Study on Sludge Formation during the Oxidation Process of Turbine Oils

Against the backdrop of increased needs for longer operating life of turbine oils, there is a tendency to use amine-type antioxidants for steam turbine oils as well as gas turbine oils. Amine-type antioxidants are known to form sludge during the oxidation process, and the sludge formation from turbine oils involves the high risk for a power plant of bearing temperature rise caused by sludge deposition onto the bearing surface. But currently, there is no global specification to evaluate the sludge formation from turbine oils that have high rotating bomb oxidation test (RBOT) life. In this study, we examined 18 kinds Of commercially produced turbine oils and two kinds of originally prepared oils with amine additives on sludge formation under 120 degrees C dry turbine oil oxidation stability test (TOST) accelerated degradation test. Consequently, we found a criterion to check the quality of sludge resistance of turbine oils based on the relationship between the RBOT residual ratio and weight of filter residues(1 mu m pore filter).