Introduction to HG/T21618-1998 Wire Mesh Defoamer Standard

Introduction to HG/T21618-1998 Wire Mesh Defoamer Standard

Wire mesh demister: Standard No.: HG/T21618-1998 

Wire mesh demister, also known as wire mesh demister, wire mesh coalescer, wire mesh flame arrester, wire mesh foam catcher, deaerator packing, demister packing, etc., demister. It is used to separate the mist with a droplet diameter greater than 3-5μm entrained in the gas. When the gas with mist rises at a certain speed and passes through the filter wire mesh in the middle of the grid, the mist collides with the filaments and adheres to the surface of the filaments due to the inertia of the rising mist. The mist on the surface of the filaments further diffuses and the gravity of the mist itself settles, so that the mist forms larger droplets that flow along the filaments to its intersection. Due to the wettability of the filaments, the surface tension of the liquid and the capillary action of the filaments, the droplets become larger and larger until their own gravity exceeds the combined force of the buoyancy of the rising gas and the surface tension of the liquid, and then they are separated and fall. As long as the operating gas speed and other conditions are properly selected, the defoaming efficiency of the gas after passing through the wire mesh demister can reach the above, and the purpose of completely removing the mist can be achieved.

Wire mesh demister is suitable for gas-liquid separation devices used in vertical cylindrical equipment in chemical, petrochemical, pharmaceutical, light industry, environmental protection and other industries. HG/T 21618-1998 Wire mesh demister implementation standard

Wire mesh demister structure type: divided into two types: top-mounted and bottom-mounted. When the manhole is opened on the top of the demister or there is an equipment flange without a manhole, a top-mounted wire mesh demister is used; when the manhole is opened on the bottom of the demister, a bottom-mounted wire mesh demister is used. There is no difference between top-mounted and bottom-mounted demisters in terms of the demister itself. The difference lies in the different supporting parts required for top-mounted and bottom-mounted demisters. The supporting parts of the bottom-mounted wire mesh demister use more materials than the top-mounted type.

The mesh thickness of the wire mesh demister is divided into two specifications: 100mm and 150mm; the shelf height is 50mm. The total height including the shelf is 150mm and 200mm.

The materials of wire mesh demisters commonly used are stainless steel ( 304 wire mesh demister , 304L wire mesh demister , 316 wire mesh demister , 316L wire mesh demister , etc.), PP wire mesh demister (polypropylene wire mesh demister ), PTFE wire mesh demister (polytetrafluoroethylene wire mesh demister ), titanium wire mesh demister , etc.

The structure of wire mesh demister:      

The wire mesh demister is composed of two parts: a gas-liquid filter screen pad (composed of several mesh blocks) and a supporting part. The mesh block is composed of several layers of flat (wound) corrugated gas-liquid filter screens, grilles and distance rods. The supporting parts of the wire mesh demister generally include: beams, pressure strips, pressure plates, lugs, supporting plates, supporting rings, sealing plates, retaining rings, etc. The supporting parts are made by the container equipment manufacturer. If necessary, they can also be provided by the wire mesh demister manufacturer, but this must be stated when ordering. The wire mesh demister can also be made according to user requirements: detachable (screw distance rod), wave type, drawer type and other types. The filter type can be made according to the "HT-2001 Wire Mesh Demister Standard" or user requirements.

Example 1: DN2000mm, H=150mm, filter type is SP type, material is 316L, grille and support material is 316 top-mounted wire mesh demister, marked as: HG/T21618 wire mesh demister S2000-150 SP 316L/316.   

Example 2: DN4000mm, H=100mm, filter type is DP type, material is 316L, grille and support material is 304 bottom-mounted wire mesh demister, marked as: HG/T21618 wire mesh demister X4000-100 DP 316L/304.

The wire mesh demister (also known as wire mesh demister) is manufactured with reference to the original Ministry of Chemical Industry

HG5-1404-81

HG5-1405-81

HG5-1406-81 People's Republic of China industry standard HG/T21618-1998. 

