Development of a mathematical model for studying bioethanol–water separation using hydrophilic polyetherimide membrane

Abstract

An essentially predictive mathematical model was developed to simulate pervaporation process. The group contribution method UNIFAC was used for calculating the upstream activity coefficients. The diffusion coefficient in the membrane was predicted using free-volume theory. Free-volume parameters were determined with viscosity and temperature data, and the binary interaction solvent-polymer parameter was calculated by a group-contribution lattice-fluid equation of state (GCLF-EOS). A simulator named PERVAP was developed applying the mathematical model. Pervaporation process was simulated for separating bioethanol-water through polyetherimide membrane. The simulated results were validated using experimental data of bioethanol/water separation through polyetherimide membrane. The model presented a satisfactory performance compared to experimental data. Related to the simulation of the studied separation, a 99% molar enriched bioethanol stream was obtained with a recovery of 94%.

Process Pathways Optimization for a Lignocellulosic Biorefinery Producing Levulinic Acid, Succinic Acid, and Ethanol

“…Pervaporation membranes (E4 in Figure S5) are used to dehydrate the azeotropic water−ethanol mixture by water permeation. 52 The main process parameter is the downstream pressure of the permeate phase. A downstream pressure of 0.133 kPa was considered.…”

Process Design of a Multi-Product Lignocellulosic Biorefinery

“…Here glucose and xylose react with CO 2 to form succinic acid and oxygen. The first was a pervaporation membrane (O'Brien et al, 2000), the second a distillation column to reach to azeotropic composition and the third a pervaporation membrane in order to obtain ethanol 99.5 %wt (Alvarez et al, 2008). The purification section of the three products consists in several distillation and extraction columns.…”

Hybrid operation of the bio-ethanol fermentation

“…Whereas porous membranes selectively permeate components based upon mostly the size of particles, dense membranes achieve the separation through the mechanism of solution and diffusion [31]. Membranes used in pervaporation are pressure-driven and are both of asymmetric and composite non-porous structure [32], as illustrated in Figure 3, where a selective non-porous layer is supported by both a porous and non-woven carrier. Pervaporation of aqueous solutions of organics, such the ethanol/water solution of the fermenter broth, applies hydrophobic membranes allowing the organic component to selectively permeate through the membrane.…”

“…Membrane selectivity defines the ability of the membrane to selectively permeate a specific component through the membrane. It is expressed by a dimensionless separation coefficient [32]. Membrane stability measures the ability of the membrane to maintain both permeability and selectivity under the operating conditions for an extended duration of time [31].…”