A GENERALIZED EQUATION OF STATE APPROACH TO THE PREDICTION OF PHASE-BEHAVIOR IN CO2-BITUMEN SYSTEMS

A generalized form of the Peng-Robinson equation of state was utilized to predict phase behavior of high pressure CO2 in contact with Cold Lake Bitumen. The model requires only the average molecular weight of the solute, the molecular-weight distribution of the solute, and the hydrogen to carbon ratio in order to calculate phase equilibrium. Solute critical properties and binary interaction parameters are calculated from generalized relationships based on molecular weight and aromaticity. The generalized predictions yielded average deviations of 0.0055 weight fraction for the CO2 content in the solute and 0.0032 weight fraction for bitumen solubility in the high-pressure CO2. This compares with deviations of 0.0099 and 0.0038 weight fraction given by Huang and Radosz(1) using the SAFT equation with optimized binary interaction parameters and deviations of 0.014 and 0.0037 weight fraction using generalized values of binary interaction parameters. Experimental reproducibility for these data was estimated by Huang and Radosz to be less than 0.003 weight fraction for the CO2 content in bitumen and less than 0.002 weight fraction for the bitumen content in CO2.