Browsing by Author "Falcón, Pablo"

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    Influence of alumina fixed-bed in steam reforming of glycerol for hydrogen production (7th International Conference on Renewable Energy and Conservation, ICREC 2022 November 18–20, 2022, Paris, France)
    (Energy Reports, 2023) Maceiras, Rocío; Feijoo, Jorge; Alfonsín, Víctor; Pérez-Rial, Leticia; Álvarez-Feijoo, Miguel A.; Falcón, Pablo; Vallejo, Javier P.
    In this study, hydrogen production by steam reforming was carried out in a tubular fixed-bed reactor. The influence of some operating variables such as temperature, flow rate of the feeding glycerol solution and space velocity on hydrogen production under a non-catalyzed reaction was analyzed. The results showed that the hydrogen yield increased with temperature and decreased with the space velocity. As the feedstock flow rate increased, the hydrogen yield decreased rapidly. Compared with a reference experiment without fixed-bed, the use of non-porous alumina fixed-bed showed better results. Under the best reaction conditions (900 ◦C and a feedstock flow rate of 0.85 g/min), 17 L/h of syngas were obtained, with a purity of about 55% of hydrogen and a production of 2.7 moles of hydrogen by mol of glycerol.
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    Study of natural zeolites for hydrogen purification: CO2 adsorption capacity and kinetic mechanism
    (Fuel, 2024-11-15) Maceiras, Rocío; Falcón, Pablo; Alfonsín, Víctor; Pérez-Rial, Leticia; Feijoo, Jorge
    Hydrogen is considered a promising alternative fuel. However, in order to be used, it is necessary to achieve a high degree of purity through purification processes. Adsorption is considered one of the most important techniques for purification. In this research, the CO2 adsorption capacity and kinetic mechanism of natural zeolite were investigated with the aim to understand the carbon dioxide adsorption behaviour under different operating conditions. Multicomponent breakthrough curves of a mixture of H2/CO/CH4/CO2 were obtained at different pressures and gas flow rates. Moreover, the analysis of CO2 adsorption equilibrium and kinetics were carried out. The obtained adsorption isotherm data were fitted with different model equations. Freundlich, Sips and Toth models showed the best fit for the experimental data, indicating the heterogeneous nature of the adsorbent surfaces. The carbon dioxide adsorption kinetic was analysed using different kinetic models, obtaining that the adsorption process is both physical and chemical and that the limiting step of the diffusion process is intraparticle diffusion, although other processes are also involved such as diffusion through the boundary layer.