Our turbine oil RULER test came back as 7% phenolic and 11% amine, does anyone know how much oil needs to be drain/added to increase additive to an acceptable level?
Assuming tank volume is 6,600 litres and only 1 x 205 litre drum per day is drain/added to the system.

Frank

Hi,
when you look at RUL% number for remaining antioxidants, it is important that this shall be part of a trend analysis program (with oil sampling frequency at 3-4 times/year). Consequently, as international standards are specifying, ASTM and DIN, once you reach the condemning limits for one of the parameters, in this case the antioxidants, ASTM D-4378 specifies 25% alarm level, you can take some actions long before this 25%. In your case, you should perform additional testing such as particle counting, colorimetric (varnish) patch test, viscosity, etc... and than talk to your oil company to ask for their advise if you want to sweeten this oil reservoir. Experiences has shows us that with those low levels of remaining antioxidants (and possible other alarm oil parameters) you may more harm your equipment than salvage it. If you send me your e-mail adress, I can send you a copy of an interesting paper on the pro and contra's of sweetening.

Hi Jo
What is your email address? mine is: Frank.Cabello@bluescopesteel.com

Hi macabf,

I agree with Jo, you need to also get a TAN and RPVOT done on the used oil to determine how much the oil has deterioated. In general, if the TAN has increased by 0.3 to 0.4 mgKOH/g over the new oil and the RPVOT is at 25% of the new oil, it is time to change the oil. You may also find that as the oil gets closer to the end of it's life the rate of change in RPVOT also increases. Additives used for turbine oils has somewhat changed over the last few years. The old style product had the R&O inhibitor as a separate additive whereby sweetening the system with "over treated" drums of turbine oil could be done. However, nowadays most additive packages come as one combined pacakage making sweetening difficult and ineffective. Your oil company will be able to tell you if you can sweeten the system or not and advise you based on the oil analysis results.

quote:

Originally posted by Jo Ameye:
If you send me your e-mail adress, I can send you a copy of an interesting paper on the pro and contra's of sweetening.

I find it regrettable that you have chosen to offer sending the info individually instead to post it and share it with the rest of board’s members. Also, I see a trend recently where some other folks practice the same. I don’t know what to make of the fact that in the same time all of you welcome and like when others provide links to their offered info. Is selfishness the reason? Is it a sale pitch attempt? Or is it something else? I simple don't get it!

Hi Frank,

Personally, I was never a fan of the RULER, for simple reason that no manufacturer or blender of turbine oils ever even mentioned those parameters in their spec sheets. It is something that every user needs to establish for their own oil, and it would be valid as long as they use the same type of base oils and the same type of blended additives. If the oil type was changed or different oil with different additives is used as a make up oil, the whole established process is useless and should be started anew. In addition, there is absolutely no correlation or the results relationship between good old RPVOT and AN (as ReneWA suggested) expressed in their units, with absorbencies per millimeter or centimeter from RULER.

However, in you case, where you have established your RULER parameters, as long as you use the same oil (type and additives) as a make up oil, or use it as a sweetener, it may work for you. It is almost impossible to tell how much “sweetener” (new oil) you need to add. You may start with adding 20% of new oil and do the testing (it wouldn’t be a big deal as the RULER is pretty cheap test), and then go from there.

In any rate, I don’t mind spending a bit more and track serviceability of turbine oil by well established RPVOT, AN, and other parameters, as ReneWA suggested.

In my opinion, the scare mentioned by Jo Ameye (that you can do more harm then good with sweetening) would apply only if you new “sweetening” oil is not fully compatible with your in-service oil.
Good luck.

John
See below other results from tests carried out over a period of 4 weeks, during that time we connected a Kleentek machine which helped in reducing particle contamination and oxidation by-products.
We are looking at sweetening the oil in the 6,600 tank, the plan is to drain/add 1x205 litre drum per day to raise the antioxidant level to 25%
New oil contains 0.25% phenolic and 0.25% amine
also 80 ppm zinc which currently is down to 29 ppm.

