Modelling for part-load operation of solid oxide fuel cell–gas turbine hybrid power plant

This paper presents the work on part-load operation of a power generation system composed of a solid oxide fuel cell and a gas turbine (SOFC–GT) which operate on natural gas. The system consists of an internal reforming SOFC (IRSOFC) stack, an external combustor, two turbines, two compressors, two recuperators and one heat-recovery steam generator (HRSG). Based on experience in different levels of modelling of the fuel cell, fuel cell stack and integrated system and the inherent characteristics of a IRSOFC–GT hybrid power plant, a practical approach for simplifying part-load operation of the system is proposed. Simulation results show that an IRSOFC–GT hybrid system could achieve a net electrical efficiency and system efficiency (including waste heat recovery for steam generation) of greater than 60 and 80%, respectively, under full-load operation. Due to the complexity of the interaction of the components and safety requirements, the part-load performance of a IRSOFC–GT hybrid power plant is poorer than that under full-load operation.