Engineering

The WSA process is used to recover sulfurous substances from waste gases in the form of highly concentrated sulfuric acid. At the same time it makes use of the ensuing process heat to produce steam.

The process

The WSA process is a catalytic process. The waste gas stream containing H₂S and CS₂  is oxidized in the burner respectively in the combustion catalyzer to SO₂ .

The SO₂ is converted to SO₃ by means of a sulfuric acid catalyzer and after cooling it reacts, whilst producing steam at the same time, with the water vapor to create sulfuric acid (H₂SO₄). As a result of cooling the air in the WSA condenser, the sulfuric acid is condensed as concentrated sulfuric acid of commercial quality from 96–98%.

The reaction heat which occurs can be recovered in its entirety and any possible excess heat is used for the production of steam.

The process is adapted to suit the waste gas stream at hand. The natural gas required can, if necessary, be partly or completely replaced by elementary sulfur and thereby allows for the additional production of sulfuric acid. By the year 2008, more than 80 WSA plants had been installed around the world.