Developing Optimum Condenser Tube Life-Cycle Economics Available to Purchase

A steam surface condenser can operate very reliably for many years. However, much of the tubing will spend a good portion of its life in a most demanding environment of high stresses, mechanical vibration, temperature variations causing thermal stresses, and exposure to corrosive chemicals and waters. Traditionally used copper alloys and lower performance 300 series stainless steel alloys may, at some point during the operating life of the plant, require replacement. The challenge for the plant operations staff is to understand the possible material failure mechanisms, and once they impact profitable performance, develop a long term cost analysis to determine the lowest cost replacement solution. This paper identifies the potential causes of condenser and heat exchanger tube failures and their alternative solutions, the impact of metal transport and provides tools to assign costs to help develop an economic justification for the replacement using a life-cycle analysis. In addition to the cost for treatment chemicals, the paper identifies the impact of forced outages and derates, reduction of generation, and other operation related costs, including the future potential of CO₂ charges. Using HEI criteria, the thermal and mechanical performance of various tube materials are compared and used to build a model to justify the retube payback.