Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is a revision of HG/T 20583-2011 Specification of structural design for steel chemical vessels according to the requirements of Plan for the development and revision of the third batch of professional standards in 2017 (GONGXINTINGKE [2017], No.106) issued by the Ministry of Industry and Information Technology. It was prepared by Sedin Engineering Co., Ltd., the chief development organization, jointly with other participating development organizations under the organization of the National Technology Center of Process Equipment entrusted by the editorial department of the standard - China Petroleum & Chemical Engineering Survey and Design Association (CPCEA).
This standard replaces HG/T 20583-2011 Specification of structural design for steel chemical vessels from the implementation date hereof.
During the revision process of this standard, the drafting group, through extensive investigation and careful summarization of practical experience in engineering structural design, construction process, quality control and engineering quality acceptance of steel chemical vessels in China and reference to a large amount of information of engineering technology application of domestic and foreign engineering companies, reviewed and finalized the standard, on the basis of extensive consultation.
This standard consists of 15 clauses and 5 annexes, with the main contents as follows: general provisions; terms and symbols; cylinder, covers and their connection; flange, gaskets, bolts and nuts; man hole, hand hole and inspecting hole; openings, reinforcement and nozzles; liquid level meter, sight glass, thermometer and pressure gauge; pressure relief devices; supports; baffles at inlet and outlet; lifting lugs and davit; lighting rods, earth lug and name plate support; welding pads, insulation tacks and insulation rings; size of outsize profile and limitation of transportation; welding structure.
The following main changes have been made with respect to HG/T 20583-2011 Specification of structural design for steel chemical vessels:
1. The revision purpose and restrictions of this standard are added;
2. Some terms are adjusted;
3. The limit minimum length of cylinder is adjusted;
4. The legend of the application range of spherically dished cover is canceled, and the professional technical standard is directly quoted;
5. The requirement for cone top gradient of vertical vessel with a diameter of less than 5,600mm is added;
6. The restriction conditions of vessel flange are added;
7. The use of other flanges with mature use experience is added;
8. The restriction conditions of austenitic stainless steel bolts and nuts are added;
9. The requirement for hole spacing is added;
10. The use conditions and restrictions of reinforcing ring are added;
11. The rib plate reinforcement method of nozzle and the fixing method of embedded nozzle are added;
12. The sizes of the anchor bolts of skirt support with single ring plate bolt seat are adjusted;
13. The structural size of the buffer plate at inlet is tabulated and adjusted;
14. The thickness of steel plate with anti-vortex baffle is adjusted;
15. The requirements for inlet distributor and the setting requirements for tangential inlet wear plate are added;
16. The structural size of the baffle at gas outlet is tabulated and adjusted;
17. The setting requirements for low-temperature davit are added;
18. The requirements for minimum section of earth lug are added;
19. The number of butt joint welds is adjusted from 40 to 46; the number of weld joints of nozzle and shell is adjusted from 62 to 68; the number of fillet welds is adjusted from 12 to 18;
20. The code of lap weld is adjusted;
21. The number of welded seams of tubesheet and shell is adjusted from 9 to 15;
22. The titanium-steel composite structure is added;
23. Some clauses that are inconsistent with relevant standards are revised.
Contents
Foreword i
1 General provisions 1
2 Terms and symbols 1
2.1 Terms 1
2.2 Symbols 2
3 Cylinder, covers and their connection 3
3.1 Cylinder 3
3.2 Covers 4
3.3 Connection between cover and others 5
4 Flanges, gaskets, bolts and nuts 5
4.1 Shell flange 5
4.2 Nozzle flange 7
4.3 Special flange 8
4.4 Gasket 8
4.5 Bolts and nuts 9
5 Manhole, hand hole and inspecting hole 11
5.1 Principle 11
5.2 Quantity 12
5.3 Location 12
5.4 Type 13
5.5 Size 13
5.6 Ladder 14
6 Openings, reinforcement and nozzles 15
6.1 Opening 15
6.2 Reinforcement for opening 16
6.3 Nozzle 18
7 Liquid level meter, sight glass, thermometer and pressure gauge 22
7.1 Liquid level meter 22
7.2 Sight glass 24
7.3 Thermometer 24
7.4 Pressure gauge 24
8 Pressure relief devices 25
8.1 Principle 25
8.2 Connection pipe and flow area for relief device 25
8.3 Connection pipe for relief device 26
9 Supports 26
9.1 Saddle support 26
9.2 Leg support 27
9.3 Lug support 28
9.4 Bracket support 28
9.5 Support lug with rigid rings 28
9.6 Skirt support 29
10 Baffles at inlet and outlet 31
10.1 Buffer plate 31
10.2 Vortex breaker 32
10.3 Inlet distributor 34
10.4 Gas outlet baffle 36
11 Lifting lugs and davit 37
11.1 Lifting lugs 37
11.2 Davit 38
12 Lighting rod, earth lug and name plate support 39
12.1 Lighting rod 39
12.2 Earth lug 39
12.3 Name plate support 39
13 Welding pads, insulation tacks and insulation rings 40
13.1 Welding pads 40
13.2 Insulation tacks 40
13.3 Insulation rings 40
14 Size of outsize profile and limitation of transportation 41
14.1 Size of outsize profile 41
14.2 Limitation of transportation 41
15 Welding structure 42
15.1 Principle 42
15.2 Expression of welded seams 42
15.3 Butt weld 43
15.4 Weld joints of nozzle and shell 55
15.5 Fillet welds 80
15.6 Lap welds 87
15.7 T-type welds 90
15.8 Weld joints of tubesheet and shell 93
15.9 Choice of weld joints 98
Annex A (Informative) Gaskets of shell flange used in chemical medium 99
Annex B (Informative) Gaskets of nozzle flange used in chemical medium 104
Annex C (Informative) Anticorrosion properties of metallic and non-metallic gaskets 115
Annex D (Informative) Physical properties of metallic gasket 123
Annex E (Normative) Titanium-steel clad structure 124
E.1 Shell weld joint 124
E.2 Leakage nozzle of longitudinal and circumferential weld joints 126
E.3 Nozzle and flange 126
Explanation of wording in this standard 130
List of quoted standards 131
Standard for structural design of steel chemical vessel
1 General provisions
1.0.1 This standard is formulated to optimize and standardize the structural design of chemical vessel.
1.0.2 This standard is applicable to the general structure design of steel vessels in chemical process, and only serves as a reference for other processes and vessels made of other materials.
1.0.3 This standard is not applicable to dedicated or special structures specified in other mechanical or vessel standards.
