Phase equilibrium engineering in biorefinery reactive systems

SELVA PEREDA; FRANCISCO A. SÁNCHEZ

Vancouver

Congreso; 15th International Conference on Properties and Phase Equilibria for Product and Process Design (PPEPPD 2019); 2019

Petroleum Thermodynamics Research Group, University of Alberta

Phase and chemical equilibrium calculations are essential for the design of processes involving chemical transformations. Even in the case of reactions that cannot reach chemical equilibrium, the solution of this problem gives information on the expected behavior of the system and the potential thermodynamic limitations. There are several problems in which the simultaneous calculation of chemical and phase behavior is mandatory. This is the case, for example, of reactive distillations, where phase separation is used to shift chemical equilibrium. Several algorithms have been proposed in the literature to solve the complex non-linear problem; however, proper thermodynamic model selection has not received much attention. Nonetheless, the growing interest on CO2 capture move forward this topic and recent literature show the use of advanced equations of state to model CO2 chemical absorption.In this work we perform simultaneous phase and chemical equilibrium calculation using the Group Contribution with Association equation of state (GCA-EOS), aiming to assess reactive systems in the framework of biorefinery development. In this work, we use a non-stoichiometric approach for the Gibbs energy minimization procedure and Michelsen?s phase stability analysis to find a solution. The lack of equilibrium data in reactive mixtures is quite common; therefore, group contribution methods allow designers to gain knowledge on the changes in phase behavior as the reaction proceeds. During the last decade, GCA-EOS has been extended to first- and second-generation biofuels and most of the oxygen-bearing organic compound families. In addition, the model has shown good predictive capacity to describe the non-ideality of complex polyfunctional molecules, which are typical in most of the biomass conversion routes.