Dynamic Modeling and Control of a Steam Reformer-Fuel Cell Power System Operating on LPG for Vehicular Applications

Abstract

The core aim of this study is to develop a control scheme based on a rigorous mathematical model that will be able to capture the dynamic features of a 1 kW_p fuel cell power system based on LPG reforming that satisfies acceptably power variations in vehicular applications. The integrated system consists of an LPG steam reformer followed by a water-gas-shift reactor. A high temperature PEM fuel cell accompanies the system and receives the produced hydrogen having high tolerance in CO levels (up to 1000 ppm). A burner that exploits the anode off-gas and an additional supply of fresh LPG meets system’s heat requirements, while further stream heat integration and individual coolers complement system autonomy and efficiency. Material and energy balances fully apply in system reactors and fuel cell (no axial/radial distributions are introduced), while energy balances for the cold and hot streams are developed for the intensive heat exchanging network. Model validation with available experimental data and thermodynamic results confirm the accuracy of the proposed mathematical modeling scheme. A set of simulations of the integrated system including closed loops of predefined conventional PI controllers is applied in order to evaluate the effectiveness of the respective control scheme.