1.0.4 In addition to this standard, the structural design of steel chemical vessel shall also comply with the requirements of the current relevant standards of the nation.
2 Terms and symbols
2.1 Terms
2.1.1
pressure
force vertically applied to unit surface area of a vessel, which refers to gauge pressure hereof, unless otherwise indicated
2.1.2
nominal pressure nominal in name or form but not in reality
compressive strength of the standard vessel or part at the reference temperature, which is related to the mechanical properties and dimensional characteristics of the standard vessel or part
2.1.3
nominal size
nominal size of the vessel or part which is close to the actual size, usually used to indicate the diameter, length, thickness and other sizes of a vessel or part
2.1.4
raised face, RF
a kind of flange sealing face, i.e. raised narrow sealing plane, of which the contact surface with gasket is located on the inner side of bolt hole
2.1.5
full face, FF
a kind of flange sealing face, also known as wide sealing face, of which, the contact surface with gasket is located on the inner and outer sides of bolt hole
2.1.6
welding
method of bonding workpieces by heating or pressing, or both, with or without filling materials
2.1.7
welding structure
connecting structure manufactured by welding; the structure formed by welding the vessel part is also a welding structure
2.1.8
welded seam
joint formed by welding fusion between welding parts. According to the relative positions of weldments and the welded seam formed, it may be roughly classified into butt weld, fillet weld, plug weld, groove weld and edge weld
2.1.9
weld reinforcement
height of the metal part above the connecting line of two weld toes on the surface of butt weld
2.1.10
weld joint
joint of two or more parts connected by welding, including welded seam, fusion zone and heat affected zone
2.2 Symbols
A——the distance from the center line of the saddle base plate of the horizontal cylindrical vessel to the tangent line of the cover, mm;
DN (Dn)——the nominal diameter of vessel or part, mm;
Hf——the straight edge height of cover, mm;
Hi——the embedded length of plug-in nozzle, mm;
L——the distance between tangent lines of two covers of horizontal vessel, mm;
l——the extension length of nozzle and its connecting flange, mm;
PN——the nominal pressure nominal in name or form but not in reality of vessel or part, MPa;
pd——the design pressure of vessel or part, MPa;
Ra——the average radius of cylinder, mm;
Rm——the lower limit of standard tensile strength of steel, MPa;
Td——the design temperature of vessel or part, ℃;
δn——the nominal thickness of vessel wall, mm;
δnt——the nominal thickness of nozzle, mm;
DC1——the mid-plane diameter of the large end of regular conical shell, mm;
DC2——the mid-plane diameter of the small end of regular conical shell, mm;
Dm——the mid-plane diameter of shell or part, mm;
Do——the outer diameter of vessel shell or part, mm;
dop——the opening diameter of vessel shell or part, mm;
W——the limit distance between the opening edge and the longitude line of discontinuous points, mm;
α——the half vertex angle of regular conical shell, °;
δn1——the nominal thickness of the large end of regular conical shell, mm;
δn2——the nominal thickness of the small end of regular conical shell, mm;
δr——the nominal thickness of the reinforced section of the cylinder connected with the conical shell, mm.
3 Cylinder, covers and their connection
3.1 Cylinder
3.1.1 The nominal diameter DN of cylindrical vessels and their parts should be selected according to the current national standard GB/T 9019 Nominal diameter for pressure vessels. When the cylinder is made of steel plate through rolling and welding, its nominal diameter DN shall be based on the inner diameter value, with 50mm as a unit for 300~1,000mm and 100mm as a unit for more than 1,000mm; when the cylinder is made of steel tube, its nominal diameter DN is expressed by an integer value close to the actual inner diameter of the steel tube. In the current national standard GB/T 9019 Nominal diameter for pressure vessels, the minimum nominal diameter DN is DN150 and the maximum nominal diameter is DN13200. When the matching with standard cover or standard flange is not considered, this restriction may not apply.
3.1.2 When the cylinder is of surfacing structure or loose lining composite structure, its nominal diameter should be based on the inner diameter of the base layer. When the cylinder is made of composite plate, its nominal diameter should be based on the inner diameter of the composite layer.
3.1.3 Special size series or foreign nominal diameter series in English units may also be adopted for the nominal diameter of vessel cylinder in special occasions or matched with foreign projects.
3.1.4 The length of the circular cylinder separately used as a vessel should not be less than 3 .
3.2 Covers
3.2.1 For medium and low pressure cylindrical pressure vessels, standard elliptical cover is preferred, dish cover, spherically dished cover, flat cover, conical cover and spherical cover may also be adopted. Standard covers may be selected according to the current national standard GB/T 25198 Heads for pressure vessels.
3.2.2 Spherically dished cover may be used as the end cover of vessel or as the middle cover of two independent pressure chambers of vessel. The inner radius of the cover should be 0.75~1.0 times the inner diameter of the cylinder. The design of the spherically dished cover shall meet the requirements of the current national standard GB/T 150.3 Pressure vessels - Part 3: Design.
3.2.3 Covers formed first and then spliced should be adopted for vessels with a diameter of DN>4,000mm.
3.2.4 When a conical cover is connected with the cylinder, and the straight edge height Hf of its large or small end cannot meet the length of the reinforced section of the cylinder required by the design, the size of the connected cylinder shall be adjusted to meet the design requirements.
3.2.5 When a vertical vessel is placed on a concrete or steel platform, and the bottom cover only bears the weight load of the stored medium and its deadweight load, a flat cover may be used as the bottom cover.
3.2.6 The half-cone apex angle of conical cover for vertical vessel containing solid materials should not be greater than 90° minus the repose angle.
3.2.7 For the top cover of vertical vessel or the temporary test cover of pressure component with low pressure is made of steel plate, when the diameter of the cylinder DN>1,600mm, the top cover should be equipped with stiffeners to improve the cover rigidity and reduce the plate thickness. The plate thickness and stiffener size shall be determined through calculation. The stiffeners may be subjected to parallel arrangement, #-shaped arrangement and circumferential-radial arrangement.
3.2.8 When the umbrella-shaped conical roof is used as the top cover of the vertical vessel, the diameter of the cylinder shall not be greater than 5,600mm. The cone top gradient shall not be less than ∠1: 6, but not be greater than ∠3: 4. Roof thickness shall be determined through calculation.
3.3 Connection between cover and others
3.3.1 Full penetration structure shall be adopted for the welded seams of the spherically dished cover or non-flanging conical cover and the cylinder or flange.
