BY

HuguesPosschelle,GAExpertise,USAS.Damodaran,ThermodyneTechnologies,IndiaV.S.Bharadwaj,ThermodyneTechnologies,India

AT

GREPALMA- GUATEMALAAUGUST2016

BOILERSFORPALMOILMILLSRECENTTRENDS– SELECTION&FEATURES

PALMOILMILLSSTEAM– FUEL– POWERBALANCE

PROCESSSTEAMDEMAND• 350kg-500kgofsteampertonneofFFB.

� Forboiler selection450kg-600kgboilercapacitypertonneofFFB.Thisincludessteam

fordeaerator

WASTEFUELGENERATED� 130kgofMesocarpFibreat39%moistureandahigher healingvalue(HHV)of2800

kcal/kg(13%ofFFB).

� 60kgofcascarashellat14%moistureandaHHVof4390kcal/kg(6%ofFFB).

� 230kgofEFBat70- 75%moistureandaHHVof1225kcal/kg(~23%ofFFB)(needs

shredding &dewateringforuseasaboiler fuel)

� OTHERFUELGENERATED

- BiogasfromETP

- PalmKernelshelldeoiledcakefromsolventextractionplant

POWERDEMAND• ~21kWepertonneofFFBforcrudepalmoilplant.

• Extraforkerneloilplantandrefineryplant

BOILERSFORPALMOILMILLS� Selfsustainingpowergenerationmetwithsaturated(orslightly

superheated)steamat21bar(g)pressureandtoachievefueldisposal(100%palmfibre),boilerefficienciesaretypically63%onHHVandgasoutlettemperaturesarearound300oC.

� Anyhigherefficiencyresultsinfuelsaving.

� Ifallthegeneratedwastefuelsareburntinahighefficiencyboilerthen1TPHofsteamcanbegeneratedfor1TPHofFFB.Extrasteam(0.5TPH)canbeusedforpowergeneration.

� SteamParametersadoptedinamodernpalmoilmill

� 21bar(g)/lowSH/Lowefficiency Fuelsteampowerbalance

� 31bar(g)/SH/highEfficiency Resultsinsavingoffueland

� 41bar(g)/SH/highefficiency highergenerationofpowerforuseeitherinintegrated

refineryorexportofpowerasdesiredbyenduser

FUELSTEAMANDPOWERBALANCESl. No. Plant processing capacity (FFB) TPH 10 20 30 40 60 90 120

1 Waste fuel generated2 Palm fibre - 13% of FFB TPH 1.3 2.6 3.9 5.2 7.8 11.7 15.63 Palm shell - 6% of FFB TPH 0.6 1.2 1.8 2.4 3.6 5.4 7.24 EFB at 50% moisture - 12% of FFB TPH 1.2 2.4 3.6 4.8 7.2 10.8 14.45 Process steam requirement TPH 5 10 15 20 30 45 60

6 Power generation potential (kWe) for process steam requirement Refer Note 1

7 at 21 bar(g) / 250 oC kWe 130 270 400 580 900 1400 20008 at 31 bar(g) / 330 oC kWe Not Viable 600 900 1250 1900 3000 50009 at 45 bar(g) / 410 oC kWe Not Viable Not Viable 1350 1900 2900 4500 625010

11 Steam generation potential from utilisation of all the waste fuels generated TPH 9.8 19.6 29 39 59 88 117

12 Max power generationfor above conditions Refer Note 2

Note 1: The power generation values are indicative considering multi stage turbines and may vary depending on the turbine manufacturer.Note 2 : Power Generation will be 2 to 3 times that indicated at 7,8,9 depending on the fuel and steam utilisation and matching COGEN cycle(extraction or extraction condensing turbine)

BOILERSSIZING&SELECTION

� DESIGNINPUT

� DESIGNCONSIDERATIONS

� BOILERCONTROLS

� INDUSTRYSPECIFICREQUIREMENTS

DESIGNINPUTS(FORBOILERSIZING)…

� FUELCHARACTERISTICS

� BOILERPARAMETERS

Capacity,SteamoutletPressure,Temperature,Feedwatertemperature.

