Filter cakes compressibility

In compressible filter cakes, the porosity varies from a minimum next to the filter septum to a maximum at the cake surface. How could you include such a variation within the context of a simulation program Remember that as the porosity changes, the local fluid velocity will also change as a result of... 

The specific resistances obtained are independent of applied load, suspension concentration and membrane type, as expected for non-compressible filter cakes. Tests with uniform latex particles have given permeabilities in very good agreement with Equation 2, using a value of 5 for the Carman-Kozeny constant. 

Figure 7.3. Flow through a compressible filter cake...

R.J. Wakeman, A numerical integration of the differential equations describing the formation of and flow in compressible filter cakes. Trans. Inst. Chem. Eng. 56, 258-265 (1978). 

Shake vigorously a mixture of 105 g (1.0 mol) of purified benzaldehyde (Expt 6.133), 38.8 g (0.2 mol) of methyl a-D-glucopyranoside (1) and 29.5 g of freshly fused and powdered anhydrous zinc chloride (0.22 mol) in a conical flask in a mechanical shaker for about 10 hours, until a clear solution is obtained. Allow the solution to stand at room temperature for a further period of 18 hours and then pour it into 700 ml of iced water (2). Stir the mixture vigorously, filter off the solid which separates and wash the compressed filter cake with light petroleum (b.p. 40-60 °C) to remove as much of the unreacted benzaldehyde as possible. Remove the solid from the Buchner funnel, stir or shake it vigorously with a solution of 12g of sodium metabisulphite in 120 ml of water, filter and wash the filter cake with water. Crystallise the solid from hot water, or after drying in a vacuum desiccator, from a mixture of chloroform and ether. The pure product has m.p. 165°C, [oc]d° + 112° (c0.5 in CHC13), the yield is 29 g (52%). 

Compressibility, filter cake, 310, 311,316 cell measurements, 314 calculation example, 314... 

Tiller, F.M. Horng, L.L. Hydraulic deliquoring of compressible filter cakes. Part I. Reverse flow in Alter presses. AIChE J. 1983,29, 297-305. 

FIGURE 22.27 Variation of hydraulic and effective pressures in a compressible filter cake. 

FIGURE 22.39 Frank M. Tiller, et al., Hydraulic Deliquoring of Compressible Filter Cakes, Part I Reverse Flow in Filter Presses, AIChE Journal, vol. 29, no. 2, AIChE, p. 298 Figure 1, Figure 2 p. 299, Figure 3, March 1983. 

The mass is cooled and leached in the bucket with 400 ml. of cold water. An iron pestle is used to break up lumps and improve contact. The resulting slurry is filtered rapidly using a Buchner funnel, a fast filter paper, and a paraffin-lined filter flask. The well-compressed filter cake is washed with 100 ml. of water, added in three or four portions. The combined filtrate and wash liquor is transferred to a polyethylene bottle for storage. About 65 to 75% of the titanium from the original mineral is present in the solution. 

Constant-pressure cake filtration with non-Newtonian suspending fiuids has received considerable attention [Kozicld, 1990]. The average ecific resistance has been found to vary considerably as a fimction of the flow behaviour index N even during the filtration of apparently incompressible materials [Shirato et al, 1977], Later papers extended the analysis to compressible filter cakes and constant rate and variable pressure and rate filtrations [Shirato et al, 1980a, b]. 

Holdich, RG, 1993, Prediction of solids concentration and height in a compressible filter cake, hit. J. Mineral Processing, 39 pp 157-171. 

Typical uses Batch processing of solids forming incompressible and moderately compressible filter cakes. 

Typical uses Batch processing of suspensions forming compressible filter cakes where dry cakes and/or efficient post-treatment are required. 

Typical uses Semi-continuous processing of solids forming compressible filter cakes that require efficient post-treatment. 

Typical uses Deliquoring of finer particle suspensions forming compressible filter cakes. 

Wakeman R.J. and Rushton A., 1976. The removal of filtrate and soluble material from compressible filter cakes, Filtr. Sep., 13, 450-454. 

As in example 9.3, determine the time necessary for the filtration of 50 m of the same slurry in the same filter but assuming a compressible filter cake with cake resistance a following the law... 

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