Evaluation of the water-gas shift and CO methanation processes for purification of reformate gases and the coupling to a PEM fuel cell system

In this work, the water-gas shift (WGS) and the CO methanation reactions on a Co/γ-Al2O3 catalyst and the coupling of these reactors to a proton exchange membrane fuel cell were investigated. Results of chromatographic analyses showed that when the reactors are fed with a H2/CO (1000 ppm) mixture, high conversions of CO into methane (90%) or CO2 (83%) are observed for the methanation and WGS processes, respectively. These reactions are strongly influenced by the presence of carbon dioxide, particularly in absence of water, for which the methanation of CO2 is clearly observed. In both cases, some additional production of CO is also apparent. The fuel cell polarization data showed a reduction of the CO poisoning effect for fuel cells with a PtRu/C anode fed with H2/CO (1000 ppm) mixture, after the coupling with the methanation or the WGS reactors. In agreement with chromatographic analyses, higher fuel cell efficiency was observed when the coupling was made with the methanation reactor.