Browsing by Author "Sanchez-Garcia, Jose Angel"

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    Development of highly permeable ultra-thin Pd-based supported membranes
    (2016-12-01) Fernandez, Ekain; Sanchez-Garcia, Jose Angel; Melendez, Jon; Spallina, Vincenzo; van Sint Annaland, Martin; Gallucci, Fausto; Pacheco Tanaka, D. A.; Prema, Radha; TECNOLOGÍAS DE HIDRÓGENO; Tecnalia Research & Innovation; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
    This paper reports the preparation and characterization of ultra-thin (∼1 μm thick) Pd-based supported membranes for hydrogen purification. Ultra-thin membranes have been prepared by a combination of PVD magnetron sputtering and electroless plating techniques. The membranes have been characterized for single gas and mix gas permeation at temperatures between 350 and 500 °C and they have shown to exhibit very high hydrogen fluxes combined with a good perm-selectivity (H2/N2 ≈ 500). These results have been compared with the performance of highly permeable membranes reported in the literature. The influence of the morphology of the deposited Pd-based layers on the membrane performance has been investigated and discussed.
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    The influence of mixing water on the thermophysical properties of nanofluids based on solar salt and silica nanoparticles
    (AMER INST PHYSICS, 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA, 2016-05-31) Muñoz-Sánchez, Belen; Nieto-Maestre, Javier; Iparraguirre-Torres, Iñigo; Sanchez-Garcia, Jose Angel; Julia, Jose Enrique; García-Romero, Ana; Rajpaul, Vikesh; Richter, Christoph; Tecnalia Research & Innovation; VALORIZACIÓN DE RESIDUOS
    The use of nanofluids (NFs) based on Solar Salt (SS) and nanoparticles (NPs), either as Thermal Energy Storage (TES) material or as Heat Transfer Fluid (HTF), is attracting great interest in recent years. Many authors [1,3] have reported important improvements on the thermophysical properties (specific heat capacity cp,thermal conductivity k) of NFs based on SS and ceramic NPs. These improvements would lead to important savings and better performance of TES facilities on new Concentrated Solar Power (CSP) plants due to lower quantities of material required and smaller storage tanks. To achieve these advantageous features in the final NFs, it is essential to avoid NP agglomeration during their preparation. Different synthesis procedures have been reported: mixing of solid NPs within a SS solution by means of ultrasounds [1-3], direct mixing of solid NPs and molten salt [4]. In this work, NFs based on SS and 1% by wt. of silica NPs were synthetized from a SS-water solution and a commercial water-silica NF called Ludox HS 30% (Sigma-Aldrich). The influence of the mixing water volume (MW) on the cp of NFs was evaluated. With this aim, the cp of these samples was measured by Differential Scanning Calorimetry (DSC) both in the solid and the liquid state. In addition, the distribution of sizes was measured during the whole preparation process by Dynamic Light Scattering (DLS). Further information about sizes and uniformity of the final NFs was obtained from Scanning Electron Microscopy (SEM) images. X-ray Diffraction (XRD) patterns of the SS and final NF were performed.
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    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.
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    Preparation of nanofluids based on solar salt and boehmite nanoparticles: Characterization of starting materials: Characterization of starting materials
    (AMER INST PHYSICS, 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA, 2016-05-31) Muñoz-Sánchez, Belen; Nieto-Maestre, Javier; Iparraguirre-Torres, Iñigo; Sanchez-Garcia, Jose Angel; Julia, Jose Enrique; García-Romero, Ana; Rajpaul, Vikesh; Richter, Christoph; Tecnalia Research & Innovation; VALORIZACIÓN DE RESIDUOS
    A nanofluid composed of Solar Salt (SS) and boehmite nanoparticles (A) in a concentration of 1% by weight, is proposed as thermal storage medium for Concentrated Solar Power (CSP) plants. A wide characterization of the raw materials has been done, focused on their thermal stability and the nanoparticle primary size and shape among other properties such as its specific heat and crystalline structure. Some features of the final nanofluids have been also investigated: thermal stability, nanoparticle sizes and their distribution and specific heat. The showed results confirm that these materials are thermally stable in the working temperature range both individually and combined. In addition, the synthesis procedure implemented is effective to keep the nanoparticle sizes in the nanometric range (<100 nm). These findings mean the first step to carry on research and characterization of this nanofluid.