Manual for investigation and correction of feedwater heater failures

A closed surface feedwater heater performs a key role in the regenerative Rankine cycle. It heats water fed to the boiler, thereby, decreasing heat rate and improving cycle performance. Shell and tube heat exchangers are used to achieve this benefit . However, these heat exchangers often operate under conditions of high-velocity gases, liquids and combinations of the two, plus high temperatures and pressures. These conditions tend to cause high failure rates. Feedwater heater failures can have a detrimental impact on plant performance, availability, and other components. The failure causes may be related to design, fabrication practices, construction materials, abnormal operating modes, cycling, or the manner in which the feedwater heater is operated and/or maintained. Appropriate corrective actions, if any are possible, can only be selected after the root cause of a failure is identified. Simply identifying a failure mechanism does not necessarily identify the actual root cause. This manual was written for use by utility engineers and operation and maintenance personnel in investigating and correcting feedwater heater component failures. 63 figs., 4 tabs.