Colorimetric Test Method

Dear Macabf

We are working with QSA test (from AnalystINC), for determining the Varnish Potential Rating in Turbine Oil from Gas Turbines. Also, we use the ISOPur technology for removing the Varnish, and we have found good correlations, according to the GE TIL 1528-03. If you need more information don't hesitate to contact to us.

Hi Christian
Thanks for replying, is it posible to get information on the QSA test method? as I don't think it's a recognised standard. The second question is why did you favour Isopur to Kleentek? The reason I'm asking is that I'm looking for the best test and equipment to remove varnish.
Frank

Macabf
QSA test is provided by AnalystINC in USA. We have been using it in several gas turbines in Latin America (Mexico, Uruguay, Argentina), and we have had good correlation with the field. QSA isn't a ASTM test.

In the other hand, we use ISOPur technology for removing varnish (in Gas Turbines) according the recomendations of GE (TIL 1528-03). We haven't used Kleentek technology.

If you want more details (ej oil analysis reports, etc), please write to schmid@sicelub.com. This is my email.

Colorimetric analysis is the basis of the best varnish testing, used by us in our VPI (Varnish Potential Index TM) test. While the exact procedures are proprietary, it is probably similar to the QSA test and other "patch" type color measurements. Try reading publications from Dr. Sasaki, Kleentex and Greg Livingston...you should be able to figure it out with a little imagaination..

Thank you Andy, I have the article, and will look at both tests.
It's a pity both methods can't be shared as they seem to be the most accurate and easiest to carry out, and specially when varnish is such a huge problem world wide.

Frank

I also thank you Christian, and yes I would like if possible whatever you are willing to give e.g. oil analysis reports, type of filtration, Isopur model number etc.
I believe you can buy the Isopur Agglomerator only either the LR or HR
Frank

The QSA test is based on the colorimetric test. There is currently an effort underway in ASTM (D02, C01) to establish this as a standard. For the time being, Analysts is the only independent lab offering this test in the US and this test is a critical part of turbine oil monitoring. (Especially gas turbines.)

With regards to the GE TIL, there are many aspects of gas turbine varnishing that are omitted from this piece. The issue is more complicated than simply deciding between electrostatic separators, as is evident from dozens of gas turbines that are still experiencing valve sticking problems after the installation of these technologies. These technologies should be considered an essential part of the solution, but certainly not the entire solution.

Andy - sa wa dee khrap. thanks for the reference.

Thanks for the update Greg, in the meantime I'll be using the Ultra Centrifuge as the test for rating varnish potential, in conbination with RPVOT.
As far as the varnish removal goes, we'll either install CC Jensen filtration, Isopur, Kleentek, or a combination of both filtration and particle agglomeration. Anything has to be better than 20 micron nominal which what we have.
Frank

Frank
I have a couple of papers that may be of considerable interest to you on this subject. Feel free to write me and I'll send them over.
Greg

As Greg has said, efforts are underway to establish a standard method.

We are quite willing to divulge our VPI method to an ASTM Committee,when asked.

Any questions, contact me at andy.sitton@focuslab.co.th

Thanks for the repply Andy
I also heard that the whole method will not be submitted to ASTM and part kept as propietary information by the lab concerned.
Frank

hello
we use in our plant an mineral oil with viscosity 8-11 cst and color 0.5 (astm 1500)for new oil. I know that with time the oil becams dark, what I need to know is the limit of the color in used oil
The same question for turbine oil

quote:

Originally posted by macabf:
Thanks for the repply Andy
I also heard that the whole method will not be submitted to ASTM and part kept as propietary information by the lab concerned.
Frank

We are working with ASTM on the standard and will be sharing the test methodology, but not the interpretive guidelines based on our field research.

For everyones info, we have formally submitted our VPI method to the ASTM committee with no commercial strings attached, hopefully it can become freely available knowledge soon.

We are giving ASTM first crack at it, but if they turn it down, we are willing to share it for research sake, with anyone, as well, it is a really simple test and with low cost equiment (simple lab glassware, PC, scanner and photoshop)

andy.sitton@focuslab.co.th

Greg made a very good point, that simply deciding on the type and brand of varnsih removal system is not the total solution, it is really little more than a band-aid approach...root cause analysis of the varnsih must be perfromed, and then the root casue removed or at least reduced to levels that the varnish removal system can handle....

Also note my good friend Mark Smith's comments about the interpretation of the varnish test results,regardless of which test method is approved or employed, you are gonna need an interpretation of the results...the gravimetric patch still holds this key and what is seen under the microscope is still just as important as any number...independent labs are still where this expertise will be, by seeing so many different types of turbines with so many different types of oils...these "trained eyes" will still be the best root cause detection sources...Andy

For the varnish potential rating of Group II turbine oils I will use the following standard tests and limits:
TAN +0.6
RPVOT <25% of original
Ultra Centrifuge, mild 3-4, moderate 5-6, severe 7-8
System Filtration - 3 micron beta 75
Hopefuly I will filter out most of the insolubles and monitor progress with the obove tests.

Hi Frank

I'm not trying to be a pessimist here...the test protocol that you've put together has value. However, the only test that will tell you anything about the varnish potential that you’ve listed is the UC test. You should never see AN's above 0.3 in turbine oils and RPVOT has no correlation whatsoever to varnish. (Lots of research available on this.) A much more valuable trending tool for you is the RULER instrument – an indispensable tool for turbine oil condition monitoring.

One other interesting note for you…

The average size of a soft contaminant (varnish precursor) in an operating turbine reservoir is 0.08-microns. When the system is not operating, many of these soft contaminants will agglomerate together and form particles with an average size of 1-micron. 3-micron mechanical filters will be of limited use to you with regards to removing soft contaminants.

Greg

Send me your email address and I'll email you a copy of our test method mate...we are in Bangkok...not too far away.....

Andy Sitton

Andy
My email address:
Frank.Cabello@bluescopesteel.com

Thanks

We are operating gas and steam turbine and have been getting conflicting results from different labs for the varnish index. We would like to obtain the method and colormetric charts so we can do the testing in-house. Can anyone assist us. The laboratories we use wont give us the test methods so we cant compare apples with apples.

my email is serendepidy@hotmail.com, if anyone would like to forward on some information. Many thanks in advance.

A company in Fishers Indiana is offering a varnish test kit based on MPC per ASTM D02.C0.01 It has a spectometer included that takes a lot of the guess work out of comparing to a color chart. Other than that, I dont know where you would get the chart.

quote:

Originally posted by serendpidy:
We are operating gas and steam turbine and have been getting conflicting results from different labs for the varnish index. We would like to obtain the method and colormetric charts so we can do the testing in-house. Can anyone assist us. The laboratories we use wont give us the test methods so we cant compare apples with apples.

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