Implementing Cyclopentane Hydrates Phase Equilibrium Data and Simulations in Brine Solutions

Cyclopentane hydrate-based salt removal is considered to be a possible promising technology for desalination. In order to optimize such processes, phase equilibrium data of cyclopentane hydrates (CPH) in saline solutions are crucial. Lamentably, these data sets are still incomplete. Therefore, earlier we published a limited experimental and modeling study on CPH equilibrium with some salts present. This study extends experimental equilibrium to four more common brine systems: Na2SO4, MgCl2, MgCl2-NaCl, or MgCl2-NaCl-KCl at various salt concentrations. Importantly, four thermodynamic approaches (the standard freezing point depression equation based (SFPD), Hu-Lee-Sum (HLS) correlation, and the two van der Waals and Platteuw-based Kihara and activity-based occupancy correlation (ABOC) methods) are compared to this new set of experimental data. Results show that simulations agree adequately with measured data. Nonetheless, the ABOC method is the best model to reproduce rapid and consistent equilibrium data of CPH in brine, whatever the electrolytes involved.