Top Seven Shell and Tube Heat Exchanger Failure Mechanisms (#7 – Poor Design)

#7 – Poor Design

“Poor Design” could mean a lot of things in the world of heat exchangers. It’s critical to understand all the things that factor into the design of a shell & tube heat exchanger. With the right partners, it’s easy to take a lot of guesswork out of the equation to ensure you end up with a unit that performs as needed with a reliable life expectancy.

In short, below are some common issues that poor design can result in:

  1. Fouling – We have discussed fouling in a prior segment, so you already know what it entails. Avoid it by ensuring that your design team understands how to run a full thermal analysis on your process. Managing flow rates and pressure drops is low-hanging fruit to avoid some kinds of fouling. Additionally, some processes may be sensitive to high temperatures and overheating the process could lead to chemical changes that create fouling. Also, keeping your equipment well- and regularly-maintained and start by choosing the right type of exchanger, as some process have very narrow operating windows and require a certain style of exchanger to function at all. Fouling can be brought on by many mechanisms – stick with folks who can handle the thermal and mechanical design of your heat exchanger and understand how to analyze and design around those and you’ll be off to the best possible start.
  2. Bad Material Choices – Without metallurgical advice, your otherwise thoughtful design could end up with the need for additional cleaning, thicker tubes than necessary, or – worse – corrosion issues that lead to wall thinning and/or build-up of fouling layers, reducing its service life while increasing the potential for dangerous leaks.
  3. Pressure Drop Problems – Designing a unit without consideration for pressure drop can lead to low velocities that allow certain process chemicals to plate out on interior surfaces and creates fouling.
  4. Poor Adjacent Piping Design & Bad Overall Equipment Layout – Leads to overly complex and convoluted piping and access problems for maintenance and cleaning in the future. Additionally, this can lead to poor process fluid velocities, which, again, can lead to fouling.
  5. Wrong Size – Under-sizing a unit in an attempt to save cost can easily backfire and result in a unit that barely performs if at all.
  6. Insufficient Cleaning/Maintenance Plan – Leads to poor performance and, ultimately, failure.

Don’t fall prey to poor design – with the right guidance from an experienced partner, you can avoid the pitfalls associated with cutting corners and keep your long-term cost of ownership low and reliability high.