Glass ballotini

Massimilla et al. (M5) measured the rate of absorption of carbon dioxide in water from a mixture of carbon dioxide and nitrogen. Used as solid phase were silica sand particles of average equivalent diameter 0.22 mm, or glass ballotini of average equivalent diameter 0.50 and 0.80 mm. Columns of 30-and 90-mm i.d. were used, and the column height was varied from 100 to 1200 mm. 

Ostergaard (02) measured the wall-to-bed heat-transfer coefficient in a bed of 3-in. diameter. The media were air, water, and glass ballotini of0.5-mm diameter. It was observed that the heat-transfer coefficient for a liquid fluidized bed near the point of incipient fluidization could be approximately... 

For the transport of coarse particles, the relative velocity between the liquid and solids is an important factor determining the hold-up, and hence the in-line concentration of solids. Cloete et a/. 65) who conveyed sand and glass ballotini particles through vertical... 

Boland and Geldart reported experiments with glass ballotini in a specially designed two-dimensional bed (Boland and Geldart, 1971). To... 

Binary mixtures of glass ballotini and steel beads of nearly equal size (-500 pm and -275 pm, respectively) also exhibit reduced electrostatic activity, as measured by suspended electrodes (Guardiolaet al., 1992). The highly conducting steel beads were added to the glass particles in amounts up to approximately 10% by volume. 

Cold particles of glass ballotini are fluidised with heated air in a bed in which a constant flow of particles is maintained in a horizontal direction. When steady conditions have been reached, the temperatures recorded by a bare thermocouple immersed in the bed are ... 

For particles of glass ballotini with free falling velocities of 10 and 20 mm/s the index n has a value of 2.39. If a mixture of equal volumes of the two particles is fluidised, what is the relation between the voidage and fluid velocity if it is assumed that complete... 

By studying suspensions containing two different solid components, it is possible to obtain a fuller understanding of the process of sedimentation of a complex mixture. Richardson and Miiki.i " 3 investigated the sedimentation characteristics of suspensions of glass ballotini and polystyrene particles in a 22 per cent by mass ethanol-water mixture. The free-falling velocity, and the effect of concentration on sedimentation rate, were identical for each of the two solids alone in the liquid. 

The behaviour of a suspension of high concentration (e < 0.85) is shown in Figure 5.24, where it is seen that the glass ballotini settle out completely before any deposition of polystyrene particles occurs. 

The formation of bubbles at orifices in a fluidised bed, including measurement of their size, the conditions under which they will coalesce with one another, and their rate of rise in the bed has been investigated. Davidson el alP4) injected air from an orifice into a fluidised bed composed of particles of sand (0.3-0.5 mm) and glass ballotini (0.15 mm) fluidised by air at a velocity just above the minimum required for fluidisation. By varying the depth of the injection point from the free surface, it was shown that the injected bubble rises through the bed with a constant velocity, which is dependent only on the volume of the bubble. In addition, this velocity of rise corresponds with that of a spherical cap bubble in an inviscid liquid of zero surface tension, as determined from the equation of Davies and Taylor ... 

Figure 6.21. The increase in heat transfer coefficient caused by glass ballotini fluidised in water ...

Solvent extraction can be automated in continuous-flow analysis. For both conventional AutoAnalyzer and flow-injection techniques, analytical methods have been devised incorporating a solvent extraction step. In these methods, a peristaltic pump dehvers the hquid streams, and these are mixed in a mixing coil, often filled with glass ballotini the phases are subsequently separated in a simple separator which allows the aqueous and organic phases to stratify. One or both of these phases can then be resampled into the analyser manifold for further reaction and/or measurement. The sample-to-extractant ratio can be varied within the limits normally applying to such operations, but the maximum concentration factor consistent with good operation is normally about 3 1. 

In an early attempt to remove mists from a gas stream, by using a fluidized bed as a kind of filfer (Meissner and Mickley, 1949), if was found that the operation worked well if the bed particles had a porous structure, and that when non-porous particles were used fluidization ceased (i.e. the bed quenched) at very low moisture contents. This view is supported in work on the effect of bed moisture on the fluidization characteristics of fine powders (D Amore et al., 1979) in which if was shown that porous materials can tolerate considerably more liquid than non-porous particles (such as glass ballotini, sand and limestone) before what these workers call bed compaction occurs. Smith and... 

To verify this approach, we carried out some experiments measuring the discharged mass per time of glass ballotini, pellets made out of microcrystalline cellulose (C Sfearmatrans Sanaq... 

FIGURE 20.18 Flow of Cellet 5 (pellets made of microcrystalline cellulose), glass ballotini, and Sugar sphere (pellets made of sugar) with different diameters out of a hopper with an ori ce diameter of 5 mm. (From Leuenberger, H. and Lanz, l Aplv. Powder Technol., 16, in press (2005).)... 

Air-water-glass Ballotini beads Argon 41 Scintillation detector Fluidized bed 9,79... 

FIG. 20-74 Effect of binder viscosity and liquid content on final granule porosity for the drum granulation of 15 pm glass ballotini. Decreasing granule porosity corresponds to increasing extent of granule consolidation. [Iveson et ah. Powder Tech., 88, 15 (1996).] With kind permission from Elsevier Science SA, Lausanne, Switzerland. 

Rieger and Ditl 6-PTD. Glass ballotini-water/aqueous glycerol (1994)... 

Nienow (1996) hydrofoils Ekato Intermig (one and two). Blue glass ballotini (Pg = 2950 kg/m ), bronze shots (Pg = 8450 kg/m )-water... 

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