Simulation of ethanol extractive distillation with mixed glycols as separating agent

Abstract

-Extractive distillation is an alternative for ethanol dehydration processes that has been shown to be more effective than azeotropic distillation and, in close proximity, to be very competitive against the process that uses adsorption with molecular sieves. Glycols have been shown to be the most effective solvents in extractive distillation, mainly ethylene glycol and glycerol. In this work, an extractive distillation column was simulated with the Aspen Plus software platform, using the RadFrac module for distillation columns, to investigate the effect on the separation of the ethylene glycol-glycerol mixture composition, the separating agent feed stages, the separating agent split stream feed, and the azeotropic feed temperature. The NRTL model was used to calculate the phase equilibrium of these strongly polar mixtures. A rigorous simulation of the extractive distillation column finally established was also performed, including a secondary recovery column for the mixture of solvents and a recycle loop, to simulate an industrially relevant situation. This simulation allowed establishing the complete parameters to dehydrate ethanol: the optimal stage for separating agent feed is stage 4; the most adequate composition for the glycols mixture is 60 mol% ethylene glycol and 40 mol% glycerol. Finally, energetically efficient operating conditions for each one of the columns were established through a preliminary pinch analysis.

Exergetic and Economic Assessment of Distillation Hybrid Configurations for Bioethanol Refining

“…Three azeotropic and extractive distillation configurations were selected from the works reported in the literature [7,16,9,2]. For the two dehydrating distillation processes, the selected configurations were the conventional column and two other integrated configurations which perform relatively very well in term of product purity, throughputs and energy consumption.…”

“…distillation and dehydration units). In the area of energy requirement several researchers worked to reduce energy consumption of either distillation stand alone or hybrid units containing azeotropic, extractive or pervaporation unit [1,6,7,8,2]. The hybrid configurations of distillation with three extractive sequences were compared based on energy requirement and second law efficiency on the basis of similar feed and product specifications [9].…”

Review of extractive distillation. Process design, operation, optimization and control

“…Regarding design, optimization and control, the community is much larger. It was also investigated by the aforementioned authors (Lang, 1992;Lang et al, 1994Lang et al, , 1995Lelkes et al, 1998aLelkes et al, , 2002Lelkes et al, , 2003aYou et al, 2015aYou et al, ,b, 2016a and several teams all over the world: American (Luyben, 2008a(Luyben, ,b, 2013(Luyben, , 2015(Luyben, , 2016a(Luyben, ,b,c, 2018a, Chinese from Taiwan region (Arifin and Chien, 2008;Hsu et al, 2010;Wu et al, 2013;Chen et al 2015Chen et al , 2016, Brasilian (De Figueirêdo et al, 2011Brito, 2015;Brito et al, 2016), Colombian (Gil et al, 2009(Gil et al, , 2012(Gil et al, , 2014, Italian (Errico and Rong, 2012;Errico et al, 2013Errico et al, , 2015 and Mexican (Gutiérrez-Guerra et al, 2009;Torres-Ortega et al, 2014; teams and recently many teams from mainland China (Lei et al, 2002(Lei et al, , 2014Li et al, 2016Han et al 2015;Luo et al, 2014Luo et al, , 2015Wang et al, 2012Wang et al, , 2015aWang et al, , 2016Wang et al, , 2018aZhang et al, 2014…”

Análise Econômica De Cenários Da Recuperação Do Etanol No Contexto Da Extração Do Óleo De Soja Utilizando Etanol Como Solvente

“…A simulação da destilação extrativa com glicerol foi baseada no trabalho de Gil et al (2014), conforme mostra Figura 2, sendo modificados o número de pratos e pratos de alimentação e as especificações de topo e fundo para se obter o conjunto de colunas que gerem um menor custo para esta carga específica. Nesta simulação, as especificações de projeto foram: composição de mássica etanol topo da C-01 de 99,9%, composição mássica de etanol no fundo da C-01 de 0,0065% e composição mássica de glicerol no fundo da C-02 de 99,99%…”

“…Um dos desafios para a implementação da extração de óleo de soja com etanol é justamente a recuperação do etanol. Alguns processos de purificação do etanol já são conhecidos: a destilação alcoólica simples, obtendo-se etanol hidratado ou também através da destilação extrativa com etileno glicol (Li & Bai, 2012) e glicerol (Matugi, 2013;Gil et al, 2014).…”