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2 2012

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Efficiency of acetone-butanol-ethanol-water system separation by pervaporation

Marszałek J., Kamiński W. L.

Chemical and Process Engineering

2012

Vol. 33, nr 1

131-140

The article focuses on multicomponent system separation with the use of an innovative membranebased technique i.e. pervaporation. Pervaporation is a membrane technique for separation of liquid mixtures on solid nonporous membranes. Pervaporation is used in this study to separate a quaternary system acetone-butanol-ethanol-water. Such a system may be derived from ABE fermentation process, and the resulting product, biobutanol, is a potential biofuel and may be used in internal combustion engines. Experiments in the study involving concentration of butanol by pervaporation were performed using PERVAP 4060 flat-sheet commercial membrane. To describe the PV process a semi-empirical approach was used. As a result of experiments and calculations permeance coefficients were obtained. Separation and permeance factors were calculated to assess the efficiency of the system separation. Beforehand, activity coefficients were determined for all the components of the mixture with the NRTL equation. Separation coefficients for all the components differed depending on process parameters: concentration, feed flow rate and process temperature. The study confirmed the separation effect of the quaternary system. The most interesting results were obtained for the concentration of butanol. Pervaporation allows to concentrate butanol over 10 times. The permeance coefficient reached for butanol an average value of 7.06 10-3 in comparison with the results for ethanol 3.24 10-2 and acetone 1.83 10-2 [kmol(m2h)-1]. The temperature change from 50 to 70 [degrees]C led to an increased permeance factor and there was no apparent effect on it in the feed flow rate. Due to the hydrophobicity of the membrane water fluxes in the quaternary system were negative.

Activity of zinc in the liquid Bi-In-Sn-Zn alloys determined by Knudsen method

Zajączkowski A., Gąsior W., Onderka B.

Archives of Metallurgy and Materials

2012

Vol. 57, iss. 3

838-843

The Knudsen effusion method was used for measurements of mass loss rate of liquid Bi-In-Sn-Zn alloys, in the temperature range from 572 to 768 K. The studies were carried out for the alloys with the ratio of Bi:In:Sn equal 2:6:2, 2:2:6 and 8:1:1. The obtained results were used for the calculation of zinc vapour pressure over liquid Bi-In-Sn-Zn alloys and next the activity of zinc in the Bi-In-Sn-Zn liquid phase. It was found that for the investigated alloys the activity of zinc shows the considerable positive deviation from the Raoult's law.

Stosując efuzyjna metodę Knudsena pomierzono szybkość ubytku masy cynku z ciekłych stopów Bi-In-Sn-Zn, w zakresie temperatur od 572 do 768 K. Badania zostały przeprowadzone dla stopów o stosunku zawartości molowych Bi:In:Sn równym 2:6:2, 2:2:6 oraz 8:1:1. Wyniki badań zostały wykorzystane do obliczenia równowagowej prężności par cynku nad ciekłymi stopami Bi-In-Sn-Zn, a następnie aktywności cynku. Stwierdzono, że dla zbadanych stopów aktywność cynku wykazuje znaczne dodatnie odstępstwa od prawa Raulta.