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Abstract: This paper presents a two-dimensional model of a preferential oxidation (PROX) reactor to be used in a beta 5kWe hydrogen generator (HYGen II), to integrate with Polymer Electrolyte Fuel Cells (PEFCs). PROX reactors require careful temperature control systems, in order to enhance optimization and control of the unit. The model concerns chemical kinetics and heat/mass transfer phenomena occurring in the reactor. Aim of the model is to investigate the effects of the molar ratio O2/CO, the gas hourly space velocity (GHSV) and the inlet temperature on process performance of the reactor, in order to obtain high CO conversion and high selectivity with respect to the undesired H2 oxidation. The model plays a key role in overcoming the issues of system design, by evaluating the temperature and the gas concentration profiles in the reactor. Simulation results showed the strong dependence of the overall performance upon the operating conditions examined. [Copyright &y& Elsevier]

One of the more investigated fuel processor subsystems, for polymer electrolyte fuel cell electric vehicles (PEFCV), is the carbon monoxide clean-up step. At present, the research efforts are addressed to develop a system able to reduce, at level acceptable for PEFCs (particularly in transient response), the amount of CO in the stream outgoing of the reformer.A unit, working as post-filter of the CO preferential oxidation (PROX), based on the reversible complex formation and dissociation reaction between CO and CuCl, able to overcome the main limits of the PROX (instantaneous cold-start and dynamic removal of CO in reformate to less than 10 ppm) has been analyzed. The experimental approach of this study has regarded the screening of different supports (Al2O3, carbon, SiO2) and the identification of optimal operating conditions (temperature, pressure, GHSV, adsorption/desorption time). [Copyright &y& Elsevier]

Abstract: Modeling studies have been conducted on Preferential Oxidation (PROX) Reaction, covering chemical kinetics and heat/mass transfer phenomena that occur in a shell and tube system, to be used in a beta 5kWe hydrogen generator for Polymer Electrolyte Fuel Cells (PEFCs). The critical issue in the PROX reactor design is to achieve temperature control along the catalyst bed, because poor selectivities primarily result from excess reactor temperature. Aim of the model is to investigate the effects of the reactor dimensions on process performance, in order to obtain high CO conversion and high selectivity with respect to the undesired H2 oxidation. The CO removal from simulated reformate was examined, by evaluating the temperature and the gas concentration profiles along the reactor. The sensitivity analysis showed that the overall performance is strongly dependent upon the geometrical configurations examined. [Copyright &y& Elsevier]