Effect of reverse Boudouard reaction catalyst on the performance of solid oxide carbon fuel cells integrated with a dry gasifier

Abstract

A solid oxide carbon fuel cell (SO-CFC) integrated with a dry gasifier was operated on activated carbon fuel and the effect of adding a reverse Boudouard gasification catalyst on the performance and long-term operation characteristics of the SO-CFC was investigated. The reactivity of the carbon fuels for the Boudouard gasification reaction was analyzed by a thermal analysis at various operating conditions. The SO-CFC was then operated on gasified fuel gas consisting of CO2 and CO obtained from the integrated dry gasifier. The SO-CFC operated on activated carbon fuel with 5wt.% K2CO3 achieved a maximum power density of 202, 262, and 271mW/cm2 at 750, 800, and 850°C, respectively; the SO-CFC fueled with activated carbon fuel without a catalyst meanwhile yielded maximum power density of 168mW/cm2 at 850°C. By using electrochemical impedance spectroscopy, the effect of adding the catalyst on the gasification products and subsequently on the performance of the SO-CFC was studied. A long-term degradation test was conducted by continuously operating the SO-CFC at 50mA/cm2 for 518h at 750°C. During the long-term degradation test, the average degradation rate of the SO-CFC was found to be 183mV/kh. The post-mortem SEM and XRD analyses of the SO-CFC after the long-term test revealed the presence of carbon deposits and oxidation of Ni at the anode, causing a relatively higher degree of degradation in the SO-CFC integrated with the dry gasifier during the long-term operation. The addition of the K2CO3 based dry gasification catalyst significantly enhances the performance of the SO-CFC integrated with dry gasification, but during long-term operation, the degradation rate is found to be higher than that of conventional H2 fueled SOFCs.