Additive & Bench Test Development

Transcription

1 dditive & Bench Test Development Jeffrey M. Guevremont, Ph.D. Sr. R&D Scientist Technology Development fton Chemical 2015 STLE Tribology Frontiers: Pre-Conference Workshop dvances & Opportunities in Lubrication: Wind Turbines Sunday, October 25, :30am 12:30pm Grand Hyatt, Denver, Colorado

2 Technology Development pproach Field Lubricant performance rated in highly variable environment Changing wind speeds and directions Starts and stops that result in high transient loads Wide operational temperature range Water and other contamination pprovals / Specifications Tests aimed at judging ability of lubricant in field Standardized testing Tests of fully formulated fluids Pass / fail criteria Offshore wind farm using 5MW turbines in the North Sea off the coast of Belgium Bench Tests Tests aimed at understanding impact of lubricant and additives Test fully formulated fluids to singular additives Results can be used to model rig or field test results

3 Time Cycle of Testing New Idea New Idea Discuss Result Synthesis (Months) Discuss Result Synthesis (5 Days) Testing (Years) Field Testing Testing (Days/Weeks) Rig Testing

4 Time Cycle of Testing New Idea New Idea Discuss Result Synthesis (5 Days) Discuss Result Synthesis (1 Day) Testing (Days/Weeks) Rig Testing Testing (0.1 Day) Bench Testing Bench testing saves time and money Bench testing can also reduce variability of results and improve understanding of additives!

5 OEM pprovals and Industrial Specification Requirements Industrial Specification Requirements DIN Part 3 ISO ISO Gearbox Suppliers Hansen Transmissions Winergy Moventas (Metso) Bosch-Rexroth (L+S) GE Transportation Systems (GETS) Eickhoff Nanjing Bearing Suppliers SKF FG / Schaeffler Timken NSK Koyo Lubrication System Suppliers Hydac Parker Hannifin Internormen CC Jensen Nissens (DK)

6 Test Categories Included in OEM pprovals 1. Viscometrics and Shear Stability Kinematic Viscosity Viscosity Index Brookfield Viscosity Dynamic Viscosity Shear stability 2. Physical Properties cid value Density Flash point Pour point Storage Stability Evaporation Loss Water content Cleanliness Heat capacity 3. Surface Properties Demulsibility ir Release Foaming ir entrainment 4. Corrosion Copper Iron/Steel Bearings 5. Oxidation Oxidation Stability, Temperature Oxidation Stability, Bearing Oxidation Stability, Gear 6. Load Carrying and Wear Scuffing tests Wear tests EP tests Micropitting tests 7. Filters and Filterability Various material and size Temperature 8. Fluid Compatibility Repeat of many of tests in all categories 9. Seal Compatibility Static, many materials and temperatures Dynamic, many materials Other Compatibility Paint Sealants/Gaskets Cage material Hoses 14. Product Durability High Temperature Low Temperature Sludge Formation 16. Service Performance / Field Trial Field Trial greement Number of individual tests is much longer

7 Tests Required for a Commercial Wind Turbine Fluid s seen earlier, these tests have common themes Focus on two areas that bench testing can really help

8 Picking the Right Bench Test OR HSV HFRR MTM SLIM EHD Surface nalysis Used to study additive. Sensitive to, but generally not used to study. NTIWER GENTS FRICTION MODIFIERS CORROSION INHIBITORS DETERGENTS DISPERSNTS OXIDTION INHIBITORS RUST INHIBITORS DEMULSIFIERS There is already a wealth of knowledge on how many additives affect performance in bench tests FOM INHIBITORS PPD VII

9 Low Temperature Properties Low temperature visometrics are important for restarting of turbines in low temperature environments Solubilizers Thickeners Base Oils Low Temperature Viscosity

10 Comparison of Industry Standard Low Temperature Testing Mini-Rotary Viscometer MRV Cold Crank Simulator CCS Brookfield Viscometer Fixed BV Brookfield Viscometer Scanning BV Rotational Viscometer Rotational Viscometer Rotational Viscometer Rotational Viscometer Temperature range: -15 C to -40 C Temperature range: -10 C to -35 C Temperature range: -5 C to -40 C Temperature range: -5 C to -40 C Cooling rate: Very slow (variable) Cooling rate: Very fast Cooling rate: very fast, hold Cooling rate: 1 C per hour Shear rate: 0.4 to 15 s -1 Shear rate: 10 4 to 10 5 s -1 Shear rate: up to 100 s -1 Shear rate: 0.2s -1 Results: Yield Stress (Pa) at final temperature Viscosity (cp) at final temperature Results: Viscosity (cp) at final temperature Results: Viscosity (cp) at final temperature Results: Viscosity (cp) during cooling cycle Gelation Index

11 Rotational Rheology (i.e. Scanning Brookfield) Velocity (v) Rotational Rheology (i.e. MRV and Fixed BV) Velocity (v) Oscillatory Rheology Frequency (ω) Cool Cool Cool Velocity (v) Velocity (v) Frequency (ω) Output Viscosity (T), Limited network information Output Viscosity at EOT, No information during cooling cycle Output Viscosity (T) with network information during cooling cycle

