Wetting pressure

Figure 8-115. Correction for wet pressure drop, C , (after Dauphine) used by permission, Bolles, W. L., Pet. Processing, Feb. thru May (1956), using data of Dauphine [13].

Figures 9-32A and B [98] illustrate the correlation of wet pressure drop and system vapor rate at various liquid rates for No. 2 Nutter rings however, other available data indicate that other sizes of Nutter rings, Pall rings, and selected other packing shapes correlate in the same manner.

Figure 9-32A. Correlation of No. 2 Nutter Rings superficial capacity vs. wet pressure drop for 4 data sets and 3 separate tests. Note the 10 1 pressure drop range. Reproduced by permission from Nutter, D. E. and Perry, D., presented at New Orleans, La. meeting of American Institute of Chemical Engineers, March (1988), and by special permission of Fractionation Research, Inc. all rights reserved.

AP = Wet pressure drop, in. liquid/ft packed height (Nutter)... 

Another integrity test referred to as the pressure hold test makes use of the fact that below the transition pressure no bulk flow of the test gas takes place. Therefore, in a pressure hold test, once a filter system is in place and the filter medium wetted, pressure is applied to the system and then shut off and sealed. If there are no leaks in the system or holes in the membrane larger than the corresponding test pressure used, the pressure should remain constant. If the pressure drops, there is a leak somewhere in the system that should be corrected. The pressure hold test is popular in testing filter assemblies and systems in... 

Pressure drop. Wet pressure drop on the tray is determined by the resistance of the aerated mass to vapor flow (Sec. 6.3.3). As the nature of the dispersion is different, one would expect a different mechanism to cause pressure drop in the spray regime. This has been confirmed by experiments (88,114). To date, not enough is known about the nature of this mechanism. 

Pressure drop. Pressure drop is calculated as per Secs. 6.3.1 to 6.3.3, using Fair s pressure drop correlation. Usually, it is good practice to design for a pressure drop of 3 to 5 in of liquid (approximately 0.08 to 0.12 psi) per tray. If outside this range it is best to adjust the fractional hole area (if dry pressure drop dominates) or the weir height (if wet pressure drop dominates). 

Construct the wet-pressure-drop line, on log-log coordinates, for pressure drops below column loading. For most packings of commercial interest, the relationship between the wet and dry pressure drops can be given by... 

For each packing, sketch an empirical curve such that (a) its upper end passes through the point Fsf, APF with a slope approaching infinity, and (b) its lower end becomes tangent to the straight, wet-pressure-drop line at an abscissa value of Fsf/2. These two pressure-drop curves for the loading regions are shown by the dashed lines of Fig. 11.1. 

Conventionally Heating (Thermally Convective Wet Pressure Decomposition)... 

Penetration encompasses movement through openings between fibers and yams, stitching, seams, closures, or flaws by mechanisms such as wicking, wetting, pressure gradients, bulk flow, and so forth. For penetration to occur there must be a hole. 

Figure 1 Schematic of two-stage HK pore filling model showing the principal features of the model mesopore isotherm (1) capillary condensation pressure (2) condensed fluid interval (3) film wetting pressure (4) empty pore interval and (5) monolayer interval.

V, = vapor superficial velocity, ft/sec C2 - wet pressure drop intercept coefficient... 

TABLE 11.5 Static coefficient of friction for piastic or WPC deck boards, measured using a simplified inclined plane method. All measurements were done in the most slippery directions, that is, along the grain. Date for dry and wet pressure treated lumber are given for a comparison... 

Adrian, W.J. (1973). A comparison of wet pressure digestion method with other commonly used wet and dry ashing methods. Analyst. 98, 213-216 Alcock, N.W. (1987). A hydrogen peroxide digestion system for tissue trace metal analysis, Biol.Trace Bern. Res. 13, 363-370... 

Tray Pressure Drop h, includes dry and wet pressure drop as... 

Now we turn our attention to wet pressure drop. As h represents the pressure drop that vapor goes through the aerated hquid on the tray, it can be modeled in proportion to the tray clear liquid height as... 

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