Browsing by Keyword "Membrane stability"
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Item Development of thin Pd-Ag supported membranes for fluidized bed membrane reactors including WGS related gases(2015-03-02) Fernandez, Ekain; Helmi, Arash; Coenen, Kai; Melendez, Jon; Viviente, Jose Luis; Pacheco Tanaka, David Alfredo; Van Sint Annaland, Martin; Gallucci, Fausto; TECNOLOGÍAS DE HIDRÓGENO; Tecnalia Research & Innovation; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThis paper reports the preparation, characterization and stability tests of Pd-based thin membranes for fluidized bed membrane reactor applications. Various thin membranes have been prepared by simultaneous Pd-Ag electroless plating. A simple technique for sealing of the produced membranes is reported and discussed. The membranes have been characterized for single gas permeation, and afterwards used for permeation of mixtures of gases and under fluidization conditions. The membranes have shown very high permeation rates and perm-selectivity when used as permeators. When applied in fluidized bed reactors it has been found that the membranes are stable as long as no interaction between the fluidization catalyst and the membrane surface occurs. For some catalysts a strong chemical interaction between the catalyst and the membrane surface has been observed which caused a drastic decrease in the membrane flux.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 Pd-based metallic supported membranes: High-temperature stability and fluidized bed reactor testing(2016-06-01) Medrano, Jose Antonio; Fernandez, Ekain; Melendez, Jon; Parco, Maria; Tanaka, David Alfredo Pacheco; Van Sint Annaland, Martin; Gallucci, Fausto; TECNOLOGÍAS DE HIDRÓGENO; Tecnalia Research & Innovation; EXTREMAT; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThe present work focuses on the study of a metallic supported Pd-Ag membrane for high temperature applications with a particular attention to long-term stability. In this work, a metallic supported thin-film Pd-Ag membrane has been tested for more than 800 h and sustained hydrogen perm-selectivities higher than 200000 have been measured. Furthermore, it has been demonstrated that there is no interaction of the membrane with the Ni/CaAl2O4 reforming catalyst particles, thus resulting in a constant permeance in the fluidized bed membrane reactor mode. The membrane has been tested under steam and autothermal reforming of methane conditions and the membrane performance has been quantified in terms of the hydrogen recovery and separation factors demonstrating a good reactor performance accomplishing an enhancement in the process efficiency by in-situ selective H2 separation. A decrease in ideal perm-selectivity has been observed at high temperatures (600°C). Small defects at the Pd/Ag surface as a result of interaction of the Pd/Ag later with the metallic support have been observed in after test membrane characterization, which provides appreciated information for the improvement in the performance and production of future membranes.Item Preparation and characterization of thin-film Pd-Ag supported membranes for high-temperature applications(2015-10-19) Fernandez, E.; Coenen, K.; Helmi, A.; Melendez, J.; Zuñiga, J.; Pacheco Tanaka, D. A.; Van Sint Annaland, M.; Gallucci, F.; TECNOLOGÍAS DE HIDRÓGENO; Tecnalia Research & Innovation; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThis paper reports the preparation, characterization and stability tests of thin-film Pd-Ag supported membranes for high-temperature fluidized bed membrane reactor applications. Various thin-film supported membranes have been prepared by simultaneous Pd-Ag electroless plating and have been initially sealed with a sealing procedure previously validated for Water gas shift (WGS) application (400 °C). The membranes have been characterized for single gas and mixed gas permeation, and for methane steam and autothermal reforming in a fluidized bed membrane reactor at 550-600 °C using a Ru-based catalyst. In addition, the performance of these membranes was compared to commercial membranes from REB Research & Consulting under the same reaction conditions. The applied sealing showed nitrogen leaks at 600 °C and different sealing approaches were tested solving this problem. Finally, also the long-term stability of the thin-film Pd-Ag supported membrane at 600 °C has been investigated.