‘Performance analysis of a geothermal power plant. Case study: Comoros

Abstract

The Khathala geothermal field in the Grande Comoros is under development. We propose design of a double flash geothermal power plant, which has a geofluid temperature of 2500 C. The performance analysis of this double flash geothermal power plant was evaluating by using the second law of thermodynamics, which was based on energy and exergy analysis. COCO Simulator was used to develop and simulate a dynamic model of this geothermal power plant. The energy flow rate, exergy flow rate and efficiency are calculated at several plants components, including the turbine, separator, condenser and for the whole power plant. While doing the calculation, we have accepted dead state temperature of 250C, and dead state pressure of 100 KPa. According to the simulation result, the electrical net power output is estimated to be 9.099 MW and 10.03 MW from the Optimum first and second flashing respectively. Based on the exergy of the geothermal fluid at the well reservoir, the overall second and first law efficiencies are calculated to be 6.48% and 27.76%, respectively.