Purification of turbine oil system

23 Turbine Blower..............UIN 5C2D5........UIN 3FBD1................... Electrostatic liquid cleaner
6,500 litre tank............................................................ Kleentek ELC-R100SP
............................................................................ 12L/min

Sequence #......................................1...............2...............3...............4
Date of Sample..................New oil.........29/06/2007......16/07/2007......23/07/2007......30/07/2007
Hours of Filtration.............0...............169.............408.............574
Gravimetric Patch
0.8 micron wt mg/100ml..........<1..............3...............2.7.............1

ISO Cleanliness code............18/15/10........23/22/18........19/17/11........15/13/11........17/15/11
Particle Count
# of particles >4μ..............1312............48292...........4302............286.............663
FTIR Oxidation absorbance units.4.5.............5.8.............6...............5.9.............6
TAN.............................0.23............0.31............0.31............0.29............0.28
Ruler - phenolic................................................................7%
......- amine...................................................................11.2%
RPVOT...........................310.............107
Ultra centrifuge................1...............4...............6...............5
Colour..........................L0.5............L6.5............6.5.............6.5.............6.5
Viscosity.......................66..............66..............66..............66..............67
Zinc............................82..............29..............27..............33..............29
Sulphur.........................684.............1390............1619............1402
Phosphorus......................129.............120.............118.............132.............129

Demulsibility...................41-37-2 (20)
Corrosion.......................1a
Foam......-sequence I...........300-0
..........-sequence II..........10-0
..........-sequence III.........70-20

This message has been edited. Last edited by: macabf,

Hi macabf,

Please note that I am not suggesting that there is a correlation between RULER with RPVOT and TAN as stated by John. My suggestion is to rely on the RPVOT & TAN results and other test parameters for evaluation similar to the ones you have listed.
I can see that you are in Australia, most turbine oils formulated are using a combined additive package.
You should talk to your oil supplier about getting further analysis on the used oil for the antioxidant package on the FTIR. Antioxidant additives such as butylated hydroxy toluene are often used (the phenol you are measuring in the RULER method is most likely part of the BHT as it does contain the phenol group). The FTIR can identify and measure the antioxidant level of old versus new oil, a calculation can be done to determine the amount of top up you need to bring the antioxiant level back up.
However, the success of sweetening is dependent on if you have been topping up with the older style formula or the newer style formula over the years. This may be a reason why you have seen a change in the zinc level as the formula may have changed over the years.
To find out if this is the case, you should talk to your oil supplier.

There was a series of papers presented at ASTM in December 2005 showing RPVOT was very accurate for oils using BHT/DBPC (oils RPVOT was developed for) but was not as useful for turbine oils using amine/phenol combinations. Basically when the phenols depleted, the varnish/AN started accumulating even though RPVOT was still in good shape since amines just starting to deplete. Also some of the newer antioxidant systems are acidic causing AN to decrease with initial use followed by increase.
Are you monitoring a steam or gas turbine? When were the RPVOT performed: 2 data points/5 dates? I am not that familiar with particle counts but it looks like you had a very high particle count prior to cleaning with the electrostatic cleaning but the particles started to increase again during the last sample or is increase within reproducibility of test?
I copied the below response from the bottom of page 2 of this forum when sweetening was also discussed. Gives a link to get some of the data that was presented at ASTM.
Rick - Our paper presented at ASTM Norfolk last December showed our results of 3 samples, two used turbine oils and the new oil, sent to 4 different labs, in four different parts of the world. The samples to three of the labs were unmarked to try get get some real "blind" testing results.

Of the blind labs, two of them could not even tell the difference between used oils and the new oil (by RPVOT values, of course the color would have been a dead give-away, but they must of neglected to look at that)

One blind lab maybe looked at the color of the oils, and gave results that sort of made sense, at least the new oil was higher in RPVOT than the used oils. However, they were still way off in the realive RPVOT values.

The only lab to get the results right, was the same lab than blended the oil!!And you guessed it, they were not blind, and knew it was their oil. Lo and behold, they got the new oil value right!

