-upoftheexperimentwiththeheatingandstirringofthehotplateisshowninFigure13.Thestirringratewasheldconstantat250rpmthroughoutalltheexperiments.Depositformationwasmeasuredusingthefollowingprocedure.Afterheatingfortheallottedtimeandtemperature,theagedfuelwasplacedinarefrigeratorwithatemperatureof4°Cforaminimumof24hoursbasedonASTMD2500standard,ColdSoakFiltrationTest(CSFT),whichallowsforanyremainingparticlestoprecipitateoutofthemixture.OncetheCSFTstepiscomplete,theyareindividuallyfilteredthrougha1.2-micron(µm)glass-fibrefilter,forModifiedAcceleratedMethods1-5anda1-micron(µm)PTFEfilterforModifiedAcceleratedMethods5-8,a1-micron(µm)PTFEfilter.Thefilterswereweighedinitiallyandthentheresultingagedmixtureswerevacuumfilteredtoanalyzesoftparticlegrowthintherespectivefuelmixtures.Uponfiltration,thesuctionwasturnedoffand5-mlofheptanewasaddedtogetridofanyremainingoil.After30seconds,turnonsuctionandrepeat3moretimes.Thefilterwasthenplacedinapetridishandallowedtositovernighttoallowforadditionaldrying,shouldtherebeanyheptaneremaining.Theweightofthetreatedfilterwastakenthefollowingday.Followingtheweighingofthefilters,theywerecutinhalfinordertomakesurenocontaminationoccurredbetweentheanalysisoftheresultingparticlesusingSEM-EDXandFTIR.AsummaryofalltheperformedexperimentisdisplayedinTable8

Table8:Asummaryoftheperformedexperiments

ModifiedAcceleratedMethod(MAM)

Biofuel(s) AddedOil?

AddedMetal(s)?

AddedWater?

Temperature[°C]

Time[hours]

HeatingMethod

1 B100 Freshoil No No 80 72 Oven2 B100,

B10,HVO

None No No 110 72 HeatPlate

3 B100,B10,HVO

FreshOil No No 110 48 HeatPlate

4 B100,B10,HVO

AgedOil No No 110 48 HeatPlate

5 HVO AgedOil No No 110 144 HeatPlate

6 B100,B10,HVO

AgedOil No Yes 90 48 HeatPlate

7 B100,B10,HVO

AgedOil Brass,Copper,Iron

No 90 48 HeatPlate

8 B100.B10,HVO

AgedOil Brass,Copper,Iron

Yes 90 48 HeatPlate

9 B100,B10,HVO

None Brass,Copper,Iron

Yes 90 48 HeatPlate

TemperatureProbe

HotPlate

Stirbar

Figure13:Set-upusedtoagethebiofuels

AppliedMethodsAcceleratedMethodsforOxidationofFuelOilsForthisexperiment,theAcceleratedMethodforoxidationbasedontheASTMD2274-14standardwasmodified.inthecaseoftheexperimentsperformed,theexposuretimewasadjustedfrom16hoursto48hours.Additionally,thetemperaturewasincreasedto110°Cinitiallyandthenloweredto90°Cforthetestsinterestedintheeffectofwaterandmetalsontheagingofthebiofuels.

ColdSoakFiltrationTestThemethodintroducedfromtheASTMD2500:2017wasfollowed,andassuchthesampleswereplacedinarefrigeratorat4°Cfor24hourspost-agingwiththeselectedparametersaftertherespectivebeakersweresealedusingparafilm.

VacuumFiltrationDuetothehighviscosityofthebiofuelsfiltrationusingjustgravimetricpressureswouldnotbesufficienttofilteroutparticles,andthereforebyapplyingavacuum,theprocesscanoccuratafasterpace.Twofilterswereused,thefirstofwhichwasmadeofglassfibrewithaporesizeof1.2-micron(µm)thatwasutilizedinModifiedAcceleratedMethods1-5.Meanwhile,theotherfilterwascomposedofPTFEwithaporesizeof1-micron(µm)andwasusedinModifiedAcceleratedMethods6-8.Theset-upforthevacuumfiltrationisdisplayedinFigure14below.

Filter

Hopper

Figure14:Vacuumfiltrationset-up

AppliedTechniquestoMeasureSoftParticlesFilterAnalysisUponvacuumfiltration,particleswillaccumulatedirectlyonthefilterthatcanbedirectlyanalyzed.However,whenanalyzingusingFTIRthiscancausecontaminationofthefuelspectraduetoincreasedconcentrationsofthefilter(borosilicateglassfilter)toshowuponthespectrum.ThisiswhyforModifiedAcceleratedMethod5-8afiltercomposedofPTFEwasused.ThisisnotaslargeaproblemwhenusingSEM/EDXhoweversincethereisapossibilitytoanalyzeveryspecificparticlesusingthesoftware.

