Comparison of lumping methods to adaptive characterization in representing phase equilibria of hydrocarbon mixtures using PC-SAFT EOS

This work compared three classical lumping and Lage's re-characterization methods in representing the ������7+ fraction of hydrocarbon mixtures with fewer pseudo-components. Two gas condensates, whose compositions are available in the literature, were used in the analysis. As all re-characterization methods are independent of the thermodynamic model, we chose the PC-SAFT equation of state to model the mixtures. Using all methods, we compared phase diagrams and liquid dropouts in flashes calculated using the original mixtures' composition and the re-characterized mixtures. Lage's method showed the best representation of the thermodynamic properties of the original mixtures for any number of pseudo-components. Using three pseudo-components, its accuracy for all relevant thermodynamic properties of the mixture is better, frequently by order of magnitude, than for all the other methods using four pseudo-components. For the tested cases, Lage's method needed only half of the pseudo-components of the other methods to represent the ������7+ fraction with similar accuracy.

Automated summary

This study compared three classical lumping methods and Lage's re-characterization method for representing the ������7+ fraction of hydrocarbon mixtures with fewer pseudo-components. Two gas condensates, whose compositions are available in the literature, were used for the analysis. Regardless of the thermodynamic model, the PC-SAFT equation of state was chosen to model the mixtures. The results showed that Lage's method had the best representation of the thermodynamic properties of the original mixtures, requiring only half the pseudo-components compared to other methods for similar accuracy in representing the ������7+ fraction.