Solubility and mass transfer of H2, CH4, and their mixtures in vacuum gas oil: An experimental and modeling study

In this work, the solubility data and liquid-phase mass transfer coefficients of hydrogen (H2), methane (CH4) and their mixtures in vacuum gas oil (VGO) at temperatures (353.15–453.15 K) and pressures (1–7 MPa) were measured, which are necessary for catalytic cracking process simulation and design. The solubility of H2 and CH4 in VGO increases with the increase of pressure, but decreases with the increase of temperature. Henry's constants of H2 and CH4 follow the relation of ln H = −413.05/T + 5.27 and ln H = −990.67/T + 5.87, respectively. The molar fractions of H2 and system pressures at different equilibrium time were measured to estimate the liquid-phase mass transfer coefficients. The results showed that with the increase of pressure, the liquid-phase mass transfer coefficients increase. Furthermore, the solubility of H2 and CH4 in VGO was predicted by the predictive COSMO-RS model, and the predicted values agree well with experimental data. In addition, the gas–liquid equilibrium (GLE) for H2 + CH4 + VGO system at different feeding gas ratios in volume fraction (i.e., H2 85% + CH4 15% and H2 90% + CH4 10%) was measured. The selectivity of H2 to CH4 predicted by the COSMO-RS model agrees well with experimental data. This work provides the basic thermodynamic and dynamic data for fuel oil catalytic cracking processes.