As the name itself says, in a few words, the shell-tube exchanger consists of a tube (shell) and tubes through which the cold and hot fluids circulate. In another hand, the plate heat exchanger consists of plates, through which the fluids circulate, and a sealing element, most often gaskets, but they can also be welded.
But after all, which is better?
The answer is: it depends!
The best exchanger is the one that best serves the process, consuming less energy.
If you consult a traditional manufacturer of shell-and-tube heat exchangers, he will say that this is better than the plate heat exchanger, for the following reasons:
1) It has less head loss; consequently, the pump used for handling will use less energy.
2) Easier and faster maintenance: considering that removing the caps already reveals the tubes. While the CT plates require total disassembly and replacement of the gaskets every 2 years and require more qualified labor to carry out the service.
3) More robust: The walls of the tubes are thicker which makes them more resistant and less susceptible to puncture by flow erosion whereas CTs to plates often use 0.5 mm plates which are easier to pierce.
4) Less susceptible to clogging due to the area of the tubes being greater than the spaces between the plates, which vary from 2 to 4 mm.
5) They can work at high pressures while typical plate CTs work up to 25 bar.
6) Maximum working temperatures limited to the materials used in the manufacture of gaskets.
7) When you need to change the plates of the PHE, the cost is more expensive than the new one.
On the other hand, if you consult a typical plate heat exchanger manufacturer, he will say that the plate heat exchanger is better than the shell-and-tube one due to the following parameters:
1) More economical: These are up to 5 times more efficient than shell-and-tube CTs (from the manufacturer's point of view)
2) More compact: These take up less space
3) Capacity expansion is relatively simple, just add more plates.
4) They are lighter and, consequently, the cost of transportation, handling, and installation is lower.
And now, who is speaking the truth?
We often say that everyone is right and everyone is wrong.
In some applications, the PHE is better and in others, the STHE é better.
Then, our suggestion is: You must always do a technical evaluation.
When consulting the manufacturers or distributors, ask them why their heat exchanger is better than the others.
The answers will direct you to some good insights about what you must check before buying your heat exchanger.
If you need an expert professional in thermal, rotating equipment, and sealing devices, get in touch with me.