High pressure multiphase phase equilibria of CO2-water-lignin derivatives

FRANCISCO A. SÁNCHEZ; SELVA PEREDA

Bragança (simposio en formato virtual)

Simposio; 20th International Symposium on Solubility Phenomena and Related Equilibrium Processes (ISSP 2022); 2022

Polytechnic Institute of Bragança

In the context of lignocellulosicbiomass valorization, the fractionation of biooils to recoveradded-value products is a great challenge. There are several pathwaysto break down these natural polymers, among which are thermaltreatments, such as pyrolysis and hydrolysis, as well asbase-catalyzed depolymerization or oxidative cleavage [1]. Regardlessof the conversion technology, lignin degradation gives rise to a widevariety of polyfunctional aromatic rings, with different oxygenatedsubstituents, such as hydroxyls, ethers, ketones and aldehydes, toname a few. It is worth highlighting that the great deal of compoundsthat are produced is strongly dependent on both, the raw material,and the type of treatment. Therefore, bio-oil refining calls for moreresearch on separation technologies. In particular, pioneering worksin the field of high pressure technology apply CO2extraction as a solvent-free non-destructive analytical method forthe characterization of bio-oils; and, more recently, several reviewsconsider CO2 extraction as a feasible technology forlarge-scale recovery of valuable compounds.The design and optimization ofseparation processes requires a robust thermodynamic model able topredict the phase behavior of bio-oils. Lignocellulose derivedbio-oils are complex multicomponent mixtures that comprise a largenumber of asymmetric compounds, show non-ideal behavior due to thepresence of water and organo-oxygenates and contain polyfunctionalmolecules whose properties are generally unknown. Since the largenumber of compounds comprising the bio-oil belong to the few organicfamilies mentioned above, the use of a group contribution approach isa convenient choice to facilitate the thermodynamic modeling of thesemixtures.The Group Contribution with AssociationEquation of State (GCA-EOS) [2] is particularly suitable for thispurpose. It has already shown excellent performance to model thephase behavior of complex mixtures containing natural products andbiofuels. As part of this work, we extend the GCA-EOS to describe thephase behavior of aromatic compounds from low- to high-pressure phaseequilibrium data and their binary mixtures with CO2. Next,we challenge the GCA-EOS to predict high-pressure multiphase behaviorof lignin-derived polyfunctional aromatic compounds with CO2and water, in order to assess the technical feasibility of usinghigh-pressure CO2 to fractionate a typical hydrolysatemixture reported in the literature.References[1]Abad Fernández N, Perez Velilla E, Cocero MJ, Green Chem., 2019, 21,1351-1360.[2]González Prieto M, Sánchez FA, Pereda S, J. Supercrit. Fluids,2015, 96, 53-67.p { line-height: 115%; text-align: left; orphans: 2; widows: 2; margin-bottom: 0.25cm; direction: ltr; background: transparent }p.western { font-size: 11pt; so-language: en-GB }p.cjk { font-size: 11pt; so-language: en-US }p.ctl { font-size: 11pt }a:visited { color: #800080; text-decoration: underline }a:link { color: #0000ff; text-decoration: underline }