Turbine Oil Mixup
Q: A Steam turbine owner sent in a sample of new turbine oil from a recent delivery. Analysis by Atomic Emission Spectroscopy revealed zinc, phosphorus, magnesium, calcium, barium and sodium additives present in the oil. What happened?
A: Whenever we see a situation like this, there is a collective “Oh-oh” in the lab! The additives described should never be seen in turbine oil. The most likely source is contamination of the turbine oil with engine oil either at the terminal or during transport. A common problem has been where the transporter figures “oil is oil” and neglects to thoroughly clean the tanker between oil loads. Even a small amount of engine oil remaining in valves, hoses, etc is enough to contaminate the load. The engine oil additives are harmful to the highly refined turbine oil and the turbine bearings. Excessive foaming, lack of rust prevention, lower RPVOT values, and poor demulsibility are just some of the oil problems. An abrasive hard face on the babbitted bearing faces is also possible, resulting in shaft scoring and eventual bearing face wiping. In summary, if these additives are already present in the oil, you need to have it returned immediately, and going forward, Consider
- Requiring your delivery tanker to be steam cleaned and dried thoroughly before your turbine oil is loaded.
- Certificate of analysis and retain sample from the refinery terminal to be delivered to you with your order
- Grab two retains- the first drop from the hose, and then after 5 minutes of pumping
- Always have two tanks- one for deliveries, and one for supply to the turbine, with connected piping and valve. That way, if the delivery is not to spec, you can pump it out of the delivery tank, and your supply tank is not affected.
-DPW
