Turbine Lube Oil Vapor Extractor for Westinghouse 2200MWt Turbine-Gen

[Boriqua]

Flow rate at our Turbine Lube Oil Reservoir's electric driven vapor extractor discharge is ~350scfm. We have no information on what this flow rate should be. I suspect this is extremely high and we sucking in too much outside air which could result in lube oil contamination from particulates and moisture.

Our lube oil reservoir is maintained at 5"wc vacuum by an electric driven vapor extractor. But,if the vapor extractor was to fail, the backup air eductor is not capable of maintaining the vacuum above the alarm setpoint of 0.5"wc vacuum.

We have no specs on the air eductor and don't know if the ~350scfm is excessive for this application, or if this is the expected flow rate and the backup air eductor was undersized.

Oil vapors and a small amount of hydrogen (from the Main Generator seal oil system) are released and accumulate at the Turbine Lube Oil Reservoir.

I would like to know what is the nominal oil vapor production + hydrogen production for a 2200MWt Turbine-Generator (or what is this value for your Turbine-Generator and MWt rating) to determine if we have a system problem, or if the backup air eductor is simply undersized or not functioning properly.

 

[ScottyUK]

One thought: have you asked Siemens-Westinghouse in Orlando? They have design records going back to the Westinghouse era, and from the rating of that machine it is not a particularly old set. If you can get through to the right guy - and it is sometimes a big 'if' - there are some very helpful engineers in that organisation. Getting to them is the trick!


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If we learn from our mistakes I'm getting a great education!

 

[stgrme]

Besides removing moist air and hydrogen from the Turbine Lube Oil Reservoir, the vapor extractor should also produce a slight vacuum (2" to 4" wc) in each of the bearing pedestals (housings). This vacuum in the pedestals helps to prevent oil from escaping at the shaft seals on the pedestals. Dampers at inlet or exhaust of the vapor extractor should be adjusted produce this vacuum in the pedestals.

I am familiar with Westinghouse lube oil systems, but don't recall ever seeing an eductor used as a back-up for the electric motor driven vapor extractor. Westinghouse had an AIB (Availability Improvement Bulletin) or OMM (Operation & Maintenance Memo) recommending the addition of a second vapor extractor (with an automatic start on falling vacuum) to improve reliability of vapor extraction. I suggest following Westinghouse's recommendation by adding the second vapor extractor in place of the eductor.

Best of luck!