544
Ind. Eng. Chem. Res. 2001, 40, 544-552
Separation of Xylene Isomer Vapors with Oriented MFI Membranes Made by Seeded Growth George Xomeritakis, Zhiping Lai, and Michael Tsapatsis* Department of Chemical Engineering, Goessmann Laboratory, University of Massachusetts, Amherst Massachusetts 01003-3110
Oriented MFI membranes made by secondary growth on the surface of R-Al2O3 support disks have been evaluated for the separation of xylene isomers vapors in the temperature range 22275 °C and feed partial pressures up to ∼0.7-0.9 kPa. It is found that the separation performance of these membranes is directly related to the synthesis conditions and the resulting membrane microstructure. Thick (12-18 µm) and c-oriented membranes (type A membranes) made by 24-h growth at 175 °C exhibit single-component p-xylene/o-xylene permselectivity as high as 150 at 100 °C but very modest separation factors (usually
