The effect of impurities on the performance of bioethanol-used internal reforming molten carbonate fuel cell

The effects of impurities in bioethanol, such as diethyl amine, acetic acid, methanol, and propanol, on the performance of a direct internal reforming molten carbonate fuel cell (MCFC) were investigated. A single cell with an Ni/MgO-coated anode was operated using bioethanol containing 1% impurities. The cell voltages of the single cells increased after the introduction of methanol and diethyl amine impurities. On the other hand, the single cell operated with propanol and acetic acid impurities showed somewhat worse performance than when it was operated without impurities. Activity tests were carried out to explain this phenomenon in detail. These tests showed that methanol as an impurity is reformed easily and increases the H₂ concentration in the reformed gas thereby increasing conversion and selectivity. Propanol, which is reformed incompletely, negatively affects the conversion and H₂ selectivity. Diethyl amine follows a basic reaction pathway and is reformed completely without coke formation, and acetic acid, which follows an acidic pathway, forms significant coke on the catalyst which deactivates the catalytic activity. Mixtures of these four impurities, in varying mole ratios were tested for catalytic activity, and it was found that of the mixtures tested, the one with a ratio 2:1:4:1 (methanol:propanol:diethyl amine:acetic acid) showed the best catalytic activity.