The biological Thiopaq process selectively removes and converts H2S and light mercaptans from gas streams, aqueous streams and/or light hydrocarbons to elemental sulfur or sulfate.
Product: The sulfur produced is hydrophilic; thus, it prevents equipment from fouling and blocking. Moreover, this characteristic makes the product suitable for agricultural use as fertilizer or as an insecticide. Alternatively, the sulfur can be melted to a high-purity product meeting international Claus sulfur specifications.
The Thiopaq process consists of three integrated process sections: an absorption section to remove the H2S from the gas stream, bioreactor(s) and a sulfur-separation section.
The heart of this process is the proprietary bioreactor. In this air-lift-loop reactor, sulfide (HS–) is oxidized
under controlled conditions to elemental sulfur in the presence of microorganisms. These aerobic (oxygen consuming) organisms use the released energy from the sulfide oxidation for metabolic processes. The elemental sulfur produced has a hydrophilic nature and is separated from the aqueous effluent in a proprietary three-phase separator.
The scrubbing step to remove H2S from the gas streams is integrated into the Thiopaq process and regenerates the scrubbing solution, rather than its disposal. Regeneration is possible because the alkalinity consumption due to the absorption of H2S is compensated by the oxidation of H2S to elemental sulfur.
Operating conditions: The absorber operates at the pressure of feed and at bioreactor temperature. The bioreactor operates at atmospheric pressure and 30–35°C. If the feed is available at a higher temperature, then it requires cooling before entering the absorber.
Licensors: UOP LLC, Shell Global Solutions B.V. and Paques B.V.