Innovative Hybrid Cycle Solid Oxide Fuel Cell- Inverted Gas Turbine with CO2 Separation

Decentralized power generation and cogeneration of heat and power is an attractive way toward a more rational conversion of fossil or bio fuel. In small scale power production fuel cell – gas turbine hybrid cycles are an emerging candidate to reach higher or comparable efficiency than large scale power plants. In spite of the advantages of this hybrid technology, many technical barriers have to be overcome to develop a highly efficient system. The present contribution introduces an innovative concept of hybrid cycle that allows to reach high efficiency maintaining the fuel cell operating under atmospheric condition and thus avoiding fuel cell pressurization technical problems. Carbon dioxide separation represents an additional advantage. A thermodynamic optimization approach, based on the system energy integration, is used to analyse several design options. The methodology proceeds in two steps: modelling the system for a set of decision variables and optimizing their values. The innovative system is analyzed and compared with state of the art fuel cell - gas turbine hybrid cycle. Exergy analysis has been performed. Optimization results prove the existence of designs that, neglecting the pressure drops, achieve exergy efficiency higher than 75%.