A method for characterization of bitumen

Characterization of bitumen is a necessary step to perform phase equilibrium computations involved in bitumen production and processing. This study presents a methodology for bitumen characterization using a residue curve map. A fugacity-activity coefficient approach is applied to model the thermodynamic equilibrium of the species in the gas and liquid phases. The Peng-Robinson equation of state (PR-EoS) and NRTL activity model are utilized to calculate the fugacity and activity coefficients in the gas and liquid phases, respectively. The proposed model was evaluated using experimental simulated distillation (SD) data as well as experimental solubility data of light hydrocarbon (CH4, C2H6) and non-hydrocarbon gases (CO2, N2) in bitumen. The molecular weight, specific gravity, and SD curves were represented using defined pseudo-components. The tuned EoS was able to regenerate the solubility data with an acceptable accuracy (AARD less than 5.6% and 4.5% for hydrocarbon and non-hydrocarbon solvents, respectively). The proposed method can be applied for bitumen characterization and to predict the solubility of the light gases in bitumen.