Dear readers,

We have GE 5001 gas turbine that we use for power generation along with 3 other gas turbine operating in droop.

Recently this GT was observed to have oil leakage from its axial air compressor, right where extraction air is taken from its 4th stage for turbine shell cooling.

This leakage was observed after the GT was started after a shut down and the only job performed was chemical cleaning of the compressor.
Our best guess is that this oil is travelling from bearing #1 (thrust and journal assembly) right before the compressor.

Can you please highlight any other possibilities for this oil leakage and what its source might be?

 

It surely sounds like you have a problem with the No.1 Bearing labyrinth seal or the Sealing Air supply for that bearing.

Was anyone working around that area at all ? It is a big problem as the oil will also be passing into and through the compressor and causing a lot of contamination in the compressor. I'm pretty well afraid that you need to shut down and do a No.1 bearing inspection. As a last resort, check the bearing sealing air line for any problems.

 

@glenmorangie, no job was preformed on bearing#1.

But now that I think of it, blinds were placed at 8 different locations including the off-take from where sealing air for bearing is taken. These blinds were placed in accordance with the procedure for chemical cleaning.

The blinds were reverted soon after, but it is worth looking into. The GT is operational for over a month now with a steam hose applied where oil is leaking to avoid any fire. But as you said it must be seriously harming the compressor.

 

Yes, I think you need to take a look at it. It is too close to the possible source of the problem, maybe you have a misplaced gasket or something obstructing the Sealing Air flow.

It wouldn't take too long to shut-down and check it but you are also going to need to perform a very good compressor wash before you re-start, you have a lot of oil in there, particularly in the later compressor stages where it is hotter and the oil will be burned on to the compressor blading.

You really need to take a shutdown as soon as possible.

Keep in touch and report back

Good Luck

 

Any chance that the main oil tank vacuum has reduced considerably as compared to pre-shutdown values? also any chance that mist eliminator filter is choked?