ManualCollectionMethodWhenagingofallofthefuelsiscomplete,somebiofuelsproducealargeamountofsludgeorstickyparticlesinthebottomofthebeakerthatconsistsofcomponentsofthefuelsthatprecipitatedout.Ifthereisalargeamountofthesestickydepositsonthebeaker,theyhaveatendencytoblockthefiltersandmakeitdifficulttofilterproperly.

AnalyticalTechniquesThemaintechniquesusedtoanalyzethecompositionoftheparticleswasFTIR-ATRandSEM-EDX.ThecombinationofthesemethodsisveryeffectiveduetotheirabilityoftheSEM-EDXtoprovidetheexactcomponentsfoundpersample,whichhelpsinterprettheFTIRspectramoreaccurately.

Fourier-transformInfraredSpectroscopywithAttenuatedTotalReflection(FTIR-ATR)FTIR-ATRwasusedtoexaminethecompositionoftheproducedsoftparticlesusingthePerkinElmerSpectrum100FT-IRSpectrometer.Inthiscase,aSpectrum100wasusedwithaDATR1DiamondZincSelenidecrystal.Additionally,thesamplesweretestedusingpressuregauge(pressurepushingdownonfilters)valueof15toensurecontactoftheparticlestothecrystal.Forthecasesofanalysisofstickyparticlesobtainedmanuallyfromthecornerofabeaker,theparticlewasplaceduponthesensortogetaninitialreading.Tobesurethereadingisn’taffectedbyremainingfueldroplets,onedropofheptanewasplacedonthesampleandallowedtodryfor10minutes.Afollow-upanalysiswasthenperformedtocheckifanymajordifferencescouldbeidentified.

ScanningElectronMicroscopy(SEM)APerkinElmerSpectrum100ScanningElectronMicroscopewasoperatedinlowvacuummodetoanalyzetheproducedorganicparticlesusinganelectronbeamofbetween20and25kV.Additionally,theX-rayDispersiveSpectroscopy(EDX)functionwasutilizedtoobtainvaluableinformationabouttheelementalcomponentsfoundintheidentifiedparticles.

Results

AgingofB100withFreshOil(MAM1)Thismethodinvolvedagingsixfuelssamples,withthecompositionsasshownpreviouslyinTable8,at80°Cfor72hoursinanoven.AfterrunningFTIRonthefilters,theresultswerenotindicativeofsoftparticleformationsincethepeaksontheFTIRonunagedandagedwerenearlyidenticalasFigure15shows.

Furthermore,usingSEManalysisitwasfoundthatitwasincreasinglydifficulttodistinguishthedifferencebetweentheagedsamples,andthereforeitwasconcludedthatverylittleifany,softparticlescouldbeidentifiedusingthismethod.

AgingofBiofuels(MAM2)Forthisversionoftheacceleratedmethod,three350-mlsamplesofHVO,B10,andB100wereheatedat110°Cfor72hourswithastirringrateof250rpm.Uponwhichtheywereplacedinarefrigeratorof4°Cforanadditional72hours.Inthiscase,therewasobservedparticlesintheHVOandstickyparticlesthatformedintheB10samplethatproduced

Unaged B100 1Name

Sample 029 By Administrator Date måndag, februari 19 2018Description

4000 6503500 3000 2500 2000 1500 1000

Aged A1 fuel 1Aged A2 fuel 1Aged B1 fuel 1Aged B2 fuel 1Aged C1 fuel 1Aged C2 fuel 1

NameSample 015 By Administrator Date fredag, februari 16 2018Sample 017 By Administrator Date måndag, februari 19 2018Sample 019 By Administrator Date måndag, februari 19 2018Sample 021 By Administrator Date måndag, februari 19 2018Sample 023 By Administrator Date måndag, februari 19 2018Sample 025 By Administrator Date måndag, februari 19 2018

Description

4000 6503500 3000 2500 2000 1500 1000

Figure15:FTIRspectrumforunagedB100(top)andagedsamplesusingModifiedAccelerationMethod1(bottom)

significantcloggingofthe1-2micronvacuumfilter.TheagedsamplescanbeseeninFigure16.

Table9:FTIRresultsforB100,B10andHVOwhenagedfor72hours

Sample OH-stretchpeaks

C-HStretchpeaks

Carbonylpeaks CarboxylicIonpeaks

B100 + + +

B10 +++ ++ +++ +HVO + +

SmallparticleswereseenfloatingintheagedB100,whileinB10therewasavisiblelayerofthickoilyfilmonthesurfaceofthebeaker.Somuchso,thatittookaconsiderableamountoftimetofilterthroughduetothecloggingfactorasTable10shows.Additionally,thesamplesforB100andHVOremainedclearaftertheagingprocess,meanwhile,theB10sampleswerecloudyandunclear.TheB10wasoriginallyadarkgreenhue,whileHVOwasinitiallyclear.TheresultsfromtheFTIRcanbeseeninTable9,whereB10wasthemostvisiblysusceptibletodegradationfollowedbyB100andthenHVO.

