This paper describes about antioxidant replenishment in turbine oil, reactive nature of oil degradation products i.e. varnish and effectiveness of antioxidant additive readditization. Presented at STLE (Tribology and Lubrication Engineering Society), Annual Meeting, Las Vegas, 2016.

1. Reactive Nature of Oil
Degradation Products
Greg Livingstone, Cristian Soto &
Jatin Mehta

2. © 2016 Fluitec International
Presentation Overview
Oil Degradation
Products are Reactive
They First React with
Antioxidants
Maintaining an oil
with low levels of
degradation products
extend oil’s life
Outline
1. Oxidation creates radicals
2. Chemistry of Degradation Products
3. Impact on Bleed & Feed and Antioxidant Synergism
4. Experiment to demonstrate the reactive nature of degradation products

3. © 2016 Fluitec International
Oxidation produces Reactive Chemistries
Radicals

4. © 2016 Fluitec International
Free Radicals can be observed by ESR
Source: James White, “Micro Electron Spin Resonance: Unlocking Free Radicals in Used Lubricants; Oil Doc 2015

5. Chemistry of Oil
Degradation Products

6. Analyzing the Deposit

7. Characterizing the Deposit

8. © 2016 Fluitec International
Deposit Chemistry: Example 1
Bearing Sleeve Deposits from a CO2 Compressor

9. © 2016 Fluitec International
Analysis of the Deposits
Degradation Chemistries
• Water (3349 cm-1)
• Organo-phosphate
(1100-1000 cm-1)
• Esters (1740 cm-1)

10. © 2016 Fluitec International
Deposit Chemistry: Example 2
• 3 Year Old Steam Turbine used in
a waste incineration plant
• Located in Contaminated
Environment

11. © 2016 Fluitec International
Characterized the Deposits
11
Degradation Chemistries
• Carboxylic Acids
• Esters
• Aromatics

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Deposit Chemistry: Example 3
Methanol Compressor Train

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Analysis of the Deposits
Degradation Chemistries
• Carboxylic Acids (1706
cm-1)

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Deposit Chemistry: Example 4
Deposit from an ammonia compressor

15. © 2016 Fluitec International
Analysis of Deposit
4000 6503500 3000 2500 2000 1500 1000
116
-13
-10
0
10
20
30
40
50
60
70
80
90
100
110
cm-1
%T
738cm-11068cm-1
1453 cm-1 702cm-1
1380 cm-1
2958cm-1 1560cm-1
2926cm-1
673cm-1
1205cm-1
998cm-1
1612cm-1
836cm-1
1660cm-1
2855cm-1 784cm-1
1316cm-12872cm-1
1234cm-1
1703.m-1
3203cm-1 1513cm-1
3055cm-1 893cm-1
1769cm-1
Primary Amide
Carboxylic
Acids
Ammonia Amides

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Acids
Water
Example 5: Analysis of Steam Turbine Sludge
Ref:: Livingstone, WootonRef: Livingstone, Wooton

17. © 2016 Fluitec International
Reactions can makes very gooey substances
Ref: Livingstone, Wooton

18. Degradation products
may impact “bleed &
feed” results

19. © 2016 Fluitec International
Data from several bleed & feed operations
1 2 3 4 5 6 7
Phenols Before 20% 41% 32% 5% 24% 55% 12%
Bleed & Feed % 10% 12% 14% 15% 25% 27% 30%
Estimated
Result 28% 48% 42% 19% 43% 67% 38%
Phenols After 21% 44% 37% 16% 41% 65% 37%
Effectiveness 13% 43% 50% 79% 89% 83% 96%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0% 5% 10% 15% 20% 25% 30% 35%
Effectiveness
Bleed & Feed Rate

20. © 2016 Fluitec International
Observations
Fresh antioxidants are immediately consumed when first introduced to in-service oil.
This lowers the economics of bleed & feed and additive replenishment.
The higher the bleed & feed percentage, the more effective it is.

21. Different Effectiveness
of Antioxidant Addition
to In-Service Lubricants

22. © 2016 Fluitec International
Effectiveness of AO Replenishment in Used Oils
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
AntioxidantConcentration
Measured AO (wt%) Expected AO (wt%) (Measured - Expected)
Expected active AO levels after additive replenishment

23. © 2016 Fluitec International
Effectiveness of AO Replenishment in Used Oils
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
AntioxidantConcentration
Measured AO (wt%) Expected AO (wt%) (Measured - Expected)
Measured AO levels after additive replenishment

24. © 2016 Fluitec International
Effectiveness of AO Replenishment in Used Oils
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
AntioxidantConcentration
Measured AO (wt%) Expected AO (wt%) (Measured - Expected)
Difference (Measured – Expected)

25. © 2016 Fluitec International
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
AntioxidantConcentration
Measured AO (wt%) Expected AO (wt%) (Measured - Expected)
Minimal AO Synergy
Effectiveness of AO Replenishment in Used Oils

26. © 2016 Fluitec International
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
AntioxidantConcentration
Measured AO (wt%) Expected AO (wt%) (Measured - Expected)
Excellent AO Synergy
Effectiveness of AO Replenishment in Used Oils

27. © 2016 Fluitec International
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
AntioxidantConcentration
Measured AO (wt%) Expected AO (wt%) (Measured - Expected)
Reactive by-products cause lower than expected results
Effectiveness of AO Replenishment in Used Oils

28. Impact of Antioxidant
Addition after
Degradation Products
are Removed

29. © 2016 Fluitec International
Experiment
1. The AO levels were determined in in-service oils with MPC’s >40
2. Amines and Phenols were measured by RULER and the concentration by
weight was calculated
3. A known amount of amines and phenols were added to each sample.
4. The sample was then filtered through a selective media to remove the
oil degradation products. MPC values were <5 after filtration.
5. The same level of amines and phenols were added to each filtered
sample.
6. The filtered and unfiltered samples were compared.

30. © 2016 Fluitec International
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Sample 1 Sample 2 Sample 3
Amines Before Amines After Amines After Filter Phenols Before Phenols After Phenols After Filter
The Impact of Oil Degradation Products to
Antioxidant Addition
Calculated Concentration of Amines & Phenols in In-Service Samples

31. © 2016 Fluitec International
The Impact of Oil Degradation Products to
Antioxidant Addition
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Sample 1 Sample 2 Sample 3
Amines Before Amines After Amines After Filter Phenols Before Phenols After Phenols After Filter
Amines & Phenols Levels after Spiking

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The Impact of Oil Degradation Products to
Antioxidant Addition
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Sample 1 Sample 2 Sample 3
Amines Before Amines After Amines After Filter Phenols Before Phenols After Phenols After Filter
Amines & Phenols Levels after Filtration to remove degradation products and then spiking

33. © 2016 Fluitec International
The Impact of Oil Degradation Products to
Antioxidant Addition
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Sample 1 Sample 2 Sample 3
Amines Before Amines After Amines After Filter Phenols Before Phenols After Phenols After Filter
+1%
+10%
+14%
+5%
Improvements were shown after degradation products were first removed
+2%
+44%

34. © 2016 Fluitec International
Not All Degradation Products are Reactive
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Sample 4 Sample 5 Sample 6
Amines Before Amines After Amines After Filter Phenols Before Phenols After Phenols After Filter
-1%
-2%
0%
0%
0%
-2%

35. © 2016 Fluitec International
Summary
• Some oil degradation products are reactionary.
• There are hundreds of different types of oil degradation products and not all of them
will be reactive.
• MPC and FTIR are two methods that can be useful in measuring oil
degradation products.
• Removing oil degradation products from in-service oils should have a
positive impact on the life of the oil.