I work on upgrading of GE frame 9e, Mark IV. It seems that Lube oil is leaked from bearings, and it should be charged regularly in the lube oil tank. Does anybody have an estimate about the amount of this leakage? How often we need to charge new oil to the tank?
>I work on upgrading of GE frame 9e, Mark IV. It seems that
>Lube oil is leaked from bearings, and it should be charged
>regularly in the lube oil tank. Does anybody have an
>estimate about the amount of this leakage? How often we need
>to charge new oil to the tank?
This is pretty far from a controls-related issue, even if the unit has a Mark IV. What kind of upgrading are you doing?
The issue with lube oil leakage from bearings is: Where is it going?
Which bearing(s) are leaking?
What kind of hazard is the leakage creating? If it's in the Load Compartment, it could contribute to a fire hazard--and you DO NOT want a fire in the Load Compartment--ESPECIALLY if the unit has a hydrogen-cooled generator (which lots of Mark IV-era Frame 9Es had). I saw the after-effects of a fire in a large process plant in the Load Compartment of a unit with a hydrogen-cooled generator. The plant fire brigade was summoned to the turbine-generator after the fire had been discovered by the operators and they manually discharged the fire protection into the WRONG compartment. The fire was caused by lube oil leaking into the Load Compartment (a serious leak which was known to the operators--and neglected by management), and when the fire brigade and saw the fire was still going and was being fed by the L.O. pumps, they shut down EVERY pump--including the D.C Emergency Seal Oil pump. Which allowed hydrogen to leak out of the turbine-end generator seal and catch fire and melted the end shield around the generator shaft. It was a miracle the generator didn't explode.
Tripping and slipping of personnel can also be a huge problem for some oil leaks.
If the Number 2 bearing is leaking oil into the turbine, that can cause serious problems with coking in the turbine nozzles.
And if the Number 1 bearing is leaking into the inlet, that can cause issues with axial compressor cleanliness.
And, a leaking Number 4 bearing can cause a fire in the Load Compartment, also.
And, a leaking Number 5 bearing cause problems with the brushes and brush rigging--and an explosion and fire in the Collector Compartment.
As a general rule, when the L.O. level drops to near the Low Level Alarm setting (see the L.O. System P&ID for details) it's time to add oil to restore it to slightly above the normal setting. (Some L.O. System P&IDs have some estimates of quantities required to get to normal and the Low- and High Level alarm settings).
But, the most direct answer to your question is: Add oil as necessary to prevent the Low Level Alarm. It doesn't trip the unit, but people become immune to alarms that exist for even hours, and it could be forgotten long enough to result in loss of L.O. Pressure and a turbine trip.
As for "acceptable" leakage rates (barrels-per-day or -week or -month)--that's entirely up to site management. There is no stated acceptable leakage rate that I've ever seen. In some parts of the world, oil on the ground can result in a fine and imprisonment--for polluting the environment as well as causing a hazard to personnel. It's mostly about tolerance of site personnel, and local regulations and/or laws.
But, really--who likes to work on a dirty, oily, messy turbine? Even just operating a dirty, oily, messy turbine is not pleasurable. And, if there's ever an emergency in the area where oil has accumulated, it can be very hazardous to personnel.
I knew of a turbine with a Mark IV control system that had such a bad oil leak for so many years (more than a barrel per week, sometimes more!) in the Load Compartment that the oil ran through the foundation-embedded conduits into the vault under the Control Compartment. The oil vapours rose up into the Mark IV (where the cables entered the Mark IV) and Generator Protection Panel, and dissolved some of the printed circuit cards and protective relays. It was a bloody mess! The floors, the walls--every surface in the Control Compartment--including inside the Mark IV control panel, was covered with an oily film. The owner spent tens of thousands of US dollars replacing the Mark IV components, and protective relays in the GPP, and cleaning the Control Compartment--probably close to a hundred thousand US dollars. Not to mention all of the oil they had put in the unit over nearly a decade making up for the oil leak. Oh, yeah--they also had multiple fires in the Load Compartment, too....
We are experiencing similar leak in 9FA GT unit with a hydrogen-cooled generator. Couldn't able to trace the exact leak where from. However, investigation still going on and we too have initial suspect ion from bearing no:2.
GT lube oil reservoir level constant decreasing trend observed and investigation under process.