Experimental validation of hybrid distillation‐vapor permeation process for energy efficient ethanol–water separation

Abstract

BACKGROUND: The energy demand of distillation-based systems for ethanol recovery and dehydration can be significant, particularly for dilute solutions. An alternative separation process integrating vapor stripping with a vapor compression step and a vapor permeation membrane separation step, termed membrane assisted vapor stripping (MAVS), has been proposed. The hydrophilic membrane separates the ethanol-water vapor into water-rich permeate and ethanol-enriched retentate vapor streams from which latent and sensible heat can be recovered. The objective of this work was to demonstrate experimentally the performance of a MAVS system and to compare the observed performance with chemical process simulation results using a 5 wt% ethanol aqueous feed stream as the benchmark.

A Two-Stage Continuous Fermentation System for Conversion of Syngas into Ethanol

“…A promising method has been described recently [24]; -When feeding the fermentation with "real world" producer gas derived from pyrolysis of biomass, toxic contaminants that inhibit syngas fermentation [7,25] have to be removed by a gas cleaning process; -The relatively high costs for media ingredients required to support growth of the biocatalyst [26,27] suggest that the operational costs of syngas fermentation will remain in an uneconomical range, unless cheaper sources of growth medium are found for this process.…”

Cellulosic Bioethanol Production

“…This leaves room for newer, more energyefficient systems to be developed, especially based on membrane-separation techniques. In a study on a hybrid distillation-vapor permeation [10] using a hydrophilic membrane to separate the ethanol-water vapor from the stripper into a water-rich permeate and ethanol-enriched retentate vapor, the energy demand was reduced significantly. For a feed with a concentration of 5 wt% ethanol the energy demand for a stripper was 6 MJ kg −1 ethanol to reach a vapor of 40 wt% while it was reduced to 2.2 MJ kg −1 ethanol to reach an ethanol concentration of about 80 wt%.…”

Poly(vinyl alcohol)/ZIF‐8‐NH2 mixed matrix membranes for ethanol dehydration via pervaporation

“…The typical separation process involves distillation near to the azeotropic point, followed by zeolite 3A adsorption or a steam membrane process using organic or zeolite 4A membranes. [8][9][10] However, this process is generally operated under high temperature and consumes a lot of heat energy. Alternatively, pervaporation process is a very promising technology as it can be operated under moderate working conditions.…”