Lube System Flush Before new Charge of oil and possible additive depleation

Just changing the oil doesn't solve a varnish build-up problem. The amount of varnish build-up in the system will be re-absorbed by the new oil, thus holding it in suspension and causing the phenolic AO to deplete at a very quick rate. Once the phenolic AO depletes you will see the amine more than likely drop at an even faster rate. During this whole process your turbine is making more oxidation and the whole varnish build-up process happens again but at a much faster rate.

One way to solve this problem is to install an electrostatic oil filtration system on the old oil prior to a change out to completely strip varnish build-up from the internal metal surfaces. Once the varnish build up has been removed from the internal metal parts, then you have to decide if the oil is suitable for continued use or if the oil should be replaced. We always recommend that a sample of the oil be sent to the OEM oil manufacture to help make this decision.

If the oil needs replaced keep the permanently installed electrostatic oil cleaner on the system it will protect the new oil AO additive package by removing the oxidation by-products as your system creates them. It will also remove particles and wear contamination. This procedure will yield a long term solution to varnish prevention and life of the lubricant as well as unmatched contamination control.

All of this can be done while the turbine is in use and is less expensive and more effective than a flush where chemical contamination is added to the system to remove the varnish build-up. The problem is it is almost impossible to completely 100% remove the chemical or detergent added to the flushing oil to flush a system. Little pockets of fluid get caught in the piping and do not completely get drained during the flushing procedure. Then the chemical or detergent would have small amount contaminating the new oil.

Another solution you might be able to do is add a certain amount of NEW oil to your system and add an electrostatic oil cleaner to remove the varnish from the oil and any varnish build-up from the internal metal surfaces. The addition of NEW oil will sweeten up the phenolic AO and then you should increase the sampling to monitor the levels of AO additives. This is less expensive than a complete change and can be effective.

If you would like to discuss further or see some performance data please feel free to contact me:

paul@oilkleen.com
813.333.6356

Thank you for your response. We do have an ISOPur system on this unit. The oil was replaced in june. We have a series of Ruler test including June, Sept, Early Jan, Late January. The corresponding Phenol numbers are: 92%, 37%, 11%, 23%. One theory has been that the Phenol is being consumed by a reaction with residual deposited varnish on the metal surfaces. We have not yet done a QSA but we will.

oh really? ISOPur? well let me say that "Stripping Varnish build-up" and making a "white" patch or low QSA number are two different things completely. A lot of companies claim to be varnish removal systems, but stripping the pounds and pounds of varnish build up is what real varnish removal is. The QSA patch test only measures what level of insoluble/soluble varnish is in the oil in suspension, but doesn't tell you how much internal build up you have.

I don't know how ISOPur systems strip varnish build up, but with OILKLEEN, it takes the huge amount of surface area in our collection media to hold the pounds and pounds of varnish being stripped from a metal surface.

Here is some past data and performance:

http://www.youtube.com/watch?v=ubjts3ut5V4

However, you are correct if you had varnish build up on the internal parts prior to the oil change out it will destroy the new oil AO additive package at a quick rate. Your rate seems very quick so you must have a lot of build up.

One other thing to check is the NEW oil reference on the RULER test. Did you send a sample of your NEW oil to compare the used? or did you use what the lab had on file?

Also, I would find a lab that could do a FTIR of a sample of NEW oil versus the USED oil sample. At OILKLEEN we are now using the FTIR because it seems to be extremely accurate each time as long as you have the NEW oil to compare with.

Hope this helps!

unfortunately, the closest thing to a new sample was the sample after installation. However, the lab we used has several virgin samples of the DTE 732. They provided us with the graphs of the samples to show how similar they are. All of them were within plus or minus 4. Keep in mind, the first sample registered at 92%, now we are down below 20%.

Neal, I work for Fluitec International and live an hour or so away from Raleigh. We are the OEM of the RULER as well as various varnish removal components. Please fee free to contact me at the below number, I would be happy to perform some on site RULER & varnish testing as well as review your options. Please take a look at this link when you get the opportunity it explains the history of varnish.
http://www.fluitec.com/videos/ESP_Technology/

Jeff Chapin
315-447-3780
j.chapin@fluitec.com

The best varnish test in the world is simply looking at the internal metal surfaces that are covered by oil. Sometimes this is tough, but there are several places to access even while a system is running.

