A Group Contribution Equation of State for Biorefineries. GCA-EOS Extension to Bioether Fuels and Their Mixtures with n-Alkanes

Abstract

Biomass processing routes involve mixtures of organo-oxygenated compounds of almost all the organic families. Typically, these mixtures are highly nonideal, and models to describe their phase behavior should take into account specific association interactions. In this work, the group contribution with association equation of state (GCA-EOS) is applied to the thermodynamic modeling of mixtures comprising ethers and alkanes. A databank of about 2800 experimental data points of phase equilibria and excess enthalpies is used to parametrize the GCA-EOS and challenge its predictive capacity. Based on the correlation of selected equilibrium data of linear monoethers and n-alkanes, the model is able to predict accurately the phase behavior of linear and branched monoethers not included in the parametrization, as well as that of the polyethers. This work is part of a broader project for the development of a robust and predictive thermodynamic model for process and product design in the context of biomass valorization.

Modeling Phase Equilibria of Ethers and Alcohols with GCA-EOS for Assessing the Coblending of Advanced Biofuels

“…In this case, the excess enthalpy increases with the ether alkyl chain, though the model calculations follow the experimental data qualitatively. Regarding this effect of increasing the alkyl chain, it is worth noting that alkane + ether mixtures effectively exhibit lower excess enthalpies as alkyl groups are added to the mixture, behavior that the GCA-EOS describes accurately . Hence, an invariant experimental trend, as the one depicted in Figure a, is difficult to sustain and also to predict with a group-contribution approach.…”

“…Model Parametrization. The GCA-EOS table of parameters already includes the ether 26 and alcohol 20 groups, as well as their interactions with the alkyl groups, either to represent their own carbon backbone chain or their mixtures with hydrocarbons. Therefore, in this work, the only degrees of freedom to model mixtures comprising ethers and alcohols are the binary interaction parameters among them.…”

“…In this work, we specifically extend the GCA-EOS to binary mixtures of linear, branched, and polyethers with alcohols using a single set of parameters. This work is the continuation of a previous article, which assessed the modeling of pure ether vapor pressure data and their phase equilibrium in mixtures with alkanes …”

“…This work is the continuation of a previous article, which assessed the modeling of pure ether vapor pressure data and their phase equilibrium in mixtures with alkanes. 26…”

Phase equilibria modeling of biorefinery-related systems: a systematic review

“…[53], [192], [201], [204]- [208] 10 [21], [209]- [217] 12 [18], [21], [22], [112], [166], [194], [218]- [223] 1 [224] Monte Carlo…”