Packed towers packing factor

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... 

Lobo et al. [47] proposed the packing factor, F, and experimentally determined that it better represented the data than the calculated a/e term. Values calculated using surface area per cubic foot and percent free gas space from manufacturer s tables can be as much as 40% off. The ralues are dependent upon the method of packing the tower, i.e., dry dumped, wet dumped, or wet dumped and shaken. The latter condition may approximate the situation after a tower has been running a while and the packing settled. 

Figure 9-24A. Packing factors (stacked packing selected grids). Used by permission of Morris and Jackson, Absorption Towers But-terworth Scientific Publications, and imperial Chemical Industries, Ltd., and adapted by U.S. Stoneware Co. (now, Norton Chemical Process Products Corp.).

Countercurrent flow data in towers with shaped packings are represented by Figure 13.37. The pressure drop depends on the viscosity of the liquid and on the flow rates and densities of the liquid and gas, as well as on characteristics of the packing which are represented here by the packing factor F. Nominally, the packing factor is a function of the specific surface as and the voidage e, as... 

Figure 1337. Corn-elation of flow rates, typical pressure drop behavior, and packing factors of random packed beds. [Eckert, Foote, and Walter, Chem. Eng. Prog. 62(1), 59 (1966) Eckert, Chem. Eng. 14 Apr. 1975)]. (a) Correlation of flow rate and pressure drop in packed towers, (b) Typical pressure drop data 2 in. porcelain intalox saddles, with F = 40, in a bed 30 in. dia by 10 ft high, (c) Packing factors, F, of wet random packings-...

A packed tower with 3 in. metal pall rings will be analyzed for the system of Example 13.15. The packing factor is F = 15 sqft/cuft. 

Figure 14.16. Flooding velocities in liquid-liquid packed towers [J.S. Eckert, Encycl. Chem. Process. Des. 21, 149-165 (1984)]. V = ft/hr (superficial velocity) C = continuous phase D = disperse phase a = sqft area of packing/cuft A = difference s = void fraction in packing p = viscosity centipoise continuous phase p = Ib/cuft o = (dynes/cm) interfacial surface tension F = packing factor.

Packing Nominal size, in. Approximate average weight per ft3 of tower volume, lb Approximate average total surface area of packing, ft /ft3 of tower volume Percent tree-gas space = t x 100 Packing factor, ap/e3, effective surface area/(void fraction)1, ft3 per ft3 of tower volume (dry-packed values for use with Fig. 16-20)... 

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