caa a22 4500 378927981 CHVBK 20180305123622.0 cr unu---uuuuu 161128e20040120xx s 000 0 eng 10.2202/1542-6580.1025 doi (NATIONALLICENCE)gruyter-10.2202/1542-6580.1025 The Catalytic Evaluation of Structured Zeolite Catalysts [Elektronische Daten] [Klaus P Möller, Jonas L. L. Hedlund, Olov Öhrman, Velaphi Msimang] ZSM-5 films, with thicknesses between 150 and 2300 nm, supported on 3 mm diameter alumina beads are characterised in terms of their catalytic activity and selectivity for tri-isopropylbenzene cracking and para-xylene isomerisation at 450 °C. A reaction-diffusion model adequately represents the experimental data and is used to estimate intrinsic reactivity and diffusion properties of the zeolite films. Results show that the external activity, overall activity and the diffusivity increase with increasing film thickness. The variation in reactivity and diffusivity, when compared to physio-chemical data, are a result of structural defects and non-homogeneities of the zeolite film. The measured diffusivities are within an order of magnitude of those extrapolated from literature. Thick zeolite films have the largest Thiele modulus as the increase in zeolite film thickness dominates over the structural defects. The largest selectivity improvements are observed for thick zeolite films. ©2011 Walter de Gruyter GmbH & Co. KG, Berlin/Boston Reaction engineering nationallicence Zeolite films nationallicence xylene isomerisation nationallicence diffusion nationallicence model nationallicence Möller Klaus P. University of Cape Town, km@chemeng.uct.ac.za aut Hedlund Jonas L. L. Luleå University of Technology, Sweden, jonas.hedlund@km.luth.se aut Öhrman Olov Luleå University of Technology, Olov.Ohrman@km.luth.se aut Msimang Velaphi University of Cape Town, velaphi@chemeng.uct.ac.za aut International Journal of Chemical Reactor Engineering De Gruyter 2/1(2004-01-20) 2:1 2004 2 ijcre https://doi.org/10.2202/1542-6580.1025 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.2202/1542-6580.1025 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Möller Klaus P. University of Cape Town, km@chemeng.uct.ac.za aut NATIONALLICENCE 700 1- Hedlund Jonas L. L. Luleå University of Technology, Sweden, jonas.hedlund@km.luth.se aut NATIONALLICENCE 700 1- Öhrman Olov Luleå University of Technology, Olov.Ohrman@km.luth.se aut NATIONALLICENCE 700 1- Msimang Velaphi University of Cape Town, velaphi@chemeng.uct.ac.za aut NATIONALLICENCE 773 0- International Journal of Chemical Reactor Engineering De Gruyter 2/1(2004-01-20) 2:1 2004 2 ijcre CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter