Behaviour modelling of a PEMFC operating on diluted hydrogen feed

Abstract

SUMMARYThe polymer electrolyte membrane fuel cell (PEMFC) using reformate gas as fuel is regarded as an attractive solution for the near-term introduction of fuel cells in stationary or mobile power generation market.With respect to hydrogen feeding, the reformate gas fuelling involves additional polarization losses because of the hydrogen dilution and the impurities contained in the gas.In this paper a one-dimensional model has been developed to investigate the behaviour of a PEMFC operating with reformate gas mixture.The model, based on a semi-empirical approach, considers the kinetic reactions in the anode side taking into account the effect of reverse water-gas shift (RWGS) due to the presence of CO 2 in the fuel. As it is well known, the exhaust stream from fuel reformers can contain a high carbon dioxide concentration (420%) that can have a detrimental effect on the fuel cell performance because of the combination of the dilution and the formation of CO by the RWGS reaction.The numerical simulation results have been compared with the experimental data, obtained in the test room of Industrial Engineering Department of Cassino University, and a good match has been observed.The model has been developed by using a simplified approach that, nevertheless, can allow to obtain a good numerical prediction of the fuel cell performance reducing the simulation time and computational efforts.

Experimental Characterization and Numerical Modeling of PEMFC Stacks Designed for Different Application Fields

“…The numerical model proposed in this section [10] has been developed following a simplified approach that is more practical in some applications like that at system level research. Therefore, it can be a useful numerical tool able to predict the performance of a PEMFC unit when it is one of the components in a more complex energy conversion system.…”

“…[17,18]. The parameter k, as suggested by Mann et al [17] is considered a fitting parameter (or an empirical parameter that describes the membrane conditions) and its value can be chosen in the range [10][11][12][13][14][15][16][17][18][19][20].…”

“…(5-9) and assuming that the voltage drop caused by the activation losses is mainly due to the cathode side reaction, so that the anode activation overpotential can be neglected. g act;c fb i E Nernst À V cell À g ohmic (10 In Table 3 the calculated values of b i both for ST12AC and ST13WC PEMFC stacks are summarized. …”

“…According to the plug flow approximation, this exponential decay depends on the gas flow velocity in the gas flow channels [10]. II.…”

“…The numerical analysis has been carried out by using a one-dimensional model [10] and based on an empirical and mechanistic modeling technique. The model has been developed in order to foresee the performance of each stack, once tuned its semi-empirical coefficients.…”