Pressure drop at flooding point

The pressure drop (Ap/H)pi at the flooding point can be determined using Eq. (4-54)  

Pressure Drop Calculation Acc. to the t rvL Model Presented in Chapter 5 

Chapter 5 presented a model, derived from Eq. (5-2), for determining the pressure drop of any types of irrigated packings, based on the resistance coefficient for two-phase flow 

The equation is valid throughout the entire operating range up to the flooding point. The resistance coefficient for two phase flow tvL acc. to Eqs. (5-6), (5-7) and (5-8), is a function of the Reynolds number of the Hquid and the form factor x of packings, vlrvL = f(M ReL). 

The form factors x for the individual packings can be found in Tables 6-la-c. They provide a direct comparison between the predicted pressure drops for the individual types of packings without requiring any calculations or experiments. 

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AP = Air pressure loss, in. of water APflood = Pressure drop at flood point for all random packings, in. of water/ft of packing height APd = Dry bed pressure drop, in. water/ft packed height... 

Pressure drop at flooding point in packed towers... 

Figure 9-34D. Pressure drop correlation at flood point for use with Table 9-33. Used by permission of Zenz, F. A., Chemical Engineering, Aug. (1953) p. 176 all rights reserved.

As a comparison or alternate procedure, the pressure drop at the flooding point as indicated by the upper break in the pressure drop curve can be estimated from Table 9-33 and Figure 9-34D for rings and saddles [81]. The values in the table multiplied by the correction ratio gives the pressure drop for the liquid in question, expressed as inches of water. 

Diunped Packing Pressure Drop Below and at Flood Point, Liquid Continuous Range... 

Pressure Drop at Upper Break Point (Flood) With Water... 

Pressure drop Generalized model of Bravo, et al. [ 111 ], in combination with Stichlman [112]. Pressure drop at the flood point as a function of the flow parameter at the flood point is given in Figure 9-62 [108] for several packings using the Stichlman model equations for various system pressures [108]. 

Figure 9-64. Pressure drop at the flood point as a function of ioad-ing. Values are calculated using the Stichimair et al. model and distillation conditions using cyclohexane/n-heptane and Gempak 2A packing. Note ordinate (N/m /m)/3.3853 = in. Hg/m. Reproduced by permission of the American Institute of Chemical Engineers, Fair, J. R. and Bravo, J. L., Chemical Engineering Progress, V. 86, No. 1 (1990) p. 19 ail rights reserved.

The Kiefer and Gill correlation. Zenz (76) discovered that packing pressure drop at the flood point decreases as the packing capacity increases. A similar observation was reported by Strigle and Rukovena (15,77) and Ma kowiak (736). Kister and Gill (60) applied this principle to derive a simple flood point correlation... 

Equation (8.1) expresses the pressure drop at the flood point as a func-... 

Values are based on countercurrent flow of liquid and air at atmospheric pressure. In the range between the loading region and the flooding point, an approximation of pressure drop Ap at gas mass velocity G can be obtained from Ap = ApF(G/Gm). The pressure drop at the loading point is usually in the range of one-fourth to one-sixth of the pressure drop at the flooding point... 

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