What does that tell you? It tells me that RPVOT does not work with true unknown samples, in true blind testing, and that most RPVOT results are made-up by random number generators or dart-boards!!
(rememeber the accountant job-applicant joke..how much do you want it to be, boss?)

email me at andy.sitton@focuslab.co.th if you want to see the data

John
I am the inventor of the RULER so I will try and answer some of your concerns. The RULER is used world-wide for a variety of systems - links to papers available at www.Fluitec.com. I believe Turbomeca a major aircraft engine company has written the RULER into its specs. SKF has developed a RULER test for greases which I believe is in the round robin stage of ASTM. There are ASTM procedures for using RULER on turbine oils.
The problem is many additive and oil companies are doing research with the RULER but don't want data given out to general public for various reasons. So personal contact is the more acceptable avenue. Second there are numereous papers being presented on RULER/turbine oils but are not published again for various reasons making it hard for public sharing. Also there are the issues of copyright forcing interested parties to get data from sponsoring organization not the author.

With respect to RULER acceptance:
My previous reply has e-mail for one of the papers presented at ASTM 2005 symposium on turbine oil oxidation symposium. Presumably you can now get electronic copies of all of the papers presented but even though its coming up on two years still not sure of availability. Several papers showing good correlation between RULER and RPVOT for phenol systems, differences occur for phenol:amine systems. RULER provides valuable information on antioxidant system so that results of RPVOT can be better understood with regard to varnish and oxidation.

NORIA Conference Louisville May 2007
Session Titled Sludge and Varnish - 4 of the 5 papers used the RULER as means to monitor antioxidants. Albemarle, an additive company, was one of the authors
STLE Conference Philadelphia May 2007 -
Ontario Power presented a favorable paper on RULER in Condition Monitoring III
Several Papers in Power Generation I and II using RULER specifically to monitor phenol replenishment. Problem is STLE allows presentation with out publication. I believe NORIA is the same.
The papers indicated the pitfalls that may occur with turbine sweetening come from adding phenol/amine combinations when only the phenols are depleting so you end up with a large aminehenol ratio which promotes sludging from amines. RULER allows you to identify the antioxidant that is depleting/needs replenishment. In cases such as this thread where both antioxidants have been depleted almost completely the phenol:amine ratio would remain intact so sweetening seems an option assuming work to restore cleanliness of oil/system is possible.

Why did NORIA put a smily face in place of amine: phenol does = face?

Guess it does. : p without space = face.

Hi John,
It was only my objective, based on 25 years of lubrication experiences, to present the pro's and contra's of topping up lubricant reservoirs. Not more than you can read in the Machinery Lubrication magazine, July-August 2007, page 46 (article Drew Troyer). Maybe my English was not that correct, for which my apologizes.

quote:

Originally posted by John Micetic:
Hi Frank,

Personally, I was never a fan of the RULER, for simple reason that no manufacturer or blender of turbine oils ever even mentioned those parameters in their spec sheets. It is something that every user needs to establish for their own oil, and it would be valid as long as they use the same type of base oils and the same type of blended additives. If the oil type was changed or different oil with different additives is used as a make up oil, the whole established process is useless and should be started anew. In addition, there is absolutely no correlation or the results relationship between good old RPVOT and AN (as ReneWA suggested) expressed in their units, with absorbencies per millimeter or centimeter from RULER.

However, in you case, where you have established your RULER parameters, as long as you use the same oil (type and additives) as a make up oil, or use it as a sweetener, it may work for you. It is almost impossible to tell how much “sweetener” (new oil) you need to add. You may start with adding 20% of new oil and do the testing (it wouldn’t be a big deal as the RULER is pretty cheap test), and then go from there.

In any rate, I don’t mind spending a bit more and track serviceability of turbine oil by well established RPVOT, AN, and other parameters, as ReneWA suggested.

In my opinion, the scare mentioned by Jo Ameye (that you can do more harm then good with sweetening) would apply only if you new “sweetening” oil is not fully compatible with your in-service oil.
Good luck.

