TECNALIA Publications Repository :: Browsing by Author "Pacheco Tanaka, David A."

Browsing by Author "Pacheco Tanaka, David A."

Now showing 1 - 17 of 17

Acid precipitation followed by microalgae (Chlorella vulgaris) cultivation as a new approach for poultry slaughterhouse wastewater treatment
(2021-09) Terán Hilares, Ruly; Garcia Bustos, Kiara A.; Sanchez Vera, Fabio P.; Colina Andrade, Gilberto J.; Pacheco Tanaka, David A.; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
Poultry slaughterhouse wastewater (PSW) contains high organic matter and nutrients requiring thus a special treatment before its final disposal. In this work, acid precipitation (H2SO4) followed by microalgae “Chlorella vulgaris” cultivation both in batch and continuous processes was studied as an alternative method for PSW treatment. By reducing the pH value of PSW from 6 to 7 to 4, about 80% of the total chemical oxygen demand (CODT) was removed as sludge. In the supernatant, the COD residual was efficiently removed (83%) by microalgae in the batch process, using an internal-loop concentric tube photobioreactor (4.5 L). Moreover, in continuous process, after 89 h, the COD value resulted lower than 200 mg L-1 and 1.2 g L-1 of microalgae in the output line. The proposed PSW treatment method is promising from economic and environmental viewpoints, since the microalgal biomass can be valued in a biorefinery context.
Boehmite-phenolic resin carbon molecular sieve membranes-Permeation and adsorption studies
(2014-11-01) Teixeira, Miguel; Rodrigues, Sandra C.; Campo, Marta; Pacheco Tanaka, David A.; Llosa Tanco, Margot A.; Madeira, Luís M.; Sousa, José M.; Mendes, Adélio; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
Composite carbon molecular sieve membranes (c-CMSM) were prepared in a single dipping-drying-carbonization step from phenolic resin solutions (12.5-15wt.%) loaded with boehmite nanoparticles (0.5-1.2wt.%). A carbon matrix with well-dispersed Al2O3 nanowires was formed from the decomposition of the resin and dehydroxylation of boehmite. The effect of the carbon/Al2O3 ratio on the porous structure of the c-CMSM was accessed based on the pore size distribution and gas permeation toward N2, O2, CO2, He, H2, C3H6 and C3H8. c-CMSM with higher carbon/Al2O3 ratios had a more open porous structure, exhibiting higher permeabilities and lower permselectivities. c-CMSM performance was above the upper bound curves for polymeric membranes for several gas pairs, particularly for C3H6/C3H8 (permeability toward C3H6 of 420 barrer and permselectivity of 18.1 for a c-CMSM with carbon/Al2O3 ratio of 4.4).Unsupported films were also prepared (carbon/Al2O3 ratio 7.3) and crushed into small flakes. Equilibrium isotherms of H2, N2, O2, CO2, C3H8 and C3H6 at 293K were determined on these flakes to obtain the kinetic and adsorption selectivities toward gas pairs of interest; obtained adsorption and diffusion coefficients accurately predicted the permeabilities of all studied gases except CO2 (experimental and predicted permeabilities of 1148 and 154 barrer, respectively).
Composite-alumina-carbon molecular sieve membranes prepared from novolac resin and boehmite. Part I: Preparation, characterization and gas permeation studies
(2015-05-04) Llosa Tanco, Margot A.; Pacheco Tanaka, David A.; Rodrigues, Sandra C.; Texeira, Miguel; Mendes, Adélio; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
Abstract Supported composite alumina-carbon molecular sieve membranes (c-CMSM) were prepared from in house prepared novolac phenolic resin loaded with boehmite nanoparticles in a single dipping-drying-carbonization step. A porous α-alumina tube support was dipped into a N-methyl-2-pyrrolidone solution containing polymerized novolac resin loaded with boehmite, subsequently dried at 100 C and carbonized at 500 C under nitrogen environment. The structure, morphology and performance of the membranes were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), carbon dioxide adsorption and permeation of N2, O2, He, H2 and CO2. SEM showed carbon membranes with a thin and very uniform layer with a thickness of ca. 3 μm CO2 adsorption isotherms indicated that the produced carbon membranes presented a microporous structure. The c-CMSM exhibited good gas separation properties. The permselectivity surpass the Robeson upper bound for polymeric membranes, especially regarding ideal permselectivities of pairs H2/N2 = 117, and He/O2 = 49. Aging effects were observed after membrane exposure to ambient air. However with a thermal treatment under nitrogen atmosphere the permeance of nitrogen increases.
