Page 283 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

Mechanical Separations 255

- particle-laden gas
Materials of construction
Packing of York-Fiberbed high efficiency mist eliminators consists of
ceramic, glass, polypropylene, fluoropolymer fibers. Cages and
frames are fabricated from all stainless steels and other weldable
alloys as well as FRI?

Figure 4-27A. Details of a cylindrical York-Fiberbed@ mist eliminator.
Courtesy of Otto H. York Co., Inc., Bullet in 55B.

particle size removed may be much smaller. Just as for
other types of mist eliminators, the performance is affect-
ed by the properties of the liquid particles, entraining gas,
temperature, pressure, liquid viscosity, particle size distri-
bution of entrained material and the quantity of total
entrainment, and the desired process removal require-
ment. Some designs of these units provide excellent per-
formance removal efficiencies at a wide range of rates
(turndown), even at low gas rates.
Pressure drop is usually low depending on many fac-
tors, but can be expected in the range of 2 to 20 inches of
water [33].

Baffle Type Impingement

There are many baffle type impingement separators. Figure 4-278. Fiber-pack@ mist eliminator pack separators. By per-
The efficiency of operation for entrainment is entirely a mission, Koch Engineering Co., Inc. Note that other manufacturers
function of the contacting action inside the particular have basically the same concept; however, the identification of
unit. There are no general performance equations which types are peculiar to each.
will predict performance for this type of unit; therefore
manufacturers’ performance data and recommendations liquid droplets run down on the plate surfaces counter-
should be used. A few of the many available units are current to the up-flowing gas stream. See Reference [59]
shown in Figures 428 to 431. Many use the Chevron-style for performance study.
vertical plates as shown in Figures 417A and 430. Spacing of the plates and their angles is a part of the
design using the manufacturers’ data. Multiple pass designs
Baffles (Chmons/Vanes) can result in higher recovery efficiencies. The units can be
designed/installed for vertical or horizontal flow.
One of the common impingement plate assemblies is Some of the same physical properties of the liquid and
of the Chevron “zig-zag” style of Figures 417A and 430. gas phases as well as temperature and pressure and the
This style of impact separation device will tolerate higher amount of entrained liquids (or solids if present) and the
gas velocities, high liquid loading, viscous liquids, reason- expected particle size and its distribution control the
able solids, relatively low pressure drops. The collected design and performance of these units also.