3.3.2 When the standard elliptical cover based on outer diameter is connected with the standard pipe flange, the hubbed butt welded flange should be adopted, and the wall thickness of the cover shall be appropriate to that of the end of the flange connection. If the structural size is not limited, the short section connection of cylinder shall be added.
3.3.3 When the standard elliptical cover, dish cover, cone cover with folded edge or flat bottom cover based on inner diameter is connected with the standard pressure vessel flange, the wall thickness and straight edge height Hf of the cover shall meet the requirements of flange connection. When the requirements cannot be met, short sections of cylinder shall be added.
4 Flanges, gaskets, bolts and nuts
4.1 Shell flange
4.1.1 Flange connection may be adopted for the section connection of the vessel cylinder or the connection between end cover and cylinder. However, flange connection should not be used when the diameter (DN) of the cylinder is greater than 3,000mm, or the design pressure (pd) is greater than 6.4MPa and the design temperature (Td) is greater than 350℃.
4.1.2 For vessels that do not require airtightness, angle steel may double as flange for the connection between end cover and cylinder or between sections of the cylinder. The number of bolts for angle steel doubling as flange should be a multiple of 4, and the arrangement and size of bolt holes shall meet the requirements of bolt connection for angle steel of corresponding size.
4.1.3 The flanges used for the connection between vessel cylinders with inner diameter as the nominal diameter or between cylinders and covers should be selected according to the current professional standards NB/T 47020~47027-2012 Flanges, gaskets and stud bolts & nut for pressure vessels; when the vessel cylinder is made of steel tube, the flange for connection between cylinders or between cylinder and cover should be selected according to the current professional standard HG/T 20592 Steel pipe flanges (PN designated).
4.1.4 The flanges used for connection between vessel cylinders (including steel pipe cylinder) with English unit as nominal diameter or between cylinder and cover should be selected according to the current professional standards HG/T 20615 Steel pipe flanges (Class designated) and HG/T 20623 Large diameter steel pipe flanges (Class designated).
4.1.5 When flange connection is adopted between cylinders of vacuum vessel or between cylinder and cover, the vacuum flange standard, pressure vessel flange standard and steel pipe flange standard may be selected. For the selection of pressure vessel flange and steel pipe flange, the nominal pressure grade of the flange shall be greater than or equal to 0.6MPa when the vacuum degree is below 600mmHg while greater than or equal to 1.0MPa when the vacuum degree is greater than or equal to 600mmHg.
4.1.6 For vessels containing explosive medium and moderately toxic medium, the nominal pressure grade of the vessel flange shall not be less than 0.6MPa; for vessels containing extremely and highly toxic media and highly permeable medium, the nominal pressure grade of the vessel flange shall not be less than 1.0MPa.
4.1.7 The sealing face of connecting flange shall be a male and female face or tongue and groove face. When the equipment is vertically arranged, the female or groove face shall be upward; when the equipment is horizontally arranged, the female or groove face should be located on the cylinder or a fixed part.
4.1.8 When the surface roughness of sealing face required by the sealing gasket is higher than that specified in the pressure vessel flange standard, the surface roughness of sealing face of the vessel flange shall be determined based on the sealing gasket requirements.
4.2 Nozzle flange
4.2.1 The nozzle flange of chemical vessels shall meet the requirements of current professional standards HG/T 20592~20614 Steel pipe flanges, gaskets and bolting (PN designated) and HG/T 20615~20635 HG/T 20615~20635 Steel pipe flanges, gaskets and bolting (Class designated). The connection size in HG/T 20592 Steel pipe flanges (PN designated) may be matched with the metric flange standard of the same grade of other domestic or foreign standard flanges, and see Annex C of HG/T 20592-2009 Steel pipe flanges (PN designated) for the matched domestic or foreign flange standards. The connection size in HG/T 20615 Steel pipe flanges (Class designated) may be matched with the English flange standard of the same grade of other domestic or foreign standard flanges, and see Annex D of HG/T 20615-2009 Steel pipe flanges (Class designated) for the matched domestic or foreign flange standards. The connection size in HG/T 20623 Large diameter steel pipe flanges (Class designated) may be matched with the English flange standard of the same grade of other domestic or foreign standard flanges, and see Annex B of HG/T 20623-2009 Large diameter steel pipe flanges (Class designated) for the matched domestic or foreign flange standards.
4.2.2 When male and female face or tongue and groove face is adopted as the sealing face of the nozzle flange of the vessel, male or female flange shall be adopted for the nozzle located on the top and side of the vessel, and tongue or groove flange shall be adopted for the nozzle located at the bottom of the vessel.
4.2.3 For vessels containing explosive medium and moderately toxic medium, the nominal pressure grade of the vessel nozzle flange shall not be less than 1.6MPa; for vessels containing extremely and highly toxic media and highly permeable medium, the nominal pressure grade of the vessel nozzle flange shall not be less than 2.0MPa.
4.2.4 For vessels containing extremely and highly toxic medium or highly permeable and moderately toxic medium and liquefied petroleum gas, hubbed butt welded flange should be adopted as its nozzle flange.
4.2.5 Hubbed butt welded flange shall be adopted as the nozzle flange of the vessel under low temperature, high temperature and fatigue conditions.
4.2.6 Special threaded flange, lens gasket and its bolts and nuts for high pressure may be selected according to corresponding current professional standards.
4.2.7 The surface roughness of the sealing face of nozzle flange shall be determined according to the selected sealing gasket. The surface roughness of the flange sealing face of common sealing gasket may be determined by reference to the current professional standards HG/T 20614 Specification for selection of steel pipe flanges , gaskets and bolting (PN designated) and HG/T 20635 Specification for selection of steel pipe flanges, gaskets and bolting (Class designated).
4.3 Special flange
4.3.1 The connecting flange at the cylinder end of high pressure vessel or at the specific nozzle connecting end of vessel should be subjected to design of flange, flange cover or end cap and bolts and nuts according to the selected sealing structure type.
4.3.2 Flanges with mature use experience should be adopted for flange connection in situations with high pressure, high temperature, frequent temperature change, high erosion and mechanical vibration.
4.3.3 Welded annular gasket should be adopted to seal the flange for the situations with high temperature, high pressure, no leakage and few disassembly times.
4.4 Gasket
4.4.1 Gasket for angle steel flange shall be a full face soft gasket, of which the material shall be selected according to medium properties, and thickness shall not be less than 1.5mm.
