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Thin Alumina barrier layers on porous stainless steel tubular supports with improved superficial roughness for temperature resistant Palladium membranes

pubblicazioni - Presentazione

Thin Alumina barrier layers on porous stainless steel tubular supports with improved superficial roughness for temperature resistant Palladium membranes

In questo lavoro viene descritta la preparazione di membrane al palladio a barriera ceramica per alta temperatura, ottenute mediante deposizione di uno strato di allumina su supporti in acciaio inossidabile poroso con diverso livello di rugosità, utilizzando la tecnica il dip-coating e sol di boehmite.

Hydrogen as an energy vector represents the most affordable perspective for an eco-sustainable energy system to face challenges such as poor air quality, greenhouse gas emissions and growing energy consumption rate. Therefore the demand of high purity hydrogen will considerably increase calling for more efficient production and separation processes. H2 could be produced application of using membrane reactors capable to combine the reaction and the gas purification in a single process unit to either methane reforming or water gas shift. Palladium based membranes are the best candidates for such applications due to their high H2 permeability and selectivity, their thermal stability and catalytic activity. As a direct consequence, the synthesis of thin, defect-free and long lifetime Pd-based membranes represents a relevant task. To reach this goal, a porous support is necessary to give mechanical stability to very thin Pd dense layers. Porous metal supports are very promising candidates having numerous advantages over the widely studied ceramic supports, but their application is limited by temperature due to the occurrence of intermetallic diffusion phenomena from about 400°C. The intermetallic diffusion of elements from the support to the Pd layer can be prevented by deposition of a ceramic barrier layer between the support and the Pd layer. Moreover, it can improve the morphological characteristics of the support surface, which usually is still very poor. Our study focuses on the deposition of ceramic Alumina barrier layer on porous stainless steel supports (PSS) having different level of roughness by using the dip-coating technique and boehmite sols. It will be shown the successful preparation of Palladium membranes.

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