CHEMICAL EQUILIBRIUM STUDY OF SYSTEMS RELATED TO BIOFUELS – TEACHING EXPERIENCE WITH THERMODYNAMIC ANALYSIS OF HYDROGENATION OF VEGETABLE OILS

Résumé

Total hydrogenation of vegetable oils to yield hydrocarbons is an emerging processfor production of biofuels. Some researchers have been chosen tristearate as amodel compound to represent vegetable oils in the calculations. The first problemis that its thermodynamic data were not available in literature, their values wereestimated by using the Joback’s contribution method. Based on the comparison toenthalpy of formation estimated in this work and in Smejkal et al., it was concludedthat the chosen method can influence in the result of thermodynamic data. In thiswork, we realised that the basic thermodynamic analysis of the reaction system wasperformed presenting some misconceptions and problems which must be betterdiscussed and checked. Calculations were done in classroom and as home-work,then the results have pointed out corrections.