12 Relating Complex Viscosity to the Elastic and Viscous Behavior of Commercial Wind Turbine Oils Viscosity at at 40 C (cp) Brookfield Viscosity Complex Viscosity Oil Oil Oil Oil B B Oil Oil C C Oil Oil D D Oil Oil E E Oil Oil F F Oil Oil G G Oscillatory Rheometer results correlate to Brookfield Viscosity There is more to learn from the OR data

13 Relating Complex Viscosity to the Elastic and Viscous Behavior of Commercial Wind Turbine Oils Brookfield Viscosity Complex Viscosity Oil Oil Oil Oil B B Oil Oil C C Oil Oil D D Oil Oil E E Oil Oil F F Oil Oil G G Viscosity at at 40 C (cp) Elastic behavior (G ) at -40 C Viscous behavior (G ) at -40 C Oil Oil B Oil C Oil D Oil E Oil F Oil G Oil Oil B Oil C Oil D Oil E Oil F Oil G Modulus (Pa) at 40 C Modulus (Pa) at 40 C 200 0

14 Oscillatory Rheology Gives More Than Just Viscosity Oil Oil B Complex Viscosity (Pa s) Two oils showing different viscosity curves as temperature decreases Temperature ( C) Sample gaining structure Differences in viscosity can be attributed to changes in the elastic and viscous modulus of the oil as temperature decreases

15 Summary Oscillatory rheology (OR) used for the development of a wind turbine fluid to be used in extreme cold environments OR used to systematically optimize low temperature viscosity of base oil, thickener, and solubilizers Measuring the elastic and viscous behavior of an oil during the whole cooling cycle Correlates to BV and gives more information than BV Red flag any combinations that form any type of structure measurable by the OR OR allows testing of singular additives, binary mixtures as well as fully formulated fluid Greater insight into unwanted interactions in the fluid

16 Bearing Durability Bearing durability is important to achieve the predicted lifetimes of equipment Friction Modifiers Solubilizers ntiwear dditives Friction, ntiwear film formation

17 Previous Results from Research on Industry Standard Gear and Bearing Protection Testing Rolling 4-Ball Test Lower thin film friction increases life to pitting Reduce subsurface stress FE8 High P in tribofilms reduces wear High P in tribofilms creates a stronger film that is more resistant to wear FZG (micropitting) Lower boundary friction improves micropitting life Lower boundary friction means less stress in the aspirityaspirity contact

18 Friction Measured with Mini Traction Machine (MTM) Friction coefficients from MTM have been correlated to FZG gear tests Lower friction results in longer life Choose test conditions to mimic operating conditions of wind turbines

19 MTM Friction : Competitive Wind Turbine Oils Friction Coef. 80 C 50%SRR 35N Load 1 m/s Friction: Lower is better B C D E F G H I Candidate Reference 1 Look for best friction performance of known chemistries under benchtop wind turbine conditions Iterate discovery process of idea-formulate -test-discuss

20 fton Knows how to Prevent Fatigue Friction Coef. 80C 50%SRR 35N Load 1 m/s Friction: Lower is better B C D E F G H I J K L M N O P Q R S T 1 Reference Iterative process quickly gives many candidates with low friction Turn to another bench test to differentiate good friction candidates

21 Measuring Tribofilm Formation with MTM-SLIM Results from MTM with Spacer Layer Imaging Method (SLIM) have been correlated to bearing and gear fatigue and wear Film formation and presence of high P in the film is better for fatigue and wear

22 Not Too Thick, Not Too Thin, Just Right nm Fluid Fluid B Fluid C Thin Film Friction Coefficient Thin / smooth tribofilms give the lowest thin film and boundary friction Castrol Fluid Optigear Mobil Fluid SHC XMP B 320 Fluid BP/ fton C

23 Its ll bout the Pressure Motivation to study chemistry at higher pressures Industry standard tests Field tests High load transient loads

24 Normalized P Need High mount of Phosphorus in Film at High Pressure GPa 3 GPa Tribofilm %P: Higher is better B Fluid Fluid B B Fluid B C Fluid HI24881 D Need fluid that can with stand occasional high pressures mount of P in film increases as pressure increases

25 Summary MTM and MTM-SLIM used for the development of a low friction wind turbine fluid that performs under high loads MTM used to systematically optimize desired friction and antiwear properties MTM used to measure friction properties of fluid MTM SLIM used to study tribofilm formation and composition Red flag any fluids with high friction or poor tribofilm composition MTM allows testing of singular additives, binary mixtures as well as fully formulated fluid Greater insight into wanted or unwanted interactions in the fluid

26 Candidates with Good Rheology, Low Friction and Good Tribofilms have been Identified Bench test development saves time and money DOE testing creates understanding of additive impacts on formulations Increase speed of development and improve chance of success in rig and field testing 0020

27 Thank You!