(378d) Utilizing Phase Equilibrium Conditions for Separating Hydrogen from Hydrogen-Compressed Natural Gas Blends

As hydrogen emerges as a crucial tool for future decarbonization efforts, the concept of "Hydrogen Blending" – the incorporation of hydrogen into natural gas pipelines – has rapidly gained attractions to reduce carbon emissions. However, before widespread adoption of hydrogen pipelines can occur, thorough investigation into "Hydrogen Deblending" – the process of separating hydrogen from HCNG (Hydrogen-Compressed Natural Gas) – is imperative to ensure the availability of pure hydrogen as needed. In this study, we introduce a novel gas separation method utilizing clathrate hydrates. Clathrate hydrates, crystalline inclusion compounds formed through hydrogen bonding, offer a water-based solution for scalable and sustainable gas storage and separation. We propose an innovative gas separation system that utilizes successive hydrate formations to store natural gas within hydrates while enhancing the purity of hydrogen in the vapor phase. Through in-situ gas chromatography analysis during hydrate formation, we assessed gas compositions and quantified gas storage capacities for individual guest species. Our findings demonstrate that the designed successive hydrate formation process can achieve approximately 79% hydrogen recovery with a purity of 99%, demonstrating the viability of hydrate-based separation techniques.