� BOILEREFFICIENCY

� AMBIENTCONDITIONS

� OTHERSTATUTORYANDAUXILIARYSTIPULATIONS

INFLUENCINGFACTORS…

• PROXIMATEANALYSIS&ULTIMATEANALYSIS

• ASHCHARACTERISTICS

• PHYSICALCHARACTERISTICS

• FUELSIZING

FuelCharacteristics…

FuelCharacteristics…

• PROXIMATEANALYSIS

• Fixedcarbon

• VolatileMatter

• Totalmoisture

• Ash

TypicalBioMassFuelAnalysis- Proximate

PalmFibre Palmshell EmptyFruitBunch

Sawdust(partialdry)

FixedCarbon %wt. 11- 12 17.50 8.53 12- 13

VolatileMatter %wt 44– 45 65.40 37.83 60- 64

TotalMoisture %wt 38- 39 14.30 50.00 18– 20

Ash %wt 5- 6 2.80 3.64 1– 1.5

HigherHeatingValue

Kcal/kg 2920 4400 2460 4000- 4500

AshCharacteristics

• Quantum

• AlkaliCompounds

• Chlorine(asChlorides)

• Fusibilitytemperatures

AshAnalysis– FusibilityTemperatures

PalmFibre

Palmshell

EmptyFruitBunch

InitialDeformation

Temperature

oC 1120 1070 930

Softening temperature oC 1180 1130 990

Fluid temperature oC 1280 1290 1210

TypicalRequirementOfFuelSizing

• ShreddedbiomassGrateFiring(Spreader)

� 100%<100mmlong

� 95%<50mmlong

� 50%<15mmlong

• SemiPreparedBiomassGrateFiring(GravityFeed)

• SemiPrepared/UnderPrepared

BOILEREFFICIENCY• CONSIDERATIONS

Ø INITIALCOSTVs.RUNNINGFUELCOST

Ø ENERGYCONSERVATION

Ø WASTEFUELUTILISATION

– GOVERININGFACTORS

Ø Excessair

Ø FluegasOutletTemperature

Ø MoistureandHydrogencontentinFuel

Ø AmbientTemperatureandMoistureinAir(Humidity)

Ø CompletenessofCombustion

Ø EffectivenessofInsulation

BOILERPARAMETERSCAPACITY - Eitherat0.5TPHpertonneofFFBor

highertogeneratemorepower(forPower

export/otherutilisation)

PRESSURE - 21/31/41/65bar(g)dependingonfueland

powerbalance

STEAMTEMPERATURE - 300to410oC(highersteamtemperature

notadvisedduetochlorinepresence)

FEEDWATERTEMPERATURE- 105to120oC(120oCisbettersuitedtotacklesulphurcorrosionissues)

Pressureandsteamtemperaturearethebasicdesignconsiderationsforapalmoilmillboiler.

DESIGNCONSIDERATIONS

� Largefurnacewithconservativevolumetricloading

� Lowfurnaceoutletgastemperaturetoreduceashdeposition

� Strategiclocationandapportioningofsecondaryairforbetter

combustion

� Judicioustransversepitchofsuperheatertoreduceashfouling

� Specialspacersforsuperheaterassemblies(Forlargetransverse

pitch)

� Judicioustransversepitchofbanktubestoreduceashfouling

Managementofcombustionandalkalifoulingissuesofpalmwastefuelswithfollowingdistinctivefeatures…

DesignConsiderations…MembraneWallDesign

• Membranewalldesignischaracterizedby:

– Gastightchamber

– Effectiveutilisationoffurnaceradiantsurface

– Significanteliminationofrefractoryandreduction

ofrefractorymaintenance

– Lesscycletimeforinstallation

– Excellentresponsetoboilerloadchanges

CARBONSTEEL– ASTM

� DRUMS - SA516Grade70

� WATERWALLS - SA210GradeA1(Seamless) /SA178GRA(ERW)

� BOILERBANK - SA210GradeA1(Seamless) /SA178GRA(ERW)

� ECONOMIER - SA210GradeA1(Seamless) /SA192(Seamless)

/SA178GradeA(ERW)

� SUPERHEATER - SA210GradeA1(SEAMLESS)

(up tosteamtemperature400oC)ALLOYSTEEL– ASTM

� SUPERHEATERSSA213GradeT11UPTO460oC(steamtemperature)SA213GradeT22UPTO510oC(steamtemperature)

SEAMLESSVSERW

ERWsuccessfullyusedupto67bargpressure inINDIAforfurnace,boilerbankandeconomiser

Beyond67barseamlesstubesused

ERW– provenreliabilityover30years

DesignConsiderations …BoilerQualityMaterial-TypicallyUsed

SUSPENDEDPARTICULATEMATTER(SPM)

– UNCONTROLLED - 8to9g/Nm3atinletofSPMabatementdevice

SPMCONTROLDEVICES

– Multicyclone - upto400mg/Nm3 at10%O2 Typicalgassidedraftlossofabout80mmwc

– Wetscrubber - upto100mg/Nm3 at10%O2 Typicalgassidedraftlossbetween80to150mmwc

venturitypescrubbersarewithhighergassidepressuredrop.

– ESP - upto50mg/Nm3at10%O2 Generallywithpre-collector.Typicalgassidepressuredropof

25mmwc.ESPconsumespowerforparticulatecapture.Typically

25%ofthe installedESPconnectedpower.

– BagFilter - upto50mg/Nm3at10%O2 Typicalgassidedraftloss150mmto200mmwc

DesignConsiderations…GasEmissions(Typical)

DesignConsiderations…GasEmissions(Typical)

• WetscrubberLowinitialcost,butstillcanmeetSPMlevelsof100mg/Nm3.

Slurryhandlingtobeaddressed.

• ESPwithPre-collectorLowgassidepressuredrop.AcidcondensationduringlowloadandstartupconditionscanbemanagedwithautomatedtemperaturesensingbypassdamperstoprotectESP.

PrecollectorisinstalledtoaddressissuesofESPfires/extremepuffs

Highinitialcost,especiallyinlowersizes(lessthan30T,Mill)

• BagFilterHighgassidepressuredropwithassociatedhighpowerconsumption.

Mediumlevelinitialcost,especiallyinlowersizes.OfferslowestSPMlevels.

• BothESPandbagfilterareoptionsavailablefordryashcollectionandlowSPMlevels.

� OtherGaseousEmissions

� NOx(OxidesofNitrogen)Generallyuncontrolled andtypicallybetween400– 500ppmforpalm

Wasteforlowerlevelsexternalmechanismsareemployed forAbatement

� SOx(SulphurDiOxide)Dependsonfuelboundsulphur.Generallylowwithpalmwastefuels

andadditionallyalkaliinfuelInhibitsdewpointcorrosiontemperature

riseandacidattack.Typicallyabout300ppmiffuelsulphuris0.2%by

Weight.

NOxandSOx- generallywithinpermissiblelevelinmanycountries,Doesnotwarrantanyadditionalcontroldevice.

Whereapplicable,lowNOxcanbemetwithin-furnacecapture/Externalabatementdevice

DesignConsiderations…GasEmissions(Typical)

SOOTBLOWERS• STEAMSOOTBLOWERS

- Typicaloperatingpressure11barto21bar

- LongRetractSteamSootBlower(LRSB)• ForHighlevelcleaningrequirement

• Locationcanbeathighgastemperaturezones

• Maximumcleaningon-linedevice

- RotarySootBlower(RSB)• Forlowlevelcleaningrequirement

• Canbelocatedonlyatgaszoneswithlessthan550�C

• SONICSOOTBLOWERS• Operatesonsoundsignalsoflowfundamentalfrequencyandhigh

intensity.Pneumaticallyoperatedusingcompressedair(Plantairat5-7kg/cm2(g))

• Typicallyoperatingtimeof10-12secatintervalsvaryingbetween30minto90min

• Cancoverhigh,medium,andlowgastemperaturezones

• Usedwhenashisfriableandlowadhering

• Cancomplementincombinationwithsteamsootblowersforstickyandadheringash

BIOGASUTILISATION• Biogasfromeffluenttreatmentplantcanbeusedintwoways

- Directlyinbiogasengine,producingelectricalpower

- Asauxiliaryfuelinboiler

• TypicalanalysisMethane,CH4 60%byvolume

Carbon-Di-oxide,CO2 39%byvolume

Airandhydrogensulphide balance

Higherheatingvalue 5700kcal/NM3

• Whenusedinboiler– Biogaspressureatboilerinlet2500-3000mmwc

– Recommendedtoalwaysco-firewithmainfuelforsafeandsustainedcombustion

EMPTYFRUITBUNCH(EFB)– EFBischaracterisedby…

• highalkali(potash,K20)contentinash,

• lowfusibilitytemperature,

• highmoistureandlowcalorificvalue.