Table10:Propertiesoffiltrationofagedbiofuels

Sample InitialWeight[g] FinalWeight[g] ΔWeight Filtrationtime[s]

B100 0.0251 0.0300 0.0049 1080

B10 0.0250 0.0943 0.0693 3600

HVO 0.0257 0.0285 0.0028 380

Figure16:SamplesofagedB100(left),B10(middle)andHVO(right)treatedusingjusthighheat(MAM2)

AgingofBiofuelswithFreshOil(MAM3)For this version of the acceleratedmethod, 1% concentration of Scania REFoil 10W30wasadded350-mlsamplesofHVO,B10,andB100.Subsequently,theywereheatedat110°Cfor48hourswithastirringrateof250rpm.Uponwhichtheywereplacedinarefrigeratorof4°Cforanadditional72hours.

Table11:FTIRresultsforB100,B10,andHVOwhenagedwithFreshOil

C-HStretchpeaks

Carbonylpeaks

CarboxylicIonpeaks

B100 + + + B10 +++ ++ +++ +HVO + +

Table12:PropertiesoffiltrationofagedB100,B10,andHVOagedwithFreshOil

Sample InitialWeight[g] FinalWeight[g] ΔWeight FiltrationTime[s]

B100 0.0257 0.0320 0.0063 746B10 0.0259 0.1390 0.1131 4740HVO 0.0257 0.0340 0.0083 488

Muchliketheresultsfromthepreviousexperiment,B10wasfoundtobemostreactiveuponagingthebiofuelswithfreshoil.B10wasalsofoundtobeveryoily,asshowninFigure17.HVOisnoticeablymoststable,comparedtotheothertwofuels.B10hadasignificantcolorchangefromdarkgreentoanorange-redtint,whiletheHVOalsochangedfromacleartolightyellow.B100gotslightlylighter,thoughnotsignificantly.

Figure17:FiltersPost-treatmentusingMAM3showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)wheretheywereagedwith3.5ml(1%w/w)freshoilfor72hours

AgingofBiofuelswithAgedOil(MAM4)Forthisversionoftheacceleratedmethod,1%concentrationofengineoilwasadded350-mlsamplesofHVO,B10,andB100.Subsequently,theywereheatedat110°Cfor48hourswithastirringrateof250rpm.Uponwhichtheywereplacedinarefrigeratorof4°Cforanadditional24hours.

Table13:FTIRresultsforB100,B10,andHVOwhenagedwithAgedOil

C-HStretchpeaks

Carbonylpeaks

CarboxylicIonpeaks

B100 + + + B10 + ++ +++ +HVO + +

Table14:PropertiesofFiltrationofAgedHVOusingAgedOil

Whenthebiofuelswereagedwithagedoil,thepreviouslymentionedtrendofincreasedcarbonylsrelativetoC-HstretchfunctionalgroupswasobservedinB100andB10.ThetrendofincreasedcarbonylsrelativetoC-Hstretchpeaksremainsvalid,thoughactivityseemsdampenedinthiscase.Additionally,thefilterspost-treatmentarevisiblydarkerfromwhatissuspectedtobetheadditivesfromtheagedoil.Forexample,B10isconsiderablydarkandoilyrelativetothefilteredagedB100andHVO.

B100 0.0257 0.0317 0.0060 1020

B10 0.0258 0.2467 0.2209 2400

HVO 0.0256 0.0318 0.0062 1200

Figure18:FiltersPost-treatmentusingMAM4showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D),wheretheywereallagedwith3.5ml(1%w/w)oxidizedoilfor48hours

AgingofHVOwithAgedOilforanExtendedPeriod(MAM5)Forthisversionoftheacceleratedmethod,theeffectofheavilyoxidizedoilduringtheagingofbiofuelswastestedusingtwosamplesof350-cm3HVO:HVO1(nooxidizedoil)andHVO2(withoxidizedoil).Subsequently,theywereheatedat110°Cfor144hourswithastirringrateof250rpm.Uponwhichtheywereplacedinarefrigeratorof4°Cforanadditional24hours.

Table15:FTIRresultsforHVOwhenagedwithAgedOilforanExtendedPeriod

C-HStretchpeaks

Carbonylpeaks

CarboxylicIonpeaks

HVO1 + +

HVO2 + +

ThoughHVOisaverystablefuel,theprevioustrendofahighconcentrationofcarbonylsrelativetoC-HstretchfunctionalgroupswasstillrelevantalthoughabitdampenedforHVOagedwithoutoil.ItwasinterestingthatdespiteHVO1nothavinganyoilmixedin,thefiltrationtimewaslongerthantheversionwithoil.Thoughthiscouldbeexplainedawayduetothemanydifferentfiltrationpathways.UsingFTIRanalysis,HVO2hadslightlyhigherconcentrationintheOH-stretchspectra,whiletheagingofHVO1producedacarbonylpeak.TheagedHVO1wasclearandtransparentwithalight-yellowshadepost-treatment,meanwhile,HVOwasblack,unclear,andopaque.UsingTable16,itcanbeseenthattheweightchangeisincrediblysmallrelativelybetweentheHVOagedwithandwithouttheagedoil.

Table16:PropertiesofFiltrationofHVOagedwithAgedOilforanExtendedPeriod

Sample InitialWeight[g] FinalWeight[g] ΔWeight FiltrationTime[s]HVO1 0.0262 0.0313 0.0051 540HVO2 0.0263 0.0313 0.0050 384

Moreover,whenanalyzingusingtheSEMmicroscopetherewerealargeramountofparticlesthatcouldbeseeninHVO2comparedwithtraceamountsofparticlesinHVO1.Figure19showstheimagesoftheparticlesobtainedusingSEM,whichcorroboratesthetraceamountsofparticlesinHVO1(B)comparedtoHVO2(C)withacleanfilterpictured(A).TheHVOagedwithoxidizedoilproducedalargenumberofparticlesvisibleusingSEM,meanwhile,theagedHVOwithoutoxidizedoilproducedsignificantlylesstoanalyze.

AgingofBiofuelswithAgedOilandWater(MAM6)Forthisversionoftheacceleratedmethod,theeffectofwaterontheagingofbiofuelswastestedusingthreesamplesof350-mlB100,B10,andHVO.Subsequently,theywereheatedat90°Cfor48hourswithastirringrateof250rpm.Uponwhichtheywereplacedinarefrigeratorof4°Cforanadditional24hours.Itshouldbenoted,startingfromthisagingmethodthefilterusedduringVFwaschangedfroma1.2micron(µm)sizecomposedofglassfibretoa1micron(µm)sizecomposedofPTFE.

Table17:FTIRresultsforHVOwhenagedwithAgedOilandWater

C-HStretchpeaks

Carbonyl-peaks

CarboxylicIon-peaks

B100 + + +B10 + + ++HVO + + ++

Figure19:SEMresultsfromagedparticlesusingMAM5showingacleanfilter(A),AgedHVOwithoutOxidizedOil(B),andAgedHVOwithOxidizedOil(C)after144hours.

Table18:PropertiesofFiltrationofAgedSamplesusingAgedOilWater(MAM6)

*Thefilterwasheavilycloggedatthistimeproducingnoadditionalfiltration

Theresultingcompositionpost-agingisshowninTable17,whereitcanbeseenthatcarboxylionpeakswereproducedforallthreefuels,whileonlyB100producedcarbonylpeaks.

AgingofBiofuelswithAgedOilandMetals(MAM7)Forthisversionoftheacceleratedmethod,theeffectofmetalontheagingofbiofuelswastestingusingthreesamplesof350-cm3B100,B10,andHVO.Subsequently,theywereheatedat90°Cfor48hourswithastirringrateof250rpm.Uponwhichtheywereplacedinarefrigeratorof4°Cforanadditional24hours.

Table19:FTIRresultsforHVOwhenagedwithAgedOilandMetals

C-HStretchpeaks

Carbonylpeaks

CarboxylicIonpeaks

BrassB100 + + B10 +++ ++ +++ ++HVO + +

CopperB100 + + B10 ++ ++ ++ ++HVO ++ ++ ++ +

IronB100 ++ +++ +++B10 + + ++ ++HVO + +

TheresultsusingFTIRAnalysiscanbeseenaboveinTable19.ThemetalsgenerallyincreasedcarbonylpeaksandC-Hstretchpeaks,however,onlytheB10canbeshowntoproduceaconsistentcarboxylicionpeakforallmetals.ItcanalsobeshowninTable20thatwhilebothB10agedwithbrassandwater,andB10agedwithcopperandwaterhaveasignificantweightchange,B10agedwithIronandwaterhasaveryminimalweightchangepost-filtration.

B100 0.0303 0.0333 0.0030 *3396B10 0.0237 0.0271 0.0034 *2400HVO 0.0313 0.0327 0.0014 2160

Table20:PropertiesofFiltrationofAgedSamplesusingAgedOilandMetals(MAM7)

AgingofBiofuelswithAgedOil,MetalsandWater(MAM8)Forthisversionoftheacceleratedmethod,theeffectofthecombinationofmetalsandwaterontheagingofbiofuelswastestingusingthreesamplesof350-mlB100,B10,andHVO.Subsequently,theywereheatedat90°Cfor48hourswithastirringrateof250rpm.Uponwhichtheywereplacedinarefrigeratorof4°Cforanadditional24hours.

Table21:FTIRresultsforHVOwhenagedwithAgedOil,MetalsandWater

Sample OH-peaks

C-HStretchpeaks

Carbonyl-peaks

CarboxylicIon-peaks

BrassB100 +++ ++ +++ +++B10 +++ ++ +++ ++HVO ++ ++ ++ ++

CopperB100 + + + +++B10 +++ ++ +++ +HVO + + ++ ++

IronB100 + + + +++B10 +++ ++ +++ +HVO + + +

Whenagingwithagedoil,metals,andwater,theFTIRanalysisshowsmuchhigherconcentrationsofcarbonylpeaksandcarboxylicionpeaksrelativetobiofuelsagedwithaged

Sample InitialWeight[g] FinalWeight[g] ΔWeight Filtrationtime[s]1A 0.0297 0.0300 0.0003 36001B 0.0298 0.0810 0.0512 *9001C 0.0210 0.0211 0.0001 296

2A 0.0257 0.0261 0.0004 16412B 0.0347 0.0853 0.0506 *9002C 0.0238 0.0243 0.0005 *1560

3A 0.0282 0.0299 0.0017 *21603B 0.0272 0.0279 0.0007 *15003C 0.0277 0.0278 0.0001 420

oilandmetals.WhencomparingresultsinTable21above,theresultsareindicativeofalargeinfluenceofbrassonB100,comparedwiththeresultingconcentrationofactivityinB100withcopperandB100.Additionally,HVOseemstobehighlyaffectedbybrassrelativetoCopperandIron.AscanbeseeninTable22,AgedB10withcopper,agedoil,andwaterfilteredoutthemostparticlesifanassumptionismadethattheweightcorrelatestoparticles.

Table22:PropertiesofFiltrationofAgedSamplesusingAgedOil,MetalsandWater(MAM8)

*filterwasheavilycloggedatthistimeproducingnoadditionalfiltration

Itwasveryinterestingthatuponfilteringthebiofuelsageswithcopper,theyseemedtoretaintheorangecolor.Asimilarphenomenonoccurredwhenagingwithiron.

Sample InitialWeight[g] FinalWeight[g] ΔWeight Filtrationtime[s]1A 0.0303 0.0378 0.0075 *5161B 0.0270 0.0488 0.0218 19351C 0.0315 0.0320 0.0005 1140

2A 0.0325 0.0395 0.0070 *6002B 0.0275 0.1034 0.0759 *3002C 0.0299 0.0305 0.0006 *1560

3A 0.0288 0.0321 0.0033 *10803B 0.0232 0.0285 0.0053 *6603C 0.0314 0.0324 0.0010 *1920

B100agedwithWater,CopperandAgedOil

B10agedwithWater,CopperandAgedOil

B100agedwithWater,IronandAgedOil

B10agedwithWater,IronandAgedOil

AgingwithAgedOilandMetals(MAM9)Forthisversionoftheacceleratedmethod,theeffectofthecombinationofwaterandmetalsontheagingofbiofuelswastestingusingthree-samplesof350-mlB100,B10,andHVO.Subsequently,therewereheatedat90°Cfor48hourswithastirringrateof250rpm.Uponwhichtheywereplacedinarefrigeratorof4°Cforanadditional24hours.

Table23:FTIRresultsforHVOwhenagedwithMetalsandWater

Sample OH-peaks C-HStretchpeaks

Carbonyl-peaks

CarboxylicIon-peaks

BrassB100 +++ + +++ +++B10 +++ + +++ HVO + +

CopperB100 +++ + +++ ++B10 +++ + +++ +HVO ++ + ++ +++

IronB100 +++ ++ +++ +B10 + + + HVO +++ ++ +++

AccordingtoTable23,itshowsthatHVOwasgreatlyaffectedbybothCopperandIron,thoughCopperproducedcarbonylpeakswhilethelatterdidnot.Incomparingtheweightchangeforalloftheagedbiofuelsusingthedifferentmetals,thismethodproducedthemostparticlescollectedonthefilters.B10agedwithagedoilandbrassfilteredoutthemostparticlesfollowedbyB10agedwithagedoilandcopper,andB10agedwithagedoilandiron.However,itisveryinterestingthatwhenHVOwasagedwithagedoilandironitproducedaverysignificantamountoffilteredparticles.Itproducesveryredparticlesascanbeseenbelow.Furthermore,alloftheB100samplesagedproducedflaky,dryparticles.

B100agedwithBrassandWater

B100agedwithCopperandWater

B100agedwithIronandWater

HVOagedwithIronandWater

Table24:PropertiesofFiltrationofAgingSampleswithWaterandMetals(MAM9)

DiscussionProducingsoftparticlesinalaboratorywithouttheuseofanengineutilizedmanymethodsincludingthemodifiedacceleratedmethodandColdSoakFiltration.Initially,6samplesofB100wereagedusinganovenat80°Cfor72hoursbaseduponthedegradationrateofthebiofuel.Thistemperaturewaschoseninordertostaybelowtheflashpointofthebiofuelintheovensincethegasesvaporizearound110°C.However,thismethodfailedtoproduceanysoftparticlesbaseduponananalysiscompletedusingbothFTIRandSEM-EDX.Followingthis,anexperiment(ModifiedAcceleratedMethod2)wasdesignedwhere3samplesofHVO,B10,andB100wereheatedonahotplateat110°Cfor72hourswhilebeingstirredat250rpm.Thismethodprovedmorepromisingandbecamethebasistoinvestigatetheeffectofadditionalparametersincludingfreshoil(ScaniaREFoil10W30),heavilyoxidizedoil,waterandmetals(brass,copper,andiron).

