2500 mm Custom Order 8 Parts Plastic PTFE Knitting Mesh Demister Pad

 (1): General 

 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.

1.2 References

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

2.1 General

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.

D: 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.

2.2 Construction

A: Mist Eliminators shall be fabricated in one piece or in the minimum number of sections required for insertion through the vessel manway.

Mesh pads shall fit tightly into the pad containment system.

B: Mesh pad layers shall not be more than 9 inches (230 mm) thick. Where more than one layer is required, joints shall be staggered.

One-piece circular mesh pads may be spiral in form.

2.3 Supports 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.

2.4 Fastening 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). Materials

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.

3.2Non-metallic Mist Eliminators

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

3.3 Supports

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.

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

3.4 Grids

Metallic grids can be the same material as the mesh pad

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

3.5 Fastening Devices

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.

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