Can you give me any documentation on specs are testing results that gives me the absolute minimum (RPVOT_minutes) that my turbine oil is usable in my Main Turbine Oil Tank. We have a Unit Outage this fall and my turbine oil was recently tested at 192 minutes (RPVOT). Management wants to know if an oil change-out in our Main Turbine Oil Tank can wait until out next Unit Outage which will be two years from know.

Do you have any other information?
What was the RPVOT of new oil? I believe 25% of original oil is used as a guide by ASTM methods for maintaining turbine oils. Do you have any other RPVOT to know your depletion rate? Any RULER (antioxidant level), TAN, Varnish potential, etc. measurements to check quality of current oil. EPRI website might also be a good source to check.

I don't have the original (RPVOT) number when the oil was purchased but a lot of oil have been added to the system in pass years for makeup. We presently use Conoco Hydroclear VG 32 oil in our main turbine oil system but we used Mobil DTE 797 about five or six years ago. The TAN has been trending between .03 and .05 for years.

Can this oil go 2 more years??

If this oil has gone 2 years I do not know if it will go 2 there are to many varibles to consider and oil will NOT degrade in a straight line.

It may have gone from a 500 hout RBOT in say 2 years to 192 now BUT that does not mean it will last another 2 years since it will get increasingly get worse.

Trending the oil for TAN increase (from new oil) is the best answer.

Check with your lube supplier good turbine oil will run >500 hours new as far as a change out get the suppliers recomendation a TAN >1.0 is a Max limit IMHO aswell as wear debris levels.

Also might ask your oil lab about a change out recomendation Anaylysts Inc which I use in Oakland CA. may have one.
bruce CLS