Coarse prefilter wire mesh filter material with stainless steel
frame
1.General introduction of wire mesh demister
The wire mesh demister is designed to collect liquid particles
contained in the vapour phase after boiling, vacuum evaporation or
bubbling process.
Small droplets in the gas contact the wide surface of the filaments
of the mesh pad mist eliminator, gradually grow into large liquid
droplets and flow and drop by a special structure accelerating the
coalescing of the liquid droplets. The mesh pad of the mist
eliminator is highly porous, so the vapour gas passes through the
mist eliminator without hindrance, leaving only pure gas.
The process is not a type of filtering as the hole size of the knit
mesh is not specially related to the size of the liquid droplets.
This mist elimination is caused by the collision and sudden change
resulting from the flowing speed of the small liquid droplets, and
the coalescing of the liquid drips and gravity cause their descent.
This is a process combing mechanical and physical phenomenon.
2. Design of Wire Mesh Demister.
2.1General
A.Size, style, thickness, configuration, and materials are
specified in XXX Project Specification – Vessels.
B.Mist Eliminator styles are defined as follows:
C.Style G is a mesh blanket having a variable knitted density. The
vapor inlet section is the least dense and the outlet section the
densest. Typical inlet/outlet knitted mesh densities are 5 lb/ft3
(80.1) and 9 lb/ft3 (144.2). The customer can require variable
density blankets having slightly different knitted densities and
wire diameters.
Style V is to be determined by the vendor, based on the process
conditions provided by customer. Vendor may determine the mist
eliminator type best suited to meet the mist elimination
requirement. The selected style may include a mesh pad, vane or a
combination of mesh & vanes. The mist eliminator may be oriented
vertically, horizontally or at an angle determined by the vendor. A
single pad of variable knitted density may also be applied.
2.2Construction
A.Mist Eliminators shall be fabricated in one piece or in the
minimum number of sections required for insertion through the
vessel manway.
B.Mesh pads shall fit tightly into the pad containment system.
C.Mesh pad layers shall not be more than 9 inches (230 mm) thick.
Where more than one layer is required, joints shall be staggered.
D.One-piece circular mesh pads may be spiral in form.
2.3Supports and Grids
A.The general arrangement of Mist Eliminator supports and grids
shall be as factory habit unless required by customer.
B.Final details of Mist Eliminator supports and hold down grids can
also be furnished by the Mist Eliminator supplier.
C.The Mist Eliminator supplier shall furnish details of components
attached to the vessel to the vessel fabricator in time to permit
installation without altering the vessel fabrication schedule.
D.Each section of the mesh pad shall include a grid on each side.
E.Style G mesh pads shall be furnished with an inlet and an outlet
rigid welded grid. The outlet grid and blanket outlet zone of the
Style G mesh pad shall be distinctly marked “Outlet”.
F.Spiral mesh pads shall include X-type grids on both sides.
2.4Fastening Devices
As the Mist Eliminator fabricator we can supply wire ties or other
devices to fasten the Mist Eliminator sections to the supports,
attach the grids to their vessel supports, and where multiple layer
Mist Eliminators are necessary, to secure the layers together.
3. Main types of wire mesh demister
Mesh Density | Eq to: YORK | Description |
| 80 | 931 | For a given load of mist, the highest flow velocity is achieved of
all styles. Ideal where it is required to minimize the pressure
loss, possible clogging is concerned, the size of particle to be
collected is relatively large, and/or a very high efficiency is not
required. |
| 144 | 431 | Used for general purposes. An efficiency of 98 to 99% is achieved
at a velocity of 1 to 5 m/sec. |
| 192 | 421 | Used where an especially high efficiency is required. While a
pressure loss is slightly higher, it achieves an efficiency of 99
to 100% with particle sizes 3μ or more at a velocity of 1 to 6
m/sec., and is ideal where an efficiency of 90% or more is required
at a velocity of 1 m/sec. or less. |
| 216 | | Used for collecting fine particles of 1 to 3μ in size.
Especially for a low-density mist of 1.0 g or less, it is used in a
thickness of 200 to 300 mm. |
| 432 | 333 | Used for collecting fine particles. An efficiency higher than that
of 216 can be achieved. The most remarkable characteristic is that
it provides a high efficiency with a reduced thickness. |
Wire Mesh Demister Package:
