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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]

Liquid hydrocarbons conversion into hydrogen rich gas is a central process step in fuel processors for auxiliary power units (APUs) for naval applications. Diesel, together with gasoline, is the preferred fuel for these applications. The CNR-ITAE has developed an hydrogen generator based on steam reforming (SR) of n-dodecane (n-C 12 H 26 ) as surrogate of diesel, designed for a maximum hydrogen production of 1.5 Nm 3 /h. The prototype consists of an integrated catalytic reactor coupled with heat exchanger, static mixer, water–dodecane and recycle reservoirs, manual/automatic valves, pressure regulators/transducers, flow meters, and ancillaries. The unit has been engineered, focusing every single component and the system integration, to meet the requirements of small size and volume, improving thermal/mass transfer and system efficiency. This study reports the performance of the hydrogen generator with a commercial Rh-based catalyst, packed on the steam reforming reactor. Experimental tests were carried out at a molar ratio steam to carbon (S/C) of 2.5, under a gas hourly space velocity (GHSV) of 3500 h −1 , as derived from preliminary investigations in laboratory scale. Total conversion of n-dodecane and absence of carbon deposition phenomena, were observed. The syngas produced (H 2 /CO = 4.7) was adequate to feed a Solid Oxide Fuel Cell (SOFC). [ABSTRACT FROM AUTHOR]

Abstract: This study presents experimental study on a novel methane fuel processing system for hydrogen (H2) production. The unit includes into a single package the autothermal reformer, the CO shift converter, the preferential oxidation reactor and the internal heat exchangers. Effects of operative conditions, related to the H2 productivity, on the performances, were investigated experimentally, in order to evaluate the integration of the fuel processor with a Polymer Electrolyte Fuel Cell (PEFC) system for residential applications. The sensitivity analysis showed that the overall performance is strongly dependent upon the operative conditions considered. [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]