Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/490438
www.machinerylubrication.com | March - April 2015 | 49 solubility enhancer is compatible with the in-service oil. The ability of an oil to redissolve deposits depends upon it having negative free energy from a thermodynamic perspective. Le Chatelier's law (the equilibrium law) governs the balance of this energy and does so by dissolving more deposits into the oil. Adding the solubility-enhancing agent to the lubricant increases its solubility, providing the required kinetic forces to redissolve deposits back into the fluid. In many cases, a slip-stream chemical filtration system is connected to the turbine oil three months prior to an outage. The filtration system must have the capability of removing dissolved degradation products from the oil. This allows the contaminants to continually be removed from the oil and restores the ability of the fluid to dissolve more contaminants. Oil flushing services often come with a combination of technologies and flushing techniques bundled together. However, in all cases, it is critical to match the various technologies with your oil flushing objec- tives and resources. ML Case Study: Flushing Two Boiler Feed-water Pumps a coal-fired power plant had two 3,000-gallon boiler feed-water pumps with old and highly degraded turbine oil. The plant elected to try two different services to clean the systems. For the first pump, a professional oil flushing company was employed during a planned outage. at the beginning of the outage, the lube system was drained and disposed. restrictive flow areas and critical components were isolated from the flush with the creation of special- ized jumper hoses. Confined-space tank cleaning was then completed on the reservoir. a water solution with a citrus cleaner was also added to the system. an external pump and bag filters were used to generate high flow rates. at the conclusion of the chemical flush, water was removed from the system through draining and evaporation. The oil system was then charged with new oil. a high-velocity, high-tem- perature oil flush was performed to remove any other contaminants from the system. The total time for the oil flush was 2.5 weeks. approximately 100 hours were required to support the oil flush during the outage. The total cost was $150,000. The oil flush was considered a success, as all varnish and contaminants were removed from the system. For the second pump, the plant performed a solubility-enhancement system cleaning. a solubility-enhancing agent was added to the system three months prior to the outage. a suitable chemical filtration system was set up to continually clean the fluid and restore the fluid's ability to dissolve contaminants. During the outage, the used oil was drained from the reservoir and from all low points in the system. The system was then recharged with new oil. The total time for the system cleaning was three months. an estimated eight hours were required to support the oil flush. The total cost was $50,000. Once again, all varnish and deposits were removed from the system, and the oil flush was considered a success. The plant was equally satisfied with the outcome of both flushes. However, the solubility-en- hanced system cleaning was one-third the price and required fewer internal resources for support. Concerns about residual cleaning agent in the turbine oil were also eliminated.