Packed bed design

In a fully packed bed, conventional backwashing cannot take place inside the vessel, so packed-bed designs compensate for this either by having some degree of partial freeboard or by providing external backwashing. The supply water typically is from the bottom up to the top, but this design may vary. 

Using a manual technique, how to maintain proper materials flow within the convertor and avoid the bridging problems associated with conventional packed bed designs ... 

Since the maintenance of a free-flowing condition withih the feed/char inside the convertor is essential to successful system operation, every effort has been made to facilitate the flow. Thus the manually operated agitator, together with the conic shape of the convertor and the almost complete absence of any obstructions to the flow within the reactor effectively guarantee that the packed bed design will operate properly. 

Our next step is to express the partial pressures Pj, P, and P as a function of X, combine the partial pressures with the rate law, -r. as a function of conversion, and carry out the integration of the packed-bed design equation... 

The simplest packed bed design arises with a single dilute adsorbate in a carrier fluid when it can be assumed that the process is isothermal, that there is plug flow, and that there are no mass transfer resistances. In such a situation, instantaneous equilibrium exists at all points in the system. Without the axial dispersion term and taking the velocity outside the partial differential term for the convective flow, equation (6.19) is simplifled to ... 

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