Dynamic Modelling and Simulation of Solid Oxide Fuel Cell Based Auxiliary Power Unit System

Abstract

Abstract Solid oxide fuel cell (SOFC) based auxiliary power unit (APU) system using diesel fuel is expected to be an environmentally-friendly and highly-efficient alternative to supply non-propulsion power for long-haul trucks, replacing engine idling or diesel generator based APUs. The main components that govern the overall system performance are the auto-thermal reformer (ATR), which converts diesel fuel into hydrogen-rich gas, and the SOFC stack, which produces power by electrochemical reaction of the reformed fuel and oxygen. In this study, a dynamic ATR model including a reaction kinetic model with experimental validation and a dynamic SOFC stack model with induced theoretically derived electrochemical model, are constructed. Then, in order to investigate the effect of operating variables of the ATR on the SOFC stack, the two models are integrated by connecting the outlet of the ATR model to the anode inlet of the SOFC stack model. Finally, using the developed dynamic model, dynamic responses of the system to step changes in the oxygen-to-carbon ratio (OCR) and steam-to-carbon ratio (SCR), which are the main operating variables of the ATR, are examined.