4.4.2 The gasket for pressure vessel flange should be a standard gasket. General gasket standards include the current professional standards NB/T 47024 Nonmetallic gaskets, NB/T 47025 Spiral wound gaskets and NB/T 47026 Double-jacketed gaskets as well as the current national standards GB/T 29463.1 Gaskets used in tube-shell heat exchangers - Part 1: Metallic jacketed gaskets, GB/T 29463.2 Gaskets used in tube-shell heat exchangers - Part 2: Spiral wound gasket and GB/T 29463.3 Gaskets used in tube-shell heat exchangers - Part 3:Nonmetallic gaskets.
4.4.3 Refer to Annex A for the matching of parameters such as gasket for pressure vessel flange and medium.
4.4.4 Gaskets for nozzle flanges shall be standard gaskets in the current professional standards HG/T 20606~20612 Specification for selection of steel pipe flanges, gaskets and bolting and HG/T 20606~20612 and HG/T 20627~20633 Specification for selection of steel pipe flanges, gaskets and bolting.
4.4.5 Refer to Annex B for the matching of parameters such as gasket for nozzle flange and medium.
4.4.6 Nonmetallic soft gaskets and metal-jacketed gaskets should be adopted in the place where the pressure and temperature are low; metallic gaskets and metal composite gaskets or metal spiral wound gaskets should be adopted in the place where the pressure and temperature are high; gaskets with good rebound elasticity and self-tightening function should be adopted in the place where the pressure and temperature are fluctuant.
4.4.7 As for the place where ethylene oxide is adopted as the medium, the gasket should be made of PTFE material. When the medium of titanium equipment is brine or wet chlorine, the gasket shall be made of ethylene-propylene rubber.
4.4.8 As for the place where trace fiber is not allowed to mix with medium, fibrous gaskets shall not be adopted.
4.4.9 In the place with hydrogen corrosion, the metallic framework and metal wrapping materials of metallic gasket or nonmetallic gasket should be made of austenitic stainless steel.
4.4.10 Self-tightening or semi-self-tightening gaskets should be adopted for high pressure vessels.
4.4.11 The anticorrosion properties of common metallic and nonmetallic gaskets may refer to Annex C, and the physical properties of common metallic gaskets may refer to Annex D.
4.4.12 When selecting asbestos products or asbestos-containing materials, local laws and regulations shall be considered.
4.5 Bolts and nuts
4.5.1 The studs for pressure vessel flange shall be selected according to the current professional standard NB/T 47027 Stud bolts & nuts for body flange. The matching of stud and nut materials shall meet those specified in Table 2 "Table for matching of flange, gasket, stud and nut materials” in NB/T 47020-2012 Type and specification for pressure vessel flanges.
4.5.2 Bolts, studs and nuts for steel pipe flanges shall be selected according to the current professional standards HG/T 20613 Bolting for use with steel pipe flanges (PN designated) and HG/T 20634 Bolting for use with steel pipe flanges (Class designated). The matching of steel pipe flanges, gaskets and bolts and nuts shall conform to the current professional standards HG/T 20614 Specification for selection of steel pipe flanges, gaskets and bolting (PN designated) and HG/T 20635 Specification for selection of steel pipe flanges, gaskets and bolting (Class designated).
4.5.3 Full-threaded hexagon head bolts or hexagon head bolts may be adopted for angle steel flanges according to the connection thickness.
4.5.4 Bolts, studs and nuts for austenitic stainless steel flanges should be made of materials with a smaller or similar linear expansion coefficient.
4.5.5 Bolts and nuts for pressure vessel flanges under high temperature, high pressure, low temperature and fatigue conditions shall be polished double end studs or full thread studs with a thinner middle part.
4.5.6 Bolts and nuts for flanges under high temperature and fatigue conditions should not be made of austenitic stainless steel.
4.5.7 Bolts and nuts with a diameter of M48 and above shall be equipped with tightening devices with controlled tightening load to avoid excessive tightening load. Nuts with a diameter of M48 and above shall be equipped with hardened flat washers.
4.5.8 Bolt spacing shall meet the requirements of tightening device. See Figure 4.5.8 and Table 4.5.8 for recommended spacing for bolts of M36 and above.
Foreword i
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Cylinder, covers and their connection
3.1 Cylinder
3.2 Covers
3.3 Connection between cover and others
4 Flanges, gaskets, bolts and nuts
4.1 Shell flange
4.2 Nozzle flange
4.3 Special flange
4.4 Gasket
4.5 Bolts and nuts
5 Manhole, hand hole and inspecting hole
5.1 Principle
5.2 Quantity
5.3 Location
5.4 Type
5.5 Size
5.6 Ladder
6 Openings, reinforcement and nozzles
6.1 Opening
6.2 Reinforcement for opening
6.3 Nozzle
7 Liquid level meter, sight glass, thermometer and pressure gauge
7.1 Liquid level meter
7.2 Sight glass
7.3 Thermometer
7.4 Pressure gauge
8 Pressure relief devices
8.1 Principle
8.2 Connection pipe and flow area for relief device
8.3 Connection pipe for relief device
9 Supports
9.1 Saddle support
9.2 Leg support
9.3 Lug support
9.4 Bracket support
9.5 Support lug with rigid rings
9.6 Skirt support
10 Baffles at inlet and outlet
10.1 Buffer plate
10.2 Vortex breaker
10.3 Inlet distributor
10.4 Gas outlet baffle
11 Lifting lugs and davit
11.1 Lifting lugs
11.2 Davit
12 Lighting rod, earth lug and name plate support
12.1 Lighting rod
12.2 Earth lug
12.3 Name plate support
13 Welding pads, insulation tacks and insulation rings
13.1 Welding pads
13.2 Insulation tacks
13.3 Insulation rings
14 Size of outsize profile and limitation of transportation
14.1 Size of outsize profile
14.2 Limitation of transportation
15 Welding structure
15.1 Principle
15.2 Expression of welded seams
15.3 Butt weld
15.4 Weld joints of nozzle and shell
15.5 Fillet welds
15.6 Lap welds
15.7 T-type welds
15.8 Weld joints of tubesheet and shell
15.9 Choice of weld joints
Annex A (Informative) Gaskets of shell flange used in chemical medium
Annex B (Informative) Gaskets of nozzle flange used in chemical medium
Annex C (Informative) Anticorrosion properties of metallic and non-metallic gaskets
Annex D (Informative) Physical properties of metallic gasket
Annex E (Normative) Titanium-steel clad structure
E.1 Shell weld joint
E.2 Leakage nozzle of longitudinal and circumferential weld joints
E.3 Nozzle and flange
Explanation of wording in this standard
List of quoted standards
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is a revision of HG/T 20583-2011 Specification of structural design for steel chemical vessels according to the requirements of Plan for the development and revision of the third batch of professional standards in 2017 (GONGXINTINGKE [2017], No.106) issued by the Ministry of Industry and Information Technology. It was prepared by Sedin Engineering Co., Ltd., the chief development organization, jointly with other participating development organizations under the organization of the National Technology Center of Process Equipment entrusted by the editorial department of the standard - China Petroleum & Chemical Engineering Survey and Design Association (CPCEA).
