Experimental determination of stability conditions of methane hydrate in aqueous calcium chloride solutions using high pressure differential scanning calorimetry

The validity of differential scanning calorimetry (d.s.c.) as an alternate method of determination of thermodynamic conditions of stability of gas hydrates in aqueous media was asserted by comparison to literature data, in the case of methane hydrate in pure water and in sodium chloride solutions. Requirements for thermodynamic validity of the equilibrium temperatures measured by this technique were investigated and are discussed in details. New equilibrium data of (methane hydrate + water + methane) in aqueous calcium chloride solutions, in the concentration range from x = 8.47 · 10^-3 to x = 53.27 · 10^-3, were determined using the same method, in the pressure range 5 MPa to 11 MPa. Experimental results were compared to data computed using a model that is presented, showing very good agreement over a wide range of salt concentration. These results confirm the interesting perspectives of application of this technique in the field of gas hydrate thermodynamics.