Refining distillation column removal parts wire mesh demister

Wire Mesh Demister Mist Eliminators Standard Specification

1. General introduction of wire mesh demister specification

1.1 Scope

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.

2. Design of wire mesh demister

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.

3. Materials of wire mesh demister

3.1 Metallic Mesh Pads

Materials for metallic Mist Eliminators are as per customer need. Type 304 or Type 316 mesh pads can be in accordance with ASTM A-478. Monel mesh pads can be in accordance with ASTM B-164.

3.2 Non-metallic Mist Eliminators

Non-metallic Mist Eliminators shall be PTFE or polypropylene as specified in by customer.

3.3 Supports

A.Supports welded to the vessel shall be the same material as the shell. Where the shell is lined, supports welded to the lining shall be the same material as the lining.

B.Supports not welded to the shell (e.g. beams) shall be the same material as the Mist Eliminator.

3.4 Grids

A.Metallic grids can be the same material as the mesh pad

B.For non-metallic mesh pads, the grids shall be carbon steel, coated with the same material as the mesh pad.

3.5 Fastening Devices

A.For metallic mesh pads the wire ties or other fastening devices shall be of the same material as the Mist Eliminator.For non-metallic mesh pads, the grids shall be carbon steel, coated with the same material as the mesh pad.

B.For non-metallic mesh pads the wire ties can be the same material as the mesh pad.

4. Applications of some main type of demister pad:

5. Demister Advangages:

Prevention of air pollution

Reduce of costly liquid lose

Reduce of product contamination

Improvement in process efficiency

Minimizing product losses in re-boilers & evaporators

Preventing carbon & metal entrainment in down stream catalyst cracker.

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