Hydrogen storage and carbon dioxide sequestration in TBAF semi-clathrate hydrates: Kinetics and evolution of hydrate-phase composition by in situ raman spectroscopy - Abstract -

Carbon dioxide (CO2) represents almost one third of the emissions from the combustion of fossil fuels additionally, CO2 has been identified as the mayor contributor of global warming. Hydrogen (H2), on the other hand, due to its properties is considered a promising energy carrier. Clathrate hydrates are a potential alternative for CO2 separation, capture and storage (CCS) as well as a medium for H2 storage. For instance, clathrate hydrate technologies are less energy demanding and environmentally friendly than other technologies available. However the main disadvantage of clathrate hydrates is the high pressure required for their formation. Recently, tetra-n-butyl ammonium fluoride (TBAF) has been used as an additive to form H2-TBAF and CO2-TBAF semi-clathrate hydrates with water, which are stable at much more practical conditions (atmospheric pressure and close to room temperature). Moreover, TBAF is non-volatile which means there is no contamination of the gas phase. These favorable conditions make these two semi-clathrate hydrates particularly attractive for hydrate based technologies. In order to investigate the potential of H2-TBAF and CO2-TBAF semi-clathrate hydrates for H2 storage and CO2 sequestration, kinetic data were obtained. The influence of pressure, solute concentration and formation rate was elucidated. Coupled with the kinetic results, the Raman spectra studying the structural changes that take place during formation and dissociation of the H2-TBAF and CO2-TBAF semi-hydrates were recorded in situ by Raman spectroscopy. To the best of our knowledge, these are the first results of time-dependent kinetic conditions of H2-TBAF and CO2-TBAF semi-clathrate hydrates using in situ Raman spectroscopy in an aqueous solution. Results will be presented at the conference.