Chapters authored
Reactive Distillation Applied to Biodiesel Production by Esterification: Simulation Studies
Reactive distillation is an operation that combines chemical reaction and separation in a single equipment, presenting various technical and economic benefits. In this chapter, an introduction to the reactive distillation process applied to the biodiesel industry was developed and complemented by case studies regarding the production of biodiesel through esterification a low-cost acid feedstock (corn distillers oil) and valorization of by-products (glycerol) through ketalization. The kinetic parameters of both reactions were estimated with an algorithm that performs the minimization of the quadratic differences between experimental and calculated data through a Nelder-Mead simplex method. A 4th order Runge Kutta method was employed to integrate the conversion or concentration equations used to describe the kinetics of the reactions in a batch reactor. Both processes were simulated in the commercial software Aspen Plus with the estimated kinetic parameters. The results obtained are promising and indicate that the productivity of both processes can be improved with the application of reactive distillation technologies. The simulated esterification process with an optimized column resulted in a fatty acids conversion increase of 84% in comparison to the values lower than 50% obtained in the experimental tests. Solketal production through ketalization also achieved a high glycerol conversion superior to 98%.
Part of the book: Distillation Processes
Ethanol as a Subgroup of the UNIFAC Model in the Prediction of Liquid-Liquid Equilibrium in Food and Fuel Systems
Ethanol has been employed as a solvent in biodiesel production and vegetable oil refining since it is more economically attractive and less toxic than methanol and hexane. Furthermore, ethanol has demonstrated easy recovery, good selectivity, and distribution coefficient for free fatty acids (FFA), which is the primary target in the refining process since high acidity oil can lead to the formation of side products. As the knowledge of phase equilibrium behavior of fatty systems is essential to design and optimize the extraction of FFA, this chapter will present two new UNIFAC subgroups for ethanol: EtOH-B, focused on biodiesel production; and EtOH-D, focused on the deacidification process. Except for ethanol and water subgroups fitted in this study, all remaining UNIFAC parameters were taken from the literature. The new EtOH-B and EtOH-D parameters provide a considerably lower mean square error (1.20% and 0.87%) than the other works available in the literature. The results show that new ethanol subgroups and the developed methodology are valuable tools in predicting liquid-liquid phase equilibrium for ethyl biodiesel and vegetable oil deacidification systems considered, resulting in reduced computational calculations and a relatively small split with the complex dataset established by the UNIFAC-LL model.
Part of the book: Ethanol and Glycerol Chemistry