Frank,
I will give you my honest opinion about you oil based on your analysis report.

1. Based on relatively high AN of the new oil and after being in service, it seems that your oil is blended with Group 1 base oil. In addition, relatively low initial RPVOT (310 min. for new oil, when most Group 2 turbine oils have RPVOT at minimum 800, and some in range of 1200 and up to 1800 min). Also, the presence of Zinc (and phosphorus and sulfur) lead me to believe that you have ZDTP type of antioxidant, which was generally used (and probably still is somewhere) for blending Group 1 turbine oils, rather than exclusively an ash-less additive package. If this is correct, then I don’t know how reliable RULER analysis would be for you. Maybe Bob K. can shed more light to it.

2. From my experience, I have seen the initial RPVOT (new oil) drop after the oil has been in service for awhile. However, after this initial drop, RPVOT establishes itself at some lower level and remain on that level for long time. If you look at Zinc concentration, you see the same pattern – drop from initial 86 down to upper 20 level, and remain pretty consistent at that level. That also support my thought that you probably have Zn-based antioxidants. Of course, they might be some ashless-type additives added too, but they are not exclusive.

3. Your Kleentek filter works fine. The cleanliness reported on 30 Jul, showing worst code than the one from 7 days earlier, may be affected (contaminated?) during sampling & handling, or the same sampling procedure was not utilized (e.g. draining at the sample port inconsistent?). I say this because both the Gravimetric Patch analysis and Ultra Centrifuge suggest that the sample from 30 Jul is cleaner than the one from 23 Jul.

4. I don’t know what to make of you RULER analysis, but you don’t have to sweat (yet!) too much, because your RPVOT shows approx. 35% of the remaining life, and condemning limit is when starts dropping below 25% of the remaining RPVOT. I have a sense that RULER lovers think very low of RPVOT (like, it is inconsistent and not trustworthy analysis). But guess what, in RULER literature it is suggested to run RPVOT (yes, the same “unreliable” RPVOT) whenever RULER comes down to 25% level – to check for the “Remaining Oxidative Life estimation”. Some folks love to have it both ways.

5. The one thing that puzzles me is the color of your oil. In just over two weeks it turned from 0.5 to 6.5 (similar is when I do oil change on my VW Beetle TDI). This color, and the initial high cleanliness code after you filled new oil in the machine, suggest that you guys did not make a serious attempt to flush the system, if at all.

6. I don’t know if you guys ran compatibility test between new and in-service oils before you mixed them or filled the machine. Incompatibility may cause stripping of the additives, and caused such (and worst) rapid drop-off in RPVOT. For years we successfully used services of the Herguth Labs in “dodging the bullet”, by avoiding new oils that were tested and identified as being incompatible with our in-service oil. But now you, and everyone else, can use new, and first time ASTM assembled method for testing compatibility, ASTM D 7155-06, Standard Practice for Evaluating Compatibility of Mixtures of Turbine Lubricating Oils".

7. You did not post numbers for water in oil. I don’t know of what kind media you filter is made from, but a great performance we are getting from the cellulose type filters (like what the CCJensen and others offer). They are absorbent filters, and therefore, besides capturing particles, they take care of small amounts of water in oil, if it gets there. Of course, if there is a cooling water leak or other types of water ingression, that water should be dealt with a demoisturizer. However, if your Kleentek is not an absorbent type, you can always add an absorbent scrubber to it

8. According to the viscosity, your oil is at great shape. My suggestion would be to keep that Kleentek running 24/7. Your cleanliness will look better and better, and you might even enhance the color of oil. Also, it should be of no surprise to anyone to see RPVOT reading higher once the oil is cleaner. It has been noted in literature, and from my personal experience, a high load of contaminants can cause an early (premature) pressure drop during analysis, thus showing lower RPVOT than actually is. After filtering such oil, it showed better results (higher RPVOT). Also, keep an eye on AN and cleanliness (once in a month would be sufficient but you can do more often if that would give you piece of mind), and check RPVOT every 6 months until is stabilized. After that time, you can test it just once a year as long as AN stays fairly consistent. As a footnote, our AN warning limits for Group 1 turbine oils is at 0.5, and condemning limit at 0.70, providing that the initial AN (new oil) was 0.20 - 0.25.

