H2S Emission Control by Chelated Iron Scrubbing: An Environmentally Sound Alternative to Stretford

Abstract

Geothermal steam sources used for electric power production frequently contain sufficient hydrogen sulfide to create odor nuisances and problems in reinjection of the condensate. This is particularly true in the Geysers area of Northern California where the Stretford process has been widely used to treat gaseous emissions and a variety of chemical treatment processes have been applied to the removal of hydrogen sulfide form steam condensate. Application of the Stretford process has been problematic, and recently, regulations prohibiting disposal of waste products containing significant quantities of vanadium have led power producers to giver serious consideration to alternative processing. The LO-CAT(R) Hydrogen Sulfide Oxidation Process utilizes an environmentally safe catalyst which uses iron as the redox agent. This paper describes the chemistry of the process, and compares the physical equipment and characteristics with the Stretford process. Also, the utilization of a companion process for removal of sulfide ions from condensate is discussed.