Phase equilibria of aqueous bio-component mixtures with different solvents for the design of a liquid-liquid extraction unit

The aim of this thesis was the investigation of various solvents for the liquid-liquid extraction of furfural from aqueous solutions, which are present in bio-refineries. Additionally, the potential of the solvents for the separation of acetic acid, also present in these mixtures, was tudied. Different separation methods are often studied and analysed through process simulations, which require accurate models for the studied systems. When experimental data is not available, predictive models fill this need, but a better fit can be achieved through measured data and accurately regressed parameters for a suitable thermodynamic model. This work measured liquid-liquid equilibria (LLE) for such applications for various systems over a wide range of temperatures. The measured data, along with available excess enthalpy and vapor-liquid equilibria data, was then used for regression of UNIQUAC-HOC binary interaction parameters, which allows not only for accurate LLE analysis and extraction unit simulation, but also for the simulation of distillation systems for the purification of these mixtures. The solvents studied were compared through the distribution factor and through their selectivity towards component separation. The comparisons were carried out for ternary systems with furfural, solvent and water, as well as systems with acetic acid. Additional data was also measured for quaternary systems involving both components. The work also takes into account the remaining traces of solvent in the raffinate through selectivity analysis. This study suggests that, out of the tested solvents, furfural and acetic acid can be most efficiently separated by cyclopentyl methyl ether when either of the products is desired. The next most suitable solvents are methyl isobutyl ketone and tert-amyl methyl ether, which provide good results for both components. The measured methyl tertbutyl ether data is limited by its low boiling point, but it separates furfural and HAc effectively at lower temperatures. 2-methyl tetrahydrofuran and tert-amyl alcohol provide inferior results.