Solid/liquid separation theory

This chapter summarizes the solid-liquid separation operations commonly used for the pretreatment of drying operations. We focus on the practical aspects of cake filtration, centrifngal filtration, and mechanical expression. The choice of equipment depends on the objective of the separation, the properties of the slurry, and the scale of prodnction. The details of solid-liquid separation theories are omitted. The reader is referred to the references for further information. 

In this subsection, basic design theory for preliminary sizing and specifying equipment are reviewed. Some sample design calculations are included. References cited at the end of tlie chapter can be consulted for more detailed information and design methods. For solid-liquid separation methods, the reader should refer to Liquid Filtration, 2" edition, by N. P. Cheremisinoff, Butterworth-Heinemarui Publishers (1998). 

For derivations that are more complex and a more detailed description of solid-liquid separation applications, the reader is referred to specialist texts e.g. Coulson and Richardson (1991), Purchas (1981), Purchas and Wakeman (1986), Matteson and Orr (1987), Wakeman (1990a,b), Cheremisinoff (1998), Sinnott (1999) and Svarovsky (2000). Several types of drier and associated drying theory are considered in detail in a number of texts, including Nonhebel and Moss (1971), Keey (1972, 1978, 1991), Masters (1985) and Coulson and Richardson (1991). 

Sedimentation classifiers, 76 619-620 in depth filtration theory, 11 339 in particle size measurement, 78 142-144 in solid-liquid separation, 76 656-657 Sedimentation rate... 

F.M. Tiller (Ed.), Theory and Practice of Solid-Liquid Separation, University of Houston, Houston, 1978. 

Tiller, F.M., Filtration Theory Today, Chem. Eng., 73,13, 151, 1966. Svarovsky, L., Advanced in Solid Liquid Separations I, Chem. Eng., 86,... 

Tiller, F.M., and P.J. Lloyd. 1978. Theory and practice of solid liquid separation. Houston, TX University of Houston. 

This chapter is written with three objectives in mind. First, the importance of the size and concentration of the particles to be treated in determining the eflFectiveness of some solid-liquid separation processes is evaluated. Second, past theories are used to examine how particle sizes and concentrations are altered by these treatments. Third, interrelationships among the individual unit processes that comprise a complete treatment system are investigated to provide a base for an integral treatment plant design. These aims are undertaken using a typical water treatment system as employed in practice to remove turbidity from surface water supplies. Before addressing these objectives, it is useful to review some mathematical expressions of particle size distributions, and to identify some important properties of these functions. 

Purchas DB. Practical applications of theory. Croydon Solid/Liquid Separation Technology, Uplands Press 1981. Chapter 10, 595-693. 

Kelsall, D. F. 1966. The theory and applications of the hydrocyclone. In Solid-Liquid Separation, Poole, J. B. and Doyle, D. (eds.). London Her Majesty Stationary Office (HMSO). 

Yim S.S. and Kwon Y.D., 1997. A unified theory on solid-liquid separation Filtration, expression, sedimentation, filtration by centrifugal force, and cross flow filtration, Korean J. Chem. Eng., 14, 354-358. 

White, D. A. and Bashir, S., Counter current washing of ion exchange floes— theory and optimisatiou , Solid-Liquid Separation Practice III, I.ChemL. Symposium Series No. 113, The Institution of Chemical Engineers, Rughy, 41-50 (1989)... 

The entropy index as defined in equation 18.36 is potentially very useful in the fundamental evaluation of any separation processes, not just in solid-liquid separation. Besides the Russian references ", Ogawa et al. derived the same entropy index (but using mass fractions rather than volumetric ones) from information theory and proposed its use for the evaluation of any separation process. 

Interaction of particles is a very important topic in particle technology concerning both natural and industrial fields, and this work is part of a more comprehensive investigation in to solid-liquid separations. The behaviour of single particles and non-interacting concentrated suspensions is well understood thanks to Stokes and other fundamental theories [1]. Nevertheless, there is a problem when the particles are able to interact with each other in order to form different dynamic entities [2]. The main aim of this paper is to study how colloidal titanium dioxide interacts, starting from an... 

Hjorth M, Christensen KV, Christensen ML, Sommer SG (2010) Solid-liquid separation of animal slurry in theory and practice areview. Agron Sustain Dev 3 153-180... 

Essentially, extraction of an analyte from one phase into a second phase is dependent upon two main factors solubility and equilibrium. The principle by which solvent extraction is successful is that like dissolves like . To identify which solvent performs best in which system, a number of chemical properties must be considered to determine the efficiency and success of an extraction [77]. Separation of a solute from solid, liquid or gaseous sample by using a suitable solvent is reliant upon the relationship described by Nemst s distribution or partition law. The traditional distribution or partition coefficient is defined as Kn = Cs/C, where Cs is the concentration of the solute in the solid and Ci is the species concentration in the liquid. A small Kd value stands for a more powerful solvent which is more likely to accumulate the target analyte. The shape of the partition isotherm can be used to deduce the behaviour of the solute in the extracting solvent. In theory, partitioning of the analyte between polymer and solvent prevents complete extraction. However, as the quantity of extracting solvent is much larger than that of the polymeric material, and the partition coefficients usually favour the solvent, in practice at equilibrium very low levels in the polymer will result. 

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