Microporous Materials for Hydrogen Liquefiers and Storage Vessels

Abstract

Microporous Composite Materials, made of metal oxide ionic fragments inserted in carbonaceous substrates, might be used as intermediates in hydrogen phase transitions, allowing progressive switch between their gas and liquid states. When crossed by an hydrogen flow these composite materials combine adsorbing, magnetic, catalytic and thermal properties efficient in hydrogen devices, liquefiers or storage vessels. Liquefaction and storage are complementary processes in practice, although inverse in principle. Plate-fin devices filled with composite materials can conjugate many thermal functions, heat exchangers, catalytic converters and pressure expanders that are necessary stages in large-scale liquefiers. Break-even storage times permit operation of the liquefaction unit at optimum ortho-para conversion thus yielding minimum practical work to be furnished. A barrage-system of successive porous plugs inserted in Hydrogen vessels would regulate the flow rate by J-T expansions, convert part of the environmental heat in rotational energy and confer stability to the system by damping the fluctuations. Consequently storage vessels of short dormancy period might be manufactured to be of low weight and low cost. After a short review of existing devices, a logical scheme interconnecting physical, economic and technologic challenges suggests that activated carbon materials of cage-like porous structures would promote and accelerate the development of storage vessels in hydrogen transport vehicles and facilitate the liquid hydrogen production by regulating the hydrogen streams in the industrial liquefiers.