Acidity in turbine oil is caused by the oil's reaction with oxygen, which results in oxidation and the formation of acids, alcohols, carbonyls, and sludges

 Acidity in turbine oil is caused by the oil's reaction with oxygen, which results in oxidation and the formation of acids, alcohols, carbonyls, and sludges. These acids can corrode bearing surfaces and cause irreparable damage. 

Here are some things to know about acidity in turbine oil: 

Total Acid Number (TAN)

The TAN measures the oil's acidity by titrating it with a base material. The TAN is reported as mg KOH/g of the oil. 

Warning limits

A warning limit for the acid number of turbine oil is typically 0.1 to 0.2 mg KOH/g for gas turbines with more than 3,000 hours of oil life. A rise of 0.3 to 0.4 mg KOH/g above the initial value indicates that the oil is nearing the end of its service life. 

Impact of high acid levels

High acid levels correlate with an oil's propensity to coke, which is a common failure mechanism for aeroderivative turbines. 

Reducing acidity

Reducing acidity can reduce the aging of the oil and wear on equipment, which can increase equipment reliability and lifetime. 

Laboratory tests

ASTM D7414 can measure oxidation absorbance peaks to indicate oxid

ation formation.