Free radicals formed by oxidation or spark discharge are frequently at the root cause for varnish and deposit formation in turbines. Traditional methods of analyzing used oils such as viscosity measurement, acidity or carbonyl oxidation is usually inadequate to predict eminent field problems. This presentation discusses why different behavior is observed in the field for turbine oils based on Group I versus Group II base stocks and why there is a range in performance of turbine oils depending on the types of antioxidant systems that are used. A more suitable method for monitoring turbine oil acceptability in the field is to measure depletion of the various antioxidant types present in the system. This approach allows one to more accurately estimate when field problems may occur and provide sufficient time to protect the overall system and extend the lubricants useful life. Antioxidant replenishment as a strategy for extending the life of turbine oil is discussed from the viewpoints of recommended practices, advantages and pitfalls.
Author: William Moehle, and Vincent Gatto, Albemarle Corp., Dave Wooton and Greg Livingstone
Source: Reliability World 2007 Conference Proceedings
Figures and Illustrations: 16
Format: PDF - Digital Download