Browsing by Author "Fernandez, E."
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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.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.