THE INFLUENCE OF GAS GAS INTERACTIONS ON THE LANGMUIR CONSTANTS FOR SOME NATURAL-GAS HYDRATES

Hydrates of structures I and II are investigated using Monte Carlo simulations. The empty lattice is assumed to be approximately rigid and unaffected by the guest molecules. The influence of guest-water and guest-guest interactions on the Langmuir constants are estimated using interaction-site models for the guest molecules. It is shown that the guest-guest interactions have a significant effect on the size of the Langmuir constants in the absorption theory of van der Waals and Platteeuw (van der Waals, J.H., 1956. Trans. Faraday Soc., 52: 84; van der Waals, J.H. and Platteeuw, J.C., 1959. Adv. Chem. Phys., 2: 1). For reasons of consistency and extrapolation it is recommended that these effects should be included in mean-field terms rather than by empirical corrections.