347969 The Effect Of Methane Impurities In The Hydrogen Feed Of The Anode Of a Polymer Electrolyte Membrane Fuel Cell (PEMFC)

Monday, November 4, 2013
Grand Ballroom B (Hilton)
Abraham Soussan, Chemical Engineering, The City College of New York, New York, NY, Katrin Kortsdottir, Applied Electrochemistry, KTH, Royal Institute of Technology, Stockholm, Sweden and Rakel W. Lindström, Applied Electrochemistry, KTH- Royal Institute of Technology, Stockholm, Sweden

With greater demands for more sustainable and efficient energy generation, the fuel cells has gained much attention and consideration as a combined heat and power (CHP) system on various scales as well as transport as the products of the PEMFC are electricity, heat and pure water. Hydrogen can be produced from fossil or bio fuel giving a number of species, such as carbon dioxide/monoxide, water vapor, sulfur containing species and light hydrocarbons, all of which can hinder the performance and longevity of the cell.[1] [2] Methane may also be present in the hydrogen reformate and in the natural grid, as such this study aims to investigate its adsorption/desorption on the active catalyst site in the fuel cell.

 Considering the simplistic employment of a solid electrolyte with non-corrosive materials present, the PEMFC provides high power densities and steady current densities throughout the cells operation and at relatively low temperatures. Studies conducted to determine the effects of various species on the performance of the cell have been extensively reviewed for  H2S, NH3, unsaturated hydrocarbons and CO/CO2.However, they’re very few papers on addressing the behavior of alkanes in the feed of PEMFCs. Investigating the behavior of methane as an impurity present is crucial as there is potential for it to be stored with hydrogen in high dilutions.[3]

 The project addresses the behavior of the cell under the operating condition of 30% methane in the feed of the working electrode and investigates whether the methane competes with hydrogen to occupy the active Pt/C site.  Various cyclic voltammetry (CV) techniques are utilized to determine whether the methane gas is inert or a poisonous species in the PEMFC under investigation. The methane was adsorbed under the range of potentials at which hydrogen is adsorbed/desorbed (0.1- 0.2V) from the active catalyst site. The oxidation peak potential for the 0.1 and 0.2V in both the forward and reverse sweep occur at 0.58V for the baseline experiments.  The forward contaminated stripping analysis shows an oxidation peak potential of 0.5V, with a larger current density for adsorption at 0.2 V. The reverse sweep shows suppression in the adsorption/desorption region when compared to the blank exposure. This ultimately means that methane occupies the active Pt site at the higher adsorption potentials, but can easily be removed by a single sweep or by leaving the cell in open circuit.

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