Ramos-Pallares, F. Yarranton, H. W. Extending the Modified Regular Solution Model To Predict Component Partitioning to the Asphaltene-Rich Phase The modified regular solution (MRS) model is an activity coefficient approach previously developed to predict the onset and amount of asphaltene precipitation from <i>n</i>-paraffin-diluted crude oils. The activity coefficients in this model are determined from an enthalpic contribution based on the regular solution theory and a Flory–Huggins (configurational) entropic contribution. The inputs are the molar volume and solubility parameter of the crude oil pseudo-components, which are defined on the basis of the saturate, aromatic, resin, and asphaltene (SARA) fractions; however, only asphaltenes and resins are free to partition between the two phases. Hence, the model cannot predict the amount and composition of the heavy asphaltene-rich phase. In this study, the MRS model was updated to account for the partitioning of all components based on phase equilibrium data from a Western Canada bitumen mixed with <i>n</i>-pentane and <i>n</i>-heptane at ambient conditions. To match the measured phase compositions, the entropic contribution in the solvent-rich phase was set to the Flory–Huggins term and the contribution from the asphaltene-rich phase was set to zero. An approach to predict the solubility parameters and density of the pseudo-components at other temperatures and pressures was also proposed. The model was tested on a data set containing phase mass and phase compositions of a Western Canada bitumen mixed with <i>n</i>-heptane, <i>n</i>-pentane, <i>n</i>-butane, and propane at temperatures from 20 to 250 °C and pressures up to 13 MPa. The average absolute deviations in the phase mass and compositions were 7 and 12 wt %, respectively. The maximum deviations were found for the asphaltene-rich phase compositions. The model was also tested on a data set of asphaltene yields from oils from different disparate geographical locations at temperatures from 0 to 50 °C at 0.1 MPa. The average absolute deviation was 1 wt %. Predict Component Partitioning;phase compositions;MRS;phase mass;asphaltene-rich phase compositions;Modified Regular Solution Model;activity coefficient approach;SARA;asphaltene-rich phase;Western Canada bitumen;crude oil pseudo-components;phase equilibrium data;paraffin-diluted crude oils;entropic contribution;model 2020-01-14
    https://acs.figshare.com/articles/journal_contribution/Extending_the_Modified_Regular_Solution_Model_To_Predict_Component_Partitioning_to_the_Asphaltene-Rich_Phase/11604561
10.1021/acs.energyfuels.9b03489.s001