The WSA condenser in WSA and SNOX™ plants cools the process gas with atmospheric air, typically from 280°C to 100°C. This first makes the SO₃ in the process gas react with water vapor to form the sulfuric acid vapor, and secondly, the sulfuric acid vapor condenses to form the sulfuric acid liquid.

The WSA condenser consists of a steel casing containing a large number of vertical glass tubes. The acid is condensed on the inside of the glass tubes. The WSA condenser has acid proof brick-lining in the bottom section and a top section lined with a fluoropolymer.

WSA condensers are supplied only in connection with WSA or SNOX™ plant technology.