Upstream Reboiler Design and Testing for Removal of Noncondensable Gases from Geothermal Steam at Kizildere Geothermal Power Plant, Turkey

Abstract

The Kizildere geothermal power plant in Turkey is a unique geothermal power plant with an installed capacity of 20.4 MWe. The most significant characteristic of the field is the high level of noncondensable gases (NCGís), in amounts as high as 10- 20% (with an average of 13% at the inlet of the turbine) by weight of steam. The NCGs are being extracted from the condenser by gas compressors that consume about 18.3% of the total power production of the plant. An upstream reboiler process is another approach to remove the NCGís from geothermal steam before they enter the turbine. Upstream reboilers therefore provide a cleaner and less corrosive steam supply to the turbine and condenser, increasing power generation performance for very high NCG content. In this paper, upstream reboiler systems are investigated as an alternative to conventional gas extraction systems for Kizildere geothermal power plant. Both vertical tube and direct contact type reboilers have been designed and evaluated. The direct contact type is being tested at the Kizildere field and is covered in this paper since the vertical tube type has been reported upon and tested extensively in the past. The direct contact tests have been carried out in the field with a gas removal efficiency 76.3±22.6% at the base case.