In shell and tube heat exchangers the number of shell passes or the number of tube passes will always come across. The number of passes in general affects your pressure drops in shell and tube heat exchangers. This short article will show the difference between them for quick reference.
The tubes are arranged within the shell and tube heat exchangers in passes. The passes can be One, Two, Four, Six or Eight.
This arrangement can be illustrated in the figure below:
As shown below:
A Quick Note:
It’s always better to design within the general guideline as this would have an impact on cost. In other words, it’s easier to approach manufactures with common configurations to reduce you capital costs.