Brine chemistry -- scaling and corrosion. Geothermal research study in the Salton Sea region of California

Abstract

The potential for producing electrical power from the energy stored in the unusually hot, hypersaline brine deposits of the Salton Sea KGRA (Known Geothermal Resource Area) is large. Unfortunately, utilization of geothermal energy is currently hindered by severe scaling and corrosion problems. In order to solve these problems and to facilitate the commercial exploitation of geothermal resources in the Salton Sea KGRA, a research program that will determine the dependency of scaling and corrosion on brine composition and process conditions is necessary. The purpose of this report is to recommend a reasonable program of brine chemistry research that will result in the development of methods for predicting and controlling scale deposition, and in guidelines for the selection of corrosion-resistant construction materials. This report is structured in the following manner: First, background information, which is necessary for the understanding of the problems of scaling and corrosion in the Salton Sea KGRA, is presented through a review of the history of geothermal exploration and development in the Salton Sea. Second, literature relevant to the geochemistry of the Salton Sea field is reviewed and important results are emphasized. Third, current research efforts directed toward actual power plant construction are summarized and evaluated. Fourth, research which has been proposed but is not currently funded is discussed. Fifth, because silica scaling has been the most troublesome problem in the past, the basic chemistry of silica and its relationship to scaling is discussed. Sixth, recommendations for future research are made in which a fundamental engineering approach is emphasized. In this approach, experiments would be conducted on actual process equipment and detailed chemical analyses would be performed on site in well-equipped field laboratories.