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Fausto Gallucci - One of the best experts on this subject based on the ideXlab platform.
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effect of au addition on hydrogen permeation and the resistance to h2s on pd ag alloy membranes
Journal of Membrane Science, 2017Co-Authors: J. Melendez, Ekain Fernandez, Martin Van Sint Annaland, Kai Coenen, Jose Luis Viviente, Niek De Nooijer, P L Arias, D Pacheco A Tanaka, Fausto GallucciAbstract:Abstract In order to make a detailed comparison between Pd-Ag and Pd-Ag-Au membranes according to their H2 permeation properties and sulfide resistance Au was deposited by the electroless plating (ELP) technique onto one half of Pd-Ag membranes. Membranes' thicknesses are ranged between 2.45 and 3.13 µm. Permeation tests have been carried out from 400 to 600 °C under single gas conditions. The Pd91.7Ag4.8Au3.5 membrane has shown a H2 permeance of 4.71·10−3 mol s−1 m−2 Pa0.5 at 600 °C, which is one of the highest values ever reported in the literature, where the Pd-Ag-Au membranes have exhibited higher hydrogen permeation rates compared to their respective Pd-Ag membranes above 550 °C. The H2 permeation properties have been determined in terms of the degree of H2S inhibition, up to 17 ppm, and subsequent H2 flux recovery rate. Pd-Ag membranes alloyed with gold resisted 12.5 h of H2S exposure showing recovery rates of 85% and 83% for Pd91.5Ag4.7Au3.8 and Pd90.5Ag4.6Au4.9 membranes, respectively, whereas the hydrogen flux of non-gold membranes decreased below detectable values. H2/N2 ideal Perm-Selectivity of the Pd-Ag membrane was reduced to 18 after H2S tests (starting from > 1308) while Pd-Ag-Au membranes showed a better resistance to sulfur with H2/N2 selectivity values of 793 and 121 (starting from > 4115 and > 2557 respectively). No evidence of the formation of a crystalline sulfide phase on the Pd-Ag-Au alloy membrane surfaces was found in the XRD patterns after H2S exposure and also XPS characterization did not show important changes in the composition before and after the H2S exposure tests. However, SEM images showed a decrease in the thickness of the Pd-Ag membrane and signs of corrosion and roughening on its surface, while gold-alloyed membranes did not show any damage.
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Development of Pd-based double-skinned membranes for hydrogen production in fluidized bed membrane reactors
Journal of Membrane Science, 2017Co-Authors: Alba Arratibel, Alfredo Pacheco Tanaka, Iker Laso, Martin Van Sint Annaland, Fausto GallucciAbstract:Abstract This paper reports the preparation and performance characterization of new PdAg supported membranes with a porous protecting layer to protect the membrane surface from particles in a fluidized bed membrane reactor. Supported membranes with a selective layer of 1 µm and a protective layer have been prepared. Outstanding H2 permeance (5·10−6 mol m−2 s−1 Pa−1) and H2/N2 Perm-Selectivity (over 25,000) were measured at 400 °C and 1 bar of pressure difference. One membrane has been tested for more than 750 h in the presence of fluidized glass beads showing a decay in the Perm-Selectivity to approximately 5000, mainly due to sealing leakage. However, the protective layer was removed during this long-term test. Another membrane has been tested for more than 2000 h in a fluidized bed membrane reactor with a Rh reforming catalyst supported on promoted alumina in the bubbling fluidization regime. During tests with binary mixtures mass transfer limitations toward the membrane were observed due to large H2 permeance of the membranes.
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Pd-based metallic supported membranes: High-temperature stability and fluidized bed reactor testing
International Journal of Hydrogen Energy, 2016Co-Authors: J.a. Medrano, Ekain Fernandez, Martin Van Sint Annaland, J. Melendez, Maria Parco, David A. Pacheco Tanaka, Fausto GallucciAbstract:The 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.
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development of thin pd ag supported membranes for fluidized bed membrane reactors including wgs related gases
International Journal of Hydrogen Energy, 2015Co-Authors: Ekain Fernandez, Martin Van Sint Annaland, J. Melendez, Arash Helmi, Kai Coenen, Jose Luis Viviente, David Pacheco A Tanaka, Fausto GallucciAbstract:This 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.
