Thermodynamic Analysis and Optimization of IT-SOFC-Based Integrated Coal Gasification Fuel Cell Power Plants

Abstract

This work discusses the thermodynamic analysis of integrated gasification fuel cell plants, where a simple cycle gas turbine works in a hybrid cycle with a pressurized intermediate temperature–solid oxide fuel cell (SOFC), integrated with a coal gasification and syngas cleanup island and a bottoming steam cycle (reflecting the arrangement of integrated gasification combined cycle (IGCC) plants) to optimize heat recovery and maximize efficiency. This work addresses the optimization of the plant layout, discussing the effect of the SOFC fuel utilization factor and the possibility of a fuel bypass to increase the gas turbine total inlet temperature and reduce the plant expected investment costs. Moreover, a discussion of technological issues related to the feasibility of the connection among the plant high temperature components is carried out, presenting the effects of different limitations of the maximum temperatures reached by the plant piping. With the proposed plant configurations, which do not include—apart from the SOFC—any component far from the nowadays best available technologies, a net electric lower heating value efficiency approaching 52–54% was calculated, showing a remarkable increase with respect to state-of-the-art advanced IGCCs.