Exploring Alternative Designs To Integrally Geared High .

Exploring Alternative Designs toIntegrally Geared High Speed Pumps- Case StudyAbdulmajeed Al-Shaye : Saudi AramcoYousuf Al-Shuhail : Saudi Aramco

Content IntroductionCase Study - Operating ConditionsFailure AnalysisRoot CausesAlternative Pump DesignsSummary

IntroductionCaustic TransferWash Water

Introduction - Integrally Geared API 610 OH6Low specific speed ImpellerPartial emission diffuser1st Choice for engineering contractorsInducer provides adequate NPSH toimpellerVertical or Horizontal orientations

Introduction - Integrally Geared CrossSectionUpper GearboxHousingInput ShaftIdler ShaftOil PumpOil Filter\\Lower GearboxHousingBearing PlateOutput Shaft(High Speed)Mechanical SealCover PlateRemovableDiffuser InsertImpeller withInducer

Introduction – Integrally GearedAdvantages and DisadvantagesAdvantagesDisadvantages Low initial cost Requires special sealing design Single-stage Open impeller design (nowear rings) High spare parts and repair cost.Repair in specialized servicecenters Compact size and in-linemounting minimizesfoundation requirements Gearbox requires lube oil systemMay require inducer Narrow operating window More vulnerable to catastrophicfailures Limited vendors

Introduction – Low Flow High HeadOperating Range

Case Study - OperatingConditionsServiceCaustic transferWash waterFlow (GPM)40106Head (Feet)Speed (RPM)73011,000160014,838

Failure AnalysisBoth pumps experiencedfrequent seal and gearboxfailuresCaustic Transfer

Failure Analysis – CausticTransfer Batch operation to varying header pressuresPump has narrow operating window and operatesaway from BEP without proper controlPump experiences high vibrationPump experiences frequent seal leaksGearbox experiences abnormal noise

Failure Analysis – Caustic TransferMaintenance RecordCaustic transfer pump 801-P-3 AFailure Date Failure ModeDec 2001Seal failureNov 2002Gearbox failureFeb 2003Seal failureJun 2004Gearbox failureJul 2005Gearbox failure, oil leak and lowperformanceApr 2006Seal failureOct 2008Seal failureSep 2009Gearbox failure and oil leakTotalCost ( ,000

Failure Analysis – Caustic TransferMaintenance Record (cont.)Caustic transfer pump 801-P-3 BFailure Date Failure ModeNov 2002 Gearbox failureOct 2004Seal failureAug 2005 Seal failureMay 2007 Seal failureJan 2009Gearbox failureMay 2009 Gearbox failureJan 2010Seal failureSep 2010 Seal failureTotalCost ( 8,000

Failure AnalysisOne pump experienced majorRepairWash Water

Failure Analysis – Wash Water Two pumps experienced catastrophic failures

Failure Analysis – Wash WaterMaintenance RecordWASH WATER PUMP Z97-G-002 AFailure Date Failure ModeCost ( )2006Catastrophic failureRepairedUnderWarrantyOct 2008High vibration12,000WASH WATER PUMP Z97-G-002 BFailure Date Failure ModeCost ( )Mar 2008 Catastrophic failure162,000May 2011TotalHigh vibration31,000193,000

Root Causes Caustic pumpIncorrect selection of pump type since integrallygeared pump has narrow operating window forthis varying operating range Wash WaterBoth pumps experienced catastrophic failures tothe point the root cause of failure could not beidentified.

Alternative Pump Designs Horizontal Axially Split BB3Horizontal Radial Ring-Section BB4Double-Casing Diffuser Vertically Suspended VS6Sealless Multistage Canned MotorOverhung low Ns Impeller OH2Between Bearing low Ns Impeller BB2Surface mounted Electric Submersible PumpVertical in-line with High Speed Motor OH4Positive Displacement ReciprocatingPitot Tube

Alternative Pump DesignsAfter evaluation of all advantages and disadvantages andexperiences with the different pump designs, Pitot Tubepump type was selected for trial installation

Alternative Pump Designs Considerations Life cycle costSpace limitationAvailable local service centerEfficiency difference to account for electrical systemmodificationsRequirement for control systemSuspended particlesNPSHr vs. NPSHaCurve shape to match varying flow

Alternative Pump Designs –Comparison of Curves Caustic Pump

Alternative Pump Designs - CausticTransfer Replaced With Pitot Tube

Alternative Pump Designs – WashWater Replaced With Pitot Tube

Alternative Pump Designs– Pitot Tube Pump

Alternative Pump Designs – Limitationsof Pitot Tube Pump

Alternative Pump Designs - Pitot TubePumpAdvantagesDisadvantages Requires standard speed3600 RPM (higher speedrequires gearbox) Pitot tube sensitive to erosionfrom products with suspendedhard particles (requires finemesh strainer) Low initial cost Very low thrust load More sensitive to unbalancedue to large rotating mass

SummaryConsider the following main points for alternative designs: Life cycle costSpace limitationEfficiency to account for electrical system modificationsSuspended particlesOperating conditions

Thank you

Vertical or Horizontal orientations Introduction - Integrally Geared . Input Shaft Cover Plate Impeller with Inducer Idler Shaft Oil Pump Oil Filter Lower Gearbox Housing Mechanical Seal Introduction - Integrally Geared Cross Section Bearing Pl