caa a22 4500 378927760 CHVBK 20180305123622.0 cr unu---uuuuu 161128e20040906xx s 000 0 eng 10.2202/1542-6580.1043 doi (NATIONALLICENCE)gruyter-10.2202/1542-6580.1043 Oxygen Distribution in Packed Bed Membrane Reactors For Partial Oxidation Systems and its Effect On Product Selectivity [Elektronische Daten] [U. Kuerten, Martin van Sint Annaland, J.A.M. Kuipers] Packed bed membrane reactors (PBMRs) are currently considered for the distributive addition of oxygen in partial oxidation systems. Among other advantages the decreased oxygen concentrations in the PBMR can result in improved product selectivities for reaction systems in which the oxygen dependency of the target product formation is less pronounced than that of the waste product formation. Oxidative dehydrogenation (ODH) of methanol to formaldehyde (Diakov et al., 2002) and ethylbenzene to styrene (Shakhnovich et al., 1984) are industrially relevant examples of such a kinetic system.To achieve considerable selectivity improvements the oxygen concentration should be kept small compared to hydrocarbon concentrations. However, a decrease of the oxygen concentration is accompanied with a decrease in the effectiveness of the catalyst particles since the intraparticle oxygen concentration gradients (and not the hydrocarbon concentration gradients) predominantly determine the actual activity and product selectivities of the catalyst, rendering the common effectiveness factors inapplicable for the modeling of a PBMR.Furthermore, concentration profiles over the radius of the packed bed can emerge, if the radial mass transport rate of oxygen from the membrane wall to the center of the bed is insufficient compared to the local oxygen consumption rate. If the transmembrane flux is dominated by convective transport as typical with porous membranes, the radial oxygen concentration profiles result in increased product losses, and the use of a one-dimensional reactor model may result in an overestimation of the product selectivity.In this paper the effect of limitations of the oxygen mass transport in a PBMR – i.e. intraparticle and from the membrane to the centerline of the packed bed – have been discussed for the ODH of methanol and ethylbenzene. ©2011 Walter de Gruyter GmbH & Co. KG, Berlin/Boston Membrane reactors nationallicence distributive feeding nationallicence oxidative dehydrogenation nationallicence modelling nationallicence Kuerten U. University of Twente, u.kuerten@ct.utwente.nl aut van Sint Annaland Martin Twente University, m.v.sintannaland@tue.nl aut Kuipers J.A.M. University of Twente, J.A.M.Kuipers@ct.utwente.nl aut International Journal of Chemical Reactor Engineering De Gruyter 2/1(2004-09-06) 2:1 2004 2 ijcre https://doi.org/10.2202/1542-6580.1043 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.2202/1542-6580.1043 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kuerten U. University of Twente, u.kuerten@ct.utwente.nl aut NATIONALLICENCE 700 1- van Sint Annaland Martin Twente University, m.v.sintannaland@tue.nl aut NATIONALLICENCE 700 1- Kuipers J.A.M. University of Twente, J.A.M.Kuipers@ct.utwente.nl aut NATIONALLICENCE 773 0- International Journal of Chemical Reactor Engineering De Gruyter 2/1(2004-09-06) 2:1 2004 2 ijcre CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter