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PERFORMANCEOFTHEMICROGASIFIERUSEDASPOWERSOURCEFORRUBBERCREEPINGMILLbyAlexisT.BelonioandTedRedelmeier
RubberinthePhilippinesismainlyproducedinMindanaoIslandwhichsupplies99%ofthenationalrubberproduction.ThisisespeciallymoresoinZamboangaPeninsulathatsetsthenationalproductionof41.68thousandmetrictonsofrubberannually.Producingrubberblanketsfromcoagulatedfreshlyharvestedrubberlatexisthemainlivelihoodoftheruralfolks
intheregion.Foreveryhectareofrubberplantation,around20kgsoffreshrubberlatexiscollectedeveryday.Processing20-kgfreshrubberlatexwhichincludepressingthecoagulatedlatexfromformicacidinacreepingmillandthenairdryingcanproduce6kgsofrubberblanket(palecreepno.1and2)thatisreadyformarket.Freshlatexharvestedduringthedayneedstobeimmediatelyprocessedintorubber
CNCTechnicalBulletinNo.36
Figure2.TheDieselEngineOperatedCrepingMilltoProduceRubberBlanket.
Figure1.The(a)FreshRubberLatex,(b)NewlyPressedRubberBlanket,and(c)RubberBlanketBeingDried
(a) (b)
(c)
blanketstoproducequalitypalecreepno.1&2,whicharehighlysuitablefortheproductionofqualityrubberproducts.Pressingthelatextoformrubberblanketisusuallydoneonasmallrollerpressorcreepingmillthatismadeoftwo15cm-diameterby45cm-longcylindricalmetals.Onerolleroperatesfasterthantheothertocreatepressingandstretchingofmaterialsasitpassesthecreepingmill.Themainrollerrunsataspeedofaround5to10rpmandtheotherrunstwotimesslowerthanthemainroller.Airdryingtherubberblankettakesaround15daysbeforeitissoldtothemarket.Ifafarmerdoesalltheactivitiesfromtappingthelatex,mixingchemicaltocoagulate,pressingthecoagulatedlatexinthecreepingmill,andairdryingtherubberblankets,hecanearnP75.00perkg.Ofthedifferentactivitiesintheproductionofair-driedrubberlatexblanket,themosttediousactivityisthepressingofrubberlatexwhichisdonebypedalingthecreepingmachineorbyusingapetrol-fueledengine.Inordertorelievefarmersfromthetediousmanuallabor,fromhighcostofpetrol,andfromhighcostofelectricityassociatedwiththeproductionofrubberblanket,therecentlydevelopedmicrogasifierthatusesricehuskasfuelwasinstalledatarubberprocessingplantinZamboangadelSurandwasusedtoruntherollerpressforrubber.
MicrogasifierUnit
RubberCreepingMill
GasFueledEngine Rubber
Latex
RubberBlanket
Figure3.TheMicrogasifierCoupledtoRubberCreepingMill.
AsshowninFigure3above,themicrogasifierconsistsofafuelreactorwheregasisgeneratedthroughgasificationofricehusks,agasconditioningunittoremoveparticulatesandtocoolthegasbeforeitisfedintotheintakemanifoldoftheengine,apowergeneratingunitthatconvertsthegasintomechanicalpowerwhichissubsequentlyusedtodrivethecreepingmill.Figure4showtheschematicoftheoperationofthemicrogasifierasusedtodriverubbercreepingmill.AsshowninTable1,thefuelreactorhasaninnercylinderdiameterof30cmandaheightof120cmandismadeof3mm-thickmildsteelplate.Itisshieldedwithanoutercylinderhavingadiameterof50cmandaheightof180cm.Beneaththeinnercylinderisapocket-typegratethatgraduallydischargesthecharduringoperation.Thegasconditioningunit,ontheotherhand,ismadeofthesamesizeofsteelplatewiththeoutercylinderofthefuelreactor.Insideitisapipewithholesdrilledalongitslengthwith10-cmspacingtospraywatertothestreamofgasasthelatterentersthegasconditioningcylinder.
Reactor Downdraft0.30mDx1.20mH
CharGrate 8semi-circularpocketstype
ConditioningUnit ScrubberandFilterEngine 16hpfourstrokespark
ignitionOperatorRequired
1person
Figure4.SchematicofthePrincipleofOperationoftheMicrogasifier.
Table1.DesignSpecificationoftheMicrogasifier.
PackedBedFilter
WetScrubber
WaterCoolingPond
FuelReactor
GasStorage
InternalCombustion
Engine
SuctionBlower
Pump
ColdWater
HotWater
RiceHuskorOtherBiomass
PressedRubberLatex
RawRubberLatex
Attheupperportionofthecylinderisaperforatedsheetthatholds40-cmthicklayerofpebbles(with3-to10-mmdiameter),whichserveasfilterforthegas.Waterissprayedintothegaswiththeuseofagearpumpdrivenbythemainshaftofthethepowerunit.Boththefuelreactorandthegasconditioningunitareseatedinarectangularconcretetankfilledwithwatertopreventthegasfromescapingduringoperation.Thewaterinthetankisusedtoquenchburningricehusksfromturningintoashand,atthesametime,tocirculatethewaterforcleaningandcoolingthegas.Thepowergeneratingunitconsistsofa16-Hpspark-ignitionengineretrofittedtouseeithergasolineorgasasfuel.Itsmainshaftisdirectlycoupledintotheenginedrivetotransmitpowertoasuctionblowerthatsucksthegasfromthefuelreactorandfromthegasconditioningunit.Thepowergeneratingunitalsoconsistsofapumpthatcirculateswaterfromtheconcretereservoirtothescrubberandviceversa.Thesteelrollermillusedtopresstherubberlatexiscoupledtotheendoftheshaftwitha3in.-diameterV-pulleyandbeltdrive.Resultsofperformancetestsfor2hoursoperationsshowninTable2,revealthattheunitrequiresastart-uptimeof4to7mininordertoproducethegasfromricehusk(@9–12%MC).Itconsumesricehuskfuelatarateof9.3to10.5kgperhourwithacomputedspecificgasificationrateof132.85-150.00kg/hr-m2.Thereactorconsumes4.3-5.1m3ofair/hrinordertogasifythefuel.Thecomputedsuperficialgasvelocityatthefuelbedofricehuskrangesfrom1.71-2.02cm/sec.Theair-fuelratioatthegasifierreactorrangesfrom0.58-0.61kgairperkgoffuel.TheenginespeedwasmeasuredusingExtechLaser/ContactTachometerModelRPM33attherangeof2437-2531rpm.Thespeedofthesuctionblowerandofthegearpumpusedwasmeasuredusingthesameinstrumentat5147-5356rpmand1043-1218rpm,respectively.Thetemperature,whichwasmeasuredusingTypeKthermocouple-wireandExtechMulti-ChannelDataloggerModelTM500thermometer,atthegasifierreactorfuelbedwasrecordedattherangeof353°to698°Cfromthetimecombustiblegasisgenerated.Thetemperatureofthegasleavingthereactorwasmeasuredrangingfrom51°to165°Cwhilethatofthegas
Feedstock RiceHuskMoistureContent 9-12%Start-UpTime 4-7minFuelConsumptionRate 9.3-10.5kg/hrSpecificGasificationRate 132.85-150.00kg/hr-m2AirFlowRate 4.3-5.1m3/hrSuperficialVelocity 1.71-2.02cm/secAir-FuelRatio 0.58-0.61kgair/kgfuelEngineSpeed 2437-2531rpmBlowerSpeed 5147-5356rpmPumpSpeed 1043-1218rpmTemperature Reactor 353-698°CGasLeavingtheReactor 51-165°CGasEnteringtheEngine 36-41°CWaterBin NoiseLevel 92.4-94.7Db
Table2.PerformanceTestingoftheMicrogasifierUnit.
enteringtheenginewasmeasuredattherangeof36°to41°C.Thisisbecausethegaswascooledbeforeitenterstheengine.Thetemperatureofwaterenteringandleavingthescrubberranges30°to39°Cand34°to39°C,respectively.Thetemperatureofwaterinthebinwasmeasuredattherangeof27°to30°C.Thenoiseleveloftheenginewasrecordedrangingfrom92.4to94.7dBat1.5meterdistancefromtheengine.Table3showsthedesignspecificationsoftherubbercreepingmillanditsperformanceduringoperation.Bothrollershave15cm-diameterand45cm-length,however,theyhavedifferingspeedinordertocausepressingandstretchingoftherubberlatexsubsequentlyproducingrubberblankets.Thetransmissiondriveofthemachineisacombinationofgearsandbelt&pulley.Duringpressing,waterisallowedtodripontopoftherollerstopreventthelatexfromstickingintotherollersurfaces.Resultsofthetestsshowthatthecreepingmachinecanproducerubberblanketatarateof86to92kgperhour.Onepersonisneededtooperatethemachinebyfeedingitwithrubberlatex.Thegasifierunitperformssatisfactorilywhenusedasdriveorpowersourceforthecreepingmill.Operationofthemachinecanbedonebyonepersonfromstarting-upoftheunittoloadingricehusksanddischargingchar.Startingtheoperationuntilthegasisgeneratedismuchsimplerinthismodel.Thechardisposalmechanismisnottedioustotheoperatorbecauseitonlyneedsswingingtheleverupto45degreesforwardandbackwardtodischargethechardirectlyintothewaterinordertoquenchburningcharandpreventitfromturningintoash.Duringoperation,thebedofricehuskwasobservedtohaveanevendownwardmovementinsidethereactoreverytimecharisdischarged.However,furtherrefinementinthedesignofthegasifierunitneedstobedonetoimproveitsoperationandperformance.Testingofthegasifierunitforotherfarmoperationslikeburrmilling,flutedricemillingarefurtherrecommendedforfutureapplicationsofthetechnology.Fordetailinformation,contact;www.carbonneutralcommons.orgReleased:September26,2017
CreepingMillDimension
15-cmdiameterby45-cmlongsolidmetal
GritShape DiagonalRollerMillSpeed Roller1 7rpmRoller2 4rpm
TransmissionDrive Gear,Chain&Sprocket,andBelt&pulley
ThroughputCapacity 86to92kg/hrWaterDrippingRate 5litersperhourManpowerRequirement
1persontofeedfreshlatex
Table3.DesignSpecificationandPerformanceoftheCreepingMill.