Journal of Chemical and Engineering Data, Vol.56, No.4, 1573-1586, 2011
Thermodynamic Consistency Test for Experimental Solubility Data in Carbon Dioxide/Methane plus Water System Inside and Outside Gas Hydrate Formation Region
Accurate knowledge of solubility in carbon dioxide/methane + water system over wide ranges of temperatures and pressures is essential for the petroleum industry. However, experimental measurements of such solubilities (especially in gas hydrate formation region) are challenging. For instance, concentrations of these gases in water are low, and furthermore reaching the equilibrium conditions near and inside gas hydrate formation region is a time-consuming process. Those difficulties may consequently result in generation of unreliable experimental data. This work aims at performing a thermodynamic consistency test based on an area approach to study the reliability of such experimental data reported in the literature and points out the suspected inconsistent data. A thermodynamic model based on the Valderrama modification of the Patel-Teja equation of state along with non-density dependent mixing rules is used to model the solubilities in the gas/vapor and liquid water phases. For modeling the solubility of carbon dioxide/methane in water under liquid water-hydrate equilibrium conditions, the van der Waals-Platteeuw model accompanied with Henry's law approach is employed. The results show that about 23 % of all of the investigated experimental data seem to be thermodynamically consistent, 57 % inconsistent, and 20 % not fully consistent data.