Macroscopic modeling of solid oxide fuel cell (SOFC) and model-based control of SOFC and gas turbine hybrid system

In addition to high energy conversion efficiency and considerable fuel flexibility, the advantage of high-quality exhaust energy of solid oxide fuel cells (SOFC) allows it to be combined with gas turbines (GT) to form a SOFC/GT hybrid generation system. This article makes a comprehensive review on the state of the art of macroscopic SOFC models and model-based control of the SOFC/GT hybrid system. Several topics in modeling of electrochemistry and transport in SOFC are first presented, including multi-component mass transfer, internal reforming, detailed radiative heat transfer, surface diffusion, and our new viewpoints on H2/CO electrochemical co-oxidation and physical resolution of electrochemical impedance spectra, etc. Then the SOFC models are summarized in different dimensions and from steady-state to transient. After a basic summary of the balancing unit models, the issues of system layout, safe operation region, off-design and part-load operation, load following, control strategies, decentralized/centralized controllers, and hardware-in-the-loop simulation of the SOFC/GT hybrid system are investigated. Some useful data have been sorted out in tabular form for easy access. The analytical solutions can play an important role in bridging the gap between mechanistic and system-level models. Some perspectives on the advanced models and model-based control are finally presented.