Simulation and exergetic evaluation of CO2 capture in a solid-oxide fuel-cell combined-cycle power plant

• Published in: Applied energy 2014-02, Vol.114, p.417-425
• Main Authors: Petrakopoulou, Fontina, Lee, Young Duk, Tsatsaronis, George
• Format: Article
• Language: English
• Subjects: Applied sciences; CO2 capture; Combined-cycle power plant; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Exergetic analysis; Fuel cell; Fuel cells; SOFC
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2013.09.034

•An exergetic analysis is used to identify the thermodynamic irreversibilities of a power plant.•The plant includes a solid-oxide fuel-cell unit and CO2 capture.•Additional power generated in the fuel-cell unit enhances the power output of the plant.•The power plant results in a high efficiency compared both to conventional and other CO2 capture plants.•High irreversibilities are found for the solid-oxide fuel cell. The incorporation of fuel cells into power plants can enhance the operational efficiency and facilitate the separation and capture of emissions. In this paper a fuel-cell unit, consisting of solid-oxide fuel-cell stacks, a pre-reformer, and an afterburner is incorporated into a combined-cycle power plant with CO2 capture. The thermodynamic performance of the plant is examined using an exergetic analysis and it is compared with a conventional combined-cycle power plant (reference plant) without CO2 capture, as well as with other plants with CO2 capture. The inefficiencies of the chemical reactions taking place in the fuel-cell unit are found to be the main source of exergy destruction among the plant components. However, the additional power generated in the fuel-cell stacks and the afterburner enhances the overall efficiency and compensates for the energy needed for the capture and compression of the carbon dioxide. When compared with the reference plant and with alternative capture technologies, the solid-oxide fuel-cell plant with CO2 capture operates more efficiently and appears to be a thermodynamically promising approach for carbon capture.