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Recent advances on membranes and membrane reactors for hydrogen production
Chemical Engineering Science, 2013Co-Authors: Fausto Gallucci, Ekain Fernandez, Pablo Corengia, Martin Van Sint AnnalandAbstract:Membranes and membrane reactors for pure hydrogen production are widely investigated not only because of the important application areas of hydrogen, but especially because mechanically and chemically stable membranes with high Perm-Selectivity towards hydrogen are available and are continuously further improved in terms of stability and hydrogen flux. Membrane reactors are (multiphase) reactors integrating catalytic reactions (generally reforming and water gas shift reactions for hydrogen production) and separation through membranes in a single unit. This combination of process steps results in a high degree of process integration/intensification, with accompanying benefits in terms of increased process or energy efficiencies and reduced reactor or catalyst volume. The aim of this review is to highlight recent advances in hydrogen selective membranes (from palladium-based to silica and proton conductors) along with the advances for the different types of membrane reactors available (from packed bed to fluidized bed, from micro-reactors to bio-membrane reactors). In addition, the application of membrane reactors for hydrogen production from different feedstock is also discussed. © 2013 Elsevier Ltd.
Johannes A.m. Kuipers - One of the best experts on this subject based on the ideXlab platform.
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Autothermal Reforming of Methane with Integrated CO_2 Capture in a Novel Fluidized Bed Membrane Reactor. Part 1: Experimental Demonstration
Topics in Catalysis, 2008Co-Authors: Fausto Gallucci, M. Sint Annaland, Johannes A.m. KuipersAbstract:Two fluidized bed membrane reactor concepts for hydrogen production via autothermal reforming of methane with integrated CO_2 capture are proposed. Ultra-pure hydrogen is obtained via hydrogen perm-selective Pd-based membranes, while the required reaction energy is supplied by oxidizing part of the CH_4 in situ in the methane combustion configuration or by combusting part of the permeated H_2 in the hydrogen combustion configuration (oxidative sweeping). In this first part, the technical feasibility of the two concepts has been studied experimentally, investigating the reactor performance (CH_4 conversion, CO selectivity, H_2 production and H_2 yield) at different operating conditions. A more detailed comparison of the performance of the two proposed reactor concepts is carried out with a simulation study and is presented in the second part of this work.
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Autothermal reforming of methane with integrated CO2 capture in a novel fluidized bed membrane reactor. Part 1: Experimental demonstration
Topics in Catalysis, 2008Co-Authors: Fausto Gallucci, Martin Van Sint Annaland, Johannes A.m. KuipersAbstract:Two fluidized bed membrane reactor concepts for hydrogen production via autothermal reforming of methane with integrated CO2 capture are proposed. Ultrapure hydrogen is obtained via hydrogen perm-selective Pd-based membranes, while the required reaction energy is supplied by oxidizing part of the CH4 in situ in the methane combustion configuration or by combusting part of the permeated H2 in the hydrogen combustion configuration (oxidative sweeping). In this first part, the technical feasibility of the two concepts has been studied experimentally, investigating the reactor performance (CH4 conversion, CO selectivity, H2 production and H2 yield) at different operating conditions. A more detailed comparison of the performance of the two proposed reactor concepts is carried out with a simulation study and is presented in the second part of this work
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Fluidised bed membrane reactor for ultrapure hydrogen production via methane steam reforming: Experimental demonstration and model validation
Chemical Engineering Science, 2007Co-Authors: Charudatta S. Patil, Martin Van Sint Annaland, Johannes A.m. KuipersAbstract:Hydrogen is emerging as a future alternative for mobile and stationary energy carriers in addition to its use in chemical and petrochemical applications. A novel multifunctional reactor concept has been developed for the production of ultrapure hydrogen (< 10 ppm CO) from light hydrocarbons such as methane for online use in downstream polymer electrolyte membrane fuel cells. A high degree of process intensification can be achieved by integrating perm-selective hydrogen membranes for selective hydrogen removal to shift the methane steam reforming and water-gas-shift equilibriums in the favourable direction and perm-selective oxygen membranes for selective oxygen addition to supply the required reaction energy via partial oxidation of part of the methane feed and enable pure CO2 capture without costly post-treatment. This can be achieved in a proposed novel multifunctional bi-membrane bi-section fluidised bed reactor [Patil, C.S., van Sint Annaland, M., Kuipers, J.A.M., 2005. Design of a novel autothermal membrane assisted fluidized bed reactor for the production of ultrapure hydrogen from methane. Industrial and Engineering Chemistry Research 44, 9502-9512]. In this paper, an experimental proof of principle for the steam reforming/water-gas-shift section of the proposed novel fluidised bed membrane reactor is presented. A fluidised bed membrane reactor for steam reforming of methane/water-gas-shift on a commercial noble metal-based catalyst has been designed and constructed using 10 H2 perm-selective Pd membranes for a fuel cell power output in the range of 50-100 W. It has been experimentally demonstrated that by the insertion of the membranes in the fluidised bed, the thermodynamic equilibrium constraints can indeed be overcome, i.e., increased CH4 conversion, decreased CO selectivity and higher product yield (H2 produced/CH4 reacted). Experiments at different superficial gas velocities and also at different temperatures and pressures (carried out in the regime without kinetic limitations) revealed enhanced reactor performance at higher temperatures (650 {ring operator} C) and pressures (3-4 bar). With a phenomenological two-phase reactor model for the fluidised bed membrane reactor, incorporating a separately developed lumped flux expression for the H2 permeation rate through the used Pd-based membranes, the measured data from the fluidised bed membrane reactor could be well described, provided that axial gas back-mixing in the membrane-assisted fluidised bed reactor is negligible. This indicates that the membrane reactor behaviour approached that of an ideal isothermal plug flow reactor with maximum H2 permeation. © 2007 Elsevier Ltd. All rights reserved.
Martin Van Sint Annaland - One of the best experts on this subject based on the ideXlab platform.
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Recent advances on membranes and membrane reactors for hydrogen production
Chemical Engineering Science, 2013Co-Authors: Fausto Gallucci, Ekain Fernandez, Pablo Corengia, Martin Van Sint AnnalandAbstract:Membranes and membrane reactors for pure hydrogen production are widely investigated not only because of the important application areas of hydrogen, but especially because mechanically and chemically stable membranes with high Perm-Selectivity towards hydrogen are available and are continuously further improved in terms of stability and hydrogen flux. Membrane reactors are (multiphase) reactors integrating catalytic reactions (generally reforming and water gas shift reactions for hydrogen production) and separation through membranes in a single unit. This combination of process steps results in a high degree of process integration/intensification, with accompanying benefits in terms of increased process or energy efficiencies and reduced reactor or catalyst volume. The aim of this review is to highlight recent advances in hydrogen selective membranes (from palladium-based to silica and proton conductors) along with the advances for the different types of membrane reactors available (from packed bed to fluidized bed, from micro-reactors to bio-membrane reactors). In addition, the application of membrane reactors for hydrogen production from different feedstock is also discussed. © 2013 Elsevier Ltd.
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Autothermal reforming of methane with integrated CO2 capture in a novel fluidized bed membrane reactor. Part 1: Experimental demonstration
Topics in Catalysis, 2008Co-Authors: Fausto Gallucci, Martin Van Sint Annaland, Johannes A.m. KuipersAbstract:Two fluidized bed membrane reactor concepts for hydrogen production via autothermal reforming of methane with integrated CO2 capture are proposed. Ultrapure hydrogen is obtained via hydrogen perm-selective Pd-based membranes, while the required reaction energy is supplied by oxidizing part of the CH4 in situ in the methane combustion configuration or by combusting part of the permeated H2 in the hydrogen combustion configuration (oxidative sweeping). In this first part, the technical feasibility of the two concepts has been studied experimentally, investigating the reactor performance (CH4 conversion, CO selectivity, H2 production and H2 yield) at different operating conditions. A more detailed comparison of the performance of the two proposed reactor concepts is carried out with a simulation study and is presented in the second part of this work
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Fluidised bed membrane reactor for ultrapure hydrogen production via methane steam reforming: Experimental demonstration and model validation
Chemical Engineering Science, 2007Co-Authors: Charudatta S. Patil, Martin Van Sint Annaland, Johannes A.m. KuipersAbstract:Hydrogen is emerging as a future alternative for mobile and stationary energy carriers in addition to its use in chemical and petrochemical applications. A novel multifunctional reactor concept has been developed for the production of ultrapure hydrogen (< 10 ppm CO) from light hydrocarbons such as methane for online use in downstream polymer electrolyte membrane fuel cells. A high degree of process intensification can be achieved by integrating perm-selective hydrogen membranes for selective hydrogen removal to shift the methane steam reforming and water-gas-shift equilibriums in the favourable direction and perm-selective oxygen membranes for selective oxygen addition to supply the required reaction energy via partial oxidation of part of the methane feed and enable pure CO2 capture without costly post-treatment. This can be achieved in a proposed novel multifunctional bi-membrane bi-section fluidised bed reactor [Patil, C.S., van Sint Annaland, M., Kuipers, J.A.M., 2005. Design of a novel autothermal membrane assisted fluidized bed reactor for the production of ultrapure hydrogen from methane. Industrial and Engineering Chemistry Research 44, 9502-9512]. In this paper, an experimental proof of principle for the steam reforming/water-gas-shift section of the proposed novel fluidised bed membrane reactor is presented. A fluidised bed membrane reactor for steam reforming of methane/water-gas-shift on a commercial noble metal-based catalyst has been designed and constructed using 10 H2 perm-selective Pd membranes for a fuel cell power output in the range of 50-100 W. It has been experimentally demonstrated that by the insertion of the membranes in the fluidised bed, the thermodynamic equilibrium constraints can indeed be overcome, i.e., increased CH4 conversion, decreased CO selectivity and higher product yield (H2 produced/CH4 reacted). Experiments at different superficial gas velocities and also at different temperatures and pressures (carried out in the regime without kinetic limitations) revealed enhanced reactor performance at higher temperatures (650 {ring operator} C) and pressures (3-4 bar). With a phenomenological two-phase reactor model for the fluidised bed membrane reactor, incorporating a separately developed lumped flux expression for the H2 permeation rate through the used Pd-based membranes, the measured data from the fluidised bed membrane reactor could be well described, provided that axial gas back-mixing in the membrane-assisted fluidised bed reactor is negligible. This indicates that the membrane reactor behaviour approached that of an ideal isothermal plug flow reactor with maximum H2 permeation. © 2007 Elsevier Ltd. All rights reserved.
Tongwen Xu - One of the best experts on this subject based on the ideXlab platform.
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In-Situ Combination of Bipolar Membrane Electrodialysis with Monovalent Selective Anion-Exchange Membrane for the Valorization of Mixed Salts into Relatively High-Purity Monoprotic and Diprotic Acids.
Membranes, 2020Co-Authors: Wei Li, Muhammad Irfan, Yaoming Wang, Chenxiao Jiang, Yongming Zhou, Tongwen XuAbstract:The crystalized mixed salts from the zero liquid discharge process are a hazardous threat to the environment. In this study, we developed a novel electrodialysis (SBMED) method by assembling the monovalent selective anion-exchange membrane (MSAEM) into the bipolar membrane electrodialysis (BMED) stack. By taking the advantages of water splitting in the bipolar membrane and high Perm-Selectivity of MSAEM for the Cl− ions against the SO42− ions, this combination allows the concurrent separation of Cl−/SO42− and conversion of mixed salts into relatively high-purity monoprotic and diprotic acids. The current density has a significant impact on the acid purity. Both the monoprotic and diprotic acid purities were higher than 80% at a low current density of 10 mA/cm2. The purities of the monoprotic acids decreased with an increase in the current density, indicating that the Perm-Selectivity of MSAEM decreases with increasing current density. An increase in the ratio of monovalent to divalent anions in the feed was beneficial to increase the purity of monoprotic acids. High-purity monoprotic acids in the range of 93.9–96.1% were obtained using this novel SBMED stack for treating simulated seawater. Therefore, it is feasible for SBMED to valorize the mixed salts into relatively high-purity monoprotic and diprotic acids in one step.
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A novel mixed matrix membrane framework for ultrafast cation sieving.
Chemical Communications, 2020Co-Authors: Yuying Wu, Liang Ge, Fangmeng Sheng, Qiang Huang, Pengpeng Zhang, Tongwen XuAbstract:This work reported a new mixed matrix membrane architecture. Within this structure, cross-linked sulfonated polymers uniformly distributed into the two dimensional channels stacked by graphene oxide sheets. The resulting membranes show ultrafast Perm-Selectivity towards mono/multiple-valence cations.
