A Finite Volume SOFC Model for Coal-Based Integrated Gasification Fuel Cell Systems Analysis

Abstract

Integrated gasification fuel cell (IGFC) systems combining coal gasification and solid oxide fuel cells (SOFC) are promising for highly efficient and environmentally friendly utilization of coal for power production. Most IGFC system analyses performed to-date have used nondimensional thermodynamic SOFC models that do not resolve the intrinsic constraints of SOFC operation. In this work a quasi-two-dimensional (2D) finite volume model for planar SOFC is developed and verified using literature data. Special attention is paid to making the model capable of supporting recent SOFC technology improvements, including the use of anode-supported configurations, metallic interconnects, and reduced polarization losses. Activation polarization parameters previously used for high temperature electrolyte-supported SOFC result in cell performance that is much poorer than that observed for modern intermediate temperature anode-supported configurations; thus, a sensitivity analysis was conducted to identify appropriate parameters for modern SOFC modeling. Model results are shown for SOFC operation on humidified H2 and CH4 containing syngas, under coflow and counterflow configurations; detailed internal profiles of species mole fractions, temperature, current density, and electrochemical performance are obtained. The effects of performance, fuel composition, and flow configuration of SOFC performance and thermal profiles are evaluated, and the implications of these results for system design and analysis are discussed. The model can be implemented not only as a stand-alone SOFC analysis tool, but also a subroutine that can communicate and cooperate with chemical flow sheet software seamlessly for convenient IGFC system analysis.