Download pdf - BurnerMate Universal Industrial Boiler Controller · PDF fileBURNERMATE UNIVERSAL INDUSTRIAL BOILER CONTROLLER ... commissioned’ feedforward curves ... Burner management system components

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Instruments & Controls

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BURNERMATE UNIVERSAL INDUSTRIAL BOILER CONTROLLERSystemOverview

SystemOverviewFullyMeteredcombustioncontrolisnowavailable“offtheshelf”inaneconomical,pre-engineered,parameter-drivencontrol package.TheBurnerMateUniversal Industrialincludesthefollowingfeatures:

• Patented“PredictiveFullMetering”fuel-airratiocontrol• Cross-limitedActuator,“PositionPacing”• SinglePIDfuel-air,ratiotuning• Airflowtemperaturecompensation• Gasflowpressurecompensation• WindboxO2FGRTrim+FlueO2AirFlowTrim

TheBurnerMateUniversal Industrial also includesall ofthefeaturesintheBasicandExpandedversionsofBMU:

• PrecisehightorqueServoActuators(3ft-lb->720ft-lb,8sizes)

• FD,ID&FGRFanandBFWPumpVFDdrivecontrol• NFPA85compliantBurnerManagementSystem(BMS)

• IndividualInterlockAnnunciationwithadvancedLockoutDatastorage

• LowFire,FuelChangeover• FiringRate,FeedwaterandDraftcontrol• OilAtomizingPressurecontrolwithSetpointCurve• Large10”colorTouchScreenOITwithpre-programmed

graphics(Note:15”alsoavailableoncustomapplications)• Modbuscommunications

Typical Fully Metered BurnerMate Universal Industrial P & ID.

S

AE

PT

Gas

FGR

Draft

Oxygen

Draft

S

Boiler

Win

dbox

AT

Oxygen

VFDMotor

S

S

FreshAir

TE

FGR

FD

SAux 1

FT

TE

SGas

Aux 2S

S

FT

PT**

Oil

Steam

FEpulser

PT**

or dPAtomize

Oil

LT DrumLevel

SDrum

Feedwater

SDigester

Gas

FT

Fuel3

INDUSTRIAL



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TheBurnerMateUniversal Industrial isavailableoff-the-shelf for immediate delivery, requires only wiring andparametersetuptobeoperationalandisNFPA85compliantandU.L.recognized.

Predictive Metering Combustion ControlThe BurnerMate Universal Industrial offers a patentedmeteringfuel-airratiocombustioncontroltechniqueusingauniquecontrolstrategyreferredtoas“predictivemetering”.The ideal combustion control strategymaintains a presetfuel-air ratioover theentire loadrangeofaboilerdespitechangesinfuelsupply,combustionairanddraftconditions,andalsoprovidesrapidloadchangeresponse.

Traditionalfullymeteredcombustioncontrolsystemshavethefollowingweaknesses:

• TwoPIDloopsarerequired,makingtuningdifficult• CrossLimitingLead-LagcausesAirRichoperationduring

Loadchanges• SluggishresponsetoloadchangescausedbyPIDand

CrossLimitingLead-Laginteractions• AirFlowmeterinaccuraciesatlowflowrateslimitBurner

turndowncapabilities• Flowmetermalfunctionsdisable theburner,or require

manualoperationuntilrepaired• Untilnow,FullyMeteredcontrolsystemswere“custom”

sotheirbenefitswerenotavailable“off-the-shelf”

Preferred’s patented “predictivemetering” combustioncontrolstrategycombinesmultiplefuel,air,andFGR‘as-commissioned’feedforwardcurves(whichpredictServo/VSDchangesduringaloadchange),withmeasuredflowratebasedPID fuel-air ratiocontrol that incorporatesarobustcross-limitedpositionpacingalgorithm.Predictivemeteringuses“as-commissioned”measuredfuelflowrateandairflowratecurvestoensurethatthePIDfuel-airratioremainsatthe“as-commissioned”fuel-airratiosetpointforeveryfiringrate.

Predictivemetering,combinedwith“positionpacing”logic,assuresmuchmore precise actuator positioning andassures thateachservo remains “oncurve”during loadchanges.Thisallowsthecontrollertoincreaseordecreasefiringratemorequickly,withoutconcernfor“fuelrich”or“fuellean”burneroperation.ThesestrategiesareofparticularimportancewhenappliedtosensitivelowNOxburnerswithnarrowlimitsofflammability.

Because “predictivemetering” combustion control usesboth the servo actuator position feedback and fuel andairflowmeterinputs,meteringcombustioncontrolcanbeselectively “turned” off at low firing rateswhereair flowmetersmaynotbeasaccurate.Mostimportantly,ifaflowmetermalfunctions,bysimpleparameterselectiontheBMUIndustrialcontrollercanbedirectedtooperateasaparallelpositioning combustion control systemwith oxygen trimuntiltheflowmeterisrepairedorreplaced.Traditionalfullymeteredsystemscanonlyberuninmanualwhenthereisaflowmetermalfunction.

BurnerMate Universal Industrial Predictive Metering Control Schematic

Air Flow Fuel Flow

A/B

Fuel-AirRatio

Setpointcalculator

PID

f(x)

f(x)

Fuel Valve FB

Fuel Flow

Air Flow

Air Flow SP

Low FlowPID

Disable

O2 Trim

f(x)

f(x)

f(x)

f(x)

+

FGR

Aux 2

FD

FDVSD

Aux 1

f(x)

Cro

ss

Lim

ite

d P

os

itio

n P

ac

ing

Firing Rate Demand

FGR

Aux 2

FD

FD VSD

Aux 1

Fuel Valve

Commission Mode Curves

BMU Servos:



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Because“predictivemetering”ispre-programmedandonlyapplication-specificparametersetup is required tomakethecontrollerfunction,BurnerMateUniversalIndustrialismucheasier tocommissionandoperate than traditionalfullymeteredcombustioncontrolsystems.ThesinglePIDblock(ratherthanthetworequiredfortraditionalsystems)requiresthatonlyonesetofPIDvaluesneedtobetunedduringcommissioning.

Inputsfor“predictivemetering”combustioncontrolinclude:

• Combustionairflow• Combustionairtemperature• Fuel1Oilflow(pulseror4-20mA)• Fuel2(natural)gasflow• Fuel2(natural)gaspressure**• Fuel3(digesterorother)gasflow**

**Note:Thefuel3flow,gaspressurecompensation,andatomizingpressurecontroltransmittersallshareasingleBMUIndustrialinput.Onlyoneofthethreecanbeenabled(fieldselectable).

Fuelandsteamflowsarealsototalized.EachoftheseflowratesandflowtotalshasaModbusaddressfordisplayonthe localOITTouchScreenor remotely viaModbusonPlantDCSsystemOITs.

BMUIndustrialFuel-Air-FGRCrossLimitedPositionPacing“Positionpacing” is a unique featureof theBurnerMateUniversal Industrial thatassuresthepositionsofall fuel,air,andFGRServosandrelatedVSDspeedsremain“oncurve”duringloadswings.Positionpacinghelpsavoid:

• Periodsof lean combustion that can cause rumbling,vibration,orflame-outsduringfiringrateincreases

• Fuelrichconditionsthatcancausesmoking,burn-back,andexcessiveCOorunburnedhydrocarbonsduringfiringrate decreases

Withtraditionalfullymeteredcontrolsystems,thesolutiontotheseproblemsistoslowdowntheresponsetofiringrate changes, and to tighten “cross limiting lead-lag” toassurethatthefuelandairflowsremain“oncurve.”Forsuchsystems,itisnotunusualforlowtohighfireresponsetimestobe4-8minutes.

BMU Industrial “position pacing” assures that all servoactuatorsremain“oncurve”inthefollowingmanner:

• Allfuel,air,FGRservosandVSDsmovetogetherand“oncurve”--thereisnofuelorair“lead”or“lag”.

• EachServo andVSDhas precise position or speedfeedbacktoinsurethatalldevicesarecrosslimited.

