Energy and exergy based performance analyses of a solid oxide fuel cell integrated combined cycle power plant

• Published in: Energy conversion and management 2014-10, Vol.86, p.507-519
• Main Authors: Gogoi, T.K., Sarmah, P., Deb Nath, D.
• Format: Article
• Language: English
• Subjects: Applied sciences; Combined cycle; Combustion; Electric power plants; Energy; Energy. Thermal use of fuels; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Exergy; Fuel cells; Fuels; Gas turbine; Recuperators; Solid oxide fuel cell; Solid oxide fuel cells; Steam electric power generation; Steam turbine
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2014.06.006

•Energy and exergy based performance of SOFC integrated combined cycle is presented.•The system utilize the GT exhaust for fuel preheating, air preheating and steam generation.•The study considers the effect of additional fuel burning in the combustion chamber.•Detail parametric analysis is presented to show the effect of various operating parameters.•System performance is compared with another system with air recuperator before fuel recuperator. This article provides the energy and exergy based performance analysis of a solid oxide fuel cell (SOFC) – gas turbine (GT) – steam turbine (ST) combined cycle power plant. The system utilizes the GT exhaust heat for fuel and air preheating subsequently in a fuel recuperator (FR) and an air recuperator (AR) before finally producing steam in a heat recovery steam generator (HRSG) coupled with the ST cycle. It considers 30% external reforming in a pre-reformer (PR) by steam extracted from the bottoming ST plant. The study considers the effect of additional fuel burning in the combustion chamber (CC) as a means for increasing the net GT and ST power output. A detailed parametric analysis based on variation of compressor pressure ratio (CPR), fuel flow rate (FFR), air flow rate (AFR), current density, single level boiler pressure and ST inlet temperature (STIT) is also provided. Results indicate improved system performance at higher CPR. The optimum single level boiler pressure is found to be 40bar with 50% additional fuel burning. Burning of additional fuel improves the GT and ST power output, however with reduction in the plant’s overall efficiency. Further comparison of performance with a similar other system where the AR is placed head of the FR indicates slightly better performance of the proposed system with FR ahead of AR (FRAOAR).