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Sulfur Recovery
The sulfur recovery process used in most refineries is a "Claus Unit". In general, the Claus Unit involves combusting one-third of the hydrogen sulfide (H2S) into SO2 and, and then reacting the SO2 with the remaining H2S in the presence of cobalt-molybdenum catalyst to form elemental sulfur.
The conversion chemistry is:
- 2H2H2S + 3 O2 → 2 SO2 + 2 H2O (Combustion)
- 2 H2S + SO2→ 3 S + 2 H2O (Conversion)
Generally, multiple conversion reactors are required. Conversion of 96-97% of the H2 to elemental sulfur is achievable in a Claus unit. If required for air quality, a Tail Gas Treater may be used to remove remaining H2S in the tail gas from the Sulfur Recovery process.
