Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1275515
ML www . machinerylubrication.com | July - August 2020 | 15 ML is reduced. is allows the water to flash via the heat into vapor, which is then recondensed, to be rejected from the system. Because the boiling point of water is reduced, this allows the oil to be heated to a temperature low enough to stop thermal breakdown of the oil and addi- tives. Vacuum dehydrators also have the advantage of removing all forms of water, including dissolved water, which is not possible through other typical water remova l purif ication systems, such as coalescers and centrifuges. Figure 1 displays the different components in a vacuum dehydrator. Vacuum Dehydrator Experiment Machine: Steam Turbine Vacuum Dehydrator run: 60 Hours Start Date: February 29 End Date: March 3 Sump Size: 1500 liters Capacity of Vacuum Dehydrator: V10 Set Oil Temperature: 50 o C e subject machine was found with high water content (1250 ppm) in the lube oil system through the condition monitoring program. e root cause was attributed to leaking seals. Hence, it was decided to utilize this equipment for the trial. e turbine was kept in shut down during experiment to stop further water ingression through leaky seals and properly understand the effectiveness of vacuum dehydrator. For this trial, a portable vacuum dehydrator was used. It was connected to the lube oil reservoir as a kidney loop filtration system. e temperature was set at 50 o C during purification. The purification process was continued for 60 hours and water content and AN were measured for oil samples collected every 12 hours during purification. e rotating pressure vessel oxidation test (RPVOT) was also measured for new and used oil before and after purification. e results are captured below: • Water (ppm): Water content was reduced from 1250 ppm to 250 ppm within 25 hours of operation and it took 35 additional hours to further reduce the water content from 250 ppm to 100ppm. e saturation point of the used turbine oil was around 250 ppm and is highlighted in the graph with a dashed line. Therefore, free water and emulsified water can be removed rapidly from the lube oil by the vacuum dehy- drator. It is time consuming to remove dissolved water from lube oil. FIgure 2. Concentration of water vs. running hours of vacuum dehydrator. Figure 1. Vacuum Dehydrator system components. (Courtesy of Hy-Pro Filtration)