Identified as one of the single largest energy loss factors in power generation stations, condensers are a potential source of either savings or increased expenditure, especially as fuel prices increase. The performance of the condensers can be adversely affected by the build-up of sediment, scale, corrosion or biological growth inside the tubes. Conventional maintenance procedures to clean fouled tubes range from chemicals to off-line mechanical cleaners and brushes, to on-line systems and hydro-blasters. Sometimes, it takes an unconventional, innovative development in a cleaning system technology to combat ever-changing environmental challenges. Omaha Public Power District’s North Omaha Station had been drawing water from the Missouri River for many years with no discernable problems. Recently, they had experienced a steady rise in summertime backpressures, in the range of 3 to 3.5 in. HgAbs, resulting in poor condenser performance. Inspections revealed a build-up of calcium carbonate scale in the tubes. The station has five condenser units with a total of approximately 50,000 stainless steel condenser tubes, all displaying evidence of calcium carbonate build-up. A recently developed and patented mechanical system for the removal of calcium carbonate scale without any of the negative drawbacks of chemical alternatives was utilized at the station with excellent results, proven by subsequent observations. On completion of the process, back pressure dropped to around 2.0 in. HgAbs and overall performance improved markedly. While plant personnel strive to determine the cause of calcium carbonate buildup in the condenser, removing it from the station’s tubes is now a simple procedure and no longer a problem in search of a solution.

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