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Metex OPTI-MESH™ Mist Eliminators are available
in a variety of styles and configurations designed to match your
process. Styles range from very course
or “open” mesh designs to very fine or tight mesh
designs.
Mist eliminators maintain the integrity of the
plant by capturing fugitive liquids and returning them to the process.
Wire mesh
mist eliminators are the most commonly used type. They
have no moving parts and require little, if any, maintenance.
They are available in a broad range of styles, sizes and shapes.
Wire mesh mist eliminators are, made slightly oversized
and
compress to fit snugly into your vessel. This ensures that
a good vapor seal is achieved. They can be made from just
about any materials as monofilaments, multistrand or multifilament
designs.
Wire mesh mist eliminators rely primarily on physical IMPACTION
of the droplet onto a fine wire to remove liquid entrained in vapor
streams. As the droplet approaches the wire, its momentum will
keep it in a straight line than the vapor going around the wire.
If the momentum is high enough, the droplet hits the wire, wets
it and drains along the wire to where it encounters other collected
liquids.
The liquid builds up until it’s
too heavy to cling to the wire and then it falls back down to the bottom of the
vessel
where the liquid is drawn off.
Smaller droplets will be carried
with the vapor around the wire and will not be captured. The amount of liquid
that bypasses
the mist eliminator is referred to as the PENETRATION of the
mist.
| Smaller droplets may be captured by: |
- Increasing velocity (if feasible)
- Increasing droplet size (agglomeration)
- Increasing impaction sites (number or fineness of
wires)
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Every most elimination application is unique. Many times, the
optimum mist eliminator solution requires using more than a single
horizontal pad. Vane impactors, mesh agglomeration and vapor
distributors are also used to enhance performance. Inclining
the mist eliminators or switching to vertical configurations
can further enhance the unit’s performance.
Determining Mist Eliminator Size
Typically, wire mesh mist eliminators are 4 to 8 inches thick,
with 6 inches being the most common. Determining the pad’s
design diameter, once a style has been selected, involves calculating
the maximum allowable vapor velocity the pad can accommodate.
Knowing this velocity and the vapor volumetric rate, the preliminary
area of the pad and its diameter can be computed. The final
diameter can then be set by rounding up to a convenient or
commercially available vessel size.
Common Metallic Mist Eliminator Styles
Metex
Style |
Bulk Density
LBS/FT3 |
Surface Area
FT2 / FT3 |
% Void |
| 520 |
5.0 |
44 |
99.0 |
| 306 |
7.5 |
65 |
98.5 |
| 579 |
9.0 |
79 |
98.2 |
| 783 |
11.0 |
96 |
97.8 |
| 413 |
12.0 |
105 |
97.6 |
| 124 |
7.5 |
120 |
98.5 |
| 364 |
12.0 |
192 |
97.6 |
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