ReneWA,
I messed up a bit here. The point I was trying to make is that you too suggested that there is no correlation, not that there is one. In fact, I totally concur with your opinion which you stated in your previous post, and our testing practices consist of what you suggested. I am sorry if you got it differently.

Frank,
Forgot to comment on you planed sweetening. When you add new oil, make sure it is mixed well before you take a sample and test it (could be done to run through a purifier after new oil has been added, or you if can pump from this reservoir back into the same reservoir. Also, I don’t know how many independent sumps you have, but after mixing sweetened bulk and confirmed testing, you should drain those sumps and fill them with such sweetened oil. Or, are you planning to drain portion of individual sumps and replenish them with new oil?

Jo Ameye,
I am not questioning your lubrication knowledge in any way. I just get testy when people don’t want to share their knowledge and point to valuable info to the rest of patrons on this board (as you did now, but rather seek one-on-one dealing. However, it is their right to do as they please. No offence, but I just happen to detest that way of communication.

Bob K.
I get from your comments that you have no or very low confidence in repeatability and reliability of RPVOT test. But what I got from reading the articles on website that you provided (Fluitec.com), I got different impression. For example, the author suggests running RPVOT every time RULER shows 25% remaining antioxidants levels to check the “Remaining Oxidative Life estimation”. Of course, he mudded the statement by adding “if necessary”, but failed to elaborate when is necessary and when is not. But basically, it seems to me that RULER is not too reliable at low readings, and that’s why it is suggested to check it out with the, for this occasion, reliable RPVOT.

However, looking from my perspective (hydropower), where the operational conditions are very gentle on turbine oil, running RPVOT, foaming, demulsibility, and rust test once a year, and semiannually testing for viscosity, water, metals, cleanliness and AN is quite sufficient testing program. Heck, we use the same oil for approx. 30 years, and I have no justification what so ever to run RULER on a three-month basis, as suggested in some literature. That is why I said that I am not overly excited or even interested in RULER analysis. If I would have been involved in a different type of industry…than maybe I would look more closely into it, and try to justify the expense/benefit ratios.

John
I have no opinion on the reliability of RPVOT, I am just repeating what was reported at ASTM and NORIA symposia which focused more on varnish problem than AN increase from oxidation. With regard to ZDDP, I thought RPVOT should not be used on oils containing ZDDP - pressure drop affected by ZDDP/water decomposition gases. RULER is used for ZDDP measurements in combustion engine oils, greases and hydraulic fluids so would have no problem with turbine oils.
You are correct in saying you have minimal need for RULER with your system based on your oil life of over 30 years. Of course you would have saved money and had better knowledge of what the antioxidants were doing the first 25 years by running RULER every 3 months instead of RPVOT once a year (Herguth who you mentioned performs RULER analyses). RULER was designed to measure antioxidants/antioxidant intermediate products not the basestock oxidation - have on-line sensors for diesel/automotive engines, jet engines and cooking oil that do that. So once antioxidants are depeleted, rates at which the AN, viscosity, etc. change are based on the operating conditions, basestock oxidative stability, natural antioxidants, etc. which is why it is recommended that RPVOT be run once RULER drops below specified level - RULER is reliable at low concentrations(has been used to measure down to 20 ppm antioxidants) so it is not a question of reliability it is question of measuring the parameter that is changing. RULER is included for that reason in ASTM D4378-03 and 6224 In-Service Monitoring Standard Practices . So the RULER will be less premature for gas turbines than for steam turbines - in aircraft engines AN increases at 40% antioxidants due to extreme conditions so correlation beween antioxidant depletion and AN increase is very close . That is why I developed a AN test for the RULER so it could be used to both monitor antioxidant depletion and AN accumulation.

quote:

Originally posted by Bob K.:
...With regard to ZDDP, I thought RPVOT should not be used on oils containing ZDDP - pressure drop affected by ZDDP/water decomposition gases...

