Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Author: search.filters.author.Yıldırım Özcan, Nurdan

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  • Book Part
    Citation - Scopus: 3
    Performance Analysis of Single-Flash Geothermal Power Plants: Gas Removal Systems Point of View
    (Nova Science Publishers, Inc., 2012) Yıldırım Özcan, Nurdan; Gökçen, Gülden; Gökçen Akkurt, Gülden; Yıldırım, Nurdan; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Non-condensable gases (NCGs), natural components of geothermal fluids, affect the performance of a geothermal power plant (GPP) significantly. Therefore, the NCGs should be removed from the process to optimise the thermodynamic efficiency of the plant. GPPs require large capacity NCG removal systems that occupy large portion in the total plant cost and auxiliary power consumption. The flashed-steam GPPs, which are commonly used in the World, 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 this study is to develop a code for simulating flashed-steam GPPs to examine the thermodynamic performance of NCG removal systems, which represent major concerns at planning and basic design stages of GPPs. A single-flash GPP model is developed and simulated to identify the effects of input variables, such as NCG fraction, separator pressure and condenser pressure. Among the variables, NCG fraction is the most significant parameter affecting thermodynamic performance of single-flash GPPs. The net power output and overall exergetic efficiency of single-flash GPP are decreased 0.4% for compressor system (CS), 2.2% for hybrid system (HS), 2.5% for reboiler system (RS), and 2.7% for steam jet ejector system (SJES) by 1% increase in NCG fraction.
  • Article
    Citation - WoS: 22
    Citation - Scopus: 26
    Thermodynamic Assessment of Gas Removal Systems for Single-Flash Geothermal Power Plants
    (Elsevier Ltd., 2009) Yıldırım Özcan, Nurdan; Gökçen Akkurt, Gülden; Yıldırım, Nurdan; Gökçen Akkurt, Gülden; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Geothermal fluids contain non-condensable gases (NCGs) at various amounts. NCGs flow to a conventional geothermal power plant (GPP) with steam phase and should be withdrawn from the condenser by a gas removal system to prevent increase in condenser pressure and consequently decrease in power generation. Therefore, to remove NCGs from the system is critical especially at high NCG fractions. In this study, the net power output and specific steam consumption of a single-flash GPP is evaluated depending on the separator pressure, NCG fraction and wet bulb temperature of the environment, and three different conventional gas removal options which are two-stage steam jet ejector system, two-stage hybrid system and two-stage compressor system. A simulation code is written in EES to model the plant for each option. The model uses the data of Kizildere Geothermal Power Plant (KGPP) - Turkey, which is a single-flash plant with extremely high NCG fraction, to allow a comparison between the results of the modelling and the operational data of an actual single-flash GPP. Under given conditions, thermodynamic analysis resulted that NCG fraction is the most significant factor on GPP performance and the compressor system is the most efficient and robust option where the influence of the NCG fraction is limited.