Experimental Study on a Scale Prevention Method Using Exhausted Gases from Geothermal Power Stations

Abstract

For the utilizations of geothermal energy, prevention of scale deposition is one of the most important factors. In general, scale deposition is recognized at various places inside of transportation line in geothermal power stations. The silica scaling from geothermal fluids is brought about by a solution that is supersaturated with silica. It is known that silica deposition is prevented by controlling the pH of the solution by maintaining it in an acidic condition (about 5.). There are various methods to control the pH of fluids. One is the addition of mineral acid to the solution. However, this method has not been applied until the present time because of its environmental impact. An alternative pH control method using geothermal gases discharged from geothermal power stations was studies. From the environmental view point, this method is more desirable than the former because the gases are mainly composed of carbon dioxide. In this paper, the experimental study on the prevention of silica deposition will be described.