Bob, RBOT has been used for ages in reliably assessing serviceability of turbine oils; for decades before any of the phenol and amine type of additives were ever introduced. Also, for long long time ZDTP was the only type of antioxidants used in blending process. If that is true, are you saying that the whole industry lived in a la-la land by naively trusting this analysis, for which you say that it is unreliable for oils with ZDTP?

Also, if Frank or others out there that use turbine oils blended with ZDTP, then why not you or somebody else tell him (and others in similar situation) that tracking amine-phenol ratios in such case might be rather marginal, because such oil might not have sufficiently broad base of these additives necessary for the serviceability evaluation? If there are no amine-phenol-based additives in his oil (or just small quantities being present), instead of amine-phenol ratio, what should he be tracking by RULER?

Gents
The oil is group I and latest RULER results are: phenolic=5% amine=0% ZDDP=5%
TAN new=0.23, current=0.28
Gravimetric patch 0.8 microns wt mg/100ml=0.8
Particle count=15/13/11
RPVOT new=310 current=105
Ultra centrifuge new=1 current=5
Viscosity new=66 current=67
Colour new=0.5 current=6.5

Based on RULER results according to ASTM D4378 (Warning limit 25%)and low RPVOT we will sweeten the 6,600 litre tank with 2 x 205 litre drums of new oil, one in the morning and one in the afternoon.

Kleentek machine (12L/min) has done a wonderful job of improving oil cleanliness after 574 hours running, judging by the Gravimetric test results of before=3 and after=0.8
and particle count before=23/22/18 and after=15/13/11 (It has done nothing to improve ultracentrifuge or colour like I hoped it would).

This system has coarse filtration but will be fitted out with a CC Jensen 3 micron filter prior to changing the oil in mid September 07

Thanks for all your imputs, it certainly created a bit of interest.

We will monitor the antioxidant level a week after drain/adding the new oil which has not change in formulation except for the origin of the base oil.
Frank

Frank
How much time was on your oil when you got your first RULER results? Did ZDDP fall quickly? I have been analyzing turbine R&O oils off and on for about 15 years - early on I was told R&O oils are ashless and consequently never contain ZDDP/ZDTP. Earlier you confirmed a Zn content was correct. What type of turbine are you operating?

In Group 1 oils that I have analyzed in the past, the entire oxidative capability was based primarily on the phenol. The amine was an alkyl amine present for corrosion protection/minimal antioxidant capability. Aromatic amines react with the sulfur compounds in the Group 1 oils to create dark color. Does the new oil (Green solution) have a small peak around 10 seconds (amine)with a large peak around 15 -16 seconds (phenol) or are the amine and phenol peaks similar in height typical of aromatic amine/phenol antioxidant systems? ZDDP would show up as shoulder on amine. The amine went from 11 - 0% with filtering. Associated with particles removed?

If I give you my address would you send me a sample of your new oil? I am constantly on the lookout for new types of oils to make sure the RULER is up to date and if any solution modifications would be needed for this type of oil. That is why there are different color solutions available to cover the wide spectrum of oils used in different applications/types of engines.

John
Personally I prefer Disneyland to lala land - may have longer lines but flight service and special effects are much better. What type of turbine are you running that ZDDP is typical additive. Other researchers not me reported that ZDDP did not perform well in RBOT (hydrolyzes attacks copper coil). Reason TFOUT was developed for gasoline engine oils that rely primarily on ZDDP(recently amines being added as ZDDP decreased). I wasn't there but my best guess why whole industry was not in lala land is the oils relied on phenols not ZDDP for oxidation stability - presence of ZDDP would produce less defined endpoint but still would give useful results. Do you have any new oil with ZDDP?

I remember reviewing a paper out of Japan looking at sludge tendency of turbine oils for Tribology Transactions. I will see if they had any oils with ZDDP and what their performance was. Paper is back at the office.