Packings factor

Packing type Nominal size, mm Surface area, m /m Packing factor, Ep, m ... 

Fig. 24. Generalized method using log scales for estimating packed column flooding and pressure drop, AP, in kPa/m g = gravitational constant, 9.81 m/s t = kinematic viscosity in mm /s (= cSt) E, G have units of kg/(m s) are in kg/m and the packing factor, F, in can be found in...

The term Fp is a dimensionless dry packing factor, specific for a given packing type and size. Values of Fp are given in Table 14-7. For operating pressures above atmospheric, and for certain packing sizes, Lj and Gj a.re calculated differently ... 

For ordered, or structured, packings, pressure-drop estimation methods have been reviewed by Fair and Bravo [Chem. Eng. Progr, 86(1), 19 (1990)]. It is not common practice to use the packing factor approach for predicling pressure drop or flooding. For operation below the loading point, the model of Bravo et [Hydrocarbon... 

Packing factors from Kister and Gill [Chem. Eng. Progr., 87(2), 32 (1991), and Houston AIChE meeting, March 19-23, 1995],... 

Name Material Nominal size Wall thickness, mm Bed weight, kg/m Area, mVm % voids Packing factor Fp, m Dry packing factor Fpd, m Vendor... 

For this equation to apply the updated packing factors from Reference 3 or 13 must be used. 

The pressure drop for a given proposed set of conditions is determined from Figure 12 or Figure 13. which has a linear Y-axis so is easier to interpolate. Table 8 gives packing factors (F) to be used with Figures 12 and 13. 

Design of inorganic absorbers quite often involves a system whose major parameters are well defined such as system film control, mass transfer coefficient equations, etc. Ludwig gives design data for certain well-known systems sueh as NH3-Air-H20, CI2-H2O, COi in alkaline solutions, etc. Likewise, data for commercially available packings is well documented such as packing factors, HETP, HTU, etc. 

F = Factor for fractionation allowable velocity or packed column packing factor or pump developed head, ft. 

In a similar manner to the design process for packed columns, the physical characteristics and the performance specifications can be calculated theoretically for open tubular columns. The same protocol will be observed and again, the procedure involves the use of a number of equations that have been previously derived and/or discussed. However, it will be seen that as a result of the geometric simplicity of the open tubular column, there are no packing factors and no multi-path term and so the equations that result are far less complex and easier to manipulate and to understand. 

The packing factor (F) is an important design variable in determining the capacity of any packing design from a flooding, or pressure drop standpoint. This-factor was first described by Sherwood in 1938. The empirical correlation is ... 

Fp = packing factor, empirical v = kinematic viscosity, liquid, centistokes (kinematic viscosity = viscosity, centipoise/specific gravity (not density))... 

F = packing factor from Table 9-26A-E Lh = liquid mass velocity, lb/ (ft ) (hr)... 

Glitsch Packing Factors for Cascade Mini-Rings... 

Size No. Pieces/Ft Ft2/Ft3 Lb/Ft % Void Packing Factor HETP Values ... 

The use of packing factors is established in the design concepts of evaluating packed tower performance. Essentially all of the manufacturer s published data are for wet and dumped packing factors, F. Robbins proposes using... 

Figure 9-23. Flood pressure drop vs. packing factor for random packings. Reproduced with peimission of the American Institute of Chemical Engineers, KIster, H. Z. and Gill, D. R., Chemical Engineering Progress, V. 87, No. 2 (1991) all rights reserved.

Many of the packings of the various manufacturers are essentially identical in shape, size, and performance factors. Some packing manufacturers suggest adjusting packing factors for vacuum and pressure distillations however, this should only be done after consultation. 

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