Harpster, J.W., Harpster, T.J., & Welch, W.C.
“Air Storage: The True Root Cause of Condensate Dissolved Gases and Poor Condenser Performance” EPRI International Conference on Cycle Chemistry, Seattle, WA, June 26 – 28, 2012.
Abstract
During the past sixteen years, understanding of the condensation process within steam surface condensers has been advanced through the introduction of new continuous monitoring and control instrumentation. An important conclusion from this advancement has been that air in-leakage passing through the condenser does not directly degrade its performance nor promote dissolved gases in the condensate. It is only when air becomes stored in pockets, causing high concentration and partial pressures, that it can impact condenser performance and cause dissolved gases in the condensate.
This presentation/paper will briefly describe how pockets of high air partial pressures cause degraded performance and dissolved gases. The two major mechanisms will be presented where air becomes separately stored inside the condenser. The condensate chemistry parameters for two similar units can result in very different responses depending on the mechanism of air storage. Measurements from Condenser Monitoring Systems (CMS) that measure the effects of air storage will be presented. Some guidelines on how to identify air storage using plant data will be shown. The results from condenser retrofits will be presented that show the magnitude of chemical treatment and condenser performance improvement that is possible when the root causes of air storage are removed from the system. The results of modified condensers will be compared with the behavior of new bundles regarding their performance and treatment requirements.
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