Segregation, of solids

Fine suspensions are reasonably homogeneous and segregation of solid and liquid phases does not occur to any significant extent during flow. The settling velocities of the particles are low in comparison with the liquid velocity and the turbulent eddies within the fluid are responsible for the suspension of the particles. In practice, turbulent flow will always be used, except when the liquid has a very high viscosity or exhibits non-Newtonian characteristics. The particles may be individually dispersed in the liquid or they may be present as floes. 

Deposition of adamantane from petroleum streams is associated with phase transitions resulting from changes in temperature, pressure, and/or composition of reservoir fluid. Generally, these phase transitions result in a solid phase from a gas or a liquid petroleum fluid. Deposition problems are particularly cumbersome when the fluid stream is dry (i.e., low LPG content in the stream). Phase segregation of solids takes place when the fluid is cooled and/or depressurized. In a wet reservoir fluid (i.e., high LPG content in the stream) the diamondoids partition into the LPG-rich phase and the gas phase. Deposition of diamondoids from a wet reservoir fluid is not as problematic as in the case of dry streams [74, 75]. 

Mixing and Segregation of Solid Particles (J.C. Williams and N. Hamby)... 

The flow rate in a transportation pipeline has to be larger than the deposition velocity of the mineral particles in order to avoid the segregation of solids. Typical flow rates range from 1 to 2 m s for coal and oil sand froth pipelining to about 4ms for some heavy metal concentrates [2]. For mineral slurries, abrasion becomes a signiflcant concern at velocities above about 2.5 m s and a major problem above about 4.5 m s [2]. 

Flow regimes, pressure drop, liquid holdup, liquid distribution, mixing, residence time distridution, heat and mass transfer,, xial and radial segregation of solids ... 

Burgess JM, Fane AG, Fell CJD. Measurement and prediction of the mixing and segregation of solids in gas fluidized beds. Pac Chem Eng Congr 2 1405-1412, 1977. 

Gelperin NI, Zakharenko W, Ainshtein VG. Segregation of solid particles in a fluidized bed and the equilibrium distribution. Theor Foundations Chem Eng (Thor Osnovy Khim Tekh) 11 475-481, 1977. 

The sources of solid wastes per se are summarized in Tables 16.1 and 16.4.) However, dealing with any of them will involve some combination of the activities shown in Figure 16.2, i.e. collection, segregation and identification, processing, recycling, transport and final disposal. 

In this case foam can be re-entered into the mixture by this action, and solids or liquids added will enter the impeller rather rapidly. The deeper the liquid above the baffle the greater the rotating action. Bottom srvirling action allows the segregation of heavy solid particles [21]. 

Sinclair and Jackson 81 have presented a theoretical relation between pressure gradient and the flowrates of gas and solids over the whole range of possible conditions for both cocurrent and countercurrent flow. It predicts marked segregation of gas and particles in the radial direction. 

The irradiation (or ion bombardment) of solid solutions, where a scavenger can be present, should also be explored further. Here it will be important to ensure that the solids are indeed solutions before conclusions can be safely drawn. It is curious to note that the yields observed in frozen solutions are in several cases very similar to the yields in the pure crystalline solutes. This suggests the possibility that the frozen targets had segregated, and that the solute was in fact present as micro crystals. (If this is the case, it may well be that a new method can be developed on this basis for making phase studies at high dilution.)... 

Arcus gasification combuster is described and the principles upon which it works are explained. This combuster combines solid fuel gasification with the burning of the lean gases produced on a small capacity scale. The types of solid fuels which can be used are listed and these include segregated municipal waste and industrial waste such as rigid PU foam and plastics mixed with other materials. Uses of the gas produced are included. 

Fig. 3.8 XRD patterns (CuKc( source) showing a rich in selenium (x > 0.6) CdSej Tei-jt electrodeposited film, which adopts the hexagonal CdSe wurtzite structure by annealing at 520 °C (b). The as-deposited (from a typical acidic solution) film is rather amorphous (a). Segregation of a Te phase is observed in the solid. (Reprinted from Bouroushian et al. [137], Copyright 2009, with permission from Elsevier)...

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