Examinando por Autor "Furones, L."

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New synthesis method of Pd membranes over tubular PSS supports via "pore-plating" for hydrogen separation processes
(Elsevier, 2012) Sanz, R.; Calles, J.A.; Alique, D.; Furones, L.
A new synthesis method to prepare Pd membranes by novelty modified electroless plating over tubular porous stainless steel supports (PSS) has been developed. This new pore plating method basically consists on feeding both plating solution and reducing agent from opposite sides of support, allowing the preparation of totally hydrogen selective membranes with a significantly lower Pd consumption than the corresponding to the conventional electroless plating procedure. In the latter, both reducing agent and plating solution are added simultaneously in one side of the PSS support. This new plating method has been applied over raw commercial PSS supports and air calcined supports in order to generate a Fe-Cr oxide intermediate layer. A completely dense Pd membrane with a thickness in the range 11-20 m directly over tubular porous stainless steel tubes with a high roughness has been achieved. The permeation properties of the membranes have been tested at different operating conditions for pure feed gases: retentate pressure (1 - 4 bar) and temperature (350 - 450ºC). All membranes present good permeance reproducibility after several thermal cycles and a complete hydrogen ideal selectivity, since complete retention of nitrogen is maintained for all tested experiment conditions, ensuring 100% purity in the hydrogen permeate flux. The permeance of both membranes is maintained in the range of 1-3 ·10-4 mol·m-2·s-1·Pa-0.5.
Preparation, testing and modelling of a hydrogen selective Pd/YSZ/SS composite membrane
(Elsevier, 2012) Sanz, R.; Calles, J.A.; Alique, D.; Furones, L.; Ordóñez, S.; Marín, P.; Corengia, P.; Fernández, E.
A palladium selective tubular membrane has been prepared to separate and purify hydrogen. The membrane consists of a composite material, formed by different layers: a stainless steel support (thickness of 1.9 mm), an yttria-stabilized zirconia interphase (thickness of 50 m) prepared by Atmospheric Plasma Spraying and a palladium layer (thickness of 27.7 m) prepared by Electroless Plating. The permeation properties of the membrane have been tested at different operating conditions: retentate pressure (1 - 5 bar), temperature (350 - 450ºC) and hydrogen molar fraction of feed gas (0.7 - 1). At 400ºC, a permeability of 1.1 · 10-8 mol/(s m Pa0.5) and a complete selectivity to hydrogen were obtained. The complete retention of nitrogen was maintained for all tested experiment conditions, with both single and mixtures of gases, ensuring 100% purity in the hydrogen permeate flux. A rigorous model considering all the resistances involved in the hydrogen transport has been applied for evaluating the relative importance of the different resistances, concluding that the transport through the palladium layer is the controlling one. In the same way, a model considering the axial variations of hydrogen concentration because of the cylindrical geometry of the experimental device has been applied to the fitting of the experimental data. The best fitting results have been obtained considering Sieverts¿-law dependences of the permeation on the hydrogen partial pressure.