Browsing by Keyword "Hydrogen production"
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Item Direct route from ethanol to pure hydrogen through autothermal reforming in a membrane reactor: Experimental demonstration, reactor modelling and design: Experimental demonstration, reactor modelling and design(2018-01-15) Spallina, V.; Matturro, G.; Ruocco, C.; Meloni, E.; Palma, V.; Fernández-Gesalaga, E.; Melendez, J.; Pacheco Tanaka, David A.; Viviente Sole, J.L.; van Sint Annaland, M.; Gallucci, F.; Tecnalia Research & Innovation; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThis work reports the integration of thin (∼3–4 μm thick) Pd-based membranes for H2 separation in a fluidized bed catalytic reactor for ethanol auto-thermal reforming. The performance of a fluidized bed membrane reactor has been investigated from an experimental and numerical point of view. The demonstration of the technology has been carried out over 50 h under reactive conditions using 5 thin Pd-based alumina-supported membranes and a 3 wt%Pt-10 wt%Ni catalyst deposited on a mixed CeO2/SiO2 support. The results have confirmed the feasibility of the concept, in particular the capacity to reach a hydrogen recovery factor up to 70%, while the operation at different fluidization regimes, oxygen-to-ethanol and steam-to-ethanol ratios, feed pressures and reactor temperatures have been studied. The most critical part of the system is the sealing of the membranes, where most of the gas leakage was detected. A fluidized bed membrane reactor model for ethanol reforming has been developed and validated with the obtained experimental results. The model has been subsequently used to design a small reactor unit for domestic use, showing that 0.45 m2 membrane area is needed to produce the amount of H2 required for a 5 kWe PEM fuel-cell based micro-CHP system.Item Hydrogen production with integrated CO2 capture in a membrane assisted gas switching reforming reactor: Proof-of-Concept: Proof-of-Concept(2018-03-22) Wassie, Solomon A.; Medrano, Jose A.; Zaabout, Abdelghafour; Cloete, Schalk; Melendez, Jon; Pacheco Tanaka, David A.; Amini, Shahriar; van Sint Annaland, Martin; Gallucci, Fausto; Tecnalia Research & Innovation; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThis paper presents a new membrane reactor concept for ultra-pure hydrogen production with integrated CO2 capture: the membrane-assisted gas switching reforming (MA-GSR). This concept integrates alternating exothermic and endothermic redox reaction stages in a single fluidized bed consisting of catalytically active oxygen-carrier particles, by switching the feed between air and methane/steam, where the produced hydrogen is selectively removed via Pd-based membranes. This concept results in overall autothermal conditions and allows easier operation at high pressure compared to alternative novel technologies. In this work, the MA-GSR concept is demonstrated at lab scale using four metallic supported membranes (Pd–Ag based) immersed into a fluidized bed consisting of a Ni-based oxygen carrier. The performance of the reactor has been tested under different experimental operating conditions and high methane conversions (>50%) have been obtained, well above the thermodynamic equilibrium conversion of a conventional fluidized bed as a result of the selective H2 extraction, with (ultra-pure) H2 recoveries above 20% at relatively low temperatures (<550 °C). These results could be further improved by working at elevated pressures or by integrating more membranes. Even though the concept has been successfully demonstrated, further research is required to develop suitable membranes since post-mortem membrane characterization has revealed defects in the membrane selective layer as a consequence of the frequent exposure to thermal cycles with alternating oxidative and reducing atmospheres.Item Long-Term Stability of Thin-Film Pd-Based Supported Membranes(2019-02-01) Nooijer, Niek; Arratibel Plazaola, Alba; Meléndez Rey, Jon; Fernandez, Ekain; Pacheco Tanaka, David; Sint Annaland, Martin; Gallucci, Fausto; Tecnalia Research & Innovation; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS; TECNOLOGÍAS DE HIDRÓGENOMembrane reactors have demonstrated a large potential for the production of hydrogen via reforming of different feedstocks in comparison with other reactor types. However, the long-term performance and stability of the applied membranes are extremely important for the possible industrial exploitation of these reactors. This study investigates the long-term stability of thin-film Pd-Ag membranes supported on porous Al2O3 supports. The stability of five similarly prepared membranes have been investigated for 2650 h, up to 600 °C and in fluidized bed conditions. Results show the importance and the contribution of the sealing of the membranes at temperatures up to 500 °C. At higher temperatures the membranes surface deformation results in pinhole formation and a consequent decrease in selectivity. Stable operation of the membranes in a fluidized bed is observed up to 450 °C, however, at higher temperatures the scouring action of the particles under fluidization causes significant deformation of the palladium surface resulting in a decreased selectivity.Item On concentration polarisation in a fluidized bed membrane reactor for biogas steam reforming: modelling and experimental validation: Modelling and experimental validation(2018-09-15) de Nooijer, Niek; Gallucci, Fausto; Pellizzari, Emma; Melendez, Jon; Pacheco Tanaka, David A.; Manzolini, Giampaolo; van Sint Annaland, Martin; Tecnalia Research & Innovation; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThe production of pure hydrogen through the steam reforming of biogas in a fluidized bed membrane reactor has been studied. A phenomenological one-dimensional two-phase fluidized bed reactor model accounting for concentration polarisation with a stagnant film model has been developed and used to investigate the system performance. The validation of the model was performed with steam reforming experiments at temperatures ranging from 435 °C up to 535 °C, pressures between 2 to 5 bar and CO2/CH4 ratios up to 0.9. The permeation performance of the ceramic-supported PdAg thin-film membrane was first characterized separately for both pure gas and gas mixtures. Subsequently, the membrane was immersed into a fluidized bed containing Rh supported on alumina particles and the reactor performance, viz. the methane conversion, hydrogen recovery and hydrogen purity, was evaluated under biogas steam reforming conditions. The resulting hydrogen purity under biogas steam reforming conditions was up to 99.8%. The model results were in very good agreement with the experimental results, when assuming a thickness of the stagnant mass transfer boundary layer around the membrane equal to 0.54 cm. It is shown that the effects of concentration polarisation in a fluidized bed membrane reactor can be well described with the implementation of a film layer description in the two-phase model.Item Power-to-Gas Conversion Technologies and Related Systems(Taylor & Francis Group, 2018-06-21) Perez Gil, Susana; Belsue, G.; Belsue, Mikel; Tecnalia Research & InnovationWind and solar energy must play a major role to achieve 20% energy consumption from renewable energy in the EU by 2020, as proposed by the European Commission Renewable Energy Roadmap target. However, as renewable energies are variable and intermittent, they cannot be expected to provide a safe and steady supply by themselves. As a result, to achieve the transformation to a renewable energy based system, largescale energy storage is required to make use of renewable energy surplus which cannot be supplied to the grid and to offset variations. This electric power surplus can be used to produce hydrogen, which may be injected back to the existing natural gas energy grid. This conversion is carried out through water electrolysis. Hydrogen production based on renewable energy sources may help to improve management of these types of plants as they may be viewed as administrable plants by grid operators. Thanks to this technique, hydrogen is generated through water electrolysers, making the most of renewable energy surplus and becoming a sustainable hydrogen generation source.Item Syngas upgrading in a membrane reactor with thin Pd-alloy supported membrane(2015-09-14) Brunetti, A.; Caravella, A.; Fernandez, E.; Pacheco Tanaka, D. A.; Gallucci, F.; Drioli, E.; Curcio, E.; Viviente, J. L.; Barbieri, G.; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSIn hydrogen production, the syngas streams produced by reformers and/or coal gasification plants contain a large amount of H2 and CO in need of upgrading. To this purpose, reactors using Pd-based membranes have been widely studied as they allow separation and recovery of a pure hydrogen stream. However, the high cost of Pd-membranes is one of the main limitations for scaling up technology. Therefore, many researchers are now pursuing the possibility of using supported membranes with as thin as possible Pd-alloy layers. In this work, the upgrading of a syngas stream is experimentally investigated in a water gas shift membrane reactor operated in a high temperature range with an ultra-thin supported membrane (3.6 micron-thick). The membrane permeance was measured before and after catalyst packing and also after reaction for 2100 h of operation in total. Membrane reactor performance was evaluated as a function of operating conditions such as temperature, pressure, gas hourly space velocity, feed molar ratio, and sweep gas. A CO conversion significantly higher than the thermodynamics upper limit of a traditional reactor was achieved, even at high gas hourly space velocities and a 25% less reaction volume than that of a traditional reactor was enough to achieve a 90% equilibrium conversion.