Upontestingtheseparameters,atrendwasidentifiedinwhichuponagingB100,B10andHVOallshowedadecreaseinC-Hstretchfunctiongroups(3300-2280cm-1)whileanincreaseincarbonylfunctiongrouppeaks.HVOandB100generallyproducedaverysmallamountofparticlesrelativetoB10,however,differenceswerefoundbetweenthesampleswhenanalyzed.UponagingtheB100,B10andHVOwithoutanyadditives(ModifiedAcceleratedMethod2),B10showedsignificantaffinitytodegraderelativetoB100andHVO.Somuchso,thatthelengthofthetreatmentwasdecreasedfrom72hoursto48hourstoincreasefilterability.However,oneexplanationaboutthelackoflargeconcentrationofparticlesinB100canbethattheparticlesaresolubleinthefuel.Furthermore,thetrendofhavingahighconcentrationofcarbonylsrelativetoC-Hstretchfunctionalgroupspost-agingwascorroboratedinHVO(themoststableofthethreebiofuels).

Uponinvestigationtheeffectoffreshoil(ScaniaREFoil10W30)versusheavilyoxidizedoilwithaoxidationnumberof12.8fromamotorcellatScania,itwasfoundthatthefreshoildoesnothaveanyvisualeffectwhenanalyzingusingFTIR.However,uponmeasuringthe

Sample InitialWeight[g] FinalWeight[g] ΔWeight Filtrationtime[s]1A 0.0261 0.0390 0.0129 2724*1B 0.0957 0.5235 0.4278 240*1C 0.0947 0.1588 0.0641 75*2A 0.0945 0.2021 0.1076 195*2B 0.0950 0.2816 0.1866 281*2C 0.0954 0.1642 0.0688 107*3A 0.0947 0.1822 0.0875 160*3B 0.0962 0.1623 0.0661 81*3C 0.0947 0.1762 0.0815 83*

weightoftheparticlesproducedthatremainonthefilterpost-filtration,atrendofincreaseddepositscanbeidentified.Furthermore,whentheagedoilispresentitseemstoreducethenumberofparticlesthatarefilteredout.Thiscanbeseenveryclearlyincomparingtheresultsforthebiofuelswithagedoil,metalandwaterversusthebiofuelswithmetalsandwater.Thismaybeduetotheadditivesintheoilthatprecipitateoutofthefuelmixturesuponaging.UsingSEM-EDX,theconcentrationoftheseadditivescouldbeseen.Theseadditivesmayproducesomeatypeofactivedegradationprotectioninthefuel.

Uponinvestigatingtheeffectofwaterontheagingoffuel,itseemsthatwatermayplayinroleinincreasingparticlegrowthaswillbediscussedinmoredetailfortheseparatecasesofbiofuels.Thismaybethecasebecauseitoxidizesthemetals,producingparticlesintheprocessandcatalyzestheoxidationprocess.Additionally,whenB100wasagedwithagedoilandwater,alargeamountofsand-likeparticleswereformed.Similarly,forB10asmallamountofsandlikeparticleswasformed.NosuchparticleswereformedintheagingofHVOwithagedoilandwaterthough.Infact,whentheseparticleswereexaminedusingSEM,theycouldbedescribedashavingarose-likeshapetothem.SeeFigure20andFigure21.

UponexaminingtheeffectoftheagingofHVOwithoxidizedoil(ModifiedAcceleratedMethod5),itwasveryinterestingtofindthattheHVOsamplewithoutaddedoxidizedoil(HVO1)producedamoresignificant,thoughstillrelativelysmall,carbonylfunctionalgroupafteragingthefuelfor144hoursrelativetothefuelsamplewiththeheavilyoxidizedoil(HVO2).Additionally,HVO2producedaslightlylargeconcentrationofOHfunctionalgroupsrelativetoHVO1.

UponinvestigationofagingB100,B10,andHVOwithmetals(Brass,Copper,andIron)atrendofwidenedpeaksinthecarbonylregions,aswellas,carboxylionpeaks.However,atrendinparticleformationfrommosttoleaststartedtoformasfollows:

1.Fuel+Metal+Water

Figure20:SEMImagesofB100AgedwithAgedOilandWater

Figure21:SEMImageofB10AgedwithAgedOilandWater

2.Fuel+AgedOil+Metal+Water

3.Fuel+AgedOil

4.Fuel+AgedOil+Metal

5.Fuel+AgedOil+Water

AsFigure22shows,thetrenddescribedisvalidundertheagingofB100underthepreviouslymentionedconditions.Though,thedatasupportstheconclusionthatcopperispossiblythemosteffectivemetalatproducinglargeramountsofparticlestoexamine.Ironwasthesecondmostproblematic,followedbyBrass.Toconfirmthistrend,IwouldrecommendarepeatexperimentoftheexperimentagingB100withIronandWater,aswellas,agingB100withagedoilandCopper.ThecopperseemstobeverysensitivetowaterastheweightchangejumpsdrasticallybetweentheB100agedwithagedoilandcopper(B100+AO+Cu)totheB100sampleagedwithagedoil,copper,andwater(B100+AO+CU+Water).

