Minimum particle size

Table 13 can be used as a rough guide for scmbber collection in regard to minimum particle size collected at 85% efficiency. In some cases, a higher collection efficiency can be achieved on finer particles under a higher pressure drop. For many scmbbers the particle penetration can be represented by an exponential equation of the form (271—274)... 

Minimum particle size collectible with approximately 85% efficiency. 

Under these circumstances, the settling motion of the particles and the axial motion of the Hquid phase are combined to determine the settling trajectory of these particles. The trajectory of particles just reaching the bowl wall near the point of Hquid discharge defines a minimum particle size that starts from an initial radial location and is separated in the centrifuge. A radius ris chosen to divide the Hquid annulus in the bowl into two equal volumes initially containing the same number of particles. Half the particles of size i present in the suspension are separated the other half escape. This is referred to as a 50% cutoff. 

Here again an equation is estabUshed (2) to describe the trajectory of a particle under the combined effect of the Hquid transport velocity acting in the x-direction and the centrifugal settling velocity in thejy-direction. Equation 13 determines the minimum particle size which originates from a position on the outer radius, and the midpoint of the space, between two adjacent disks, and just reaches the upper disk at the inner radius, r. Particles of this size initially located above the midpoint of space a are all collected on the underside of the upper disk those particles initially located below the midpoint escape capture. This condition defines the throughput, for which a 50% recovery of the entering particles is achieved. That is,... 

Agulyanskaya et al. [507] investigated the impact of fluorine content on the particle size of niobium and tantalum oxides and powdered lithium niobate and tantalate prepared from the oxides. It was shown that fluorine concentrations lower than 10"2% wt. do not influence particle size and result in a set minimum particle size. This concentration range was referred to as being non-... 

Type of equipment Minimum particle size w Minimum loading (mg/m3) Approx. efficiency (%) Typical gas velocity (m/s) Maximum capacity (m3/s) Gas pressure drop (mm H2O) Liquid rate (m3/103 m3 gas) Space required (relative)... 

Ground calcium carbonate, extracted from the earth, is present in practically every country in the world in varying quantities in the form of limestone, marble, dolomite or chalk. Following the extraction, GCC needs to be ground. Dry grinding, the cheaper alternative, is often limited to a minimum particle size of 2- 3 microns. Wet grinding, more expensive, is used for fine and ultra fine material or when the final product must be a slurry (paper or paint application). Precipitated calcium carbonate is produced by chemical reaction between... 

Type of Centrifuge Continuous Automatically Discharged at Full Speed Automatically Discharged at Reduced Speed g-Factor Range IFC) Minimum Solid Concentration in Feed [% by Volume (C ) Possibility of Washing Minimum Particle Size, mm Minimum Filtrability Coefficient (fr)(m/sec) Maximum Retention Time (Sec)... 

When small particles are chosen, they have to be used in the form of a suspension in the liquid. The lower limit of particle size may be set by the nature of the catalyst, but is most likely to depend on how easily the particles can be separated from the liquid products. To avoid filtration, the most convenient way of separating the particles is to allow them to settle under gravity, and the minimum particle size is set accordingly. 

Some processes are governed by the maximum impeller zone shear rate. For example, the dispersion of a pigment in a paint depends upon the maximum impeller zone shear rate for the ultimate minimum particle size. However, when constant tip speed is used to maintain this, the other geometric variables must be changed to maintain a reasonable blend time, even though process results on full scale will probably take much longer than those on small scale. 

Our strategy here was to develop Pt colloids of minimum particle size which would render the water reduction by the electron relay R peirticularly effective. The goal was to obteiin hydrogen evolution rates in the microsecond time domain which would compete with beick electron transfer. First a centrifuged Pt sol protected by polyvinyl alcohol weis employed which gave clear and almost colorless aqueous suspensions even at hi Pt concentrations ( 28). Flash photolysis technique was applied for the first time to study the dynamics of intervention of the Pt particles in the water reduction process. Methylviologen (MV ) wets reduced... 

Because the exact value for the surface-free energy and the minimum particle size in the bulk samples are not known, the position taken in this paper is that a free energy of formation for... 

The only other study for which the raw experimental data are available is that of May (see Table II footnote). In this investigation, 16 samples of Dry Branch kaolinite were equilibrated with solutions containing various concentrations of silica and aluminum. His data yield an average free energy of formation of -904.8 kcal/mol. The samples were bulk material with no reported minimum particle size (personal communication). This value is close to the free energies of formation obtained by Reesman and Kittrick for bulk samples (Table II) and seems to represent the upper stability limit. 

Earlier, in Chapters 2, 4, and 5, it was pointed out that many foods contain solid particles. Thus the role of the size, shape and hardness of particles in oral perception of texture is of interest. For example, in the confectionary industry the minimum particle size that can be comprehended by the palate is said to be about 25 p,m. Further, particle sizes about 10-15 p,m are considered to be the limit of diminishing effect. On the other hand, in tooth paste, the alumina trihydrate particles with an average diameter 5-20 p,m are used and larger particles are known to contribute to gritty sensation in the mouth (Tyle, 1993). 

Min type Typical minimum particle size achieved (pm) Suitable for what maximum Mohs hardness... 

Type of Equipment Minimum Particle Size (jum) Minimum Loading (mg/m ) Approx. Efficiency (o/o) Typical Cas Velocity (m/ ) Maximum Capacity (mVs) Cas Pressure Drop (mm H2O) Liquid Rate (mVlO m gas) Space Required (relative)... 

All filters require a filter medium to retain solids, whether the filter is for cake filtration or for filter-medium or depth filtration. Specification of a medium is based on retention of some minimum particle size at good removal efficiency and on acceptable life of the medium in the environment of the filter. The selection of the type of filter medium is often the most important decision in success of the operation. For cake filtration, medium selection involves an optimization of the following factors ... 

Gravity settlers can be designed to ensure capture of some minimum particle size. If Stokes law applies, one can show that this minimum particle size is given by... 

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