GE Frame 5/LM2500 filter blocking

the Lab told me , it maybe blocked by the Sub-micron particles. but how these particles produced and why there wasn't in the solar 100 which used conoco turbine oil 32.

wxh,

you said, you are new... registered on July 2008

* did you found any history of lube oil top up on the period of Dec 2010?
* What is the trend of TAN from Nov 2010 - today?
* In your ICP / AAS test (Metal content test), what is the un-common metal which may captured there?
* Can you share the sludge picture?
You can do Insoluble Test (ASTM 893) to ensure that your oil is having un-necessary insoluble or not.
insoluble > 0.1% indicating you need to do some thing with your lubricant

regards,

Nurudin

thank your reply Nurudin
* I have its history before 2010.
* The TAN is always around 0.11mgKOH/g.
* it is zero for the Metal content. no uncommn metal and no wear particles.
* sorry, the Pic of sludge is too large to attached.

Dear WXH

As you related your problem, it is very possible that you have varnishing. You should run some test for confirming that possibility. This kind of varnishing causes filter blocking, problems in servovalves, etc.

You probably would need an external purifier for preventing the varnishing, or sludge formation. This kind of problems are usual in GE Gas Turbines. GE has a TIL about this issue.

Our Company is able to provide this kind of service (varnishing test, purification, etc) in Europe and Latin America.

If you wish more information, please, email to me to schmidmend@hotmail.com.

Thanks,

quote:

schmidmend@hotmail.com

Dear Schmid
Thank you very much. yes, it was varnish, for we found varnish in the gearbox.but i am confused that why i can not test it by cleanliness. the filter is really blocked by the sub-micron? if that how can i test it?

Hi WXH, we need to dissect the filter, open the filter and remove a 150X150mm section of undisturbed filter media, extract the dirt and debris and check by microscope, we open 20-30 filters per month and check what the filter has removed since being in service, during failures often the filter is the only area that will show the dirt and debris acquired prior to failure. We have just put three examples of filter dissection up under downloads on the R&T website, If you have difficulty getting this completed we could do for you but if so we need to put the report up here for all to see Regards, Rob S www.rttech.com.au, lab@rttech.com.au

Dear Wxh

Varnishing isn't detected with cleanliness tests, or others like TAN, RPVOT, Viscosity. You need to run Varnishing Potential Rating Tests, or Colorimetric test. Our Company could run both if you wish, for all your gas turbines.

On the other hand, submicron particles are able to block your filters, and damage your servovalve!

You need to consider an external technology for preventing and correcting this problem in your gas turbines.

I would like to help you with this issue. Our Company is able to provide oil analysis (Varnish Potentital Rating and others), and the solution for this problem.

Please, feel free to email to schmid@sicelub.com, or schmidmend@hotmail.com

Best Regards,

Dear Schmid
I know there are some equipment can move away the sludge and sub-micron particles from the oil. but I want to find what cause this. the quality of the oil? the operation of the machine? For we have another machine : solar 100 which used conoco turbine oil. it has been used for 5 years, above 20000hours. but its oil is normal and no filter blocking.

Dear Wxh

I think you should focus this issue from different point of view. No doubt that using Conoco Turbine Oil could help a lot, but, you should run a flushing before changing the brand of oil, and having in mind that you are dealing with a GE turbine, you sould consider to install an external equipment for preventing (not only move away) the formation of varnishing.

Regards,

Hi WXH, dissect the filter as that will assist with diagnosing why this machine is blocking the filter,
At present you have no info,
if you send the filter media sample to us (Not the whole filter) we will complete as an exercise at no cost to your company but we would need to place the results up on the message boards for interested folk to check out,
regards
Rob S

Check out this site for information on varnish. Many good articles, case studies and varnish mitigation technology.
http://www.rccnow.com/a_fluite...ational_services.php

Hi rttech. I dissected the filter the first time. and use the optical microscope and electron microscope to analysis it. only find a little sludge.

Eric. thanks your information.

i found there was a phenomenon that the DP increased a little after a shutdown. all in this interval, the lube system circle in a low temerture for a while.
so is that mean that the lube system running a low temperture will cause the sub-micron grown up or varnihs increase?
is there anyothers meet this problem?
or anyothers know how the temperture change frequently effect the lube oil?

Dear WXH.

That is because varnish solubility that changes with temperature. You must have a lot of soluble varnish in your systems. You need an equipment to remove them.

