Effect of furfural concentration on the performance of Diacap a ? Polysulfone dialysis membrane during ethanol pervaporation

Date

2011

Degree

Bachelor of Science in Chemical Engineering

College

College of Engineering and Agro-Industrial Technology (CEAT)

Adviser/Committee Chair

Rex B. Demafelis

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Abstract

A diacap LO 18 α-polysulfone dialyzer membrane was used to pervaporate mixtures with ethanol feed content at 1% and 3% (v/v). Increasing amount of furfural in the range of 0 to 3 percent was used in order to evaluate the membrane performance. The vacuum pressure and temperature were set at 5in Hg and 280C, respectively, while flowrate was set at 1L/min. Collection time was set at 1 min after the first drop to the cold trap. And the samples were analyzed for ethanol by of gas chromatography. The membrane was evaluated in terms of enrichment factor, separation factor and permeates flux. At 1% ethanol in the feed, the selectivity and enrichment factor of the membrane was found to be 0.9577 and 0.9573, respectively, while flux was 17.5 ml/min-m 2 . At 3% ethanol in the feed, the selectivity and enrichment factor of the membrane was found to be 1.1467 and 1.1500, respectively, while flux was 18.03 ml/min-m 2 . In the presence of furfural, for 1% ethanol in the feed, separation factor and enrichment factor was observed to decrease at 0.3% furfural in the feed with the flux equal to 17.06 ml/min-m 2 . At 3% ethanol in the feed, selectivity and enrichment factor was

observed to decrease at 0.1% furfural in the feed with flux equal to 15.83 ml/min- m

2 . The enrichment factor and separation factor at both concentration of ethanol were generally observed to decrease at the permeate stream and increase at the retentate stream at increasing furfural concentration. Permeate flux increased with increasing furfural concentration. The highest flux is at 3% furfural in the feed equal to 30.89 ml/min-m 2 and 33.61 ml/min-m 2 for 1% and 3% ethanol in the feed, resperctively. The trend was attributed to the chemical nature of furfural, particularly its molecular size and shape; membrane swelling and concentration polarization. The overall performance of the membrane in terms of pervaporative separation index was also calculated. The highest PSI for 1% ethanol was 6.58 at 0.8% furfural while at 3% ethanol, highest PSI was equal to 4.89 at 0.3% furfural concentration. The values, however, for PSI was both negative indicating a poor performance due to the tradeoff between selectivity and flux of the membrane.The study concluded that the used membrane, even though it can separate the ethanol and water mixture, is inferior or unsuitable for pervaporation in industry. It has a weak stability, very low selectivity, and fouls easily.

Language

English

Location

UPLB College of Engineering and Agro-Industrial Technology (CEAT)

Document Type

Thesis

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