Aftercoolers

An aftercooler is installed at the end of all compression stages.

The purpose of an aftercooler is:

a. Cool the compressed air so that it can shed moisture.

b. Reduce the compressed air temperature so that it can be safely handled by the users.

The figure provided here illustrates a water-cooled aftercooler. Notice that the cooling water flows on the shell side, while the compressed air flows from left to right in the tubes. As compressed air flows through the tubes, it is cooled and it sheds water (condensate). To remove the condensate, compressed air is forced to flow through a separator installed on the discharge side of the aftercooler. In the separator, compressed air is forced to swirl around, causing separation of moisture due to centrifugal force.

The separated moisture settles at the bottom of the separator, from where it is removed.