Wire Mesh Pad Demister

Hualai wire mesh pad demister installed to sulfuric acid tower
 
 
Wire Mesh Demister Mist Eliminators Standard Specification
 
1.General introduction of wire mesh demister

There are many types of mesh pad demisters, including flat type, oblique type, etc.. Usually the mesh pad thickness for flat type demister is 100mm or 150mm. With simple structure, it suits for low velocity, low mist rate gas flow. Re-entrainment easily happen when the gas velocity is too high. While the oblique type (sometimes also shown as wave shape demister) has flow guiding effect on the captured liquid droplet, leaving less liquid droplets on the downside of the mesh pad. So the oblique type demister has less resistance to the passing gas flow, and is a little harder to cause re-entrainment. It allows somehow higher velocity and mist content.

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.

3.Wire Mesh Materials

3.1Metallic 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.

3.3Supports

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.

3.4Grids

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.

3.5Fastening 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. Demister Inquiry Table if Calculation Suggestions and Service are needed

Please pay attention to the Unit when refering to this sheet.

Wire Mesh Demister workshop: