Performance of an Integrated Microtubular Fuel Reformer and Solid Oxide Fuel Cell System

摘要

A numerical model is developed to study the performance of an integrated tubular fuelnreformer and solid oxide fuel cell (SOFC) system. The model is used to study how thenphysical dimensions of the reformer, gas composition and the species flow rates of anmethane feed stream undergoing autothermal reforming (ATR) affect the performance ofnan SOFC. The temperature in the reformer changes significantly due to the heat ofnreaction, and the reaction rates are very sensitive to the temperature and species concentrations.nTherefore, it is necessary to couple the heat and mass transfer to accuratelynmodel the species conversion of the reformate stream. The reactions in the SOFC contributenmuch less to the temperature distribution than in the reformer and therefore thenheat transfer in the SOFC is not necessary to model. A packed bed reactor is used tondescribe the reformer, where the chemical mechanism and kinetics are taken from thenliterature for nickel catalyst on a gamma alumina support. Heat transfer in the reformer’sngas and solid catalyst phases are coupled while the gas phase in the SOFC is at anuniform temperature. The SOFC gas species are modeled using a plug flow reactor. Thenmodels are in good agreement with experimental data. It is observed that the reformerntemperature decreases with an increase in the reformer inlet water-to-fuel ratio and therenis a slight decrease in the voltage of the SOFC from higher water content but an increasenin limiting current density from a higher hydrogen production. The numerical resultsnshow that the flow rates and reformer length are critical design parameters because if notnproperly designed they can lead to incomplete conversion of the methane fuel to hydrogennin the reformer, which has the greatest impact on the SOFC performance in the integratednATR reformer and SOFC system.