It is very expensive to open an exchanger for inspection and repairs. Also, for exchangers that are operating well, opening them unnecessarily may cause future problems. Therefore, it is very important to have an organized procedure for making decisions. This is especially important going into a plant turnaround where a large number of exchangers will need to be investigated.
The following list of considerations can be used to help determine when to open an
• Is the exchanger leaking internally or externally?
• Does the unit need recertification?
This is usually a concern only for steam generators, which require periodic state inspection and certification.
• Is the exchanger performance satisfactory?
In other words, does the U-value or DP indicate fouling or internal damage.
• Based on this bundle’s history and the history of similar bundles in similar services, will the bundle last until the next turnaround?
Accurate inspection records are important in making this decision.
• Can exchanger be cleaned on the run?
Isolating an exchanger and cleaning it with the surrounding equipment operating entails significant safety and operating problems. This is usually done only if the exchanger and piping were designed to allow for online cleaning.
• Can the unit be chemically cleaned?
Light uniform fouling may be chemically cleanable. Locally plugged exchangers cannot be chemically cleaned. Chemical cleaning is expensive and all of the environmental and safety implications should be considered first.