Regards,

Yes, sub micron oxidation by products and varnish do come out of suspension when the oil cools down. That is why all varnish mitigation technologies do not work at both operating temperature and at cool down temperatures. Click on this link for a video demonstration and contact me to discuss your application. Thanks
http://www.youtube.com/watch?v=XN_zcBToCcI

Hi wxh, yes you most likely will have difficulty in seeing on the media, we would extract the filter debris and concentrate it on the lab analysis filter with the proprietary solvents used in the lab we can redeposited any gelled lubricant for visual analysis,
Cristian's and Eric's last posts are correct, most likely the system has some varnish potential, check out ways the system can be filtered, least expensive would be roll type cellulose filters, electrostatic would long term best BUT you should not be making varnish/damaging the fluid, you most likely should root cause why the turbine fluid is being damaged
Rob S

If you need help with a technology that will remove both soluble and insoluble oxidation by products and varnish in turbine oil, please contact me at eric@rccnow.com. Good Luck

for the turbine oil problem I posted above. we found there were much foam in the oil tank. so i checked back with the test result last time. found there were higher air release. the highest is 5.7. but another oil which is conoco turbine oil used in Solar is only 3.4. it have the similar MPC with the oil whose air release is 5.7.
so last time ,I did a test for the turbine oil as below:
first to test the oil's foam property, air release ,color and MPC. then used Membrane which is 0.4um to filter the oil, to test the foam property, air release again.

found the result as below:
1. there is a large increased for the foam property.
2. the air release keeps as same with the result of before filter.

so, Can I conclusive that:
1.the foam propert increased should be caused by the anti-foam additive removed.
2. the air release increased campared with fresh oil was caused by oil degraded.

Then there is question: which caused the air release increased. it is only 1.4 for fresh oil. and almost all of the items are normal.

Wxh

Maybe this paper helps you!
http://www.machinerylubricatio...foamant-additves-oil

Regards,

WXH: Where are you from? Maybe I can find someone local to contact and help find a solution to your problem.

thanks for you kind. i am from Conocophillips China. it will be very glad if you can help us.

attached is the FTIR compared with fresh oil. I do not know how to read it. is there anybody can do me a favor?

Hi wxh,

I am not familiar with GE turbines. Does the GE turbines contain any silver plated components? If the oil in use contains zinc either in it's formulation or through cross contamination, zinc will react with the silver to produce a sludge like material.

Turbine oils generally have a dissolved anti foam unlike the silicon anti foam additive used for engine and gear oils which is dispersed in the oil. As the antifoam used in turbine oils is dissolved, it is unlikely that the filters have stripped the anti foam out. But you may need to check which anti foam is used.

If the oil is foaming badly, check if poor maintenace practices are the cause - such as dirty pumps or containers or dirty oil from header tanks. You will need to get a foaming tendency test done on the oil ASTM D892. If the oil does not foam during test duration, then it is not the antifoam or depletion of antifoam. It will be a system induced foam problem and you will need to identify what is causing this.

There is also a phenomena caused by certain filter media that cause static generated sparks caused by molecular friction of the oil as it flows through small clearances. This will cause thermal degradation and varnish problems. I believe it can be found in main lube filters where flow rates are very high or in last chance filters where flow rates are low. I had a look at the FTIR scan provided. The peaks in that range look like thermal degradation by products. This is caused by breaking up of the C-C bond to give an unsaturated product like an olefinic group. But it's been a long time since I've seen a FTIR scan. Looking at the filter media or a different filtering mechanism may help reducing the spark discharge.

The air release of new oil is never the same once the oil has been placed in the system. Air release and foaming tendencies are affected by amount of dirt, presence of water and the amount of degradation by products in the oil.

Group I base oils have higher aromatic content therefore can dissolve more varnish. Whereas group II base oils being more refined have less solvency than group I base oils so will have lower tolerance to degradation by products. You may want to check the difference in base oil between the conoco and caltex product. However, the type of anti oxidants used also play a key role in turbine oil oxidative and thermal stability. There are papers written on antioxidant systems with some suggestion that antioxidants based on PANA only are prone to more sludging and varnish issues. Whereas others based on amine and phenol chemistry requires good monitoring of the phenolic group because if it depletes too far then varnish can form. The phenolic group is sacraficial to the amine group. You will need to search for these papers.

MHI or mitsubishi heavy duty industries call for a sludge test to be done on the oil. It is a requirement of japanese standards for MHI.It's called a MHI thermal stability or dry TOST test. It is where the filter residue is weighed and measured. It may give you a clearer indication of the short time sludge performance of the oil with high RPVOT values.

I hope this is of some help on your quest.

Hello WXH,

just to consider as an alternative if you do have a varnish issue ...I believe Hypro Filtration have some very effective products for dealing with Varnish

good luck