How do mineral oil and synthetic oil differ in performance in turbine lubrication?

• A. Mineral oils are cheaper but provide less performance under extreme conditions.
• B. Synthetic oils generally offer better high-temperature stability and oxidation resistance.
• C. Synthetic oils are cheaper.
• D. Mineral oils perform identically at all temperatures.

Answer: (B)

In turbine lubrication, oil chemistry determines how a lubricant behaves under heat and exposure to air. High operating temperatures and oxygen drive oxidation and thermal breakdown, which can thicken into varnish or sludge and erode film strength.

Synthetic oils are engineered with more stable molecular structures that resist oxidation and maintain lubricating film over a wider temperature range. This gives them better high-temperature stability and oxidation resistance, so they protect bearings and gears more reliably under extreme conditions and often last longer between changes. That’s why the statement highlighting their superior high-temperature stability and oxidation resistance is the most accurate description of how mineral and synthetic oils differ in turbine service.

Mineral oils tend to be cheaper but don’t hold up as well to heat and oxidation, leading to faster degradation and more deposits. They are not identical in performance across temperatures, and synthetic oils are not generally cheaper.