Electrochemical Filter Design for the Removal of CO Contaminant in Reformate Hydrogen

Carbon monoxide contamination in reformate hydrogen decreases the performance of the proton exchange membrane (PEM) fuel cells significantly through anode poisoning. The cost, in terms of parasitic power losses and reactor volume for decreasing the CO concentration to a tolerable level, can be high. Here, we demonstrate a PEM-based twin-cell electrochemical filter that offers the possibility of a compact and efficient device to reduce the CO concentration to 10 ppm or lower. The potential and flow are switched between the two filter cells so that alternative CO adsorption and oxidation occur in each cell, while providing a continuous flow of H-2 to a fuel cell. The effects of filter switching time and applied potential on CO concentration of gas exiting the filter are presented for a 1,000 ppm CO in nitrogen anode stream and a 4% H-2/N-2 cathode stream flowing at 100 and 40 cc/min, respectively.