Modeling hydrocarbon droplet dissolution in near-critical or supercritical water using GCA-EOS and non-ideal diffusional driving force in binary mixtures

SÁNCHEZ, FRANCISCO A.; HE, PING; GHONIEM, AHMED F.; PEREDA, SELVA

JOURNAL OF SUPERCRITICAL FLUIDS

ELSEVIER SCIENCE BV

Año: 2019 vol. 146 p. 1 - 14

0896-8446

In this work, the mixing of a hydrocarbon droplet in near- and super-critical water (NCW/SCW) is mathematically modeled, coupling thermodynamic properties calculation with transport processes. In non-ideal systems, mass transfer is captured using the generalized Maxwell-Stefan equations with the driving force expressed in terms of the fugacity gradients. The GCA-EOS is used to predict the thermodynamic properties and phase equilibrium compositions. We select n-decane, n-triacontane, benzene, naphthalene and 1-decylnaphthalene as representative hydrocarbons. Our simulations show delayed mixing processes as the temperature approaches the upper critical solution temperature (UCST) of the mixture, consistent with the impact of non-ideal diffusional driving forces evaluated from pure thermodynamic calculations. Results also show that the phase behavior notably affects the non-ideal driving forces near the UCST, which confirms the importance of coupling accurate thermodynamic models in predictive mixing studies.