Operating conditions influence on VMD and SGMD for ethanol recovery from aqueous solutions

Abstract

This work focuses on Vacuum Membrane Distillation (VMD) and Sweeping Gas Membrane Distillation (SGMD) as a separating technique of ethanol from aqueous solutions. VMD was studied at moderate temperature (30, 40 and 50°C) and pressure (0.11, 0.20 and 0.30 atm) conditions, whereas SGMD was studied at different temperatures (50 and 70°C) and air-flow rates (10x10 -6 and 20x10 -6 m 3. min -1 ). These techniques were experimentally studied using prepared ethanol-water solutions and fermented broths, with ethanol at 10% w/w. Under these operating conditions and using prepared ethanol-water solutions, an average total flux of 22.61 and 1.6 kg . m -2. h -1 , and concentration factors of 2.3 and 1.7 were obtained for VMD and SGMD, respectively. For fermented broths, total flux of 17.66 and 0.9 kg . m -2. h -1 , and concentration factors of 1.8 and 1.9 were obtained for VMD and SGMD, respectively. The fouling impact was also studied, finding a significant effect of pressure (vacuum) for VMD technique; mainly due to the biomass presence in the solution. Experimental results show that applying pressurization/depressurization cycles decreases membrane fouling, stabilizing flux and concentration in the permeate. While for SGMD configuration, the incidence of fouling was significantly lower. ABSTRACTHow to cite: Cotamo-De la Espriella, R. J., Barón-Núñez, F. W., Muvdi-Nova, C. J. (2015). Operating conditions influence on VMD and SGMD for ethanol recovery from aqueous solutions. CT&F -Ciencia, Tecnología y Futuro, 6(2), 69-80. INFLUENCIA DE LAS CONDICIONES DE OPERACIÓN EN VMD Y SGMD PARA LA RECUPERACIÓN DE ETANOL DE SOLUCIONES ACUOSAS INFLUÊNCIA DAS CONDIÇÕES DE OPERAÇÃO EM VMD E SGMD PARA A RECUPERAÇÃO DE ETANOL DE SOLUÇÕES AQUOSAS 70E ste trabalho está focado na Destilação com Membranas em Vácuo (VMD em inglês) e com Gás de Arrastre (SGMD, em inglês) como técnica para a separação do etanol de soluções aquosas. A VMD foi estudada utilizando condições moderadas de temperatura (30, 40 e 50°C) e pressão (0.11, 0.20 e 0.30 atm), enquanto a SGMD foi estudada em temperaturas de 50 e 70°C e fluxos de ar de 10x10 -6 e 20x10 -6 m 3. min -1 . As técnicas foram estudadas de forma experimental utilizando soluções etanol:água preparadas e caldos de fermentação, ajustando a concentração de etanol a 10% w/w. Sob estas condições de operação e utilizando soluções etanol:água preparadas, conseguimos obter flux totais médios de 22.61 e 1.6 kg . m -2. h -1 , e fatores de concentração de 2.3 e 1.7 para VMD e SGMD, respectivamente. No caso dos caldos de fermentação, obtivemos flux totais médios de 17.66 e 0.9 kg . m -2. h -1 , e fatores de concentração de 1.8 e 1.9 para VMD e SGMD, respectivamente. O impacto da incrustação também foi estudado, encontrando um efeito significativo da pressão (de vácuo) para a técnica VMD; principalmente, causada pela presença de biomassa na solução. Provas experimentais mostram que aplicando ciclos de pressurização/despressurização diminuímos a incrustação da membrana, estabilizando o fluxo e a concentração no perm...

Concentration of 1,3-dimethyl-2-imidazolidinone in Aqueous Solutions by Sweeping Gas Membrane Distillation: From Bench to Industrial Scale

“…The influence of several operating variables on the SGMD processes has been previously investigated [6,7]. The temperatures of the feed and sweeping phases have been identified as the most relevant process conditions; in particular, the temperature difference between the two phases must be taken into consideration.…”

Ethanol Separation from an Ethanol–Water Solution Using Vacuum Membrane Distillation

“…Among the four setups in MD, VMD and SGMD draw more attention as ethanol separation methods, since both allow for a higher flux of the permeate with a decent concentration of alcohol [6][7][8][9]. From the literature, it was found that only a few studies have been carried out on the MD process applied to recover alcohols (mostly ethanol).…”

“…Gryta et al [11] investigated a range of ethanol concentrations in a fermentation medium and concluded that the selectivity depends on the feed temperature; indeed, increasing from 30 • C to 60 • C, the enrichment factor varied from 4 to 6. Cotamo-De La Espriella et al [7] analyzed and compared two configurations, VMD and SGMD, using prepared water-ethanol solutions and water-ethanol mixtures from fermented broths. At first, they considered working under moderate vacuum conditions for VMD, using membranes with a pore diameter up to 5 µm for SGMD; this was the first study reporting the comparison of the two techniques under similar operating conditions.…”