Pervaporative separation of methyl acetate–methanol azeotropic mixture using high‐performance polydimethylsiloxane/ceramic composite membrane

Abstract

Methyl acetate is a very important green solvent, which is often produced by esterification using excess methanol as one of the reagents. Therefore, costefficient separation of the methyl acetate/methanol mixture is important. However, the formation of a methanol/methyl acetate azeotrope at atmospheric pressure results in high energy consumption for their separation using distillation such as extractive distillation. In order to reduce the energy consumption, pervaporation (PV) was used to replace the distillation in this study. Two membranes, polydimethylsiloxane and polyoctylmethylsiloxane, were first compared in the PV separation of the methyl acetate/methanol mixture. Then the effects of different operating parameters such as temperature, feed flow rate, permeate pressure, and so on were investigated. Total flux was up to 100 kg/(m 2 ·hr) at 50°C, whereas the separation factor ranges from 1.2 to 5.0.Results showed that the methyl acetate/methanol azeotrope could be broken in the studied concentration range and high flux could be obtained. Furthermore, the change of activation energy with feed methyl acetate concentration and membrane thickness with temperature was investigated. To demonstrate the potential of the industrial applications, the stability in separation of 32 wt.% methyl acetate-methanol mixtures for 15 days was investigated. ORCIDWanqin Jin https://orcid.org/0000-0001-8103-4883 FIGURE 15 Membrane stability in the PV of 32 wt.% methyl acetate-methanol mixture at 25°C FIGURE 14Effects of downstream pressure on separation factor and total flux at 20°C and a fixed flow rate of 1,000 ml/min 10 of 12 LI ET AL.

Heat-Integrated Pervaporation–Distillation Hybrid System for the Separation of Methyl Acetate–Methanol Azeotropes

“…The data presented in our previous study were used in the present study to simulate the PV process. 25 The proposed model for the PV process was investigated by simulating the effect of feed concentration on the membrane performance, as shown in Figure 2. The degree of consistency between the experimental and predicted data was observed to be acceptable because R 2 was over 0.95, confirming the accuracy of the model.…”

“…It is necessary to validate the model describing the PV process before performing the simulations. The data presented in our previous study were used in the present study to simulate the PV process . The proposed model for the PV process was investigated by simulating the effect of feed concentration on the membrane performance, as shown in Figure .…”

“…An ∼1.5 μm-thick PDMS/ceramic composite membrane was fabricated in our laboratory; this membrane was previously tested for the separation of a MeAc–MeOH mixture; , the experimental data were discussed in a previous work and only used for simulation here. The detailed calculation process of the separation performance is shown in Supporting Information.…”

“…In this study, a polydimethylsiloxane (PDMS) ceramic membrane was employed to separate the MeAc–MeOH mixtures; this membrane exhibited a higher flux and separation factor compared to those of other commercial MeAc-selective membranes. , In addition, membranes with MeOH selectivity show low flux, which leads to an increase in the membrane area and incurs high investment cost . The heat transfer during PV was studied using experiments and calculations, which proved that the heat required for PV was primarily based on the energy supplied by the vacuum pump and feed stream.…”

A Systematic Methodology for the Synthesis of Advanced Reactive Distillation Technologies

“…The normal boiling point and types of azeotropes are detailed in Table S12 in the Supporting Information. As a result, the ester product is usually removed as the methanol-methyl acetate azeotrope, whose treatment has been studied in various membrane applications. − Hence, MA-RD could potentially be used.…”