Effect of operating conditions on pervaporation of methanol/methyl tert-butyl ether mixtures

Methanol/methyl tert-butyl ether (MTBE) mixtures were separated by pervaporation (PV) using polyvinyl alcohol (PVA) membranes. Effects of operating conditions such as temperature, permeate pressure, feed flow rate and composition on the membrane performance were studied. Experimental results were obtained at different methanol concentrations (10-30 wt.%) and temperatures (25-45 degrees C) as well as vacuum pressures in the range of 15-35 mbar. Separation factor of the PVA membrane for methanol was found to be greater than that for MTBE. According to the results of experiments, it was observed that increasing methanol concentration in the feed enhances the membrane swelling, because solubility parameter of methanol is closer to that of PVA than MTBE. Temperature and methanol concentration have the same effect on separation factor and total flux. Total flux increases and separation factor decreases with increasing both temperature and methanol concentration. In contrary, the membrane performance enhances with decreasing vacuum pressure and increasing feed flow rate. However, it was found that small variations in vacuum pressure have no significant impact on total flux of PV. (C) 2007 Elsevier B.V. All rights reserved.