The THIOPAQ O&G process integrates gas purification with sulphur recovery in a single unit. The sour feed gas first comes into contact with the lean solution in the absorber. This solution absorbs the H2S to form sodium sulphides, and sweet gas exits the absorber, ready for use or further processing.
Depending on the sour feed gas pressure, the sulphide-loaded ('rich') solution is routed to a flash vessel or directly to a bioreactor, which is operated at atmospheric pressure and ambient temperature. Here, the micro-organisms oxidize the sulphide to elemental sulphur. The process solution is recirculated over the absorber, while part of the solution is routed to the sulphur recovery section, in order to remove elemental sulphur from the system.
The produced elemental S is separated from the solvent using a decanter centrifuge. The recovered water is recycled back to the process via the bioreactor. A small slipstream of the solvent is bled from the system to prevent an accumulation of salts beyond the allowed maximum.