Composite-alumina-carbon molecular sieve membranes prepared from novolac resin and boehmite. Part II: Effect of the carbonization temperature on the gas permeation properties
(2015-03-02) Llosa Tanco, Margot A.; Pacheco Tanaka, David A.; Mendes, Adélio; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
The influence of carbonization temperature on the permeation properties and aging of thin (4 μm) supported carbon molecular sieve membranes (c-CMSM), prepared from in house synthesized novolac phenolic resin loaded with boehmite nanoparticles, were studied. Just after membrane carbonization (fresh membrane), high permeance to N2 and O2 and low O2/N2 permselectivities were observed; the highest permeations were observed for carbonization end temperatures between 500 °C and 700 °C. After leaving the c-CMSM 1 day in the air, a large decrease in the permeation and considerable increase in the permselectivity were observed due to the reduction of the pore size by oxygen chemisorption and water physical adsorption; the permeability to H2 and H2/N2 ideal permselectivity for a membrane carbonized at 550 °C are close to palladium membranes for low temperature (<100 °C). The effect of the permeation characteristics of the membranes carbonized at various temperatures and the removal of water adsorbed in the pores by heat treatment were studied.
CuO/ZnO catalysts for methanol steam reforming: The role of the support polarity ratio and surface area
(2015-09-01) Mateos-Pedrero, Cecilia; Silva, Hugo; Pacheco Tanaka, David A.; Liguori, Simona; Iulianelli, Adolfo; Basile, Angelo; Mendes, Adelio; Ligouri, Simona; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
The effect of surface area and polarity ratio of ZnO support on the catalytic properties of CuO/ZnO catalyst for methanol steam reforming (MSR) are studied. The surface area of ZnO was varied changing the calcination temperature, and its polarity ratio was modified using different Zn precursors, zinc acetate and zinc nitrate. It was found that the copper dispersion and copper surface area increase with the surface area of the ZnO support, and the polarity ratio of ZnO strongly influences the reducibility of copper species. A higher polarity ratio promotes the reducibility, which is attributed to a strong interaction between copper and the more polar ZnO support. Interestingly, it was observed that the selectivity of CuO/ZnO catalysts (lower CO yield) increases with the polarity ratio of ZnO carriers. As another key result, CuO/ZnOAc375 catalyst has proven to be more selective (up to 90%) than a reference CuO/ZnO/Al2O3 sample (G66-MR, Süd Chemie).The activity of the best performing catalyst, CuO/ZnOAc-375, was assessed in a Pd-composite membrane reactor and in a conventional packed-bed reactor. A hydrogen recovery of ca. 75% and a hydrogen permeate purity of more than 90% was obtained. The Pd-based membrane reactor allowed to improve the methanol conversion, by partially suppressing the methanol steam reforming backward reaction, besides upgrading the reformate hydrogen purity for use in HT-PEMFC.
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 PROCESOS
This 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.
Fluidized Bed Membrane Reactors for Ultra Pure H2 Production - A Step forward towards Commercialization
(2016-03-19) Helmi, Arash; Fernandez, Ekain; Melendez, Jon; Pacheco Tanaka, David A.; Gallucci, Fausto; van Sint Annaland, Martin; TECNOLOGÍAS DE HIDRÓGENO; Tecnalia Research & Innovation; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
In this research the performance of a fluidized bed membrane reactor for high temperature water gas shift and its long term stability was investigated to provide a proof-of-concept of the new system at lab scale. A demonstration unit with a capacity of 1 Nm3/h of ultra-pure H2 was designed, built and operated over 900 h of continuous work. Firstly, the performance of the membranes were investigated at different inlet gas compositions and at different temperatures and H2 partial pressure differences. The membranes showed very high H2 fluxes (3.89E 6 mol m 2 Pa 1 s 1 at 400 C and 1 atm pressure difference) with a H2/N2 ideal perm-selectivity (up to 21,000 when integrating five membranes in the module) beyond the DOE 2015 targets. Monitoring the performance of the membranes and the reactor confirmed a very stable performance of the unit for continuous high temperature water gas shift under bubbling fluidization conditions. Several experiments were carried out at different temperatures, pressures and various inlet compositions to determine the optimum operating window for the reactor. The obtained results showed high hydrogen recovery factors, and very low CO concentrations at the permeate side (in average <10 ppm), so that the produced hydrogen can be directly fed to a low temperature PEM fuel cell.
