Clear/Greenish "snot" in Feedwater Pump Oil Cooler

[todcaesar]

Sorry for the graphic description but that really is what it looks like.

The lube oil cooler for our Feedwater turbine/pump became fouled(as made evident by the higher temp and lower delta temp). We pulled the tube bundle out and found a clear and greenish slime on the tube fins. Chemisrty found no water in the slime which makes some sense since it wasn't the milky opaque water oil emulsion I have seen in automotive oil. I have uploaded a picture, but I am not sure if it worked.

Chemistry got a spike on their Fourier Transform Infrared Spectroscopy at the oxidation point and said this was oil varnishing due to aging.

Thing is, it has happened twice to the #2 Pump in the past 7 years but not our #1 or #3 pump and the oil gets exchanged among the pumps over time as each takes its turn on the oil conditioner (boowser).

Any thoughts about what this slime is?

Thanks, Tod

 

[unclesyd]

You have definitely been slimmed.

I would do a quick check for bacteria.

I've also seen something similar where a small amount of synthetic oil was mixed with a petroleum based oil. It wasn't nearly as bad as you display.

What is your lubricant base?

What is the temperature around the cooler?

 

[todcaesar]

Chemistry initially they said not a bacterial issue, but they did not specifically test for it. We have one swab left, How can we test for it? They used to have a kit that turned pink, but they expired. Would a microscope show anything?

I have heard of oil additives clashing but there has not been any change in oils used, though someone mentioned WD-40 might have been used. Again, I would expect to see the problem on all the pumps.

The oil is BP Turbinol Select 32. I attached the spec sheet; but, it is unclear about the base.

When it was running hot the temperature was 138 degF coming out of the cooler and 155degF out of the bearings. Normally it runs 10-15 deg lower.

 

[todcaesar]

Front page of attachment

 

[unclesyd]

The bacteria, et al, will show up under a microscope.

The mention of excellent water separation strongly indicate a paraffinic base stock. There in nothing wrong with our choice of oil as it is used everywhere. I asked a friend that sells a very similar paraffinic based turbine oil to look at you picture. His comment was that he hasn't seen anything that approaches the degree of you problem. An additional comment was that it looks like bacterial slime that one would find in a sump where there was improper water removal on idle equipment.

Has the tube bundle been cleaned lately?

Can your lab check for iron in the slime?