Influence of Electrolytes on Methane Hydrate Formation and Dissociation

Natural gas hydrate creates a lot of problems during its transportation and production by plugging gas pipelines and process equipment. This work envisages the effect of electrolytes (NaCl and CaCl2) at different concentrations on methane hydrate formation and dissociation. Extensive observations on equilibrium pressure and temperature during hydrate formation and dissociation have been made. The experiments were conducted in the temperature range of 261 to 270 K and pressure range of 2.6 to 3.0 MPa. Both sodium chloride and calcium chloride salts were found to have significant inhibiting effects on hydrate formation and dissociation with the latter having stronger effects. Gas consumption was found to vary with the progress of the hydrate formation as well as the concentration of salts in the hydrate cell. The dissociation enthalpies of methane hydrates in the presence of the above salts were also determined using the Clausius-Clapeyron equation based on the phase equilibrium data.