
The Claus reaction to convert H2S into elemental sulfur requires the presence of one mole of SO2 for each two moles of H2S:
(1) 2H2S + SO2 → 3S + 2H2O
To provide that ratio of components, the first step in the Claus process is the combustion of one-third of the H2S in the feed gas:
(2) H2S + 1.5 O2 → SO2 + H2O
Combining equations (1) and (2), the overall process reaction is:
(3) 2H2S + O2 → 2S + 2H2O
Catalyst
(3) COS + H20 → H2S + CO2
(4) CS2 + 2H20 → 2H2S + CO2
(1) 2H2S + SO2 → 3S + 2H2O
To provide that ratio of components, the first step in the Claus process is the combustion of one-third of the H2S in the feed gas:
(2) H2S + 1.5 O2 → SO2 + H2O
Combining equations (1) and (2), the overall process reaction is:
(3) 2H2S + O2 → 2S + 2H2O
Catalyst
(3) COS + H20 → H2S + CO2
(4) CS2 + 2H20 → 2H2S + CO2