Gas Hydrate Phase Equilibrium in the Presence of Ethylene Glycol or Methanol Aqueous Solution

Abstract

In this communication, experimental hydrate dissociation data for the ethane, carbon dioxide, or hydrogen sulfide + ethylene glycol + water system are first reported at 0.1, 0.2, 0.35, and 0.5 mass fractions of ethylene glycol in aqueous solution. The experimental data were generated using an isochoric pressure-search method. The experimental hydrate dissociation data are compared with the corresponding literature data and the experimental dissociation data for ethane, carbon dioxide, or hydrogen sulfide simple hydrates in the presence of pure water reported in the literature. A discussion is made on the reliability of the few sets of experimental hydrate dissociation data reported in the literature for the ethane, carbon dioxide, or hydrogen sulfide + ethylene glycol + water system. We finally report experimental hydrate dissociation data for the methane + methanol + water system at 0.55 and 0.65 mass fractions of methanol in aqueous solution. The experimental hydrate dissociation data are compared with the corresponding literature data and the experimental dissociation data for methane hydrates in the presence of pure water reported in the literature. It is shown that the few sets of experimental hydrate dissociation data reported in the literature for the methane + methanol + water system at high concentrations of methanol in aqueous solution may not be very reliable. A discussion is made on the inhibition effect of methanol at its very high concentration in aqueous solution.