10.2.1 The mechanism of air extraction
The mechanism by which non-condensable gases are transported between the points of entry to the condenser shell and the discharge to atmosphere can be subdivided into three stages:
- Transfer of incondensable gases from the main condensing zone to the air cooling section of the condenser.
- Cooling of the incondensable gases and associated steam in the air cooling section.
- Extraction and compression of the incondensable gases from condenser vacuum to atmosphere.
In order to meet the objectives outlined earlier, it is important that all three stages in the process are carried out efficiently.
Details of how this is achieved are described, and the different equipment types are reviewed.