Flooding point curve

A typical form of flooding-point curve for spray towers is shown in Figure 13.35 where values of udf are plotted against ucf. The limiting values of each flowrate as the other approaches zero may be determined readily from equations 13.34 and 13.35. Thus, when... 

Figure 13.35. Flooding-point curve for spray tower...

The last popular version of the GPDC chart that contained a flood-point curve was the Eckert correlation (53,72). This version (Fig. 8.17)... 

Figure 7-16 shows an additional flooding point curve for the parameter ... 

For distillations, it is often of more interest to ascertain the effect of entrainment on efficiency than to predic t the quantitative amount of liquid entrained. For this purpose, the correlation shown in Fig. 14-26 is useful. The parametric curves in the figure represent approach to the entrainment flood point as measured or as predicted by Fig. 14-25 or some other flood correlation. The abscissa values are those of the flow parameter discussed earher. The ordinate values y are fractions of gross hquid downflow, defined as follows ... 

Kister [93] has developed a new approach at establishing the flood point that appears to suit the available data and is obviously more accurate than reading the upper curve on Figure 9-21C. 

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. 

Fig. 9.14 Flooding point diagram of centrifugal extractors (see Fig. 9.9). Curve 1 marks the lower limit, when the rotor is filled with heavy phase curve 2 marks an upper hmit, when the rotor is filled with light phase curve 3 marks the limit of the total throughput of both phases.

The GPDC charts in Figs. 14-55 and 14-56 do not contain specific flood curves. Both Strigle and Kister and Gill recommend calculating the flood point from the flood pressure drop, given by the Kister and Gill equation... 

Upon this discovery, Eckert began to research the Norton company s data files [9]. His findings revealed that the flood points were accurate at the family of curves shown in Fig. 7.11. Please note that these curves... 

As indicated in Figure 4, the HETP values for different packings decrease with increasing liquid flow. The endpoint of the plotted curves are the flooding points where liquid droplets are withdrawn with the gas. The best separation... 

Flooding points, as well as pressure drop curves, may be determined in the separation column, but it is better to exclude mass transfer effects and use a special experimental set-up. 

Sharp rate of rise of pressure drop. A sharp rate of rise of pressure drop with vapor rate may be an even more sensitive flooding indicator than the magnitude of pressure drop. The flood point can be inferred from a plot of pressure drop against vapor or liquid flow rate, and is the point where the slope of the curve changes significantly (Figs. 14.3,14.4). In tray columns, the slope change can be relatively mild (curve 1 in Fig,... 

Since differential pressure recorders and their installation are expensive, there is often a tendency to minimize their use. One alternative proposed is the installation of static pressure gages. This may be satisfactory if the slope of the pressure drop versus load curve is known to be very steep at the flooding point (Fig. 14.4, curve 2), but is very poor otherwise. Even with steep slopes, this alternative will lower the quality of the data and is not recommended (268). 

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