1. Introduction Wire mesh demister is a gas-liquid separation device. The gas passes through the wire mesh pad of the demister to remove the entrained mist. This standard HG/T21618-1998 is based on the original Ministry of Chemical Industry standards HG5-1404-81, HG5-1405-81 and HG5-1406-81, combined with the actual use experience of wire mesh demisters and the advanced technology introduced in the device. The newly revised standard has the following changes compared with the original standard: 1. The original three standards are merged into one standard for easy selection. 2. The diameter range and specifications of the demister are adjusted, and the nominal diameter specifications are appropriately encrypted. 3. The wire mesh type used in the demister has been added, and the basic parameters of the wire mesh have been given. 4. The material varieties of wire mesh and grille have been added. 5. The process calculation content about wire mesh demister has been added to facilitate selection. 

2. Subject content and scope of application This standard specifies the structure, type, specification, size, technical requirements, marking, selection and use regulations of wire mesh demister. This standard is applicable to gas-liquid separation devices used in vertical cylindrical equipment in chemical, petrochemical, pharmaceutical, light industry, environmental protection and other industries. It is used to separate mist with a diameter greater than 3-5μm in the gas. The specification range of wire mesh demister is DN300-Dn5200mm. 

3. Reference standards 

GB 343 "General purpose low carbon steel wire" 

GB 711 "High-quality carbon structural hot-rolled thick steel plate and steel strip" 

GB 3110 "Brass wire"

GB 3120 "Nickel Wire"

GB 3128 "Tin Bronze Wire for Weaving Nets"

GB 3206 "High-quality Carbon Structural Steel Wire"

GB 3274 "Carbon Structural Steel and Low-alloy Structural Steel Thick Plate and Strip"

GB 3623 "Titanium and Titanium Alloy Wire"

GB 4237 "Hot-rolled Stainless Steel Plate"

GB 4240 "Stainless Steel Wire"

GB/T13384 "General Technical Conditions for Packaging of Mechanical and Electrical Equipment"

JB 3316 "Industrial Metal Woven Square Hole Mesh"

4. Structure

3.0.1. The wire mesh demister is composed of a gas-liquid filter mesh pad (composed of several mesh blocks) and a support.

3.0.2. The mesh block is composed of several layers of flat corrugated wire mesh, grilles and distance rods, as shown in Figure 3.0.2.

Marking example:

Example 1: DN2000mm, H=150mm, filter type is SP plastic, material is 316, grille and support material is 304 top-mounted wire mesh demister, marked as: HG/T21618 wire mesh demister S2000-150 SP 316/304 Example 1

: DN4000mm, H=100mm, filter type is DP plastic, material is 316L, grille and support material is 304 bottom-mounted wire mesh demister, marked as: HG/T21618 wire mesh demister S4000-100 SP 316L/304

5. Type

5.0.1. Wire mesh demisters are available in two types: top-mounted and bottom-mounted, as shown in Figures 5.0.1 and 5.0.2.

The diameter range of top-mounted wire mesh demister is DN300-5200mm.

The diameter range of bottom-mounted wire mesh demister is DN700-34800mm

. 5.0.2 The type and basic parameters of the gas-liquid filter used in the wire mesh demister shall be in accordance with the provisions of Table 5.0.2.

Table 5.0.2 Type and basic parameters of gas-liquid filter

Note: ① Other types of gas-liquid filter screens can be used, such as non-metallic screens, multi-strand metal wire screens, metal wire and non-metallic wire interwoven screens, etc. Their parameters and performance can be inquired from professional defoamer manufacturers.

      ② The volume weight data of the gas-liquid filter screens listed in the table are obtained based on a density of 7930Kg/m3. If other materials are used, this data will be revised accordingly

. 5.0.3 The gas-liquid filter screens with the mesh types listed in Table 5.0.2 should be measured and confirmed. The gas-liquid filter screens with mesh types other than those in Table 5.0.2 should also provide the basic and necessary parameters.

Note: ① Specifications outside the nominal diameter range can be negotiated

       ② DN is the effective diameter of the wire mesh demister

       ③ The weight of the wire mesh is the weight of the SP type gas-liquid filter mesh block. If other types of gas-liquid filters are used, this value should be adjusted.