Pilot Testing of a Novel Hydrogen Sulfide Abatement Process - Mak-Ban Unit 3, Bulalo, Philippines, Geothermal Field.

Abstract

Anew liquid phase oxidation process for abatement of hydrogen sulfide emissions from geothermal power plants was tested in 1991 at Mak-Ban Unit 3, Bulalo, Philippines geothermal field. The process comprises contacting neutralized cooling tower circulating water with a small, substantially less-than-stoichiometric amount of an oxidizing biocide required to oxidize sulfide to sulfate. Determining precise abatement efficiencies in the Unit 3 direct contact condenser proved extremely difficult. Process monitoring suggested that the oxidation reaction in the direct contact condenser resulted in up to 50 - 77% abatement of emissions from both the vent gas ejectors and degassing at the cooling tower. Microbiological growth in the circulating water was controlled by periodically adding a second (non-oxidizing) biocide. The oxidizing biocide treatment had little, if any, effect on circulating water corrosivity.