Kinetics measurements and in situ Raman spectroscopy of formation of hydrogen–tetrabutylammonium bromide semi-hydrates

The kinetics of formation of H2–TBAB semi-clathrate hydrates was studied in this work in order to elucidate their potential for H2 storage. The influence of pressure (5–16 MPa), TBAB concentration (2.6 mol% and 3.7 mol%) and formation method (T-cycle method and T-constant method) on the hydrate nucleation, hydrate growth and H2 storage capacity was determined. The results showed that kinetics is favored at higher pressures and solute concentrations. Additionally, the hydrate phase formation and dissociation was study for a solution of 2.6 mol% of TBAB in situ by using the Raman spectroscopy technique. The inclusion of H2 in the semi-hydrate phase was confirmed. The results showed the importance of H2 mass transfer on the storage capacity of the H2–TBAB semi-hydrates.

► The kinetics of formation of H2–TBAB semi-hydrates were studied.
► Kinetics is favored at higher pressures and solute concentrations.
► Less stochastic behavior was observed when the T-cycle method was applied.
► Optimal hydrogen storage is mainly affected by hydrogen mass transfer limitations.