Collector efficiencies, single

Filtration a W volumetric concentration of filter medium d single- number of collector collectors efficiency (v,d) V contact opportunities ... 

Tufenkji N, Elimelech M (2004) Correlation equation for predicting single-collector efficiency in physicochemical filtration in saturated porous media. Environ Sci Technol 38 529-536 Turner BL, Kay MA, Westermann DT (2004) Colloid phosphorus in surface runoff and water extracts from semiarid soils of the western United States. J Environ Qual 33 1464-1472 van Genuchten MT (1980) A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci Soc Am J 44 892-898... 

The relationship between the filter coefficient and the single collector efficiency is obtained by combining the preceeding two equations ... 

N. Single Spherical Collector Efficiencies. Four collection mechanisms are considered in the present analysis inertial impaction, interception. Brownian movement and Coulombic forces. Although in our previous analysis the electrical forces were considered to be of the induced nature (13), there is evidence that it is the Coulombic forces which dominate the electrical interactions between the particle and collector (, ], 22). Taking the net effect as the simple summation of each collection mechanism results in the single spherical collector efficiency equation. 

Note from Eqn. (38) that since the volume fraction of each phase varies throughout the bed, so will the assembly average velocities and hence, the single collector efficiencies. 

In the present paper our previous analysis of fluidized bed filtration efficiencies has been extended by considering more realistic methods for estimating the single collector efficiencies as well as more recently reported experimental results. In general the predicted values of the fluidized bed filtration efficiencies compare favorably to the experimental values. For electrically active fluidized beds, direct measurements of the particle and collector charges would be necessary to substantiate the results given here. 

Since physical parameters were held constant in these experiments, the theoretical single collector efficiency, r/(p, c)theor, is constant at 0.00256. The experimental attachment efficiency, a(p, c)exp, however, varies from 0.014 to 0.94, depending on the chemical composition of the solution. In the presence of a high concentration of Ca2+, the attachment coefficient approaches 1. This means that, in the absence of a repulsive chemical interaction, the mass-transport rale as calculated with Eq. 4 successfully describes the performance of these laboratory columns. At low ionic strength (pNa = 3.0), the sticking coefficient is reduced to a value of 0.014 by repulsive chemical interactions (presumably primarily electrostatic) between the suspended latex particles and the stationary glass collectors. Only 1.4% of the contacts produced by mass transport lead to attachment and deposition of the latex particles from the suspension. 

For all capture mechanisms where the suspended particles are independent of one another and capture results from individual encounters with the collectors making up the porous medium, the filter coefficient A is independent of the suspended particle number density n. Examples of this behavior are seen in the single spherical collector efficiencies given by Eqs. (8.3.15), (8.3.23), and (8.4.26). If the incoming suspended particle number density is q and the filter medium is uniform and unclogged, Eq. (8.5.13) integrates to... 

The modification is seen to parallel the incorporation of the Stokes-Oseen function (Eq. 8.3.24b) into the solution for the collector efficiency of a single cylindrical collector. A similar change would be made for an assemblage of cylindrical collectors, though the volume fraction function that would replace the Stokes-Oseen function would differ from the one for spherical collectors. 

Figure 10.5 Solar collector efficiency curve of an advanced flat plate collector (prototype I - single cover prototype 2 - double cover)...

The single collector efficiency (ri) is approximately given by X]j where is the efficiency due to direct interception only. Direct interception is believed to be the most dominant capture mechanism in the water sensitivity phenomenon. A special and extreme case of this mechanism is the so-called sieve filtration. Considering the particle sizes Involved in this phenomenon (few microns in size) and the range of flow velocities used in this work... 

Single-collector efficiency for monolayer filtration vreis estimated with the expression developed by Rajagopalan and Tien [128], obtained by the combination of the trajectory analysis of a spherical particle in the vicinity of a spherical collector with the contribution of the Brownian diffusion. For fine-fine capture step, filtration becomes driven by the fine-fine interaction forces yielding a multilayer deposit for which the filter coefficient no longer remains constant in time. The change of the filter coefficient as a function of the specific deposit was estimated using the correlation developed by Tien et al. [129]. Extra information about trickle-bed deep-bed filtration model is given in Iliuta and Larachi [130] and Iliuta et al. [119]. 

Baffle separators of the Venetian blind, V, W, and wave types are widely used for spray removal. They have small space requirements and low pressure drops. They operate by diverting the gas stream and ejecting the droplets onto the collector baffles. Efficiencies of single stages may be only 40-60%, but by adding multiple stages, efficiencies approaching 100% may be obtained. 

Theoretical dependence of filter efficiency of a single collector (proportional to the rate at which particle contacts occur between particles and the filter grain by mass transport) on particle diameter. For particles of small diameters transport by diffusion increases with decreasing size. Contact opportunities of the larger particles with the filter grain are due to interception and sedimentation they increase with increasing size. 

The corrosive electrochemistry parameters are listed in Table 7.4. From Fig. 7.30 and Table 7.4, it can be seen that, after adding xanthate 5x 10" mol/L, the corrosive potential of galena electrode decreases from -48 to -94 mV, the corrosive current of the galena eleetrode decreases from 3.45 to 0.99 pA/cm, the polarization resistance increases to 18.7 kG and the inhibiting eorrosive efficiency increases to 28.34. Figure 7.31 shows that the EIS of galena electrode appears to have single capacitive reactance loop characteristic and the radius of the capacitive reactance loop increases with the increase of collector concentration. 

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