Controlling H2S Emissions in Geothermal Power Plants

Abstract

Geothermal power plants are environmentally attractive since they employ a renewable energy source; however, geothermal steam contains varying amounts of noncondensable gases (NCG), such as carbon dioxide (CO,) and hydrogen sulfide (&S) which, if not dispose of correctly, may cause environmental, health and safety problems. Also, if the carbon dioxide is to be further processed to produce beverage grade carbon dioxide, the hydrogen sulfide must be removed to extremely low levels. In some locations, H,S is present in sufficient quantities to represent a reasonable raw material for producing elemental sulfur, which can be sold as a product for producing sulfuric acid or fertilizers. This article describes various methods for controlling hydrogen sulfide emissions in geothermal power plants. The technical aspects of each system are described in detail, in addition, to disposal of the byproducts produced by each system, which has become a major consideration in Europe.