Contamination Control For Wind Turbines

Transcription

1 Contamination Control For Wind Turbines ASME Graduate Student Workshop October 2009 Bill Needelman Chief Science Advisor Donaldson Company, Inc

2 Study by Professor E. Rabinowicz, MIT Six to seven percent of the Gross National Product is required just to repair the damage caused by mechanical wear. Note: Currently ~$1 trillion Loss of Usefulness Obsolescence (15%) Surface Degradation (70%) Accidents (15%) Corrosion (20%) Mechanical Wear (50%) Abrasion Fatigue Adhesion

3 Wind Turbine Reliability & Performance 25 % of Cost of Ownership of Wind Turbines is Maintenance Reliability Problems Gearbox > Blades > Generators 80% Of Operating Problems Due to GBX Mostly Gearbox Repair & Replacement Bearings are #1 Cause of Gearbox Failures Most Gearbox Warrantees ~2 Years, Costly Repairs Start ~4 th Year 90% Anticipated Energy Production 5% GBX, 3% Wind, 2% All Others

4 Hard Particle Damage Bearing Fatigue Hard Ductile (e.g. T15 & Steel) Hard Rigid (e.g. Al2O3 & SiC) Hard Friable (e.g. TiC) 1 Life Relative to Non-Dented Bearings Debris Particle Size Ref: Kotzalas & Needelman, AWEA Wind Power Conf, 2008

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6 Outline Problems Caused by Oil Contamination Particle Filters Water Contamination Control Best Practices Benefits & Conclusions

7 Types of Contaminants Particles - Hard & Soft Water Air/Gases Fuels, Acids, Glycols

8 What is a MICRON? MICRON Unit of Measurement 1 Millionth of a Meter (micrometer) Or " µ = Micron Symbol PARTICLE SIZE 100µ=Grain of table salt 70µ=Typical human hair diameter 40µ=Lower limit of visibility 10µ=Talcum powder 2µ=Bacteria 1µ 100 µ 10 µ 40µ

9 The Particle Zoo

10 19/17/15 18/16/14 20/19/17 21/20/18 23/22/20 21/20/18 26/24/22 16/15/13 15/14/12 TOO DIRTY TO EVALUATE

11 Major Types & Sources of Hard Particle Contaminants in Wind Turbines Hard Particles Manufacturing Swarf Machine Chips, Casting Sand, Grinding Debris, Abrasives Internal Wear Debris Gear Tooth Wear Internal Corrosion Products Rust, Aluminum Oxide Environmental Grit Airborne Mineral Dust, Sand Bath Tub Model

12 Hard Particle Problems Rolling Contact Fatigue Abrasive Wear & Erosion Lubricant Oxidation

13 Mechanical Wear By Hard Particles Abrasive Wear Adhesive Wear All Three Forms of Wear Result in Loss of Clearance, Rough Surfaces, and Greater Friction Rolling Contact Fatigue

14 Gear Tooth Contacts Sliding Contacts Rolling Contact

15 Gear Friction Increases As Gear Tooth Surface Roughens

16 Rolling Contact Fatigue: Surface Origin Spalls Spalled Area Initiation point Roller Path 16

17 Older Bearings Failed By Sub-surface Initiated Fatigue Spalling Load Dynamic Fluid Film Thickness (µm) Slag Inclusion In Steel

18 Particles & Surface Initiated Fatigue Particle Caught Load

19 Particles & Surface Initiated Fatigue Load Surface Dented, Crack Initiation

20 Particles & Surface Initiated Fatigue Load Crack Propagation Cracks Spread With Repeated Cycles

21 Particles & Surface Initiated Fatigue Fatigue Spall Crater Forms Hard Particles Released Load Spall

22 The Challenge Cleaner Gear Oil Drier Gear Oil Same For Hydraulic Fluids

23 ❷ ❸ ❹ ❸ ❷ ❶ Element Design DT Steel Std ❶ 1 Outer Wrap Collapse n/a High Collapse n/a n/a epoxy coated steel for stainless steel ❷ support and for support and 2 Support Mesh (2) spacing spacing DT Steel Coreless epoxy coated steel for support and spacing ❸ 3 Flow Control Layers (2) ❹ 4 Synteq Media synthetic layers to strengthen media thin glass-fiber media for performance synthetic layers to strengthen media thin glass-fiber media for performance synthetic layers to strengthen media thin glass-fiber media for performance

24 Filter Media Types - Wire Mesh - Cellulose - Synthetic (Glass Fiber)

25 Pressure Loss Across A Filter Element ( P) Pressure Loss Flow Rate X Viscosity X Tortuosity Gear Oil Oils: High Viscosity Gear Boxes: Moderate Flow Rates Fine Filters: High Tortuosity