0 0,02 0,04 0,06 0,08 0,1 0,12

B100 B100 + FO B100 + AO

B100 + AO + W B100 + AO +B

B100 + AO + CU B100 + AO + FE

B100 + AO + B + W B100 + AO + CU + WB100 + AO + FE + W

B100 + B + W B100 +CU + W

B100 + FE + W

AMOUNT OF PARTICLES FORMED USINGDIFFERENTAGING PARAMETERSWITH

Figure22:ParticlesformedwithagingB100withdifferentcombinationofparameters

Figure23:ParticlesformedwithagingB10withdifferentcombinationparameters

ForB10,theresultsidentifybrassasthemetalthatproducesthehighestamountofparticlesuponaging.ThecombinationofB10fuelwithIronandWaterproducedaverylargeamountofparticles.Itshouldbenoted,thatB10tendstoproduceveryoilyparticles,thereforeonemustbeawarethatperhapsthefilterweightgainmaynotbeentirelyattributedtoparticles,butmaybecompromisedbyasmallamountofoilstillabsorbedinthefiltermaterial.Inthiscase,inordertofurthersupportthetrendofbrasshavingthestrongesteffectonaging,itwouldberecommendedtorepeattheexperimentofwhichB10wasagedwithagedoilandcopper(MAM72B),andB10agedwithagedoilandbrass(MAM71B).Thismayshowthatbrasshasalargeeffect,sincethecollectedvalueswereverycloseforthesesamples.Additionally,itmightbeusefultorepeattheexperimentfortheagingofB10withagedoil,brass,andwater(MAM81B)andB10agedwithagedoil,copper,andwater(MAM82B)toonceagainfurtherestablishthepreviouslyidentifiedtrend.

0 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,4 0,45

B10 B10 + FO B10 + AO

B10 + AO + W B10 + AO +B

B10 + AO + CU B10 + AO + FE

B10 + AO + B + W B10 + AO + CU + WB10 + AO + FE + W

B10 + B + W B10 +CU + W

B10 + FE + W

AMOUNTOFPARTICLESFORMEDUSINGDIFFERENTAGINGPARAMETERSWITHB10

Figure24:ParticlesformedwithagingHVOwithdifferentparameters

TheresultsfromagingHVOinFigure24showsthattheadditionofthefreshoilproducedmoreweightchangeincomparisontheHVOagedwithagedoil.Furthermore,thesampleagedwithagedoilandwateralsoshowsdecreasedparticlegrowth.UponanalyzingtheweightsobtainedfromtheHVOsamplesagingwithoilandwater,Ironshowsadominanteffect.Moreover,theIrononceagainproducesthemostweightchangewhenHVOwasagedwithwaterandmetals.Ironcanbedeemedtobethemosteffectiveatproducingparticles,followedbycopper.OneexperimentthatcouldberedonetotestwhetherthetrendholdsistoageHVOwithagedoilandIron(HVO+AO+FE)becauseifthatweretoproducemorethanHVO+AO+CuthenthetrendofIronbeingmosteffectiveatproducingparticlescouldbeconfirmed.

0 0,02 0,04 0,06 0,08 0,1

HVOHVO + FOHVO + AO

HVO + AO + WHVO + AO +B

HVO + AO + CUHVO + AO + FE

HVO + AO + B + W HVO + AO + CU + WHVO + AO + FE + W

HVO + B + WHVO +CU + W

HVO + FE + W

AMOUNT OF PARTICLES FORMED USINGDIFFERENTAGING PARAMETERSWITH

ConclusionThefocusofthisprojectwastodevelopamethodinwhichsoftparticlesthatnaturallyforminatruckdieselengineinalabsetting,andthentoanalyzetheeffectofdifferentparametersthattendtoleadtodegradationofthefuel.Thiswasaccomplishedbyfirstheatinga350-cm3oftheselectedfuelsampleina600-cm3beakermixedwithparametersofinterest(agedengineoil,metals,water,etc.)for48hoursat110°C(90°Cforanysampleswithwater).Subsequently,thesesamplesarethenstoredinarefrigeratorat4°Cfor24hourstoallowforanyremainingparticlestoprecipitate.TheywerethenanalyzedusingFourier-TransformInfraredSpectroscopy(FTIR)andScanningElectronMicroscopywithX-rayenergy-dispersivespectroscopy(SEM-EDX).Atrendwasidentifiedwherethelargestamountofparticlesbyweightwereproducedinthefollowingorderfromgreatesttoleast:1.Fuel+Metal+Water

