A H2-selective MFI zeolite membrane was crystallized as a layer on a porous ceramic tube. At 510C, this membrane could separate H2 from iso-butane/iso-butene with mixture separation factors of 70, and H2 permeances of about 1m3(STP)/m2hbar. In membrane-supported iso-butane dehydrogenation, the conversion of iso-butane was increased by a factor of almost 2. However, a detailed analysis of the experiment showed that 2/3 of the conversion increase was based upon the dilution of the feed by the sweep gas and 1/3 was due to the H2 removal.
Membrane Supported Catalytic Dehydrogenation of Iso-Butane using an MFI Zeolite Membrane Reactor. U.Illgen, R.Schäfer, M.Noack, P.Kölsch, A.Kühnle, J.Caro: Catalysis Communications, 2001, 2[11-12], 339-45
Table 26
Diffusion in Natural Mordenite
Ion | Temperature (C) | D(cm2/s) |
Na+ | 10.0 | 1.37 x 10-13 |
Na+ | 24.0 | 2.54 x 10-13 |
Na+ | 41.0 | 4.43 x 10-13 |
Na+ | 48.2 | 6.31 x 10-13 |
Na+ | 55.0 | 8.92 x 10-13 |
K+ | 20.0 | 1.22 x 10-13 |
K+ | 41.5 | 2.54 x 10-13 |
K+ | 50.5 | 3.35 x 10-13 |
K+ | 59.5 | 4.34 x 10-13 |
K+ | 67.5 | 5.86 x 10-13 |
Rb+ | 13.5 | 3.40 x 10-14 |
Rb+ | 22.0 | 1.31 x 10-13 |
Rb+ | 28.0 | 1.71 x 10-13 |
Rb+ | 38.5 | 4.81 x 10-13 |
Rb+ | 41.5 | 9.34 x 10-13 |
Cs+ | 28.75 | 5.00 x 10-15 |
Cs+ | 38.75 | 7.00 x 10-15 |
Cs+ | 46.5 | 8.00 x 10-15 |
Cs+ | 56.5 | 9.00 x 10-15 |
Cs+ | 68.0 | 1.00 x 10-14 |
Cs+ | 97.0 | 2.00 x 10-14 |
Ca2+ | 27.0 | 1.13 x 10-17 |
Ca2+ | 53.5 | 3.63 x 10-17 |
Ca2+ | 71.0 | 8.92 x 10-17 |
Ca2+ | 81.5 | 1.65 x 10-16 |
Table 26 (continued)
Diffusion in Natural Mordenite
Ion | Temperature (C) | D(cm2/s) |
Ca2+ | 93.0 | 2.64 x 10-16 |
Sr2+ | 29.5 | 1.50 x 10-16 |
Sr2+ | 56.0 | 7.80 x 10-16 |
Sr2+ | 64.5 | 2.35 x 10-15 |
Sr2+ | 75.0 | 4.13 x 10-15 |
Ba2+ | 18.5 | 4.50 x 10-16 |
Ba2+ | 34.5 | 5.10 x 10-16 |
Ba2+ | 54.5 | 1.84 x 10-15 |
Ba2+ | 64.5 | 2.58 x 10-15 |
Ba2+ | 77.5 | 5.10 x 10-15 |