Catalytic Removal of Hydrogen Sulfide from Geothermal Fluids

Abstract

UOP Sulfox technology successfully removed 500 ppm hydrogen sulfide from simulated mixed phase geothermal waters. The Sulfox process involves air oxidation of hydrogen sulfide using a fixed catalyst bed. The catalyst activity remained stable through the life of the program. The distribution of hydrogen sulfide conversion products was affected by the pH; low pH favored elemental sulfur, whereas high pH favored water soluble sulfate and thiosulfate. Operation with some liquid water present assured full catalytic activity. Dissolved salts reduced catalyst activity somewhat. Application of Sulfox technology to synthetic geothermal fluids resulted in a straightforward process with no requirements for auxiliary processes to various types of vapor dominated and high and low salinity liquid dominated geothermal systems is discussed.