In this contribution, a method based on a solid solution theory of clathrate hydrate for multiple cage occupancy, host lattice relaxation, and guest-guest interactions is presented to estimate hydrate formation conditions of binary and ternary gas mixtures. We performed molecular modeling of the structure, guest distribution, and hydrate formation conditions for the CO₂ + CH₄ and CO₂ + CH₄ + N₂ gas hydrates. In all considered systems with and without N₂, at high and medium content of CO₂ in the gas phase, we found that CO₂ was more favorable in occupying clathrate hydrate cavities than CH₄ or N₂. The addition of N₂ to the gas phase increased the ratio concentration of CO₂ in comparison with the concentration of CH₄ in clathrate hydrates and made gas replacement more effective. The mole fraction of CO₂ in the CO₂ + CH₄ + N₂ gas hydrate rapidly increased with the growth of its content in the gas phase, and the formation pressure of the CO₂ + CH₄ + N₂ gas hydrate rose in comparison to the formation pressure of the CO₂ + CH₄ gas hydrate. The obtained results agreed with the known experimental data for simple CH₄ and CO₂ gas hydrates and the mixed CO₂ + CH₄ gas hydrate.

Ozone storage capacity in O₃+ O₂+ N₂+ CO₂clathrate hydrate was estimated theoretically.

An original approach accounting for multiple cavity occupancy, host lattice relaxation and the description of the quantum nature of guest behaviour has been used for the estimation of the thermodynamic properties of pure hydrogen and binary C₂H₆ + H₂ hydrates with the possibility of multiple filling of cavities by guest molecules. It has been found that the pure hydrogen cubic structure II (CS-II) hydrate is more thermodynamically stable than the cubic structure I (CS-I) hydrate in a wide range of p–T regions. However, at low pressure, the stabilisation of the CS-I hydrate can be realised for H₂–C₂H₆–H₂O systems even with small concentrations of ethane in the gas phase. However, in this case, the amount of stored hydrogen strongly depends on the ethane concentrations in the gas phase. At low concentration of ethane, the amount of hydrogen stored, 2.5 wt%, in CS-I hydrate can be achieved at T = 250 K. We believe that the present approach can be useful for understanding the thermodynamic properties of the binary hydrate and it can support the experimental exploration of novel hydrogen storage materials based on clathrate hydrates.