Hydrate phase equilibria for gas mixtures containing carbon dioxide: A proof-of-concept to carbon dioxide recovery from multicomponent gas stream

Three-phase equilibrium conditions (aqueous liquid-hydrate-vapor) of CO2-N2 binary mixtures in the temperature range of 271.75 K to 284.25 K and the pressure range of 12 to 235 bar. In addition, three-phase (aqueous liquid-hydrate-vapor) behavior for CO2-CH4 mixture were measured in the temperature range of 272 to 284 K at the constant pressures of 15, 20, 26, 35 and 50 bar. In high concentration of CO2, upper quadruple points were also measured. The obtained data indicates that three-phase equilibrium temperatures become higher with increasing concentration of CO2. For the prediction of three-phase equilibrium, the vapor and liquid phases were treated by employing the Soave-Redlich-Kwong equation of state (SRK-EOS) with the second order modified Huron-Vidal (MHV2) mixing rule and the hydrate phase with the van der Waals-Platteeuw model. The calculated results showed good agreement with experimental data. The concentration of vapor and hydrate phases was also determined experimentally. This work can be used as the basic data for selective separation process by hydrate formation.