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OP-I-30Fig. 1. Hydrodynamics and concentration profiles in the fluidized bed reactor for the OCMResults of the simulation shows a typical “gulf streaming” of the gas phase, with apreferred flow-path through the reactor. A severe backmixing of solids and gas in thenear wall regions is the main reason for reduced selectivity. Moreover, classical cofeedingpolicy has showed to give worse yields of ethane and ethylene.Several case studies were investigated, each having its main impact on the bedhydrodinamics: ideal porous distributor plate, perforated plate distributor anddistributed feeding policy through several feeding points. These cases showeddifferent hydrodynamic pattern, which all affected different product yields, even withthe same flow rate and same feed composition. Higher selectivity could be obtainedonly by suppressing gas back-mixing in the oxygen rich areas, thus preventing theproduct combustion.Case studies conducted in this work enable further improvements in the fluidizedbed reactor design, both in terms of feeding policy and reactor geometry. Reactorhydrodynamics has significant impact on its performance, and it has to be carefullyconsidered when improved reactor performance is expected.References[1] F.M. Dautzenberg, J.C. Schlatter, J.M. Fox, J.R. Rostrup-Nielsen, L.J. Christiansen, Catal. Today4 Vol.13 (1992) 503-509[2] L. Mlezko, M. Baerns, Fuel Proc. Technol. 42 (1995) 217.[3] G.Hutchings, in E.E. Wolf (Ed.), Methane Conversion by Oxidative Processes: Fundamental andEngineering Aspects, Van Nostrand Reinhold, New York, 1992, pp.[4] L. Mleczko, U. Pannek, Ind. Eng. Chem. Res. 35 (1996) 54-61[5] Z. Stansch, L. Mleczko, M. Baerns, Ind. Eng. Chem. Res. 36 (1997) 2568AcknowledgementsThe authors acknowledge support from the Cluster of Excellence "Unifying Concepts inCatalysis" coordinated by the Technische Universität Berlin and funded by the GermanResearch Foundation - Deutsche Forschungsgemeinschaft.95