International audienceIn this paper, a set of experimental data on the phase equilibrium of gas hydrates in the presence of binary gas mixtures comprising CO2 is presented. The procedure established allows for the determination of both the composition of the gas phase as well as the hydrate phase without the need to sample the hydrate. The experimental results obtained in these measurements have been described by means of the classical model of van der Waals and Platteeuw. The values of internal parameters of the reference state and the Kihara parameters have been re-discussed and their interdependency is pointed. Finally the new set of parameters is validated against experimental data from other sources available in the literature, or invalidated against other sources. Finally, we conclude on the difference of experimental data between laboratories. The differences are not on the classical (pressure, temperature, gas composition) data which appear equivalent between laboratories. The difference stands on the measurement composition of the hydrate phase

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HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Prototyping of a real size airconditioning system using a tetra-n-butylammonium bromide semiclathrate hydrate slurry as secondary two-phase refrigerant-Experimental investigations and modelling

International audienceGas hydrates are crystalline water based solids composed of a three-dimensional network of water molecules. They form a network of cavities in which molecules of light gases can be encapsulated depending on their size and affinity. Gas hydrates can, by their nature, not be classified as chemical compounds since they do not possess a definite stoechiometry. In contrast they have to be regarded as solid solution phases, the stoechiometry of which is not fixed but depends on the composition of the surrounding liquid. At equilibrium, the composition dependence of the hydrate phase can be described by means of the classical van der Waals and Platteeuw model (van der Waals and Platteeuw, 1959). In the framework of the model, Langmuir constants are used for expressing the relative ability of light components to get enclathrated within the cavities. The work consists in considering again the enclathration of host species, not at thermodynamic equilibrium, but during the crystallisation process taking place under non-equilibrium conditions. It aims at proposing a new formulation for the hydrate composition as a function of new intrinsic constants which are based on Langmuir kinetic constants