Demister pad designed for tail gas scrubbers enviromental
protection
What are demister mist eliminators?
The wire mesh demister is an assembly of knitted wire mesh
supported on, and held down by, high open area grids. It is made to
any size and shape and may be installed in all new and existing
process vessels. Wire used in DEMISTER fabrication is of the
highest quality. It is smooth, clean and bright for rapid liquid
drainage. Stainless steels and exotic alloys are fully annealed to
provide maximum corrosion resistance. Perfect fit is assured even
in out- of-round vessels, eliminating all vapor by-passing.
Wire mesh demister pad units can be engineered to fit the smallest
laboratory still, the largest refinery or petrochemical tower.
Wire Mesh Demister Standard Specification:
1.General
1.1Scope
A.This Standard Specification covers the general requirements for
design, construction, fabrication, and material of Mist Eliminators
specified in XXX Project Specifications.
B.Exceptions or variations shown in the Project Specifications take
precedence over requirements shown herein.
1.2References
Unless noted below, use the edition and addenda of each referenced
document current on the date of this Standard Specification. When a
referenced document incorporates another document, use the edition
of that document required by the referenced document.
A.American Society for Testing and Materials (ASTM) A-478,
Specification for Chromium-Nickel Stainless and Heat-Resisting
Steel Weaving and Knitting Wire.
B.ASTM B-164, Specification for Nickel-Copper Alloy Rod, Bar, and
Wire.
Metal Wire Mesh Pad Demister Type and Applications
Mesh density (stainless steel) | Application |
| 50 kg/m3 | Heavy fouling, e.g. evaporators |
| 80 kg/m3 | Moderate fouling, e.g. vessel boilers |
| 110 kg/m3 | Light fouling |
| 145 kg/m3 | Heavy duty, e.g. oil and gas separators |
| 170 kg/m3 | General purpose, not totally clean |
| 195 kg/m3 | Optimum efficiency & pressure drop |
| 240 kg/m3 | High density with high separation efficiency |
| 112 kg/m3 | General purpose, clean service |
| 145 kg/m3 | Find droplet removal in clean service |
Working Theory of Wire Mesh Demister
A mist eliminator is a device usually used in vapor-liquid
separator columns, which removes the liquid droplets entrained in a
vapor stream. The mist eliminator may be mesh type, vane pack type
or other structure intended to aggregate the tiny mist into
droplets. So the droplets are heavy enough to be separated from the
vapor stream.
The mist eliminator can reduce the residence time required to
separate a given droplet size by reducing the volume and cost of
separation equipment. The mist eliminators are often used where
vapor quality is important in regard to entrained liquids,
particularly where separator equipment costs are high (for example,
high pressure systems), or where space or weight saved are
valuable.
When the marine vessels process the brine by desalination, the
brine is flash heated into vapor. In flashing, the vapor carries
droplets of brine, that had better to be separated before
condensing. Otherwise it will contaminate the vapor with salt. That
is what the mist eliminator does. The pure vapor condenses on tubes
in the desalination plant, and water is collected from the system.
Wire Mesh Demister Installation:
