17-6020-compressor maintenance and operation

COMPRESSORMAINTENANCEANDOPERATIONPublishedbyRikeService,Inc.NewOrleans,Louisiana(USA)Compressorsarealargeinvestment.Theyserveinthefield,gasolineplants,refineries,pipelinetransmission,chemicalplants,andaircompressors(control).MaintenanceandoperatingcostperyearDirectmaintenanceat160perinstalledinvestmentLubeoil1/1320newinstalledinvestmentFuel=15%newinstalledinvestment($2.00MCFdiscounted)RikeService,Inc.3FundamentalsExample:Fieldunitof300BhpInstalledcost($750/Bhp)=$225,000Maintenance/Yr.=$3,750($12.50/Bhp/yr)LubeOil/Year=700($2.33/Bhp/yr)Fuel/Year=7,500($25.00/Bhp/yr)$11,950($40.00/Bhp/yr)Aruleofthumbis10%oftheinstalledcostformaintenance,lubeoil,andfuel.RikeService,Inc.4FundamentalsEfficientutilizationrequiresthatunitsbekeptrunning,keptloaded.Maintenanceischallengingtooperations,maintenance,engineering,andmanagement.Agoodmaintenanceprogramresultsinminimumdowntime,partsandlabor,fuelcost,andlubeoilcost.RikeService,Inc.5CompressorOperationsRoutineproceduresincludestarting-stopping(emergency),andloading-unloading.Safetyduringstartingincludeshandlingfuelgasandignitionswitch.Beforeturningignition“On”,cleanpowerandcompressorcylinders.For2-cycleengines,crankthemleastonerevolution:4-cycleengines:tworevolutions.Gaspurgecompressorcylinders.Safetyduringrunningincludesmonitoringlubeoilpressureandtemperature.Enginesareloadedbyexhausttemperature(670-700°Ffullload—750°Foverloadorcarboninvalve).Listenfornoisesandlookforoverheatingoflubeoilandjacketwater.RikeService,Inc.6InspectionRoutineTwiceeachtourforattendedunitsandtwicedailyforattendedunitsCriticaltemperaturesandpressuressuchassuctionanddischargeoncompressorcylindersandallontheengine.Listenforunusualnoises,monitoroperatinglevelsoflubeoil,lubricators,jacketwater,andlookforleaks(lubeoilandwater).Gasleakscouldoccuraroundtherodpackinggland,compressorcylindervalves,reliefvalves,andblockvalves.RikeService,Inc.7InspectionRoutineObservepumpandfanoperationstobesurethebearingsarecool.Checkforliquidinthesuctionsurgedrumandallvolumebottles.“DailyReportofEngineRoomOperation”shouldincludethelubricationschedule,maintenancerecord,anddowntimerecord.Figure2:FixedClearancePocketFigure3:SidePassageClearancePlugsFigure4:ValveCapClearancePocket&StackValvesFigure5:SuctionValveUnloaderRikeService,Inc.13HorsepowerUtilizationTocompressmoregas,useidlehorsepower.Compressorunitcapacityfactors(developedBhp)dependsoncompressorcylinderclearance,suctionpressure,dischargepressure,enginespeed,andsuctiontemperature.(Fig.1)CompressorcylinderclearanceRikeService,Inc.14HorsepowerUtilizationInherentclearancechangesrequireabasicchangetothecompressorcylinder.Forexample,removesegmentsfromthepistonends,orinstallspacerringsbetweenthecylinderheadandthebody.Alsoremovecylinderheadmaterial(jacketed)orplacespacerringsunderthesuctionanddischargevalves.RikeService,Inc.15HorsepowerUtilizationManufacturedmethodsforaddingclearanceincludeheadandfixedvolumeclearancepocket(Fig.2)orsidepassageplugs(Fig.3).UseexternalclearancebottlestoaddclearanceLimitpassagevelocityto2500feet/minandcalculateby:Fig.6:DistrictCompressor50HPCSGHGasCompressors-3UnitsFig.9:C-BModelGMV–6TCUnitFig.10:C-BModelGMV–6TCUnits800BhpFig.11:GWGCompressorCapacityandBHPCurvesRikeService,Inc.24HorsepowerUtilizationEngineSpeedQandBhpdirectlyrelatedtoenginespeed.AdjustspeedtomaintainPsatdesiredlevelwithinthedesignoftheunit.Runningaunitat110%overloadiscommon.RikeService,Inc.25HorsepowerUtilizationSuctiontemperatureQ1/TsBhpnotaffectedsignificantly.Suctiontemperaturenotacontrolledfactor.Capacitychangesfromnighttodayoperations.Evidentfromthegaschartsfromthecompressor.RikeService,Inc.26HorsepowerUtilizationEfficientutilizationofexistinghorsepowerAssuctionpressureincreases,expectanincreaseincapacityandadecreaseinhorsepowerperMMcfcompressed.Avoidhorsepowerpurchasesbypeakgatheringsystemvolumeelimination,loopinggatheringsystemlines,increasingfieldseparatorpressurewithinreason,andeliminateunnecessarysystempressurelosses.RikeService,Inc.27HorsepowerUtilizationUseidlehorsepowerbyloweringsuctionpressures,and/ordecreasingfieldseparatorpressure.Studytheeffectonfieldincomeandplantincome.Introducegasinterstage.Ifeconomicallyfeasible,installagatheringsystematinterstagepressure.Producewellstothehighestinterstagepressurethatallowsdesiredproductionrate.RikeService,Inc.28HorsepowerUtilizationFuelEconomicsOperateminimumnumberofenginesthatcanbeloaded.Usefeweratfullload.DualServiceCompressorsArrangeunitssothatothersuctionanddischargepressurescanbeused.Thismayrequirenecessaryleadlinejump-overs.RikeService,Inc.29HorsepowerUtilizationControllingDischargePressurerealizedbycorrectsizingofcontrolvalves,dischargelines,andpulsationdampeningdevices.OperatingchangecautionsBesurenewconditionsarewithindesignlimitsofengineload,compressorcylinderload,andthepipingsystem.Checkrodloadsbothfordoublea