Modeling of bubbling and slugging flow regimes

For slow (rate-limiting) kinetics (i.e., low k ), it can be shown from Equation 4.18 that the process is dominated by the chemical kinetics (A ) group, with the bed hydrodynamics (e.g., bubble diameter) making very little difference. However, for relatively fast reactions, the interphase mass transfer group kyA) plays a preeminent role, with the fraction of solids within bubbles, q y, also becoming important. 

Analytical solution of the mole balance equations is only likely to be possible when a number of simplifying assumptions can be made such as those adopted previously where we assumed a single irreversible first-order reaction, no change in molar flow due to reaction, isothermal reactor, negligible variation in pressure, plug flow of gas in the bubble phase, and either perfect mixing or plug flow in the dense phase (see Ref. [46]). Assumptions must also be made with respect to the respective 

Both the distributor region (commonly called the grid zone ) and the freeboard region above the dense bed can also play major roles in determining overall reactor performance. These regions have been subjected to separate reactor models (as reviewed by Ho [45]). 

3 Modeling of reactors operating in high-velocity fiow regimes 

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