Modeling of a Transport or Riser Reactor

Thompson et al. [1999] have presented a general model, valid for bubbling and turbulent fluidized beds that merges the two limiting models (two-phase and one-phase with axial dispersion) by allowing key parameters to vary continuously with the superficial velocity. 

One problem arising in the modeling of transport reactors is the slip, which is the difference between the interstitial velocity of the solid and the gas  

The slip velocity is generally taken to equal the terminal velocity of the solid, u, which was discussed in Section 13.3. Substituting Wi in (13.6-1) by Usjs and Upp by Us,p/ 1 - s) leads to the following expression for the void fraction s  

Slip ratio in a riser reactor versus the superficial gas velocity. From Whittington [1972]. 

As written here, the equations do not account for vaporization. They assume immediate and perfect contact of gas and solid. Also, the reactor is considered to be adiabatic. 

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