Hydroelectric Dam - Westinghouse Hydroelectric Turbine
Severe Oil Degradation
This oil field facility is producing 17,000 barrels of oil per day, and is one of North America’s largest CO2 sequestering projects. The oil has been in service in this large centrifugal compressor for over 20,000 hours. The one anti-oxidant (phenolic) is almost completely consumed, however, the remaining anti-oxidant (aminic) is still in good concentration in the oil.
Figure - This large Dresser Datum Centrifigual Compressor is being utilized to sequester CO2 gas in one the largest projects of it`s kind in North America.
Additional testing including Rotating Pressure-Vessel Oxidation Testing (RPVOT) and Membrane Patch Colorimetry (MPC) for varnish potential indicate that the oil oxidative stae is stable and that no insolubles are forming in the oil that could lead to varnish. The analytical ferrogram also showed only nomimal component wear, and showed no visual signs of insoluble bodies (varnish precursors). As a result of the combined testing it was determined that no maintenance activities were warranted and that the compressor be resampled after 1,000 hrs operation to monitor this condition.
Figure - The RULer testing indicated a significant depletion of the phenolic anti-oxidant in the oil, however additional testing indicated that the oil was still in good operating condition.
Aluminum Mill - Aero-Derivative Gas Turbine
Incorrectly Blended Turbine Oil
WearCheck was contracted to provide Advanced Oil Monitoring (AOM) services for 4 Rolls-Royce aero-derivative gas turbines being commissioned in an aluminum mill to provide power to the plant. 100,000 litres of turbine oil was delivered to the plant and the four turbines were filled. The reliability technicians drew baseline samples from the four turbines and submitted the samples for AOM analysis. Surprisingly the RPVOT showed very little anti-oxidant present in all four systems. Additionally, Linear Sweep Voltammetry (RULer) testing showed very little phenolic anti-oxidant present in the oil. All other properties of the oil appeared normal. An early resample was suggested and the four turbines were resampled in two more months time. This time the analysis showed a critical concentration of phenolic anti-oxidants, and the MPC test for varnish showed a dramatic increase in insolubles present in the oil, which were also visually confirmed in the analytical ferrogram (top picture 200x magn).
Figure - An aluminum mill commissioned four Rolls-Royce aero-derivative turbines and performed Advanced Oil Monitoring (AOM) at start-up and within two months of operation to monitor the oil and system condition.
It was suggested that the turbine oil had not been properly blended. One of the turbines was drained, flushed and re-filled with a new charge of turbine oil. Subsequent AOM testing showed that the anti-oxidants had been restored in the turbine, and that the new turbine oil had been properly formulated. As a result of taking action within a few months, the varnish did not being to accumluate in the turbine, and in fact the drain and flush was sufficient to remove the insolubles from the system.
Figure - Unexpectedly the new turbine oil showed an issue with formulation, having only marginal amounts of phenolic anti-oxidant present, which rapidly led to the formation of insolubles in the turbine.