Eckert packing factor

Table 13-7 The Eckert packing factors Fp in ft 1 for dumped packing11...

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-...

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.

Based on the above reliability studies, the author recommends the Eckert flood correlation (the flood curve on Fig. 8.17) only for random packings whose packing factors Fp exceed 60. 

For high packing factors (Fp > 60), Eq. (8.1) predicts flood pressure drops greater than 2 in of water per foot of packings. In this situation, Eq. (8.1) will give similar predictions to those obtained from the flood curve on the Eckert correlation (Fig. 8,17). 

Which method to use, Data interpolation is generally the most accurate and should be preferred whenever flood data are available. Otherwise either if pressure drop data are available or when pressure drop can be reliably predicted, Eq. (8.1) is recommended. When the packing factor Fp exceeds 60, the Eckert correlation, Fig. 8.17 is recommended. At... 

Predictions from the Eckert correlation are sensitive to the packing factor (Sec. 8.2.10). Strigle (15) and Kister and Gill (60) found that most packing factors reported in the literature are satisfactory. However, for a few packings, the packing factors gave poor fit to experi-... 

Kister and Gill (316) modified the Eckert chart curves empirically to fit structured packing data. For structured packings, this modified chart (Fig. 8.19c) was shown (316) to give much better predictions than the Eckert chart. For flow parameters between 0.02 and 0.2 far nonaqueous systems or 0.01 and 1 for air-water, and for packing factors between 6 and 30, Fig. 8.19c was shown (316) to work well for all... 

Packing factors to uBe or not to use Due to the limitations of the Ecksrt GPDC (Secs. 8.2.6, 8.2.8) and the problems above, many manufacturers supply no packing factors for their products. This is especially true for structured packings, where the Eckert GPDC curves do not fit experimental data well (30,31,3 lb, 80a). Unfortunately, this creates a situation where packing capacities are described by a mul-... 

Figure 15.4 shows the Eckert (1975) pressure drop correlation, which may also be used to check the approach to flooding conditions. The variables in the coordinates are defined as follows L and V are the liquid and vapor flow rates, Ibmol/hr, G is the vapor mass velocity, Ib/tt-s, p, and Pv are the liquid and vapor densities, Ib/fF, F is the packing factor, ft /fF, and is the liquid viscosity, centipoise. The column diameter is implied since G is the vapor rate per unit column cross-sectional area. The pressure drop, in inches of water per foot of packing, is reported as a parameter in this correlation. Flooding can be expected to occur at any point above the pressure drop curve of 1.5 in. of water per foot of packing. 

The packing material under consideration consists of 2.5 cm Pall rings. The estimated HETP is 45 cm and the packing factor, F= 170 m per cubic meter of packing (Vital et al., 1984 Eckert, 1975). The equivalent number of equilibrium stages, including the condenser and reboiler, is... 

Figure 13-6 The Eckert flood velocity correlation. (Fp = packing factor, ft"1 see Table 13-7. g = acceleration of gravity, ft/s2. Gvsf = mass velocity of the vapor, superficial, flood, lb/s-ft2. wL = liquid mass flow rate, lb/s. wv = vapor mass velocity, lb/s. pv = density of vapor, lb/ft3. pL = density of liquid, lb/ft3. p, = viscosity of vapor, lb/ft-s. pw — viscosity of water, lb/ft-s.) [J. S. Eckert, Chem. Eng. Prog.. 63(3) 39 (1949), by courtesy American Institute of Chemical Engineers.]...

This flow parameter is the square root of the ratio of liquid kinetic energy to gas kinetic energy. The ordinate of this correlation includes the gas flow rate, the gas and liquid densities, the a/e ratio (which is characteristic of the particular tower packing shape and size), and a liquid viscosity term. Lobo et al proposed the use of a packing factor to characterize a particular packing shape and size [17]. They determined that the a/e ratio did not adequately predict packing hydraulic performance. Eckert further modified this correlation and calculated the packing factors from experimentally determined pressure drops [18]. 

Figure 8.1.11. The ordinate of this log-log plot (Eckert, 1970), (jG Fpy/uf /pgPig, often called the capacity factor, Cp, contains the following quantities, specified with their units Gg is the superficial mass average gas velocity based on empty column cross section v gPg (Ibmass/ft -s) Fp is a packing factor (unit of 1/ft) yr is the ratio of p.. ,pi lpt, where p is the density of the liquid in Ibmass/ft pg is the liquid viscosity in centipoise Pg is the gas density in Ibmass/ft gc = 32.2. This correlation is such that the specified units for each quantity in the ordinate has to be used. The quantity Fp (unit, 1/ft) is approximately inversely proportional to the packing size (Wankat, 2007) Fp oc (characteristic packing dimension, in inches) . The abscissa of this plot (often called the flow parameter).

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