Wire Mesh Pad Deentrainers

Pads of fine wire mesh induce coalescence of impinging droplets into larger ones, which then separate freely from the gas phase. Tower packings function similarly but are less effective and more difficult to install. The pads are made of metal wires or plastic strands or fiber glass. These data apply to stainless steel construction  

The values of K in the preceding table are with a standard disengaging height of 10 in. The effect of other heights h is given by the equation 

When the pad is installed in a vertical or inclined position, the values of K should be taken 2/3 of the horizontal ones. 

At high liquid rates droplets tend to be reentrained and the pad may become flooded. Some data obtained by Poppele (1958) are cited by York (1983, p. 194). A graphical correlation credited to the Fluor Co. is represented by Branan (1983, p. 67) by the equation 

Good performance can be expected at velocities of 30-100% of those calculated with the given Ks. Flooding velocities are at 120-140% of the design rates. At low velocities the droplets drift through the mesh without coalescing. A popular design velocity is about 75% of the allowable. Some actual data of the harmful effect of low velocities were obtained by Carpenter and Othmer (1955) they found, for example, that 99% of 6 pm droplets were removed at 6.8ft/sec, but 99% of 8 pm at the lower velocity of 3.5 ft/sec. 

Type (%) Ibs/cuft sqft/cuft Pressure Vacuum 

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Knockout Drum with Wire Mesh Deentrainer For the flow conditions of Example 18.2, design a drum with a standard efficiency stainless steel wire mesh pad. For this condition, k = 0.35, so that... 

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