Abstract—A process design study was carried out, aimed at the design of a triacetin production process from glycerol, as a way to increase the feasibility of biodiesel production. Glycerol esterification with acetic acid involves three consecutive reversible acetylation reactions and in each step, water is produced, resulting in limited conversion and low selectivity [1]. One way to increase the triacetin selectivity is to continuously remove water from the reaction medium, in order to shift the equilibrium. The proposed process is based on the reaction system described by Galan
et al. [2], consisting of the esterification of glycerol using excess acetic acid as catalyst. In the first step of the present study an evaluation of the kinetic parameters was carried out, based on published experimental data [2]. The reaction conditions were then evaluated in terms of glycerol conversion and selectivity for different reaction times and temperatures. Based on the results, the process was simulated in a reactive distillation column, and different configurations were studied by using the Aspen Plus® simulator. In the separation units the NRTL-HOC equilibrium model with binary interaction parameters proposed by Hung
et al. [3] was adopted. Water removal from the top stream of the column was increased by feeding hexane as an entrainer in the reactive distillation column. Hexane is recovered in a separate unit and recycled to the process. The conceptual process specifications of an optimized industrial plant configuration were estimated for minimum specific energy consumption for production of 99.9 % molar purity triacetin with complete glycerol conversion.
Index Terms—Glycerol esterification, triacetin, reactive distillation, simulation.
Tatiane F. C. Souza and Roberto Guardani are with Escola Politécnica da Universidade de São Paulo, Brazil (e-mail:tatianefcsouza@gmail.com, guardani@usp.br).
Newton Libanio Ferreira and Maristhela Marin are with Centro Universitário FEI, Brazil (e-mail: newton.libanio@uol.com.br, marimari@fei.edu.br).
[PDF]
Cite: Tatiane F. C. Souza, Newton L. Ferreira, Maristhela Marin, and Roberto Guardani, "Glycerol Esterification with Acetic Acid by Reactive Distillation Using Hexane as an Entrainer," International Journal of Chemical Engineering and Applications vol. 8, no. 6, pp. 344-350, 2017.
