Thermodynamic Performance of Single-Flash Geothermal Power Plants From the Point of View of Noncondensable Gas Removal Systems

Abstract

Geothermal fluids contain noncondensable gases (NCGs) at various amounts. The presence of NCGs in geothermal steam results with a dramatic decrease in net power output increasing condenser pressure and total auxiliary power consumption. Hence, NCGs should be withdrawn by a gas removal equipment to improve the performance of geothermal power plants (GPPs). The flashed-steam GPPs are a relatively simple way to convert geothermal energy into electricity when the geothermal wells produce a mixture of steam and liquid. The primary aim of the study is to model and simulate single-flash GPPs to examine the thermodynamic performance of NCG removal systems, which are major concerns at planning and basic design stages of GPPs. Four different NCG removal systems, which are two-stage steam jet ejector system, two-stage hybrid system, two-stage compressor system and reboiler system are studied. The model is validated comparing model output with Kizildere GPP output, classified as deterministic and static. In this study, the net power output and specific steam consumption of a single-flash GPPs are evaluated depending on the separator pressure, condenser pressure, NCG fraction and wet bulb temperature of the environment.