Contents lists available at ScienceDirect Separation and Purification Technology journal homepage: www.elsevier.com/locate/seppur Azeotropic distillation for 1-propanol dehydration with diisopropyl ether as entrainer: Equilibrium data and process simulation Jordi Pla-Franco, Estela Lladosa ⁎ , Sonia Loras, Juan B. Montón Departamento de Ingeniería Química, Escuela Técnica Superior de Ingeniería, Universitat de València, 46100 Burjassot, Valencia, Spain ARTICLE INFO Keywords: 1-Propanol dehydration Diisopropyl ether Azeotropic distillation Computer simulation ABSTRACT Azeotropic distillation process is widely used to separate non-ideal binary mixtures into their constituent pure components. 1-Propanol dehydration was used as case study and diisopropyl ether was analysed as possible entrainer in an azeotropic distillation. The separation of some alcohols from their aqueous solution is a chal- lenging task because these aqueous mixture forms minimum boiling azeotrope. In this way, isobaric vapor-liquid and vapour-liquid-liquid equilibrium data were measured for the 1-pro- panol+ water + diisopropyl ether ternary mixture at 101.3 kPa. The data were correlated by NRTL and UNIQUAC models. A separation sequence (a decanter and a single-feed distillation column) for 1-propanol dehydration using diisopropyl ether was proposed. The simulation of the separation sequence was carried out satisfactorily by Aspen Hysys® using the thermodynamic model NRTL with the binary parameters obtained in this work. Moreover, the effect of temperature decantation was investigated in order to reduce the energy demand of the process. 1. Introduction A growing demand for energy and the negative impact that fossil fuels have on the environment make it imperative the research for other sources of energy. One of the proposals is the use of alcohols as biofuels derived from renewable sources [1,2]. Among these alcohols is the 1- propanol, which can be converted into diesel fuel by esterification re- action [3]. However, the separation of these alcohols from their aqu- eous solution is a challenging task because these aqueous mixtures form minimum boiling azeotropes, which prevent the separation of such mixtures by simple distillation. To solve this problem, membrane technology [4] or nonconventional distillations processes have been proposed, including extractive distillation (ED) [5] and azeotropic distillation (AD) [6]. These distillations are based on the addition of a third component called entrainer that alters the relative volatility of the components of the original mixture. In an ED process, the entrainer does not form an azeotrope with any of the components of the mixture to be separated. On the other hand, in an AD process, the addition of the third compound forms an additional azeotrope to carry out the desired separation. Depending on the number of phases present in the new azeotrope, the AD will be homogeneous (a unique liquid phase) or heterogeneous (two liquid phases). In both cases, it is essential to know the vapor-liquid equilibrium (VLE) data to a properly design a distillation sequence. In addition, in cases with more than one liquid phase, the knowledge of the vapor-liquid-liquid equilibrium (VLLE) data is also required. In previous works, several organic compounds were proposed as the entrainer in an ED (ethylene glycol [7] and isobutyl alcohol [8]) or AD (propyl acetate [9]) process for dehydration of 1-propanol. In this paper, and as part of our continuing research work, diisopropyl ether is selected as possible entrainer for an azeotropic distillation capable of separating 1-propanol/water mixture. In this case, a hybrid separation sequence of a decanter and a single-feed distillation column is pro- posed. The first stage was the gathering of isobaric VLE and VLLE data of the ternary system 1-propanol (1) + water (2) + diisopropyl ether (3) at 101.3 kPa. Experimental VLE and VLLE data of this ternary system is available in the literature [10] and have been compared with those obtained in this work. Ternary experimental data were found thermo- dynamically consistent after successfully passing the Wisniak and Tamir [11] modification of McDermott-Ellis test [12]. In the next stage, binary parameters for the NRTL [13] and UN- IQUAC [14] local composition models of the ternary system were ob- tained by correlating experimental phase equilibrium data. Then, the best model was selected to use in the simulation of azeotropic dis- tillation process. In this way, Aspen Hysys® v9.0 was selected as a https://doi.org/10.1016/j.seppur.2018.11.082 Received 7 May 2018; Received in revised form 26 November 2018; Accepted 27 November 2018 ⁎ Corresponding author. E-mail address: Estela.Lladosa@uv.es (E. Lladosa). Separation and Purification Technology 212 (2019) 692–698 Available online 27 November 2018 1383-5866/ © 2018 Elsevier B.V. All rights reserved. T