We are changing out 14K gallons of turbine oil during our maintenance outage and the issue of oil foaming keeps coming up for discussion. Does anyone have any experience with foaming being an issue or have you had no problems on startup? Were using Mobil 797 oil that will be clean and water free. The turbine is a GE 850MwE nuclear unit.
Clarification-We have not changed the oil yet-thats scheduled for next month. My management is concerned that during startup we will have an issue because someone heard that foaming is an issue-I'm trying to bring some facts and experience to the table to counter what I believe is a non-issue. rgf

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

use of highly refined group one base oil havily additized, will significantly reduce foaming and increase oil life.

Harish Doshi - It looks like you either have no knowledge, and I might even say no clue about turbine oils, or you have mistaken them with motor or gear oils. FYI, turbine oils are very finely balanced blends, where additives represent only 3-5% or in some cases up to 10%, and the rest is base oil. In any rate, they are definitely not "heavily additized".

As to the original question...
1. Where you see foaming occurs the most, in bearing sumps or a governor sump, or…?
2. Did you folks check (test) and confirm that the new and the old in-service oils are fully compatible, before the changeup? In some cases it has been determined that oils (more precise, additive packages) are not compatible. In such cases, providing you don’t have any air leak, formed flocks would serve as seeds for air entrainment (which you cannot see with unaided eye) and foaming (which you can definitely see).
3. If you did not test for compatibility before you replaced old oil, you may do it afterwards if you have a sample of previous oil and new (unused) oil.
4. Incompatibility can cause stripping of additives (foaming additives included). I would advise you to spend some money and test your new oil (from sump where you experience foaming), and see what happened to foaming and water separation characteristics.
5. Foaming can be nuisance at startup if your oil is cold (thus thick), and therefore, because the rate of air dissipation from oil is greatly impeded (slowed). Does foaming persist even when oil reaches usual operational temp?
6. How sure are you that the oil is clean? What the numbers are saying (ISO 4406/99)? If you only assumed that your oil is clean because it is new, you may be up for a big surprise. It is commonly observed that new delivered oil is much dirtier than your in-service oil. That’s why we filter and dehydrate every new delivered oil, before we add it as a make up oil or use it as replacement oil.

Most foam problems occur due to contamination. Just ensure that you don't introduce a contaminant during the change out. Detergents used in tank cleaning will destroy your turbine oil demulsibility and promote foaming. Flushing would be advised to remove any traces of foreign products. Similarly grease or sealing agents used to lubricate joints on tank doors, etc can also cause foaming. If you did not have a problem before you should not have one after filling if you avoid contamination. Initial foaming may sometimes be a problem if oil is too cold and there is high air entrainment at start up but it should eventually decay.

posted above is all correct all I can add is do not clean system with any water based cleaners or uou will have a potental problem. And I can also say that "new" oil is NOT always "clean and dry depending on delivery distance trucks used hoses and filters etc all must be looked at.
Bye the way ALL turbine oils of good quality now days are GPII or better base oil NOT GPI.
bruce CLS

The correct wording here should be “APPROPRIATELY ADDITIZED” instead of “heavily additzed”. It is an error. John Micetic: I respectfully disagree with your opinion about my knowledge of turbine oil.

Highly refined group one base oil (100% paraffinic) has following distinct advantages over other base oil for this application.
1. Greater Oxidation Resistance
2. Better Lubricity and higher film strength
3. Higher Natural Viscosity Index
4. Greater Water Resistance

Base oil being a large portion of turbine oil formulation, high performance base oil formulated with [technically advance additive package] compatible additives chemistry helps reduce foaming; emulsification; operating temperature; ware; sludge and varnish; etc.

Some Power Plants in USA have been using this kind of turbine oil formulation and have experienced benefits listed below.
1. Lon*** Oil Life
2. Reduced operating temperature
3. Reduction in loss of oil

I believe it would be worth your efforts to look into

Harish,

FYI, there are NO group one oils out there that are 100% paraffinic. Such thing doesn't exist. If you would say group 3 or PAO type of oil, then OK. But they are absolutely not group one oils.

quote:

Highly refined group one base oil (100% paraffinic) has following distinct advantages over other base oil for this application.
1. Greater Oxidation Resistance
2. Better Lubricity and higher film strength
3. Higher Natural Viscosity Index
4. Greater Water Resistance

Do not understand you compared to what "other base oil".??

Your statment is more correct in comparing a GPII oil to a GPI extracted oil not as you have posted.

perhaps you have some experience with some real BAD base stocks but in the USA NO ONE uses GPI any more as a turbine oil of any quality.
bruce

John Micetic & Bruce81: If you prefer you may write me an email message harish@suscom.net and I will send you information of a manufacturer of this oil.

Harish,
You can post the info (names) of this oil and the manufacturer here. I bet other folks would be interested in this info as well. This company probably have a website, too, don't they?

John: Name of manufacturer is Lubrication Engineers, Inc. Their product is "LE6451" Website address: le-inc.com

Harish, John's not showing you much respect. If I didn't know any better I'd say he was trying to be antagonistic.

John,
LE# 6451 can be found in power plants all over the world. It's made from a high quality Paraffinic base oil. Nonfoaming, excellent water seperation, exculsive anti-wear protection and extremely long lasting.

LE wrote the book on, "Long rain Technology."

"Long Drain Technology"

Bolg18 - You don't have to line up accolades for LE turbine oils as I am familiar with them. My point is that they are absolutely NOT GROUP ONE OILS. It seems that neither you nor Harish are familiar with API charts. It would be good to know what chart you two are looking at to determine which oil belongs to what group.

John: Again, I respectfully disagree with your opinion about our (myself and Bolg18) knowledge of turbine oil and API chart. I suggest you should talk to technical folks at LE (1-800-537-7683)and they will explain how group one base oil is refined to 100% paraffinic base oil.

quote:

explain how group one base oil is refined to 100% paraffinic base oil.

In a round about way You maybe discribing GPII but I have never thought much of LE anyway. ALL power plants I know of use "major OIl" products NOT LE.
GPII is whats used if not then you/they are way behind the times.
bruce

Harish,

I am not going to argue with you any more. However, the fact remains that if an oil has 100% of paraffines, that means that it has 100% of saturated hydrocarbon molecules and 0% of unsaturates or aromatics. According to API chart, this oil could be hardly classified as Group 2 oil, and more likely as Group 3 or even PAO. The same API chart shows that Group 1 oils have up to 90% of saturates and the rest are aromatics and impurities (mainly S and N). That is my point, and nothing else. I did not question quality of LE oils nor it is my intent to do so. To the contrary, LE company was always (at least for the last 4 or 5 years that I witnessed) trying to be the cutting edge of the industry. Back then they were offering their LOW TOX turbine oil that was formulated with oil that was refined by a severe hydrocracking process (to eliminate as many unsaturates as possible).

I appoligize to all. I freely admit to not having the level of knowledge and understanding of some of you. I was merely defending Harish, who I've never met.

Before I wash my hands of this discussion however I will tell Bruce that there are at least 6 to 8 plants within a 4 hour drive of my house (central PA) that are 75 to 100 % LE.

Everybody have a great weekend