Turbine Lub oil particle count
Turbine Lub oil particle count
(OP)
Hi, We have a 150MW steam turbine with associated lub oil system. We recently suffered a major bearing failure, the root cause is still not clear, however we suspect foreign object damage to the bearing from lub oil contamination. The turbine was repaired and the complete oil system including tank were flushed and cleaned through a 3 micron filter. The lub oil is normally filtered through a 34 micron (0.034mm) filter. We get monthly lub oil analysis done by our oil supplier and the oil cleanliness has starting to deteriorate since start up one month ago. Here are the results taken shortly after recommissioning and 3 weeks later:-
2 - 5 µm/100ml 23683 149893
5 -15 µm/100ml 3683 5320
15 - 25 µm/100ml 203 60
25 - 50 µm/100ml 17 20
50 - 100µm/100ml 10 0
>100 µm/100ml 3 0
The NAS cleanliness rating is 4.
Would these results be worrying?
We have no other oil cleaning or purifying facility on this system. Is this unusual?
Thanks,
Irish Al
2 - 5 µm/100ml 23683 149893
5 -15 µm/100ml 3683 5320
15 - 25 µm/100ml 203 60
25 - 50 µm/100ml 17 20
50 - 100µm/100ml 10 0
>100 µm/100ml 3 0
The NAS cleanliness rating is 4.
Would these results be worrying?
We have no other oil cleaning or purifying facility on this system. Is this unusual?
Thanks,
Irish Al





RE: Turbine Lub oil particle count
Did the lab try to identify the smaller particulate matter?
RE: Turbine Lub oil particle count
RE: Turbine Lub oil particle count
As far as the origianl root cause, I would also look for water contimination or cooler temp excursion.
Most older systems I've seen have an original small continous filtering "bowser". Nearly every plant now has a high volume fine filter skid that is run ocassionally and shared if more than one unit at site. Before a tank mod is performed during outage, it was common to run the two hoses trough a top tank door.
Good look
RE: Turbine Lub oil particle count
rmw
RE: Turbine Lub oil particle count
The filters rmw refer to are used in the skids I have seen
RE: Turbine Lub oil particle count
RE: Turbine Lub oil particle count
as a first measure i would change lube oil filters and see if the situation improves.
check oil weekly, analize particulates to determine origin... if the material is babbit the bearings are losing material
check the oil for water content too.
saludos.
a.
RE: Turbine Lub oil particle count
LO system should have been flushed after the bearing failure. Flushing procedure should have included high velocity oil flow with line orifices and bearings removed or as a minimum, with by-passes around the bearings if the bearings are not removed for oil flush. There are companies which specialize in oil flushing to assure that the LO system does not remain a problem after this type of incident and also for good preventive maintenance during the planned outage.
www.fostercove.com
Herb
RE: Turbine Lub oil particle count
2-have you used mesh to detect the particles on intrance of the bearing? I always belive this test is necassary to make sure that oil pipe line is ready to connect to bearing.