This standard replaces HG/T 20583-2011 Specification of structural design for steel chemical vessels from the implementation date hereof.
During the revision process of this standard, the drafting group, through extensive investigation and careful summarization of practical experience in engineering structural design, construction process, quality control and engineering quality acceptance of steel chemical vessels in China and reference to a large amount of information of engineering technology application of domestic and foreign engineering companies, reviewed and finalized the standard, on the basis of extensive consultation.
This standard consists of 15 clauses and 5 annexes, with the main contents as follows: general provisions; terms and symbols; cylinder, covers and their connection; flange, gaskets, bolts and nuts; man hole, hand hole and inspecting hole; openings, reinforcement and nozzles; liquid level meter, sight glass, thermometer and pressure gauge; pressure relief devices; supports; baffles at inlet and outlet; lifting lugs and davit; lighting rods, earth lug and name plate support; welding pads, insulation tacks and insulation rings; size of outsize profile and limitation of transportation; welding structure.
The following main changes have been made with respect to HG/T 20583-2011 Specification of structural design for steel chemical vessels:
1. The revision purpose and restrictions of this standard are added;
2. Some terms are adjusted;
3. The limit minimum length of cylinder is adjusted;
4. The legend of the application range of spherically dished cover is canceled, and the professional technical standard is directly quoted;
5. The requirement for cone top gradient of vertical vessel with a diameter of less than 5,600mm is added;
6. The restriction conditions of vessel flange are added;
7. The use of other flanges with mature use experience is added;
8. The restriction conditions of austenitic stainless steel bolts and nuts are added;
9. The requirement for hole spacing is added;
10. The use conditions and restrictions of reinforcing ring are added;
11. The rib plate reinforcement method of nozzle and the fixing method of embedded nozzle are added;
12. The sizes of the anchor bolts of skirt support with single ring plate bolt seat are adjusted;
13. The structural size of the buffer plate at inlet is tabulated and adjusted;
14. The thickness of steel plate with anti-vortex baffle is adjusted;
15. The requirements for inlet distributor and the setting requirements for tangential inlet wear plate are added;
16. The structural size of the baffle at gas outlet is tabulated and adjusted;
17. The setting requirements for low-temperature davit are added;
18. The requirements for minimum section of earth lug are added;
19. The number of butt joint welds is adjusted from 40 to 46; the number of weld joints of nozzle and shell is adjusted from 62 to 68; the number of fillet welds is adjusted from 12 to 18;
20. The code of lap weld is adjusted;
21. The number of welded seams of tubesheet and shell is adjusted from 9 to 15;
22. The titanium-steel composite structure is added;
23. Some clauses that are inconsistent with relevant standards are revised.
Contents
Foreword i
1 General provisions 1
2 Terms and symbols 1
2.1 Terms 1
2.2 Symbols 2
3 Cylinder, covers and their connection 3
3.1 Cylinder 3
3.2 Covers 4
3.3 Connection between cover and others 5
4 Flanges, gaskets, bolts and nuts 5
4.1 Shell flange 5
4.2 Nozzle flange 7
4.3 Special flange 8
4.4 Gasket 8
4.5 Bolts and nuts 9
5 Manhole, hand hole and inspecting hole 11
5.1 Principle 11
5.2 Quantity 12
5.3 Location 12
5.4 Type 13
5.5 Size 13
5.6 Ladder 14
6 Openings, reinforcement and nozzles 15
6.1 Opening 15
6.2 Reinforcement for opening 16
6.3 Nozzle 18
7 Liquid level meter, sight glass, thermometer and pressure gauge 22
7.1 Liquid level meter 22
7.2 Sight glass 24
7.3 Thermometer 24
7.4 Pressure gauge 24
8 Pressure relief devices 25
8.1 Principle 25
8.2 Connection pipe and flow area for relief device 25
8.3 Connection pipe for relief device 26
9 Supports 26
9.1 Saddle support 26
9.2 Leg support 27
9.3 Lug support 28
9.4 Bracket support 28
9.5 Support lug with rigid rings 28
9.6 Skirt support 29
10 Baffles at inlet and outlet 31
10.1 Buffer plate 31
10.2 Vortex breaker 32
10.3 Inlet distributor 34
10.4 Gas outlet baffle 36
11 Lifting lugs and davit 37
11.1 Lifting lugs 37
11.2 Davit 38
12 Lighting rod, earth lug and name plate support 39
12.1 Lighting rod 39
12.2 Earth lug 39
12.3 Name plate support 39
13 Welding pads, insulation tacks and insulation rings 40
13.1 Welding pads 40
13.2 Insulation tacks 40
13.3 Insulation rings 40
14 Size of outsize profile and limitation of transportation 41
14.1 Size of outsize profile 41
14.2 Limitation of transportation 41
15 Welding structure 42
15.1 Principle 42
15.2 Expression of welded seams 42
15.3 Butt weld 43
15.4 Weld joints of nozzle and shell 55
15.5 Fillet welds 80
15.6 Lap welds 87
15.7 T-type welds 90
15.8 Weld joints of tubesheet and shell 93
15.9 Choice of weld joints 98
Annex A (Informative) Gaskets of shell flange used in chemical medium 99
Annex B (Informative) Gaskets of nozzle flange used in chemical medium 104
Annex C (Informative) Anticorrosion properties of metallic and non-metallic gaskets 115
Annex D (Informative) Physical properties of metallic gasket 123
Annex E (Normative) Titanium-steel clad structure 124
E.1 Shell weld joint 124
E.2 Leakage nozzle of longitudinal and circumferential weld joints 126
E.3 Nozzle and flange 126
Explanation of wording in this standard 130
List of quoted standards 131
Standard for structural design of steel chemical vessel
1 General provisions
1.0.1 This standard is formulated to optimize and standardize the structural design of chemical vessel.
1.0.2 This standard is applicable to the general structure design of steel vessels in chemical process, and only serves as a reference for other processes and vessels made of other materials.
1.0.3 This standard is not applicable to dedicated or special structures specified in other mechanical or vessel standards.
