Þeistareykir Geothermal Power Plant – Deposits in Gas Removal System

Abstract

The National Power Company of Iceland, Landsvirkjun, has completed the construction of the Þeistareykir 90 MW geothermal power plant. Þeistareykir is in NE Iceland, 27 km SE of the town Húsavík. The power plant has been in full operation since April 2018. When operating a new geothermal Power plant, one might bump onto varies of problems that are found to a lesser or greater degree at every site depending on the geology, reservoir conditions and chemical compositions. After only few months operating condensate pumps in the gas removal system of Þeistareykir geothermal power plant started failing, closer inspection showed red-brownish deposits. Inspected deposits samples turned out to be mostly sulphur (S), selenium (Se), and partly oxygen (O) enriched products. Selenium and sulphur originating from volcanic activity as it is volatilized and transferred to the environment during volcanic activity. Later, expansions joint in the gas removal system started leaking because of corrosion, the reason being moisture and oxidizing conditions forming sulfuric (H2SO4) and selenic acid (H2SeO4)