Principles of Industrial Filtration

CARMAN, P. C. Trans. Inst. Chem. Eng. 16 (1938) 168. Fundamental principles of industrial filtration. 

Carman, P.C. (1938) Fundamental principles of industrial filtration a critical review of present knowledge. Transactions of the Institution of Chemical Engineers, 16,168-188. 

Wakeman R.J. and Tarleton E.S., 2005a. Solid/liquid Separation - Principles of Industrial Filtration, Elsevier Advanced Technology, Oxford. 

This Handbook has a descriptive role and is not intended to act as a textbook of filtration technology. For that function the reader is directed to Solid Liquid Separations (2005), Principles of Industrial Filtration (2005), Scale-up of Industrial Equipment (2005), Equipment Selection and Process Design (2006) (all by R.J. Wakeman and E.S. Tarleton, Elsevier Advanced Technology) or Solid-Liquid Filtration and Separation Technology (by A. Rushton, A.S. Ward and R.G. Holdich, 2000, 2nd Edn, Wiley-VCH). 

This Handbook has aimed to introduce a new practitioner to the range of filters and related types of equipment, especially those intended for utility service use. For each type, broad indications have been given as to their particular applications, and those recommendations are brought together in this final section. No attempt is made, however, to provide a thorough guide to filter selection for that, the reader is guided to the book by Richard Wakeman and Steve Tarleton on equipment selection (Solid/Liquid Separation Principles of Industrial Filtration, published by Elsevier Ltd, 2005). 

The principle of vacuum filtration is implemented on a large number of industrial units of different designs. The broad enormous range of available designs makes it essential to restrict the subject to a certain extent. 

Matteson, M. S. and Orr, C. Filtration Principles and Practice, 2nd edn. (Marcel Dekker, New York, 1987). Purchas, D. B. Industrial Filtration of Liquids, 2nd edn. (Leonard Hill, London, 1971). 

When planning an industrial-scale bioprocess, the main requirement is to scale up each of the process steps. As the principles of the unit operations used in these downstream processes have been outlined in previous chapters, at this point we discuss only examples of practical applications and scaling-up methods of two unit operations that are frequently used in downstream processes (i) cell separation by filtration and microfiltration and (ii) chromatography for fine purification of the target products. 

These facts have led to the review and finally the development of an alternative approach and in particular the possibilities of recovering vanadium for metallurgical use. Figure 100 illustrates the principles of the soot ash removal unit. The carbon slurry from the SGP unit is flashed to atmospheric pressure in the slurry tank (a). The slurry is then filtered on an automatic filter (b) to recover a filter cake with about 80% residual moisture and a clear water filtrate. The filter cake is subjected to a controlled oxidation process in a multiple-hearth furnace (c). This type of furnace, which is well established in many industries and specifically in the vanadium industry, allows combustion of the carbon to occur under conditions where the vanadium oxides neither melt nor corrode. This is not an easy task if one considers the problems of burning a high-vanadium fuel oil in a conventional boiler. The product is a vanadium concentrate, which contains about 75% V2O5. Compared to the old naphtha extraction-based recycle system, the new once-through process consists of only two proces-... 

Unfortunately the use of such a relation other than illustrating first principles is extremely limited in industrial applications because both the specific area of the particles Sq and the porosity 8 are extremely difficult to characterize when dealing with agglomerated solids that are also compressible. A more useful analysis can be made to characterize the filterability of a slurry by the use of the filtration equation as defined by equation (2) below, that shows how the filtration rate is affected by the filter operating parameters (pressure drop AP, filtration area A, filter medium resistance and also slurry related parameters (viscosity p, solids concentration w, specific cake resistance rj ... 

The cross-flow principle (Figure 3.76) began with the hollow fibres used in reverse osmosis, and has expanded to become one of the most important components of the filtration industry. In order to keep the surface free of deposit, high-shear conditions are employed, and these can be created either by a high suspension velocity across the medium, or by some sort of movement (rotation, vibration, etc.) of the medium with respect to the liquid flow or a nearby non-porous surface. This latter group, of movement promoted filtration, is often termed dynamic cross-flow filter systems. 

Catalysts have been bonded to insoluble polymers to allow, in principle, an appreciable simplification of PTC the catalyst represents a third insoluble phase which can be easily recovered at the end of the reaction by filtration, thus avoiding tedious processes of distillation, chromatographic separation and so on. This is of potential interest mainly from the industrial point of view, due to the possibility of carrying on both discontinuous processes with a dispersed catalyst and continuous processes with the catalyst on a fixed bed. This technique was named "triphase catalysis" by Regen (13,33,34). 

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