Catalytic Functions for Hydrogen Production and Storage
Ernest Ilisca
ABSTRACT
Unlike current hydrogen storage methods aiming for permanent storage, the method presented is a transient process that transforms liquid hydrogen into gas during a period of time that can be adjusted to suit the desired end-up application. The porous materials used in the suggested storage are similar to those acting as catalysts in industrial liquefiers, but they combine a larger variety of functions: transient adsorption, flow regulation, heat exchange, catalytic conversion of hydrogen. The material compound of the microporous plugs introduced in the vessels will be related to necessary temporal functions. Three material parameters of the catalysts: surface electronic structure, porosity, thermal conductivity ensure these main functions. Among the porous adsorbents under consideration, metal–organic frameworks present a configuration of metal ions connected via organic linkers promising materials for H2 storage due to their high surface area and their high chemical and structural tunability. Their ability to bind hydrogen at open metal coordination sites, characterized also by sharp electromagnetic gradients, allows also fast catalytic rates. While the hydrogen conversion energy emitted is a harmful inconvenience in the cooling process, it is advantageous in storage because it absorbs the environmental heat. Similarly, the inconvenience of the pressure drops produced by the catalyst porosity in the liquefiers are advantageous in the storage by producing necessary expansions that regulate the hydrogen capillary flow. Along the hydrogen current, each of successive microporous plugs retains some molecules and opens the door to a cascade, producing a JT expansion that reduces the pressure of the following compartment. The presented transient hydrogen storage using the complementary, although inverse, liquefaction and storage processes promotes a rational way in the delivery of future storage tanks and thus in the use of the hydrogen energy by integrating the production, storage and dispensing processes.
