Degraded performance of a steam surface condenser will directly affect the availability and operational efficiency of any power plant, and this in turn will always impact plant optimization. Results of eddy current testing, loss of surface area through excessive numbers of plugged tubes or turbine blade failure, life extension studies, extended power uprates, the general effects of erosion and corrosion, etc. — these are all examples of issues that may lead to the replacement of tubes, tubesheets and/or waterboxes at some point during the operational life of a power plant steam surface condenser.
Retubing, and the modular replacement of existing condenser tube bundles, are two options available to power plant owners & operators that can help to regain lost performance, and even in some cases improve on the original unit design. However, the use of different tube materials and wall thickness for retubing, as well as different tube diameters and quantities for modular replacements; means that these changes must be accompanied by the necessary detailed evaluation of the impact to the original design.
In addition to Tubes, it may also be necessary to replace existing Tubesheets and/or even Waterboxes. This work scope should always include a detailed review of the possible impacts of any changes due to these replacements. Failure to perform the necessary thermal and mechanical evaluations can lead to additional operational issues that may also impact unit performance & longevity.