Thermodynamic model for predicting phase equilibria of simple clathrate hydrates of refrigerants

In this communication, a thermodynamic model is presented for the study of the phase equilibria of clathrate hydrates of simple refrigerants. The van der Waals–Platteeuw solid solution theory is used to model the hydrate phase while it is assumed that vapor phase is an ideal gas of refrigerant ignoring its water content and the aqueous phase is considered as pure water (activity coefficient=1) ignoring aqueous solubility. The results through this model are successfully compared with the experimental data reported in the literature for clathrate hydrates of four refrigerants namely C2H2F4 (1, 1, 1, 2-tetrafluoroethane or HFC-134a or R-134a), C2H4F2 (1, 1-difluoroethane or HFC-152a or R-152a), CH2F2 (difluoromethane or HFC-32 or R-32), and C2H3Cl2F (1,1-dichloro-1-fluoroethane or HCFC-141b or R-141b).

► A thermodynamic model is presented to study the phase equilibria of hydrates of refrigerants. ► The studied refrigerants are as follows: C2H2F4, C2H4F2, CH2F2, and C2H3Cl2F. ► The presented thermodynamic model well represents/predicts the experimental dissociation data.