Page 277 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition
P. 277
Mechanical Separations 249
tem, because the wire style, size, and material also affect the
value. For pressures below 30 psig, k = 0.35 avg., then
above 30 psig, k value decreases with pressure with an
approximate value of 0.30 at 250 psig and 0.275 at 800 psig.
Certain values have been found satisfactory for estimating
systems described in Table 410 and Table 411.
For conditions of high liquid loading, use caution in
design. Use the high velocities for very fine mist to
remove the small particles, and use two mesh pads in
series with the second mesh operating at a lower velocity
to remove the larger drops re-entrahed from the first
mesh. Systems involving high viscosity fluids should be
checked with the various manufacturers for their case his-
tory experience. Lower k values are used ffor systems with
high vacuum, high viscosity liquids, low surface tension
,‘I?’
Bottom of mesh at least 12 inches above liquid surface
“”k” Gelaerd Type Mesh
Clean fiuids, moderate 0.35
liquid load, fits 90% of
process situations Very High Efficiency
High viscosity, dirty Low density or
suspended solids Herringbone, high
thhrough-pllt
-
Vacuum operations:
2” Ng. abs. -20 Standard or
16” Hg. abs. 0.27 High Efficiency
Corrosive Chemical 0.23. Plastic coated wire,
or plastic strand
Compiled from various manufacturer’s published data. Note: k values
for estimating purposes, not final design unless verified by manufactur-
er. Unless stated. all values based on stainless steel wire.
3......... .................h) . 12
4........... ............... 0.15
5 .......................... 0.19
6 .......................... 0.22
9. ......................... 0.25
8 .......................... 0.29
9..... ................... ~.0.92
10 ....................... ...c). 35
11 ........................ ..0.38
:2 .......................... 0.40
13 .......................... 0.42
14. ......................... 0.43
K-Factor, Vi[( 1 Wsec (x 0.3048 = n?/sec) I_____
*By permission, 0. H. York, Reference (21).
Note: Values based on 12 lb/cu ft wire mesh. Design practice normally
Figure. 4-17C. Pressure clrop vs K-factor for standard York-Wane mist does not exceed k of 0.4 even for higher disengaging height.
eliminators, ai r-\ivater system. y permission, Otto H. York Co., Inc.
