Solubility of hydrogen in heavy n-alkanes:: Experiments and SAFT modeling

New experimental measurements on the solubility of hydrogen in several normal alkanes, ranging from decane and up to hexatetracontane, are presented. Data cover a temperature range from 280 K to 450 K, and pressures up to 16 MPa were applied. Hydrogen solubilities of lip to 30 mol % were measured. These mixtures are described through a molecular-based equation of state based on the statistical associating fluid theory (SAFT). In the SAFT approach, all the compounds are modeled as homonuclear chains of united-atom sites interacting through a Lennard-Jones potential. Optimized values for the chain length, Lennard-Jones diameter, and dispersive energy characterize the hydrogen molecule. In the case of n-alkanes, a correlation for these molecular parameters is used. Two additional parameters, independent of the thermodynamic variables, were fitted to the experimental data of a single isopleth for each particular mixture. The agreement between the measured and predicted solubilities is excellent (overall AAD < 1.5%) in all the thermodynamic range, and does not significantly worsen as the molecular weight of the compound increases.