Modeling of gas-solid equilibrium of binary systems aided by Frankenstein PSO

Binary systems containing supercritical CO2 + hydrocarbons were used for modeling gas-solid equilibrium by a combined method including a thermodynamic model and a meta-heuristic algorithm. The Peng-Robinson (PR) equation of state was used in the classical solubility equation. In addition, Wong-Sandler (WS) mixing rules were used, and the van Laar model (VL) was included in order to evaluate the excess Gibbs free energy that appears in these mixing rules. Then, a variant of particle swarm optimization (PSO), called Frankenstein PSO (FPSO) was implemented for minimizing the difference between calculated and experimental solubility values. The results showed that the FPSO algorithm is a very powerful tool for parameter estimation on the PR-WS-VL model with good performance and accuracy, and considerably low deviations. Therefore, values calculated by the combined method (PR-WS-VL + FPSO) are considered accurate enough for physical and engineering calculations, among other uses.