CO<sub>2</sub> hydrate formation in NaCl systems and undersaturated aqueous solutions
Rod Burgass, Antonin Chapoy, Kjell M. Askvik, Bengt O. Neeraas, Xiaoyun Li
Abstract
A high-pressure experimental setup was used to obtain experimental data on the Hydrate Equilibrium (melting) Temperature (HET) of aqueous phases undersaturated with CO 2 , at different CO 2 saturation levels and with different aqueous phase compositions (sodium chloride and sodium chloride/calcium chloride). This paper details the experimental equipment, methods, test fluids, and results. To study the phase equilibria of CO 2 -brine systems and further validate the results, hydrate dissociation conditions of CO 2 in different concentrations of NaCl aqueous solutions were measured in the low-temperature region and over a wide range of pressure. Experimental results were compared against predictions of the simplified Cubic Plus Association Equation of State (sCPA-EoS) coupled with the van der Waals and Platteeuw solid solution theory.