• presenceofchlorine

– 100%EFBcanbefiredinspeciallydesignedboiler.Properfuelpreparationisessential

– EFBpreparation(Asfired)

• Recommendedsizing(linear)

100% <100mm

95% <50mm

50% <12mm

• Moisture<50%

• HighHeatingValue>2200Kcal/kg

EMPTYFRUITBUNCH(EFB)…– BoilerParameters:

OperatingPressure 45bar(g)

Superheateroutlettemperature ≯ 410�C

– SalientDesignFeaturesoftheboiler

• Airassistedgravityfeeding

• Specialdesignfuelfeeder

• ReciprocatingGrate

• Tallfurnace

• LargetransversepitchforSH,withspecialdesignspacers

• LargePitchforbanktubes

• Forboilercapacitieshigherthan40TPH,pneumaticspreadingwithtravellinggrate.(finerEFBpreparation)

BOILERCONTROLSTYPICALCONTROLS

1)Drumwaterlevelcontrol

• SingleElement

• ThreeElement

Singleelement:input- drumwaterlevelforcontrolvalveoperation.Doesnotprovidefinecontrolofwater.

Threeelementtakessignalofsteamflowaswellasfeedwaterflowinadditiontodrumlevelsignal

Drum water level control

BoilerControls…

2)Furnacedraftcontrol

Maintains furnace pressure at near atmospheric pressure over

various loads. This is done by adjusting the ID fan damper

position (or speed if with VFD) after measurement of furnace

pressure

BoilerControls…

3)Combustioncontrol

MaintainssteampressureatvariousboilerloadCombustion

airflowandfuelfeederspeedisadjustedtosuitloadand

maintainpressure

BoilerControls…

4)Steamtemperaturecontrol

Mainsteamtemperaturewithinaspecifiedrangetoensure

nearlyuniformtemperatureatturbineinletwithinthecontrol

rangeFeedwatersprayedinsteampathiscalculatedquantities

tocontrolsteamtemperature.Feedwaterqualityrequirement

tobeasspecifiedbyboilermanufacturer.

BoilerControls…

5.Deaeratorpressurecontrol

BoilerControls…

6.Deaerator levelcontrol

BoilerControls…

7)Sootblowerpressurecontrol

Tolimitsteampressureforsootblowingfromavailablemain

steamemployedonlyforhighpressureboiler

BoilerControls…

• POMsareaSTOP&GOindustry

• Duringpeakseasonunitsareoperatednonstop

• Duringleanseason– stoppeduptoeventwiceaweek

• Alsooperatedatverylowloads

BOILERSFORSTOPANDGOOPERATIONS

• Lowloadoperation/STOP&GOoperationriskslowgasflue

temperatureleadingtodewpointcorrosionissues.

• ManagedwitheitherAPHbypassorEconomiserbypassorcombination

ofboth

• ECO/APHbypassprotectsdownstreamSPMcontrolequipment

• BypassmechanismcanbeManual/Remotemanualorautomated

INDUSTRYSPECIFICREQUIREMENTS

TwinTravellingGrate

ReciprocatingGrate

TYPE : Bi-Drum Bottom Supported, Outdoor

FUEL : Palm Fibre /EFB/ PK Shell/Biogas

FIRING SYSTEM : Reciprocating grate SOOT BLOWERS : LRSB/RSB

CAPACITY : 30 TPHPRESSURE : 45 bar(g)TEMPERATURE : 440 � 5 �C

TYPE : Bi-Drum Bottom Supported, Indoor

FUEL : Palm Fibre / PK shellFIRING SYSTEM : Reciprocating grate SOOT BLOWERS : LRSB/RSB

CAPACITY : 35 TPHPRESSURE : 31 bar(g)TEMPERATURE : 400 � 5 �C

TYPE : Bi-Drum Bottom Supported, Indoor

FUEL : Palm Fibre / EFBFIRING SYSTEM : Spreader, Traveling grate SOOT BLOWERS : LRSB/RSB

CAPACITY : 60 TPHPRESSURE : 31 bar(g)TEMPERATURE : 330 � 5 �C

TYPE : Bi-Drum Top Supported, Outdoor

FUEL : Palm Fibre/ EFB/ PK ShellFIRING SYSTEM : Spreader, Traveling grateSOOT BLOWERS : LRSB/RSB

CAPACITY : 60TPHPRESSURE : 45 bar(g)TEMPERATURE : 440 � 10 �C

TYPE : Bi-Drum Top Supported, Outdoor

FUEL : Specialty BiomassFIRING SYSTEM : Reciprocating grateSOOT BLOWERS : LRSB/RSB

CAPACITY : 34 TPHPRESSURE : 44 bar(g)TEMPERATURE : 420 � 5 �C

THANKYOU