The expressions derived in the previous chapters for the enhancement factor Ea and the flux Na can be used directly for fast reactions by setting the concentration = 0. The equations for Na and Ea are hereby summarized for zero-, first-, and second-order reactions. [Pg.275]

The effective interfacial areas for absorption with a chemical reaction [6] in packed columns are the same as those for physical absorption except that absorption is accompanied by rapid, second-order reactions. For absorption with a moderately fast first-order or pseudo first-order reaction, almost the entire interfacial area is effective, because the absorption rates are independent of kL as can be seen from Equation 6.24 for the enhancement factor for such cases. For a new system with an unknown reaction rate constant, an experimental determination of the enhancement factor by using an experimental absorber with a known interfacial area would serve as a guide. [Pg.92]

So far, only pseudo-first-order and instantaneous second-order reactions were discussed. In between there is the range of truly second-order behavior for which the continuity equations for A (Eq. 6.3.a-l) or B (Eq. 6.3.a-2), cannot be solved analytically, only numerically. To obtain an approximate analytical solution. Van Krevelen and Hoftijzer [3] dealt with this situation in a way analogous to that apfdied to pseudo-first-order kinetics, namely by assuming that the concentration of B remains approximately constant close to the interface. They mainly considered very fast reactions encountered in gas absorption so that they could set Cm - 0, that is, the reaction is completed in the film. Their development is in terms of the enhancement factor, F. The approximate equation for is entirely analogous with that obtained for a pseudo-first-order reaction Eq. [Pg.321]

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