• TheBMUIndustrial“knows”howfareachservoactuatorandVSD canmove in 0.5 seconds and uses “self-adaptive”positionpacing toensure that loadchangesnevercauseanyservoorVSDtolagbehindtheothers.

• Εvery0.5seconds,theBMUIndustrialexaminesallcurvesto“find”theservoorVSDworstcase0.5second“move”causedbyarequestedfiringratechange.

• Basedonthecurves,allotherservosorVSDstargetpositionsare“scaledback”toensurethatALLdevicesarrive“oncurve”attheendofthenext0.5secondmove.

BMUIndustrial“positionpacing”isfullyautomatic,providesforsafercombustioncontrol,drasticallyimprovedfiringrateresponsetimes,andrequiresnouseradjustments.

Description CatalogNumber

BurnerMateUniversalIndustrialchassis.Includesoxygencompensationinputs,andexpandedprocessorwithdraftandfeedwatercontrol.LCDKeypadshippedlooseforenclosure-mounting. BMU-2ZN1

Note:BMUIndustrialservos,scanners,oxygenanalyzersandflowtransmittersarerequiredforacompletesystem.

FD Damper

FD VSD

Fuel Valve

Position Pacing

0.5 sec travel

0.5

sec

trave

l

Two Servo Example of Position Pacing



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BURNERMATE UNIVERSAL INDUSTRIAL BOILER CONTROLLERSuggestedSpecifications

1. Quality AssuranceTheboilercontrolsystemshallbemanufacturedandsupportedintheUnitedStatesbyPreferredInstruments.Theburnerfuel-air-FGR ratio control systemand the burner flame safeguardsystemshallbemanufacturedand labelled inaccordancewithU.L.372,U.L.1998,andCSAC22.2#199.SimplysupplyingULrecognizedindividualcomponentsisnotsufficient.Theassembledcontrolcabinetasawholemustbeinspectedforproperwiringmethods, fusing, etc., andmust be labeled as conforming toUL508AandCSAC22.1#14.InspectionandlabelingshallbesupervisedanOSHAapprovedNationallyRecognizedTestLab(NRTL).ThesystemshallcomplywithNFPA85“RequirementforIndependence,”theflamesafeguardsystemshallbeprovidedwithindependenthardware,andshallbephysicallyseparatedfromthecombustioncontrollogic.2. Predictive Metering Combustion ControlA fully metered combustion control system with oxygencompensationand(optional)VSDcontrolshallbeprovided foreachboiler.Eachsystemshallbedesignedtoprovidecontinuousboiler operationwithin boiler design limitswith a high level ofsafetyandenergyefficiency.Fuelflow,airflow,andservopositionforuptoeightservoswillbecontinuallymonitoredandheld“oncurve” during boiler load changes. For convenient setup andfasterresponseto loadchanges, thefullymeteredcombustioncontrol logic shall contain only one PID loop.As required thesystemshallprovidecontinuousmonitoringandcontrolofsteampressure(orwatertemperature),andwaterlevel.Ifaflowmeterisoutofrangeorinoperative,thecontrolstrategycanbeswitchedtoparallelpositioning,byparameterselection.Thesystemshallbefullyintegratedtotheburnermanagementsystemtoprovidefullyautomatic,safeandreliablestartupandshutdown.3. Oxygen Compensation SystemProvide a boiler breeching mounted in-situ, zirconium oxideoxygenanalyzerforeachboiler.Extractivetypeoxygenanalyzersarenotacceptableforcombustioncontrol.Theprobeshallbeofasuitable length tosense theoxygen level in themiddle thirdof thebreeching.Allwettedparts shall bestainlesssteel.Theoxygenanalyzershall:• Includecontinuousself-diagnosticswithdiagnosticcodesfor

atleast10commonfaults.• Automaticallysendthe trimcontrol to the ‘null’positionand

trigger the alarmdry contacts in the if an oxygen analyzerfaults.

• Thedetectorshallbefieldreplaceablewithoutremovingtheprobefromthestackandshallnotrequirespecialtools.

• Theanalyzershallautomaticallyperformperiodicdetectorcellimpedanceteststobeusedbytheoperatorasanindicationofcalibrationshift.

• Analyzercalibrationshallbepushbuttonsemi-automatic(notrim pots) with English language prompts and diagnosticmessages.Analyzeroutputshallbefieldselectableas0-10%or0-21%withoutfieldre-calibration.

4. WindboxOxygenFGRControlThecontrollershallacceptananalog input forburnerwindboxoxygentobeusedasameasureoffluegasrecirculationrate.During commissioning, awindbox oxygen vs. firing rate curveshallbeestablished.Thecontrollershallmodulatethefluegasrecirculationvalve (or fluegasblowermotorVSD) tomaintainwindboxoxygenonthepre-establishedcurvedespitechangesinambientconditions.

5. Atomizing Media Pressure ControlThe controller shall accept an input for atomizing steampressure or atomizing steam/ oil differential pressure. Duringcommissioning, an atomizing steam pressure (or atomizingsteam/oil differential pressure) curveshall beestablished.Thecontrollerwillmodulateanatomizingsteamflowcontrolvalvetokeeptheatomizingsteampressureoncurveatallfiringrates.6. Flame Safeguard System (FSG)Integral to the control system furnished shall be a BurnerManagement System (BMS)/ FlameSafeguardSystem (FSG)controller.Thesystemshallbedesignedtoensurethesafestart-up, on-line operation, and shutdown of fuel firing equipment.Burner management system components shall be located inthe combustion control cabinet and shall be fully integratedforautomaticsequencingof lightoffandshutdown.For safetytheBMSmicroprocessorandBMSVDshallbeonaphysicallyseparatecircuitboard.

Microprocessor-based FSG shall provide: safety interlocks,flamemonitoringprotection,and timedsequences.Sequencesshall include forced draft fan start and stop, furnace purge,burnerlightoffandshutdownandpost-purge.TheFSGshallbecapableoffiringuptothreefuels(twogasfuels,oneoilfuel),onefuelatatime.Fuelchangeovershallbefromoiltogas,orgastooilfiringshallbeaccomplishedatlowfirewithoutboilershutdownperNFPA.A front-mountedpanelwithEnglish language, four line, twentycharacter LCD message display shall be provided to displayflame signal strength, startup and shutdown sequence status,alarm, system diagnostic, first-out messages and burnerhistorical information. Historical information shall include thestatusofalllimitsandservosforthelasttenlockouts.To ensure boiler low water cutouts are working correctly, thecontrollershallbecapableofperformingadailyautomaticwatercolumnblow-downtest.Theusershallselectthetimeofdayanddurationofthewatercolumnblow-downtest.Thecontrollershallensure the lowwater cutoff switches are functioning correctly,andalarmtheoperatororlockouttheboilerifitdetectsaswitchmalfunction.To prevent nuisance trips, the flame safeguard system shallaccommodate two flame scanners with one required toprove flame.The controller shall provide120VACor 24VDCscannerpower,andaccepttwoanaloginputsforflamestrengthindications.Flamesafeguardsystemshall includeoilgunpostpurgeforoilfiring.Reliablelowfirecutoffshallbeprovided.For additional nuisance trip protection, field adjustable timedelays shall be provided for F.D. fan start, fresh air damper,minimumairflow,lowdraftcutout,andfuelpressurelimits.Fivefield selectable auxiliary relays shall be included for commonalarm,auxiliaryfanstart,blow-down,flameon,fuelvalveopen,hotwaterpumporvalve.Toprotectagainstdryfiring,anoptionshallbeavailableforhighfluegastemperaturelockout.Toensureairswitchesarefunctioning,minimumairflowpressureswitchandpurgeairflowpressureswitchshallbetestedforsafestarting.



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BURNERMATE UNIVERSAL INDUSTRIAL BOILER CONTROLLERSuggestedSpecifications

7. Feedwater ControlProvideaboilerwaterlevelcontrollercapableofsingle-,two-,orthree-elementfeedwatercontrolwiththeabilitytoautomaticallyswitch between control strategies dependent on systemdemands.8. Draft ControlThe controller shall provide two-element draft control using aPreferred Instruments JC-22XMTR draft transmitter. Burnerfiringrateshallbeusedasafeedforwardforimprovedresponseto loadchanges.Thecontrolshallprovidebothautomaticandmanualdampercontrol.Alladjustmentsshallbemadefromthefrontpaneldisplayinengineeringunits.9. Flue Gas Recirculation Valve ControlThe controller shall have a characterizable setpoint curve fordamperorvariablespeedfanoutputsignal.Allthelogicrequiredtoverifythatpre-purge,postpurge,light-off,andburnermodulatecycles are automated shall be provided within the controller.Alternatively,thecontrolwillregulateFGRaccordingtoapresetwindboxoxygensetpointcurve.10. Additional Control Requirements:• Minimumnumberoff(x)curvestobeprovidedperservo:6• Minimumnumberofpointsperf(x)curvetobeprovided:11• ColdFGR lowfirecutbackshallbeprovidedwhenFGR is

utilizedforNOxreduction.• Separate curves shall be provided for FD fan full speed

bypassofVSDincaseofVSDfailure.• Controllershall include thecapabilityof receivingaremote

firingrateinputandremotesetpointinput.• Controller shall include dual outdoor reset setpoint curves

(normalandsetback)• Controllershallincludewarmstandbystart/stopcycle.• Controllershallincludelowfirehold,andcoldstartwarmup

ramping.• All external or auxiliary power supplies necessary for

electronic transmitters (or final control element) shall beincluded.

• BoilercontrolsoftwareshallbeU.L.372/U.L.1998recognizedand inaccessible toprevent tampering.Unitcommissioningshallbebyparameterselection,notrequiringladderlogicorblockwareprogramming.

• Thecontrollershallacceptstandard4-20mA,1-5VDC,orRTD inputs for analog inputs.No special sensors shall berequired.

11. OIT Color Touch ScreenProvideasanoptionaten(10)inchOperatorInterfaceTerminal(OIT) designed to provide local operation, graphic display ofinformation, alarm message display, historical and real timetrending, remote controller tuning, x/y plots of fuel-air curvedata for intuitive commissioning, Ethernet connectivity andstandardinternetbrowserremotecommunication.TheOITshallcontainaminimumof75graphicpagesandbenetworkedtotheboilercontrolandburnermanagementsystems.TheOITshallprovidegraphicpagesallowing step-by-step commissioningofthecontrollerparametersusingEnglish languagepromptsandselections.The systemshall be an industrial hardenedoperator interfaceterminal.The terminal shallbewebenabledandallow remotemonitoringviaastandardinternetbrowserandsupportModbusTCP/IPMaster,TCP/IPSlave,RS-485ModbusMaster,BacNetIP,andEthernetcommunications.

12. High Torque Servo Features:• Easy pushbutton set-up, not requiring the adjustment of

internalorexternalpotentiometers.• Servozero,span,anddirectionoftravelshallbeaccomplished

bypush-buttonconfiguration.• Totallyenclosed,dusttight,andsplash-proofcovers.• Provideaseparatedirectactingdigitalservoactuatorforthe

fuelgasandfueloil.• Electrically isolated shaft position feedback potentiometer,

integralbrake,90°rotationin25seconds.• Theactuatorshallbecapableofbeingstopped,started,or

instantlyreversedwithoutlosingpoweroroverloading.• Servoactuatorpositioningaccuracy:0.1degrees.Servofull

strokesafestartcheckshallbeprovided.• For high torque applications such as watertube boiler air

dampers,servotorqueshallberatedminimum70ft-lbswith0.4degreeaccuracy.

• Noservofeedbackadjustmentsshallberequiredwithpush-button zero setup.Adjustable travel limit switches shall beintegral, with re-adjustment not requiring new fuel air ratiocurvere-entry.

• Servos shall be cycled during each light-off cycle, and thefeedbackfromeachservoshallbemonitoredtoensuresafeactuatoroperation.

• Servos shall be Preferred Instruments,model BMU-SM orBMU-UM(hightorque).