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PVA-Based Mixed Matrix Membranes Comprising ZSM-5 for Cations Separation
Membranes, 2020Co-Authors: Fangmeng Sheng, Noor Ul Afsar, Liang Ge, Tongwen XuAbstract:The traditional ion-exchange membranes face the trade-off effect between the ion flux and Perm-Selectivity, which limits their application for selective ion separation. Herein, we amalgamated various amounts of the ZSM-5 with the polyvinyl alcohol as ions transport pathways to improve the permeability of monovalent cations and exclusively reject the divalent cations. The highest contents of ZSM-5 in the mixed matrix membranes (MMMs) can be extended up to 60 wt% while the MMMs with optimized content (50 wt%) achieved high Perm-Selectivity of 34.4 and 3.7 for H+/Zn2+ and Li+/Mg2+ systems, respectively. The obtained results are high in comparison with the commercial CSO membrane. The presence of cationic exchange sites in the ZSM-5 initiated the fast transport of proton, while the microporous crystalline morphology restricted the active transport of larger hydrated cations from the solutions. Moreover, the participating sites and porosity of ZSM-5 granted continuous channels for ions electromigration in order to give high limiting current density to the MMMs. The SEM analysis further exhibited that using ZSM-5 as conventional fillers, gave a uniform and homogenous formation to the membranes. However, the optimized amount of fillers and the assortment of a proper dispersion phase are two critical aspects and must be considered to avoid defects and agglomeration of these enhancers during the formation of membranes.
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Novel electrodialysis membranes with hydrophobic alkyl spacers and zwitterion structure enable high monovalent/divalent cation selectivity
Chemical Engineering Journal, 2020Co-Authors: Muhammad Irfan, Yaoming Wang, Tongwen XuAbstract:Abstract Development of monovalent cations perm-selective membranes (MCPMs) for electrodialysis with the ability to improve cation flux, selectivity and reduce membrane swelling are the major concerns in different industrial applications, such as seawater desalination and wastewater purification. We designed and fabricated the novel MCPMs of quaternized poly(2,6-dimethyl phenylene oxide)s containing different lengths of alkyl spacers which were grafted directly to the nitrogen-centered cations connected to hydrophilic carboxylic and sulfonic acids groups. Pendant chains were in charge of tuning the membrane hydrophobicity and promoting the microphase separation. We observed that during changing the hydrophobicity of MCPMs, higher cation flux, greater Perm-Selectivity and more dimensional stability of monovalent cations perm-selective membrane can be achieved. The cations selectivity of prepared MCPMs was measured from electrodialysis in a Na+/Mg2+ system and compared with the commercial monovalent cation selective NeoseptaTM CIMS membrane. Highest Perm-Selectivity ( P M g + 2 N a + ) that reached up to 25.26 was observed for the MCPMs with the longest hydrophobic pendant chain which demonstrated that enhancement of membranes hydrophobicity considerably improved the monovalent cation Perm-Selectivity. These observations are quite interesting to expedite the improvement of monovalent cations perm-selective membranes for electrodialysis.
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Electro-nanofiltration membranes with positively charged polyamide layer for cations separation
Journal of Membrane Science, 2020Co-Authors: Fangmeng Sheng, Muhammad Irfan, Liang Ge, Muhammad A. Shehzad, Bin Wu, Xiuxia Wang, Tongwen XuAbstract:Abstract High performance and low-cost monovalent cation perm-selective membranes (MCPMs) are extremely desirable since the widespread demand for monovalent/multivalent cations separation. Herein, we developed a simple fabrication method for the preparation of electro-nanofiltration membranes (ENFMs), which were used as MCPMs for cations separation. The ultra-thin polyamide layer of ENFMs could offer selective channels for the transport of monovalent cations. Meanwhile, the positive charges in the polyamide layer act as useful barriers to divalent cations via electrostatic repulsion. The results show that the ENF-Q3 membrane with the highest quaternization degree owns outstanding Perm-Selectivity for Li+/Mg2+ system ( P M g 2 + L i + = 11.3 ) , which is 7 times greater than that of the commercial CSO membrane, and high Li+ flux ( J L i + = 5.79 × 10 - 8 mol·cm - 2 ·s - 1 ) at the current density of 10 mA cm−2. Moreover, the ENFMs exhibit high limiting current density and excellent long-term stability, indicating that the developed strategy is promising to scale up for industrial applications.
