Carbon monoxide clean-up of the reformate gas for PEM fuel cell applications: A conceptual review

The removal of CO from hydrocarbon-and methanol-derived hydrogen can be performed by a series of methods to achieve the 10 ppm CO limit required for proton exchange membrane fuel cell (PEMFC) applications. The fuel processing includes reforming of the feed followed by water-gas shift (WGS) and a final CO removal with the latter decreasing the CO concentration below the desirable level. Pressure swing adsorption (PSA), mem-brane separation, selective methanation (SMET) and preferntial oxidation (PROX) are the applicable techniques as the final clean-up step. The appropriate method depends on the scale but for small scale portable fuel processors, catalytic processes are more appropriate due to the operating conditions close to that of PEMFC. The PROX appears to be the best due to rapid reaction rate and mild operation conditions which renders intensification of the processes possible. Extensive research and development efforts are underway to increase catalyst activity and improve the temperature window of the reaction. & COPY; 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.