We have a whole list of potential spots for access with pictures we can send you. Just let me know. This list will show you places to access parts and determine the amount of "Varnish build up" in a system since there is no lab test that can do this. Varnish build-up in a system is the real problem.

Paul

Neal - it appears that you are not concerned about varnish but about additive depletion. First, residual fluid and deposits contain free radicals that will react with the new oil's phenols and cause accelerated depletion. Second, the phenols are the first additive to deplete with this oil and in this application. The amines are high-temperature, long-life additives. I would continue to trend the amines by RULER and continue to run the MPC test (ASTM draft) to look for varnish potential.

You may still have several years of life and expect high performance from this oil, even though the phenolic chemistries have mostly depleted.

Finally, FTIR is an excellent analytical instrument. In terms of measuring antioxidants however, it is satisfactory at measuring phenols, however may not work at measuring amines. There are other aromatic bodies in many formulations that hide the amine shoulder (1514cm-1) making it an inappropriate test for trending this additive.

Hi Neal,
I can understand your concerns regarding results by RULER technique, but fail to understand why you didn’t try to verify this “depletion” of antioxidants by running good ol’ oxidation stability test - RPVOT (if my calculator start “acting”, I grab a pencil and pad and check those “funny” looking numbers). I am almost certain that the manufacturer’s specification of your oil does not show original RULER value, but it shows oil’s original RPVOT value, which you could use as a baseline if you didn’t establish it before by testing the oil when new.

Also, another conformational (or semi-conformational) logical avenue would be to check AN, which would usually show some increase in cases where concentration of antioxidants dwindled down.

I don’t think that deposited varnish at machine/pipes walls has any significant role in this depletion. As I understand it, antioxidants are reactive to, and destroy/eliminate peroxides (precursors) which are formed in the first stage of varnish formation. Also, there is great number of end users who changed their oil while having varnish deposited throughout their system from years of operation, and no one experienced antioxidant depletion at the timeframe and the extent as you are describing.

The most often reason for additives dropout/depletion is mixing oils which are not fully compatible. I wouldn’t take for granted that two oils are fully compatible even though they are from the same manufacturer. Here, the answer is testing compatibility of in-service oil and new oil (e.g. ASTM D 7155) before acquiring new oil.

These phenolic s cannot simply disappear like a fart in the wind. Therefore, I would suggest opening up few older filters and send them to lab. Filters are the most reliable banks of information for the oil and the system equipment, but too often oil filters got tossed away after the replacements.

Adding filtration to the system always help. While here is already posted some info about benefits of electrostatic filters, I will just ad that properly sized low-flow depth-type mechanical fine (e.g. 1-3 micron) filters will do just as well, or better if subjected to the same flow as electrostatics are running at.

I am the owner of Isopur. If you give my office a call, we will be happy to come down and look at it. Ask for David.

The other possibility is you are reading the ruler test wrong. This happened to us a couple years ago. Someone was running a ruler on a system with our machine. The oil was just a year or two old and it was giving a ruler result of 31?. GE called us and asked us to explain. We sent the ruller test result to Andy Sitton at Focus Labs. He said the the person running the test did not account for a shift in the curve. The result should have been 81%. The oil supplier did an RPVOT on the oil and came up with 81.6%. I believe them.

If you get strange readings, run another test on the ruler and back it up with RPVOT. Call your oil supplier and ask what is going wrong. If you send us a copy of the test, we will check the result for you.

There are three different reagents for the RULER, depending on the type of oil in service. There are two ASTM methods, D 6971 & 6810, one measures phenolic antioxidants and the other measures phenolics and amine antioxidants. So there are a total of six different variants of this test.

Yeah, you have to pick the right one to get useful results.

Like all bench tests, it has inherent limitations. Two oils can have the same RULER results (under constant conditions) but much different oxidation stability. That is because the RULER does not account for the oxidation stability of the base stock. A PAO oil will have better oxidation stability than a mineral with the same RULER result.

Personally, I'd never change out a Frame 7FA without a thorough flush. They make varish almost as well as they make electricity, no matter what oil you use.