2.Fuel+AgedOil+Metal+Water

3.Fuel+AgedOil

4.Fuel+AgedOil+Metal

5.Fuel+AgedOil+Water

ThebiofuelsagedwithFuel+Metal+Waterproducedthehighestamountofparticles,possiblyduetotheinteractionbetweenwaterandthemetal.Meanwhile,whenthebiofuelswereagedwithFuel+Metal+Water+Agedoiltherewaslessparticleformationwhichcouldbeexplainedbyadditivesfromtheagedoilthatimprovestabilityofthefuel.AgingofbiofuelswithAgedOilproducedalargeramountofparticlesrelativetothebiofuelsagedwithAgedOilandMetal,aswellas,thebiofuelsagedwithOilandWater.Theresultsfoundthatagingofthebiofuelswithmetalsproducedahigheramountofparticlescomparativelytoagingofthebiofuelswithwater.Furthermore,thedifferentbiofuelsweremoreaffecteddifferentlybythemetalswhereB100producedthehighestamountofparticlesfromagingwithcopper,B10fromagingwithbrass,andHVOfromagingwithIron.

FuturerecommendationsSinceamethodhasbeendeveloped,thenextstepistobetterunderstandsoftparticleformationinmorerealisticparametersthatoccurintruckdieselengines.Namely,decreaseconcentrationofwaterandconcentrationofoil.Moreover,differentfiltersweretestedtofindasuitablematerialforthevacuumfiltrationstep.Infutureexperiments,theuseofa1-micronPTFEfilterwouldberecommendedduetotheminimizedeffectonfunctionalgroupsofinterestwhenanalysingusingFTIR,despitetherequiredadditionaltimeforfiltration.Additionally,theuseofthematerialcomponentsutilizedinthecurrenttruckssystemswouldaddanotherdimensionthatcouldbebeneficialforunderstandingtheformationofparticles.Throughouttheseexperiments,theeffectofoxygenhasnotbeenalargefocus,however,infutureexperiments,anaddedairstreamcouldbeusedtoaltertheconcentrationofoxygenwhileaging.Theoxygenaidsintheoxidationofthefuel,sothiswouldbeaveryinterestingparametertotestespeciallysincetheairstreamswouldallowforoxygentopenetratedeeperintothefuel.

Appendices

IRSpectra

Table25:SpectraforFunctionalGroupsidentifiedinFTIRAnalysis

FunctionalGroup IRBand,cm-1O-HStretch

BondedO-HStretchinPolymers 3500-3300C-HStretch

C-HStretchinAromaticsorC=C-H 3100-3000C-HStretchinAlkane 3000-2800

C=OStretch AldehydeC=OStretch 1740-1690KetoneC=OStretch 1750-1680EsterC=OStretch 1750-1735

CarboxylicAcidC=OStretch 1780-1710Carboxylateion(Assymetric) 1610-1550

Filter´sPost-TreatmentAgedFuelwithFreshOil(MAM3)

AgedFuelwithAgedOil(MAM4)

AgedHVOwithAgedOil(MAM5)

BA C D

Figure25:FiltersPost-treatmentofFuelsAgedwithFreshOilMAM3showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

Figure26:FiltersPost-treatmentofFuelsAgedwithAgedOil(MAM4)showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

Figure27:FiltersPost-treatmentofHVOAgedwithAgedOil(MAM5)showinganunusedfilter(A),AgedHVO1(B),AgedHVO2(C)

AgedFuelwithAgedOil,andWater(MAM6)

AgedFuelwithAgedOil,andMetal(MAM7)Brass

Copper

A B C D

Figure28:FiltersPost-treatmentofFuelsagedwithFreshOilandWater(MAM6)showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

Figure29:FiltersPost-treatmentofFuelsAgedwithAgedOilandBrass(MAM71A-C)showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

Figure30:FiltersPost-treatmentofFuelsAgedwithAgedOilandCopper(MAM72A-C)showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

Figure31:FiltersPost-treatmentofFuelsAgedwithAgedOilandIron(MAM73A-C)showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

AgingofFuelswithAgedOil,MetalsandWater(MAM8)Brass

Copper

AgingofFuelswithMetalsandWater(MAM9)Brass

A B C D

Figure32:FiltersPost-treatmentofFuelsAgedwithAgedOil,Brass,andWater(MAM81A-C)showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

Figure33:Figure32:FiltersPost-treatmentofFuelsAgedwithAgedOil,Copper,andWater(MAM82A-C)showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

Figure34:FiltersPost-treatmentofFuelsAgedwithAgedOil,Iron,andWater(MAM83A-C)showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

Figure35:FiltersPost-treatmentofFuelsAgedwithBrass,andWater(MAM91A-C)showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

Copper

A B C D

Figure36:FiltersPost-treatmentofFuelsAgedwithCopper,andWater(MAM92A-C)showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

Figure37:FiltersPost-treatmentofFuelsAgedwithIron,andWater(MAM93A-C)showinganunusedfilter(A),AgedB100(B),AgedB10(C),andAgedHVO(D)

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