Design and part-load performance of a hybrid system based on a solid oxide fuel cell reactor and a micro gas turbine

Abstract This paper addresses the design and off-design analysis of a hybrid system (HS) based on the coupling of a recuperated micro gas turbine (MGT) with a high temperature solid oxide fuel cell (SOFC) reactor. The SOFC reactor model is presented and discussed, taking into account the influence of the reactor lay-out, the current density, the air utilisation factor, the cell operating temperature, etc. The SOFC design and off-design performance is presented and discussed; the design and off-design models of a recuperated micro-gas turbine are also presented. The operating line, the influence of the micro gas turbine “variable speed” control, and the efficiency behaviour at part load are analysed in depth. Finally, the model of the hybrid system obtained by coupling the MGT and the SOFC reactor, considering the compatibility (technological constraints) of the two systems, is presented. The model allows the evaluation of the design and off-design behaviour of the hybrid system, particularly when the MGT variable speed control system is considered. The thermal efficiency of the hybrid system, taking into account its size (250/300 kWe), is noteworthy: higher than 60% at design point, and also very high at part load conditions. Such a result is mainly due to the simultaneous positive influence of SOFC off-design behaviour and MGT variable speed control. Moreover, it is possible to recover the waste heat from the gas at the MGT recuperator outlet (Tgas is about 250°C) for cogeneration purposes.

[1]  Ennio Macchi,et al.  Thermodynamic analysis of advanced power cycles based upon solid oxide fuel cells, gas turbines and rankine bottoming cycles , 1998 .

[2]  R. H. Wolk,et al.  Fuel cells for homes and hospitals , 1999 .

[3]  Scott A. Barnett,et al.  Low‐Temperature Solid‐Oxide Fuel Cells Utilizing Thin Bilayer Electrolytes , 1997 .

[4]  E. Achenbach.  Three-dimensional and time-dependent simulation of a planar solid oxide fuel cell stack , 1994 .

[5]  Svein Sunde,et al.  Monte Carlo Simulations of Polarization Resistance of Composite Electrodes for Solid Oxide Fuel Cells , 1996 .

[6]  S. D. Souza.  Thin-film solid oxide fuel cell with high performance at low-temperature , 1997 .

[7]  W. J. Dollard.  Solid oxide fuel cell developments at Westinghouse , 1992 .

[8]  Pericles Pilidis.  Digital simulation of gas turbine performance , 1983 .

[9]  V. Antonucci,et al.  Micro-modelling of solid oxide fuel cell electrodes , 1998 .

[10]  Raymond Anthony George,et al.  Status of tubular SOFC field unit demonstrations , 2000 .

[11]  Wolfgang Drenckhahn.  SOFC in dispersed power generation , 1999 .

[12]  Tatsumi Ishihara,et al.  Doped PrMnO3 Perovskite Oxide as a New Cathode of Solid Oxide Fuel Cells for Low Temperature Operation , 1995 .

[13]  Aristide F. Massardo,et al.  Internal Reforming Solid Oxide Fuel Cell-Gas Turbine Combined Cycles (IRSOFC-GT): Part A—Cell Model and Cycle Thermodynamic Analysis , 2000 .

[14]  Lars Sjunnesson,et al.  Combined solid oxide fuel cell and gas turbine systems for efficient power and heat generation , 2000 .

[15]  Paola Costamagna,et al.  Modeling of Solid Oxide Heat Exchanger Integrated Stacks and Simulation at High Fuel Utilization , 1998 .

[16]  C. Rodgers.  25-5 Kwe Microturbine Design Aspects , 2000 .

[17]  Stefano Campanari,et al.  Full Load and Part-Load Performance Prediction for Integrated SOFC and Microturbine Systems , 1999 .

[18]  N. Bessette,et al.  A Mathematical Model of a Solid Oxide Fuel Cell , 1995 .

[19]  Paola Costamagna.  The benefit of solid oxide fuel cells with integrated air pre-heater , 1997 .

[20]  Vincenzo Antonucci,et al.  Partial oxidation of CH4 in solid oxide fuel cells: simulation model of the electrochemical reactor and experimental validation , 1996 .

[21]  Aristide F. Massardo,et al.  Microturbine / Fuel-Cell Coupling for High-Efficiency Electrical-Power Generation , 2000 .