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OP-II-18PERFORMANCE OF SELECTIVE OXIDATION REACTIONS INFLUIDIZED BED REACTOR: GAS INTERPHASE TRANSFER ANDCATALYST UNSTEADY STATEPokrovskaya S.A.Boreskov Institute of Catalysis SB RAS, 630090, pr. Lavrentieva 5, Novosibirsk,Russia, pokrov@catalysis.ruNovosibirsk State University, 630090, Pirogova 2, Novosibirsk, RussiaCatalytic reactors with fluidized bed are an attractive alternative for exothermicheterogeneous processes of selective oxidation as compared with fixed bed reactorsbecause of favourable rates of heat transfer providing temperature uniformity,absence of pore-diffusion limitation and others. However, the decrease of desiredproduct selectivity is observed in a number of cases, that restrains a wide applicationof fluidized bed reactors for such processes. The latest comprehensive reviews ofstudies of catalytic systems with fluidized bed show that the major part of researchdealing with selectivity improvement is referred to hydrodynamic aspects, mainly tothe increase of gas-solid contact by modifications in design such as turbulentfluidization. A lot of mathematical models based on the assumption of steady statekinetics are elaborated to study hydrodynamic effects in these systems [1, 2].At the same time, a number of studies indicated that the unsteady state ofcatalyst surface leads to the difference of product selectivity and may provide itssignificant enhancement [3-8]. This work aims to elucidate comparative effect of gasinterphase transfer (GIT) and unsteady catalyst state on selectivity in the reactor withturbulent fluidized bed. The mathematical description on the base of dynamic kineticmodel used for present studies was given in other studies [3]. Modeling wasperformed with model kinetic scheme and catalyst state in the processes of selectiveo-xylene oxidation and propylene ammoxidation was analyzed.At first, the reaction scheme with three catalytic steps was used: a) B + [ ] → [B],b) A + ν 1 [B] → C + ν 1 [ ], c) C + ν 2 [B] → D + ν 2 [ ], where A – the reagent, B – theoxidant (oxygen), C – the desired product, D – the undesired product. Computationalruns were fulfilled at isothermal regime with contact time of 2-7 s -1 for three cases:Case 1 2 3Surface coverage steady steady unsteadyGIT coefficient, s -1 ∞ 0,5-2 0,5-2132