Ekain Fernandez - One of the best experts on this subject based on the ideXlab platform.
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effect of au addition on hydrogen permeation and the resistance to h2s on pd ag alloy membranes
Journal of Membrane Science, 2017Co-Authors: J. Melendez, Ekain Fernandez, Martin Van Sint Annaland, Kai Coenen, Jose Luis Viviente, Niek De Nooijer, P L Arias, D Pacheco A Tanaka, Fausto GallucciAbstract:Abstract In order to make a detailed comparison between Pd-Ag and Pd-Ag-Au membranes according to their H2 permeation properties and sulfide resistance Au was deposited by the electroless plating (ELP) technique onto one half of Pd-Ag membranes. Membranes' thicknesses are ranged between 2.45 and 3.13 µm. Permeation tests have been carried out from 400 to 600 °C under single gas conditions. The Pd91.7Ag4.8Au3.5 membrane has shown a H2 permeance of 4.71·10−3 mol s−1 m−2 Pa0.5 at 600 °C, which is one of the highest values ever reported in the literature, where the Pd-Ag-Au membranes have exhibited higher hydrogen permeation rates compared to their respective Pd-Ag membranes above 550 °C. The H2 permeation properties have been determined in terms of the degree of H2S inhibition, up to 17 ppm, and subsequent H2 flux recovery rate. Pd-Ag membranes alloyed with gold resisted 12.5 h of H2S exposure showing recovery rates of 85% and 83% for Pd91.5Ag4.7Au3.8 and Pd90.5Ag4.6Au4.9 membranes, respectively, whereas the hydrogen flux of non-gold membranes decreased below detectable values. H2/N2 ideal Perm-Selectivity of the Pd-Ag membrane was reduced to 18 after H2S tests (starting from > 1308) while Pd-Ag-Au membranes showed a better resistance to sulfur with H2/N2 selectivity values of 793 and 121 (starting from > 4115 and > 2557 respectively). No evidence of the formation of a crystalline sulfide phase on the Pd-Ag-Au alloy membrane surfaces was found in the XRD patterns after H2S exposure and also XPS characterization did not show important changes in the composition before and after the H2S exposure tests. However, SEM images showed a decrease in the thickness of the Pd-Ag membrane and signs of corrosion and roughening on its surface, while gold-alloyed membranes did not show any damage.
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Pd-based metallic supported membranes: High-temperature stability and fluidized bed reactor testing
International Journal of Hydrogen Energy, 2016Co-Authors: J.a. Medrano, Ekain Fernandez, Martin Van Sint Annaland, J. Melendez, Maria Parco, David A. Pacheco Tanaka, Fausto GallucciAbstract:The 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.
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development of thin pd ag supported membranes for fluidized bed membrane reactors including wgs related gases
International Journal of Hydrogen Energy, 2015Co-Authors: Ekain Fernandez, Martin Van Sint Annaland, J. Melendez, Arash Helmi, Kai Coenen, Jose Luis Viviente, David Pacheco A Tanaka, Fausto GallucciAbstract:This 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.
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Recent advances on membranes and membrane reactors for hydrogen production
Chemical Engineering Science, 2013Co-Authors: Fausto Gallucci, Ekain Fernandez, Pablo Corengia, Martin Van Sint AnnalandAbstract:Membranes and membrane reactors for pure hydrogen production are widely investigated not only because of the important application areas of hydrogen, but especially because mechanically and chemically stable membranes with high Perm-Selectivity towards hydrogen are available and are continuously further improved in terms of stability and hydrogen flux. Membrane reactors are (multiphase) reactors integrating catalytic reactions (generally reforming and water gas shift reactions for hydrogen production) and separation through membranes in a single unit. This combination of process steps results in a high degree of process integration/intensification, with accompanying benefits in terms of increased process or energy efficiencies and reduced reactor or catalyst volume. The aim of this review is to highlight recent advances in hydrogen selective membranes (from palladium-based to silica and proton conductors) along with the advances for the different types of membrane reactors available (from packed bed to fluidized bed, from micro-reactors to bio-membrane reactors). In addition, the application of membrane reactors for hydrogen production from different feedstock is also discussed. © 2013 Elsevier Ltd.