1.0.4 In addition to this standard, the structural design of steel chemical vessel shall also comply with the requirements of the current relevant standards of the nation.
2 Terms and symbols
2.1 Terms
2.1.1
pressure
force vertically applied to unit surface area of a vessel, which refers to gauge pressure hereof, unless otherwise indicated
2.1.2
nominal pressure nominal in name or form but not in reality
compressive strength of the standard vessel or part at the reference temperature, which is related to the mechanical properties and dimensional characteristics of the standard vessel or part
2.1.3
nominal size
nominal size of the vessel or part which is close to the actual size, usually used to indicate the diameter, length, thickness and other sizes of a vessel or part
2.1.4
raised face, RF
a kind of flange sealing face, i.e. raised narrow sealing plane, of which the contact surface with gasket is located on the inner side of bolt hole
2.1.5
full face, FF
a kind of flange sealing face, also known as wide sealing face, of which, the contact surface with gasket is located on the inner and outer sides of bolt hole
2.1.6
welding
method of bonding workpieces by heating or pressing, or both, with or without filling materials
2.1.7
welding structure
connecting structure manufactured by welding; the structure formed by welding the vessel part is also a welding structure
2.1.8
welded seam
joint formed by welding fusion between welding parts. According to the relative positions of weldments and the welded seam formed, it may be roughly classified into butt weld, fillet weld, plug weld, groove weld and edge weld
2.1.9
weld reinforcement
height of the metal part above the connecting line of two weld toes on the surface of butt weld
2.1.10
weld joint
joint of two or more parts connected by welding, including welded seam, fusion zone and heat affected zone
2.2 Symbols
A——the distance from the center line of the saddle base plate of the horizontal cylindrical vessel to the tangent line of the cover, mm;
DN (Dn)——the nominal diameter of vessel or part, mm;
Hf——the straight edge height of cover, mm;
Hi——the embedded length of plug-in nozzle, mm;
L——the distance between tangent lines of two covers of horizontal vessel, mm;
l——the extension length of nozzle and its connecting flange, mm;
PN——the nominal pressure nominal in name or form but not in reality of vessel or part, MPa;
pd——the design pressure of vessel or part, MPa;
Ra——the average radius of cylinder, mm;
Rm——the lower limit of standard tensile strength of steel, MPa;
Td——the design temperature of vessel or part, ℃;
δn——the nominal thickness of vessel wall, mm;
δnt——the nominal thickness of nozzle, mm;
DC1——the mid-plane diameter of the large end of regular conical shell, mm;
DC2——the mid-plane diameter of the small end of regular conical shell, mm;
Dm——the mid-plane diameter of shell or part, mm;
Do——the outer diameter of vessel shell or part, mm;
dop——the opening diameter of vessel shell or part, mm;
W——the limit distance between the opening edge and the longitude line of discontinuous points, mm;
α——the half vertex angle of regular conical shell, °;
δn1——the nominal thickness of the large end of regular conical shell, mm;
δn2——the nominal thickness of the small end of regular conical shell, mm;
δr——the nominal thickness of the reinforced section of the cylinder connected with the conical shell, mm.
3 Cylinder, covers and their connection
3.1 Cylinder
3.1.1 The nominal diameter DN of cylindrical vessels and their parts should be selected according to the current national standard GB/T 9019 Nominal diameter for pressure vessels. When the cylinder is made of steel plate through rolling and welding, its nominal diameter DN shall be based on the inner diameter value, with 50mm as a unit for 300~1,000mm and 100mm as a unit for more than 1,000mm; when the cylinder is made of steel tube, its nominal diameter DN is expressed by an integer value close to the actual inner diameter of the steel tube. In the current national standard GB/T 9019 Nominal diameter for pressure vessels, the minimum nominal diameter DN is DN150 and the maximum nominal diameter is DN13200. When the matching with standard cover or standard flange is not considered, this restriction may not apply.
3.1.2 When the cylinder is of surfacing structure or loose lining composite structure, its nominal diameter should be based on the inner diameter of the base layer. When the cylinder is made of composite plate, its nominal diameter should be based on the inner diameter of the composite layer.
3.1.3 Special size series or foreign nominal diameter series in English units may also be adopted for the nominal diameter of vessel cylinder in special occasions or matched with foreign projects.
3.1.4 The length of the circular cylinder separately used as a vessel should not be less than 3 .
3.2 Covers
3.2.1 For medium and low pressure cylindrical pressure vessels, standard elliptical cover is preferred, dish cover, spherically dished cover, flat cover, conical cover and spherical cover may also be adopted. Standard covers may be selected according to the current national standard GB/T 25198 Heads for pressure vessels.
3.2.2 Spherically dished cover may be used as the end cover of vessel or as the middle cover of two independent pressure chambers of vessel. The inner radius of the cover should be 0.75~1.0 times the inner diameter of the cylinder. The design of the spherically dished cover shall meet the requirements of the current national standard GB/T 150.3 Pressure vessels - Part 3: Design.
3.2.3 Covers formed first and then spliced should be adopted for vessels with a diameter of DN>4,000mm.
3.2.4 When a conical cover is connected with the cylinder, and the straight edge height Hf of its large or small end cannot meet the length of the reinforced section of the cylinder required by the design, the size of the connected cylinder shall be adjusted to meet the design requirements.
3.2.5 When a vertical vessel is placed on a concrete or steel platform, and the bottom cover only bears the weight load of the stored medium and its deadweight load, a flat cover may be used as the bottom cover.
3.2.6 The half-cone apex angle of conical cover for vertical vessel containing solid materials should not be greater than 90° minus the repose angle.
3.2.7 For the top cover of vertical vessel or the temporary test cover of pressure component with low pressure is made of steel plate, when the diameter of the cylinder DN>1,600mm, the top cover should be equipped with stiffeners to improve the cover rigidity and reduce the plate thickness. The plate thickness and stiffener size shall be determined through calculation. The stiffeners may be subjected to parallel arrangement, #-shaped arrangement and circumferential-radial arrangement.
3.2.8 When the umbrella-shaped conical roof is used as the top cover of the vertical vessel, the diameter of the cylinder shall not be greater than 5,600mm. The cone top gradient shall not be less than ∠1: 6, but not be greater than ∠3: 4. Roof thickness shall be determined through calculation.
3.3 Connection between cover and others
3.3.1 Full penetration structure shall be adopted for the welded seams of the spherically dished cover or non-flanging conical cover and the cylinder or flange.