26 Pore Structure Graded Pore Filter Media

27 State-Of-The Art Filter Media Conventional Media Resin Bonded New Media Bi-Component

28 Bicomponent Binder Fiber Glass microfibers Thermoplastic B Sheath Thermoplastic A Core

29 Bi-Component Filter Medium

30 Bi-Component Filter Medium Glass microfibers Thermoplastic binder fiber

31 Field Data: GE 1.5 MW Hydac Current 10um10 um Turbine #5 >4um >6um 5000 >14um Particles/ml DT New 5um 5 XP um /1/08 1/1/09 2/1/09 3/4/09 4/4/09 5/5/09 6/5/09 7/6/09 8/6/09 Dates

32 Dissolved & Free Water Dissolved Water Below Saturation Free Water Bulk Separation Free Water Emulsified

33 Major Sources of Water Contamination in Wind Turbines Water Vapor - Humidity Rain (Through Vents & Seals) New Oil

34 Oil Has A Relative Humidity (RH) At Equilibrium RH of Air Equals RH of Oil (RH Oil = %Saturation) 50% RH Air Water Molecules 50% RH Oil

35 Humidification Water moves from high relative humidity to low relative humidity 8 0 Moisture Content (% Saturation) Mobil DTE PM 220 in contact with air controlled at 90 o F & 80% RH T im e (H o u rs)

36 Problems Caused by Water Contamination in Wind Turbines Rolling Contact Fatigue Adhesive Wear Additive Dumping Oil Oxidation

37 Water Damage Bearing Fatigue 10 SAE 20 + R&O SAE 5 + EP (100/X)^0.6 Navy Data Relative Fatigue Life Water Concentration in Lubricant (PPM) Ref: Kotzalas & Needelman, AWEA Wind Power Conf, 2008

38 Water Water & Fatigue & Rolling Crack Contact Propagation Fatigue Oil + Dissolve Water Forced Into Cracks in the Contact Zone Load Hydrogen Embrittlement

39 Loss of Fluid Film Lubrication & Adhesive Wear Load Low Viscosity Water Not Able To Support Load Film Collapses Dynamic Fluid Film Thickness (um)

40 Water Damage Additive Drop-Out Fouled & Disabled Oil-Level Sensor

41 Water Damage Additive Drop-Out Courtesy COT-Puritech, Inc. Fouled & Disabled Thermostat

42 Keeping Gear Oils & Hydraulic Fluids Dry in Wind Turbines Prevention Minimize Ingression Removal Rapid

43 Regenerable Breather Dryer

44 Inhalation Captures H 2 O Exhalation Regenerates By Releasing H 2 O

45 Dry Air Blanket System TRAP Breather with Tee and Relief Valve Customer Supplied Flow Meter (Optional to adjust compressed air usage as required) Inlet Port Inlet & Outlet Installed On Opposite Corners Ideal Outlet Port Customer Supplied Shut-off Valve Orifice ARV-3: P ARV-10: P (Must be installed for proper operation of ARV) Reservoir Customer Supplied Shut-off Valve (Required for maintenance of unit) Customer Supplied Pressure Regulator with Guage (set to 100 psi) Ultrapac ARV-3: P ARV-10: P Incoming Compressed Air

46 Dry Air Blanket System Humid Air Saturated Oil Purging Humid Air Saturated Oil Dry Air Moisture Desorbing from Oil Dry Air Dry Oil Time

47 Pressure Swing Adsorption Dryer Na 12 [(AlO 2 ) 12 (SiO 2 ) 12 ] x H 2 O - 10 Angstrom Molecular Sieve

48 Dry Air Blanket Keeping Oil in Contact With Very Dry Air Head Space Air Relative Humidity (%) Reservoir Head Space Air Exchanges/hour Tim e (Hours) Oil Percent Saturation (%) Reservoir Oil Time (Hours) 2

49 Best Practices Total Contamination Control Plan 1) Design 2) Roll-Off Cleanliness 3) Transportation 4) On-Site Storage 5) Clean Maintenance Practices 6) Ingression Prevention 7) Rapid Removal

50 Best Practices For Ingression Prevention & Rapid Removal Regenerable Breather Dryer with 3 Micron Filter Dry Air System Cooler Inline Filter β 5(c) =1000 Gearbox Offline Water Absorption Filter Offline Filter β 3(c) =1000 Objectives: ISO 14/12/ ppm max

51 Bearing Life Factors NASA/STLE Roller Bearing Life Factors for Wind Turbines 2um 5 um 8 um 10 um 12 um Filter Rating Where (C) = 1000 (Microns) Adapted from Needelman & Zaretsky, STLE Annual Mtg. Proc. May 09

52 NASA/STLE Model Water Contamination & Bearing Life 7.0 Relative Bearing Life Target Maintaining Dry Oil Estimated To Increase Bearing Life ~200% Current Water (ppm)

53 Conclusions Benefits Of Excellent Contam Control Greater Gearbox Reliability More Uptime, More Production Extended Warrantees Up To 5 Year Gear Oil Life Needed Coherent Contamination Control Plan Use Best Technologies & Practices

54 Thank You For Your Interest Questions? Comments?