Hydrogen permeation studies of composite supported alumina-carbon molecular sieves membranes: Separation of diluted hydrogen from mixtures with methane: Separation of diluted hydrogen from mixtures with methane
(2021-05-28) Llosa Tanco, Margot A.; Medrano, Jose A.; Cechetto, Valentina; Gallucci, Fausto; Pacheco Tanaka, David A.; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
One alternative for the storage and transport of hydrogen is blending a low amount of hydrogen (up to 15 or 20%) into existing natural gas grids. When demanded, hydrogen can be then separated, close to the end users using membranes. In this work, composite alumina carbon molecular sieves membranes (Al-CMSM) supported on tubular porous alumina have been prepared and characterized. Single gas permeation studies showed that the H2/CH4 separation properties at 30 °C are well above the Robeson limit of polymeric membranes. H2 permeation studies of the H2–CH4 mixture gases, containing 5–20% of H2 show that the H2 purity depends on the H2 content in the feed and the operating temperature. In the best scenario investigated in this work, for samples containing 10% of H2 with an inlet pressure of 7.5 bar and permeated pressure of 0.01 bar at 30 °C, the H2 purity obtained was 99.4%.
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 PROCESOS
This 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.
Membrane optimization and process condition investigation for enhancing the CO2 separation from natural gas
(Elsevier, 2018-01-01) Llosa Tanco, Margot A.; Medrano, Jose A.; Gallucci, Fausto; Pacheco Tanaka, David A.; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
This chapter provides an overview of both conventional membrane process technologies and optimization of membrane process technologies for CO2 separation from natural gas. Among other natural gas processing operations, removal of CO2 is required to meet gas specification, typically 2% CO2 for pipeline quality gas. The use of CO2-selective membrane technologies for bulk separation of methane is increasing in the natural gas industry. CO2-selective membranes represent a more efficient alternative for CO2 separation, as in this case the separation does not undergo any phase change. The economics of the process, simple operation, and the use of compact modules have led to an increasing exploration of membrane technology for CO2 separation in the natural gas industry over competing separation technologies. This chapter presents an overview of different CO2-selective membranes for the separation of CO2 from natural gas. In particular, the recent significant advances (from 2010) reported in the literature on various CO2-selective membranes, their stability, the effect of different parameters on the performance of the membranes, the relationships between structure and permeation properties, and the transport mechanism applied in different CO2-selective membranes are summarized. Finally, the future direction for CO2-selective membranes is suggested.
The membrane-assisted chemical looping reforming concept for efficient H2 production with inherent CO2 capture: Experimental demonstration and model validation: Experimental demonstration and model validation
(2018-04-01) Medrano, J.A.; Potdar, I.; Melendez, J.; Spallina, V.; Pacheco Tanaka, David A.; van Sint Annaland, M.; Gallucci, F.; Tecnalia Research & Innovation; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
In this work a novel reactor concept referred to as Membrane-Assisted Chemical Looping Reforming (MA-CLR) has been demonstrated at lab scale under different operating conditions for a total working time of about 100 h. This reactor combines the advantages of Chemical Looping, such as CO2 capture and good thermal integration, with membrane technology for a better process integration and direct product separation in a single unit, which in its turn leads to increased efficiencies and important benefits compared to conventional technologies for H2 production. The effect of different operating conditions (i.e. temperature, steam-to-carbon ratio or oxygen feed in the reactor) has been evaluated in a continuous chemical looping reactor, and methane conversions above 90% have been measured with (ultra-pure) hydrogen recovery from the membranes. For all the cases a maximum recovery factor of around 30% has been measured, which could be increased by operating the concept at higher pressures and with more membranes. The optimum conditions have been found at temperatures around 600 °C for a steam-to-carbon ratio of 3 and diluted air in the air reactor (5% O2). The complete demonstration has been carried out feeding up to 1 L/min of CH4 (corresponding to 0.6 kW of thermal input) while up to 1.15 L/min of H2 was recovered. Simultaneously, a phenomenological model has been developed and validated with the experimental results. In general, good agreement is observed, with overall deviations below 10% in terms of methane conversion, H2 recovery and separation factor. The model allows better understanding of the behavior of the MA-CLR concept and the optimization and design of scaled-up versions of the concept.
Morphology and N2 Permeance of Sputtered Pd-Ag Ultra-Thin Film Membranes
(2016-02-10) Fernandez, Ekain; Sanchez-Garcia, Jose Angel; Viviente, J.L.; van Sint Annaland, Martin; Gallucci, Fausto; Pacheco Tanaka, David A.; Tecnalia Research & Innovation; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
The influence of the temperature during the growth of Pd-Ag films by PVD magnetron sputtering onto polished silicon wafers was studied in order to avoid the effect of the support roughness on the layer growth. The surfaces of the Pd-Ag membrane films were analyzed by atomic force microscopy (AFM), and the results indicate an increase of the grain size from 120 to 250–270 nm and film surface roughness from 4–5 to 10–12 nm when increasing the temperature from around 360–510 K. After selecting the conditions for obtaining the smallest grain size onto silicon wafer, thin Pd-Ag (0.5–2-µm thick) films were deposited onto different types of porous supports to study the influence of the porous support, layer thickness and target power on the selective layer microstructure and membrane properties. The Pd-Ag layers deposited onto ZrO2 3-nm top layer supports (smallest pore size among all tested) present high N2 permeance in the order of 10−6 mol•m−2•s−1•Pa−1 at room temperature.