3.3.2 When the standard elliptical cover based on outer diameter is connected with the standard pipe flange, the hubbed butt welded flange should be adopted, and the wall thickness of the cover shall be appropriate to that of the end of the flange connection. If the structural size is not limited, the short section connection of cylinder shall be added.
3.3.3 When the standard elliptical cover, dish cover, cone cover with folded edge or flat bottom cover based on inner diameter is connected with the standard pressure vessel flange, the wall thickness and straight edge height Hf of the cover shall meet the requirements of flange connection. When the requirements cannot be met, short sections of cylinder shall be added.
4 Flanges, gaskets, bolts and nuts
4.1 Shell flange
4.1.1 Flange connection may be adopted for the section connection of the vessel cylinder or the connection between end cover and cylinder. However, flange connection should not be used when the diameter (DN) of the cylinder is greater than 3,000mm, or the design pressure (pd) is greater than 6.4MPa and the design temperature (Td) is greater than 350℃.
4.1.2 For vessels that do not require airtightness, angle steel may double as flange for the connection between end cover and cylinder or between sections of the cylinder. The number of bolts for angle steel doubling as flange should be a multiple of 4, and the arrangement and size of bolt holes shall meet the requirements of bolt connection for angle steel of corresponding size.
4.1.3 The flanges used for the connection between vessel cylinders with inner diameter as the nominal diameter or between cylinders and covers should be selected according to the current professional standards NB/T 47020~47027-2012 Flanges, gaskets and stud bolts & nut for pressure vessels; when the vessel cylinder is made of steel tube, the flange for connection between cylinders or between cylinder and cover should be selected according to the current professional standard HG/T 20592 Steel pipe flanges (PN designated).
4.1.4 The flanges used for connection between vessel cylinders (including steel pipe cylinder) with English unit as nominal diameter or between cylinder and cover should be selected according to the current professional standards HG/T 20615 Steel pipe flanges (Class designated) and HG/T 20623 Large diameter steel pipe flanges (Class designated).
4.1.5 When flange connection is adopted between cylinders of vacuum vessel or between cylinder and cover, the vacuum flange standard, pressure vessel flange standard and steel pipe flange standard may be selected. For the selection of pressure vessel flange and steel pipe flange, the nominal pressure grade of the flange shall be greater than or equal to 0.6MPa when the vacuum degree is below 600mmHg while greater than or equal to 1.0MPa when the vacuum degree is greater than or equal to 600mmHg.
4.1.6 For vessels containing explosive medium and moderately toxic medium, the nominal pressure grade of the vessel flange shall not be less than 0.6MPa; for vessels containing extremely and highly toxic media and highly permeable medium, the nominal pressure grade of the vessel flange shall not be less than 1.0MPa.
4.1.7 The sealing face of connecting flange shall be a male and female face or tongue and groove face. When the equipment is vertically arranged, the female or groove face shall be upward; when the equipment is horizontally arranged, the female or groove face should be located on the cylinder or a fixed part.
4.1.8 When the surface roughness of sealing face required by the sealing gasket is higher than that specified in the pressure vessel flange standard, the surface roughness of sealing face of the vessel flange shall be determined based on the sealing gasket requirements.
4.2 Nozzle flange
4.2.1 The nozzle flange of chemical vessels shall meet the requirements of current professional standards HG/T 20592~20614 Steel pipe flanges, gaskets and bolting (PN designated) and HG/T 20615~20635 HG/T 20615~20635 Steel pipe flanges, gaskets and bolting (Class designated). The connection size in HG/T 20592 Steel pipe flanges (PN designated) may be matched with the metric flange standard of the same grade of other domestic or foreign standard flanges, and see Annex C of HG/T 20592-2009 Steel pipe flanges (PN designated) for the matched domestic or foreign flange standards. The connection size in HG/T 20615 Steel pipe flanges (Class designated) may be matched with the English flange standard of the same grade of other domestic or foreign standard flanges, and see Annex D of HG/T 20615-2009 Steel pipe flanges (Class designated) for the matched domestic or foreign flange standards. The connection size in HG/T 20623 Large diameter steel pipe flanges (Class designated) may be matched with the English flange standard of the same grade of other domestic or foreign standard flanges, and see Annex B of HG/T 20623-2009 Large diameter steel pipe flanges (Class designated) for the matched domestic or foreign flange standards.
4.2.2 When male and female face or tongue and groove face is adopted as the sealing face of the nozzle flange of the vessel, male or female flange shall be adopted for the nozzle located on the top and side of the vessel, and tongue or groove flange shall be adopted for the nozzle located at the bottom of the vessel.
4.2.3 For vessels containing explosive medium and moderately toxic medium, the nominal pressure grade of the vessel nozzle flange shall not be less than 1.6MPa; for vessels containing extremely and highly toxic media and highly permeable medium, the nominal pressure grade of the vessel nozzle flange shall not be less than 2.0MPa.
4.2.4 For vessels containing extremely and highly toxic medium or highly permeable and moderately toxic medium and liquefied petroleum gas, hubbed butt welded flange should be adopted as its nozzle flange.
4.2.5 Hubbed butt welded flange shall be adopted as the nozzle flange of the vessel under low temperature, high temperature and fatigue conditions.
4.2.6 Special threaded flange, lens gasket and its bolts and nuts for high pressure may be selected according to corresponding current professional standards.
4.2.7 The surface roughness of the sealing face of nozzle flange shall be determined according to the selected sealing gasket. The surface roughness of the flange sealing face of common sealing gasket may be determined by reference to the current professional standards HG/T 20614 Specification for selection of steel pipe flanges , gaskets and bolting (PN designated) and HG/T 20635 Specification for selection of steel pipe flanges, gaskets and bolting (Class designated).
4.3 Special flange
4.3.1 The connecting flange at the cylinder end of high pressure vessel or at the specific nozzle connecting end of vessel should be subjected to design of flange, flange cover or end cap and bolts and nuts according to the selected sealing structure type.
4.3.2 Flanges with mature use experience should be adopted for flange connection in situations with high pressure, high temperature, frequent temperature change, high erosion and mechanical vibration.
4.3.3 Welded annular gasket should be adopted to seal the flange for the situations with high temperature, high pressure, no leakage and few disassembly times.
4.4 Gasket
4.4.1 Gasket for angle steel flange shall be a full face soft gasket, of which the material shall be selected according to medium properties, and thickness shall not be less than 1.5mm.
