Pressure and -Rate Filtration

The dynamics of variable-rate and -pressure filtrations can be illustrated by pressure profiles that exist across the filter medium. Figure 7 shows the graphical representation of those profiles. According to this plot, the compressed force in the cake section is ... 

When crystals are fragile, effective washing is required, and clear mother liquor is desired, use gravity, top-feed horizontal pan filtration for slurries that filter at a rapid rate vacuum rotary-drum filtration for slurries that filter at a moderate rate and pressure filtration for slurries that filter at a slow rate. 

Variable Rate and Pressure Filtration for Compressible Cakes... 

The punq) characteristic is again required to evaluate variable rate and pressure filtration. The result normally required is a calculation of the time taken to filter a knorvn volume or mass of slurry. The cake depth is also inportant as most filters are of the batch type and this d th must be less than the clearance within the filter. 

To use Eq. (18--50) one must know the pattern of the filtration process, i.e., the variation of the flow rate and pressure with time. Generally the pumping mechanism determines the filtration flow characteristics and serves as a basis for the following three categories [Tiller and Crump, Chem. Eng. Prog., 73(10), 65 (1977)] ... 

Flow rate and pressure behavior for the three types of filtration are shown in Fig. 18-106. Depending on the characteristics of the centrifugal pump, widely differing cuiwes may be encountered, as suggested by the figure. 

Inside design criteria include, but are not limited to, temperature, relative humidity, filtration level, minimum air change rate, and pressurization requirements. 

The effects of the pressure and the mineral shape groups on vacuum and pressure filtration are shown in Fig 3. The changes of the 1/Kc values as an indication of the filtration rate at different pressures for dolomite and quartz can be given as two results ... 

The mathematical descrption of the process starts with the neglect of septum resistance and the use of Darcy s law (Equation 2.3) to relate filtrate flow rate and pressure drop ... 

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