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 PROCESOS
The 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.
Pd-Based Membranes for High Temperature Applications: Current Status
(2016-03-29) Gallucci, Fausto; Fernandez, Ekain; Medrano, Jose Antonio; Pacheco Tanaka, David A.; van Sint Annaland, Martin; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
Not available
Preparation and characterization of ceramic supported ultra-thin (~1 µm) Pd-Ag membranes
(2017) Melendez, Jon; Fernandez, Ekain; Gallucci, Fausto; van Sint Annaland, Martin; Arias, P. L.; Pacheco Tanaka, David A.; Tecnalia Research & Innovation; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
This work reports the preparation and characterization of ultra-thin (~1 µm thick) Pd-Ag supported membranes for hydrogen purification. Ultra-thin membranes with different thicknesses (ranging from 0.46 to 1.29 µm) have been prepared by electroless plating (ELP) technique onto asymmetric tubular porous alumina supports. The membranes have been characterized by single gas and mixed gas permeation experiments at temperatures between 300 and 500 °C obtaining a correlation for the membrane permeation as a function of the activation energy and the membrane thickness. Hydrogen permeation results of the ultra-thin Pd-Ag membranes have been compared with other highly permeable membranes reported in the literature and they show some of the highest H2permeance values. A 1.29 µm thick membrane has been tested for 1000 h at 400 °C and has shown a stable H2permeance of 9.0−9.4×10−6mol m−2s−1Pa−1with a H2/N2perm-selectivity between 3300 and 2000 at 100 kPa transmembrane pressure difference. The same membrane has been tested with a feed gas mixture of H2/N2/CO with a 15% CO content and H2binary mixtures containing N2, CH4and CO2. When tested in a catalyst fluidization environment during 100 h, the 1.29 µm thick membrane showed stable H2permeance and H2/N2perm-selectivity.
Recent Advances in Pd-Based Membranes for Membrane Reactors
(2017-01-01) Arratibel Plazaola, Alba; Pacheco Tanaka, David A.; Van Sint Annaland, Martin; Gallucci, Fausto; Tecnalia Research & Innovation; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
Palladium-based membranes for hydrogen separation have been studied by several research groups during the last 40 years. Much effort has been dedicated to improving the hydrogen flux of these membranes employing different alloys, supports, deposition/production techniques, etc. High flux and cheap membranes, yet stable at different operating conditions are required for their exploitation at industrial scale. The integration of membranes in multifunctional reactors (membrane reactors) poses additional demands on the membranes as interactions at different levels between the catalyst and the membrane surface can occur. Particularly, when employing the membranes in fluidized bed reactors, the selective layer should be resistant to or protected against erosion. In this review we will also describe a novel kind of membranes, the pore-filled type membranes prepared by Pacheco Tanaka and coworkers that represent a possible solution to integrate thin selective membranes into membrane reactors while protecting the selective layer. This work is focused on recent advances on metallic supports, materials used as an intermetallic diffusion layer when metallic supports are used and the most recent advances on Pd-based composite membranes. Particular attention is paid to improvements on sulfur resistance of Pd based membranes, resistance to hydrogen embrittlement and stability at high temperature.
Unravelling the transport mechanism of pore-filled membranes for hydrogen separation
(2018-09-12) Arratibel, Alba; Pacheco Tanaka, David A.; Slater, Thomas J.A.; Burnett, Timothy L.; van Sint Annaland, Martin; Gallucci, Fausto; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
The permeation characteristics of palladium pore filled (PF) membranes have been investigated with gas permeation and structural characterization of the membranes. PF membranes have been prepared by filling with Pd the nanoporous γ-Al2O3/YSZ (or pure YSZ) layer supported onto porous α-Al2O3 and ZrO2. The number of nanoporous layers and the applied vacuum level during the electroless plating process have been studied. Gas permeation properties of the PF membranes have been determined in a temperature range of 300-550 °C. The measured hydrogen permeances have been found to be lower than previously reported for similar membranes. It has been found that the hydrogen fluxes do not depend on the thickness of the nanoporous layers (γ-Al2O3/YSZ or pure YSZ) or on the vacuum pump employed for filling with Pd. The physicochemical characterization performed showed that the palladium deposited does not form a percolated network across the mesoporous layer(s), leading to low hydrogen permeances and thus low H2/N2 perm-selectivities.

Browsing by Author "Pacheco Tanaka, David A."

Results Per Page

Sort Options