Gas Removal of Turbine Oil in Power Plants, Measured Performance of Vacuum Oil Purification Process

Turbine oil in power plants performs two demanding duties at once: it lubricates the bearings of the turbine and generator, and it supplies the hydraulic fluid for governing and trip systems. Under these conditions, the oil continuously takes up air. Seals, breathers, pump cavitation and the violent agitation of the oil system entrain air bubbles and dissolve gas into the oil. As gas content rises, the oil becomes compressible, oil film strength falls and foam forms in the reservoir. Foam and entrained air can cause erratic governor response, bearing oil film instability and unnecessary trip risk, all of which threaten the reliable operation of the unit. Removing gas from turbine oil is therefore a routine but critical maintenance task in power plants.

The vacuum oil purification process is the established method for gas removal. Oil is drawn from the turbine oil system and passed through a vacuum chamber, where the reduced pressure causes dissolved gases to come out of solution and leave the oil. The process is carried out at controlled temperature so that only gas and light volatiles are removed, while the base oil and additive system are preserved. The degassed oil returns to the system, and continuous circulation keeps the gas content low. Because the unit operates as a bypass circuit, gas removal can run while the turbine remains in service, matching the operating pattern of the plant.

The performance of the process is measured directly through oil tests. Gas content is checked by measuring the dissolved gas level in the oil, and foam tendency is assessed in a laboratory test that shows how much foam forms and how quickly it collapses. Water content and particle counts are measured alongside, because the same vacuum process also removes moisture and the filtration stages take out solids. Readings are taken before, during and after treatment, so the plant can verify the gas content falling to the required level and confirm that the oil returns to specification. These measured results give maintenance staff clear evidence that the treatment is effective.

The measured improvement translates into stable turbine operation. With dissolved gas removed, the oil regains its incompressibility and film strength, so bearings operate with a stable oil film and the governing and trip systems respond reliably. Foam formation in the reservoir is suppressed, which reduces the risk of oil carry-over into the vapor system and of level gauge errors. Bearing and vibration-related problems caused by gas-laden oil become less frequent, and the risk of spurious trips decreases. The unit can then run with greater confidence, and maintenance intervals for oil-related issues lengthen.

From the plant's perspective, the vacuum oil purification process is practical to operate and verify. The unit connects to the oil system through standard valves, runs with minimal supervision, and treatment results are confirmed by routine oil tests that plant staff already perform. Continuous or scheduled operation keeps gas, moisture and particle levels within limits, so oil quality no longer depends on occasional manual intervention. Because the oil is preserved rather than replaced, oil consumption and disposal costs stay low, and the plant avoids the downtime associated with oil changes. The measured performance makes the process easy to justify and manage.

In summary, the vacuum oil purification process delivers measured, reliable gas removal for turbine oil in power plants. By reducing dissolved gas and foam to specification while the unit operates, it stabilizes bearing lubrication and control response, lowers trip risk and supports long-term, economical turbine maintenance.