6533b823fe1ef96bd127f496

RESEARCH PRODUCT

The Application of CFD Methods for Modeling of a Three-Phase Fixed-Bed Reactor

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The mathematical model of the three-phase fixed-bed reactor (TBR) consisting of the continuity equation, the momentum balances of each phase and mass balances of reaction mixture components were presented and discussed. These balances are the result of averaging by means of Euler’s procedure and form the basis of the Computational Fluid Dynamics (CFD). Although the CFD model is based on fundamental principles some empirical relations (closure lows) must be implemented into the momentum balance in order to ensure a proper description of the dynamics of very complex three-phase system. Therefore, the sensitivity of a multiphase CFD model with respect to relations defining drag forces between phases, distribution of porosity in the cross-section of the reactor and the values of Ergun constants was analyzed. As an example of advantages resulting from using CFD model in computations of hydrodynamic parameters the process of catalytic wet air oxidation (CWAO) of phenol carried out in the trickle-bed reactor was presented. The comparative calculations showed that the CFD model describes better the hydrodynamic phenomena in the bed than the simple plug flow model and as a result predicts much more accurate the outlet concentrations of reacting components.