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.