The EUROCLAUS process recovers elemental sulfur from hydrogen sulfide (H2S) containing gases, which originate from gas treating plants such as alkanolamine units or physical solvent plants. Yields up to 99.7% overall sulfur recovery without any further tail gas clean up are possible.
The EUROCLAUS process has a thermal stage followed by three catalytic reaction stages. Sulfur is removed between stages by condensers. Two reactors are filled with standard Claus catalyst while the last reactor is filled with selective oxidation catalyst. In the thermal stage, acid gas is burned with a substoichiometric amount of controlled combustion air such that, the tail gas leaving the second reactor contains typically 0.8 vol.% to 1.0 vol.% of H2S and 100–200 ppmv sulfur dioxide (SO2). The low SO2 content, produced with a hydrogenation catalyst, converts SO2 to H2S in the reactor bottom.
The last reactor oxidizes H2S to sulfur at more than 85% efficiency. However, because this catalyst neither oxidizes H2S to SO2 nor reverses the reaction: total sulfur recovery up to 99.3% efficiency can be obtained. If more than 99.3% sulfur recovery is required, one additional Claus reactor stage may be installed upstream of the selective oxidation reactor.
Licensor: Comprimo Sulfur Solutions, a member of Jacobs Engineering Group