Maximum bed height

Equation 8 has not been rigorously tested on freely bubbling beds because of the difficulty of making precise independent measurements of Dg or Ug under such conditions. It has been verified for slugging beds, however, as is shown in Figure 3. In the case of slugging, the surface level of the bed oscillates considerably, and in this case, the maximum bed height is used for H in Equation 8. 

Using this maximum working velocity and the contact time, the maximum bed height can be determined as follows ... 

At the bottom of the bed, the particles will be not only under the pressure of the other layers of solids but also under the hydraulic pressure of the liquid. Thus, the maximum bed height should be also be determined by using the particle strength data. The following equation could be used for the evaluation of the maximum bed height (Inglezakis, 2002) ... 

The maximum bed height that should be used without liquid redistribution depends on the type of packing and the process. Distillation is less susceptible to maldistribution than... 

The maximum bed height below which the bed will be freely bubbling can be calculated from... 

A second technique defines the minimum bubbling velocity as the velocity corresponding to the maximum bed height. 

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