4.4.2 The gasket for pressure vessel flange should be a standard gasket. General gasket standards include the current professional standards NB/T 47024 Nonmetallic gaskets, NB/T 47025 Spiral wound gaskets and NB/T 47026 Double-jacketed gaskets as well as the current national standards GB/T 29463.1 Gaskets used in tube-shell heat exchangers - Part 1: Metallic jacketed gaskets, GB/T 29463.2 Gaskets used in tube-shell heat exchangers - Part 2: Spiral wound gasket and GB/T 29463.3 Gaskets used in tube-shell heat exchangers - Part 3:Nonmetallic gaskets.
4.4.3 Refer to Annex A for the matching of parameters such as gasket for pressure vessel flange and medium.
4.4.4 Gaskets for nozzle flanges shall be standard gaskets in the current professional standards HG/T 20606~20612 Specification for selection of steel pipe flanges, gaskets and bolting and HG/T 20606~20612 and HG/T 20627~20633 Specification for selection of steel pipe flanges, gaskets and bolting.
4.4.5 Refer to Annex B for the matching of parameters such as gasket for nozzle flange and medium.
4.4.6 Nonmetallic soft gaskets and metal-jacketed gaskets should be adopted in the place where the pressure and temperature are low; metallic gaskets and metal composite gaskets or metal spiral wound gaskets should be adopted in the place where the pressure and temperature are high; gaskets with good rebound elasticity and self-tightening function should be adopted in the place where the pressure and temperature are fluctuant.
4.4.7 As for the place where ethylene oxide is adopted as the medium, the gasket should be made of PTFE material. When the medium of titanium equipment is brine or wet chlorine, the gasket shall be made of ethylene-propylene rubber.
4.4.8 As for the place where trace fiber is not allowed to mix with medium, fibrous gaskets shall not be adopted.
4.4.9 In the place with hydrogen corrosion, the metallic framework and metal wrapping materials of metallic gasket or nonmetallic gasket should be made of austenitic stainless steel.
4.4.10 Self-tightening or semi-self-tightening gaskets should be adopted for high pressure vessels.
4.4.11 The anticorrosion properties of common metallic and nonmetallic gaskets may refer to Annex C, and the physical properties of common metallic gaskets may refer to Annex D.
4.4.12 When selecting asbestos products or asbestos-containing materials, local laws and regulations shall be considered.
4.5 Bolts and nuts
4.5.1 The studs for pressure vessel flange shall be selected according to the current professional standard NB/T 47027 Stud bolts & nuts for body flange. The matching of stud and nut materials shall meet those specified in Table 2 "Table for matching of flange, gasket, stud and nut materials” in NB/T 47020-2012 Type and specification for pressure vessel flanges.
4.5.2 Bolts, studs and nuts for steel pipe flanges shall be selected according to the current professional standards HG/T 20613 Bolting for use with steel pipe flanges (PN designated) and HG/T 20634 Bolting for use with steel pipe flanges (Class designated). The matching of steel pipe flanges, gaskets and bolts and nuts shall conform to the current professional standards HG/T 20614 Specification for selection of steel pipe flanges, gaskets and bolting (PN designated) and HG/T 20635 Specification for selection of steel pipe flanges, gaskets and bolting (Class designated).
4.5.3 Full-threaded hexagon head bolts or hexagon head bolts may be adopted for angle steel flanges according to the connection thickness.
4.5.4 Bolts, studs and nuts for austenitic stainless steel flanges should be made of materials with a smaller or similar linear expansion coefficient.
4.5.5 Bolts and nuts for pressure vessel flanges under high temperature, high pressure, low temperature and fatigue conditions shall be polished double end studs or full thread studs with a thinner middle part.
4.5.6 Bolts and nuts for flanges under high temperature and fatigue conditions should not be made of austenitic stainless steel.
4.5.7 Bolts and nuts with a diameter of M48 and above shall be equipped with tightening devices with controlled tightening load to avoid excessive tightening load. Nuts with a diameter of M48 and above shall be equipped with hardened flat washers.
4.5.8 Bolt spacing shall meet the requirements of tightening device. See Figure 4.5.8 and Table 4.5.8 for recommended spacing for bolts of M36 and above.
Contents of HG/T 20583-2020
Foreword i
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Cylinder, covers and their connection
3.1 Cylinder
3.2 Covers
3.3 Connection between cover and others
4 Flanges, gaskets, bolts and nuts
4.1 Shell flange
4.2 Nozzle flange
4.3 Special flange
4.4 Gasket
4.5 Bolts and nuts
5 Manhole, hand hole and inspecting hole
5.1 Principle
5.2 Quantity
5.3 Location
5.4 Type
5.5 Size
5.6 Ladder
6 Openings, reinforcement and nozzles
6.1 Opening
6.2 Reinforcement for opening
6.3 Nozzle
7 Liquid level meter, sight glass, thermometer and pressure gauge
7.1 Liquid level meter
7.2 Sight glass
7.3 Thermometer
7.4 Pressure gauge
8 Pressure relief devices
8.1 Principle
8.2 Connection pipe and flow area for relief device
8.3 Connection pipe for relief device
9 Supports
9.1 Saddle support
9.2 Leg support
9.3 Lug support
9.4 Bracket support
9.5 Support lug with rigid rings
9.6 Skirt support
10 Baffles at inlet and outlet
10.1 Buffer plate
10.2 Vortex breaker
10.3 Inlet distributor
10.4 Gas outlet baffle
11 Lifting lugs and davit
11.1 Lifting lugs
11.2 Davit
12 Lighting rod, earth lug and name plate support
12.1 Lighting rod
12.2 Earth lug
12.3 Name plate support
13 Welding pads, insulation tacks and insulation rings
13.1 Welding pads
13.2 Insulation tacks
13.3 Insulation rings
14 Size of outsize profile and limitation of transportation
14.1 Size of outsize profile
14.2 Limitation of transportation
15 Welding structure
15.1 Principle
15.2 Expression of welded seams
15.3 Butt weld
15.4 Weld joints of nozzle and shell
15.5 Fillet welds
15.6 Lap welds
15.7 T-type welds
15.8 Weld joints of tubesheet and shell
15.9 Choice of weld joints
Annex A (Informative) Gaskets of shell flange used in chemical medium
Annex B (Informative) Gaskets of nozzle flange used in chemical medium
Annex C (Informative) Anticorrosion properties of metallic and non-metallic gaskets
Annex D (Informative) Physical properties of metallic gasket
Annex E (Normative) Titanium-steel clad structure
E.1 Shell weld joint
E.2 Leakage nozzle of longitudinal and circumferential weld joints
E.3 Nozzle and flange
Explanation of wording in this standard
List of quoted standards
