Solid particles in liquid

There are a large number of processes in the chemical industries that handle a variety of suspensions of solid particles in liquids. The application of filtration techniques for the separation of these heterogeneous systems is sometimes very costly. If, however, the discrete phase of the suspension largely contains settleable particles, the separation can be effected by the operation of sedimentation. The process of sedimentation involves the removal of suspended solid particles from a liquid stream by gravitational settling. This unit operation is divided into thickening,... 

The retentivity relative to solid particles (e.g., spherical particles of polystyrene of definite size) is found from experiments determining the amount of these particles in the suspension to be filtered before and after the filter media. The retentivity K is determined as follows where g, g" =amounts of solid particles in liquid sample before and after the medium, respectively. 

Zweiteriiig, T.N., 1958. Suspension of solid particles in liquids by agitators. Chemical Engineering Science, 8, 244. 

When high concentrations of particles are to be settled, the surrounding particles interfere with individual particles. This is particularly important when settling high concentrations of solid particles in liquids. For such hindered settling, the viscosity and fluid density terms in Equation 8.6 can be modified to allow for this. The walls of the vessel can also interfere with settling4,9. 

Suspending of Solid Particles in Liquid in Stirred Tanks... 

Bubble columns in which gas is bubbled through suspensions of solid particles in liquids are known as slurry bubble columns . These are widely used as reactors for a variety of chemical reactions, and also as bioreactors with suspensions of microbial cells or particles of immobilized enzymes. 

Particulate flow A y y solid particles in gas solid particles in liquid gas fluidized beds liquid fluidized beds... 

Figure 1. A model of a cavitation nucleus (after Frenkel -Harvey) as an unwettable (hydrophobic) solid particle in liquid [3],...

Roman R.V., Todose R.Z., Studies on transfer processes in mixing vessels suspending of solid particles in liquid by modified Rushton turbime agjtators. Bioprocess Engng. 15 (1996),... 

In this and the following chapter we shall be concerned mainly with dispersions of colloidal solid particles in liquids. Two closely related questions arise. First, under w hat conditions will the dispersion remain in the dispersed state We need to know the answer to this before suitable methods of preparation of a stable dispersion can be defined and understood. 

Zwietering, T.N. (1958). Suspending of Solid Particles in Liquid Agitators, ChemESci. 8, pp. 244-253. 

Clearly, colloidal particles lie on the border-line between coarse particles, which obey the ordinary sedimentation laws, and atoms and molecules, which do not it is therefore not surprising tnat colloidal particles behave as they do. Although we shall be concerned mainly with suspensions of solid particles in water, it should be realized that colloidal suspensions of solid particles in liquids other than water can be produced. 

Microscopic analysis of received suspensions showed that particles of BaS04 posses pronounced anisometry (they represent sticks with length-to-diameter ratio about 4, that explains the sigmoid shape of sedimentation curves with extreme) (Fig. 5.19). At the initial moment of sedimentation the rotation of stick-shaped particles is possible, that determines additional resistance to sedimentation proceeding (analogously to viscosity increase) and slowing down of rate of deposition accumulation. Moreover, at free precipitation particles of spherical form are oriented in movement direction in that way to create maximum resistance to movement. This also reduces the precipitation rate of solid particles in liquid and embarrasses the definition of their actual sizes. In this connection, equivalent radius re (radius of spherical particle precipitating with the same rate) was determined by results of sedimentation analysis. 

Suspensions are defined as the stable dispersions of fine solid particles in liquids. Due to the widespread use of suspensions in industry, accurate analysis of their fluid dynamical behavior is needed to carry out the design calculations in many flow processes. According to the theoretical considerations the fluid dynamical behavior of a suspension may depend on a very large number of factors. In this respect, material characteristics of liquids and solids in the dispersion and the composition of the mixture in terms of solid volume fraction, particle size distribution, and interactions between solid particles can be mentioned. 

Indeed, depending on the viscosity (be it of pure fluid or of a suspension of solid particles in liquids), the absorption of the ultrasonic wave takes place after only a few centimeters distance from the emitter. Relatively simple solutions to this problem have already been referred to above. These involve either complementary mechanical agitation to move and expose the particles to the ultrasonic field or the use of a continuous treatment cell mounted externally to the vat in a flow loop. 

Lewis EW, Bowerman EW. Fluidization of solid particles in liquids. Chem Eng Prog 48 603-610, 1952. 

Patwardhan VS, Tien C. Distribution of solid particles in liquid fluidized beds. Can J Chem Eng 62 46 54, 1984. 

Nanofluids, a concept developed by Choi at Argonne National Laboratory [ 14], is a new class of heat transfer fluids that are composed of suspended nano-sized metallic or nonmetallic solid particles in liquid media. Nanofluids when properly prepared display significantly enhanced heat transfer capacities relative to those of traditional heat transfer fluids. From the practical application viewpoint, the most critical concerns are the agglomeration and poor suspension stability of the metallic or non-metallic nanoparticles in a given fluid medium. 

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