Self-supporting hydrate template with hydrate seeds and promoter liquids for semi-continuous formation of hydrogen hydrates

Abstract

The derivation of an energy-efficient formation process of hydrogen hydrate is a challenging task for hydrogen storage. This work introduces a successive hydrate formation strategy for hydrogen storage within a porous hydrate self-support under static conditions. Sodium dodecyl sulfate (SDS)-induced porous hydrate was prepared as a ‘supporting matrix,’ and this support enables rapid nucleation and growth of hydrate from the matrix surface. To examine the feasibility of the proposed successive hydrate formation process, SDS solutions were injected into the porous hydrate support in single feed charge and multiple feedings. The successive formation of hydrogen hydrate from SDS solutions through multiple injections enhances the mass transfer of guest molecules throughout the entire reactor, leading to increase in the gas storage capacity and water-to-hydrate conversion by up to 107%. Even with a high water-to-gas volume ratio, the hydrogen storage density in the multiple injection case doubled compared to the single injection case. Regardless of the degree of subcooling, the injection of SDS solutions into the hydrate matrix induced immediate nucleation and extended the reaction regions, as confirmed by numerous reactor experiments and Raman observations. These findings have the potential to advance the use of gas hydrates for hydrogen storage by improving energy efficiency and eliminating the agitation energy cost.