Why has my gas turbine lube oil gone black. 1

[serendepidy]

I run a gas turbine compressor station on a large gas pipeline. The lube oil on the gas tubines on two stations have gone black in colour. The oil checks out otherwise, regarding every component of it's specification, temperature has bone monitored and particle count checks out. We would like to know why the oil has gone black as normally it is a bright red/colour. Is it an issue and should it warrant a lube oil change out ?

 

[TD2K]

Impossible to answer till you determine why it has gone black.

Black obviously could be used by overheating of the oil, could there be something that the oil has picked up? Contaminates?

Have you sent a sample to the manufacturer and asked them for their comments?

 

[rmw]

Are there any components in the oil that aren't on your turbine oil specifications?

And, have you mixed brands of oil, meaning, combined oils from two or more manufacturers together in the same turbine sump?

Has anyone mixed a different type of lubricant with the oil? Has there been a recent overhaul where outside lubricants like STP, etc might have been used and contaminated the oil?

So you have an oil filtration system, not the filters on the turbine, but a "turbo-toc" or "Hilliard" type oil clean up filter system? That might be worth trying, seeing if you can take a side stream off and filter out the contaminants.

Black can indicate different things with different types of oils and lubes.

Is there anything in the gas you are transmitting (as gas can occasionally get into bearing housings) that would react with components in the oil? Amines, mercaptans, etc?

Could you be leaking cooling water into the turbine sumps?

Lots of possible sources for contamination.

These are a few things that pop into my mind.

rmw