EXPERIMENTAL-STUDY ON PROPANE HYDRATE EQUILIBRIUM CONDITIONS IN AQUEOUS-ELECTROLYTE SOLUTIONS

Hydrate equilibrium data (aqueous solution - gas - hydrate) on propane hydrates in electrolyte solutions containing NaCl, KCl, CaCl2 and their binary and ternary mixtures, and in a synthetic sea water were experimentally obtained in the temperature range 263 - 276 K using a ''pressure search'' method. The ionic strengths of the solutions ranged from 0.7 to 4.77 in molality units. The data obtained in 10 wt% NaCl solution in this work were close to one set of published data but were in disagreement with two other sets of published data having their own mutual disagreement. The inconsistency was investigated by employing a ''temperature search'' method for this solution. The two sets of data obtained in this work by the two different procedures were in close agreement with each other. The predictive method of Englezos and Bishnoi was used to compute the equilibrium pressures at the experimental temperatures for all the electrolyte solutions studied. The computed values matched the experimental data obtained in this work very well, including those for 10 wt% NaCl solution.