How to select a Heat Exchanger?

From the simplest to the most complex industrial heating process,are needed to carry out the fundamental functioning of efficiently transferring heat from in medium to another. They are one of the most commonly used process equipment in industries.

Regardless of whichever industrial sector you find yourself in, you are essentially looking for the same product – that is, a heat exchanger that will efficiently get the job done for you.  So the question remains, how do you figure which one is right for you?

Selecting the right heat exchanger is of critical importance. The wrong selection can lead to poor plant performance, operability issues and equipment failure.

10 Criteria to choose a heat exchanger

To make this selection easy, we have listed out the 10 criteria to be considered before selecting the right heat exchanger:

1. Application (i.e. sensible vapor or liquid, condensing or boiling)
2. Operating pressures & temperatures (including startup, shutdown, normal & process upset conditions)
3. Fouling characteristics of the fluids (i.e. tendency to foul due to temperature, suspended solids…)
4. Available utilities (cooling tower water, once-through cooling water, chilled water, steam, hot oil…)
5. Temperature driving force (i.e. the temperature of approach or cross and available LMTD)
6. Plot plan & layout constraints
7. Accessibility for cleaning and maintenance
8. Considerations for future expansions
9. Cost – One must consider Purchase Cost, Installation Cost, Operating Cost and Maintenance Cost.
10. Mechanical considerations such as 1) material of construction; 2) thermal stresses (during startup, shutdown; process upset and clean out conditions); 3) impingement protection.

By answering the above criteria, you can select an ideal heat exchanger design based on the operation specification. Whether it is a new process  or modifying the process with new equipment, the right model of the heat exchanger is important for process optimization. Any time a heat exchanger is being replaced, the opportunity should be taken to re-assess if the type used is best for the given process.  Operating changes since initial installation as well as advancements in the field of heat transfer may point towards a different type as being optimal.