APPLICATION OF THE LCVM MODEL TO MULTICOMPONENT SYSTEMS - EXTENSION OF THE UNIFAC INTERACTION PARAMETER TABLE AND PREDICTION OF THE PHASE-BEHAVIOR OF SYNTHETIC GAS CONDENSATE AND OIL SYSTEMS

The LCVM model of Boukouvalas et al. (1994) uses the translated and modified Peng-Robinson equation of state (EoS) coupled with the Original UNIFAC excess Gibbs energy (G(E)) model and introduces a new mixing rule (a linear combination of the Vidal and Michelsen ones) for parameter a in the attractive term of the EoS. The UNIFAC parameter table is here extended to include several gas/CH2, gas/ACH, gas/ACCH2, and gas/gas pairs. Correlation and prediction results for binary systems are very satisfactory, including systems with large size differences of their components - where other EoS/G(E) models fail - as well as at very high pressures (up to 2000 bar). These parameters are then applied to the prediction of bubble- and dew-point pressures, K values and volume percent liquid (VPL) of synthetic gas condensate and oil systems. Very satisfactory results are again obtained except, as expected, in the high pressure section for VPL of gas condensates. The results are comparable with models using conventional mixing rules with regressed binary parameters, and again superior to other EoS/G(E) models.