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Industry Standard of the People's Republic of China
HG 205831998
Specification for Structural Design of Steel Chemical Vessels199811-18Published
State Administration of Petroleum and Chemical Industry
1999—03—01
Industry Standard of the People's Republic of China
Specification for Structural Design of Steel Chemical Vessels VesselsHG20583-1998
Editor: China Huatai Engineering Corporation
Approval Department: State Petroleum and Chemical Industry Bureau Implementation Date: March 1, 1999 National Chemical Engineering Construction Standard Editing Center (formerly the Engineering Construction Standard Editing Center of the Ministry of Chemical Industry) 1999 Beijing
This standard (HG20583-1998) is based on the original standard (HGJ17-89), based on the experience gained since its implementation, and based on the content of national standard GB150-1998 and the standard specifications of domestic and foreign engineering companies in recent years. The new revised standard has the following major changes compared with the original standard:
1. Some standards involved in the content of this standard have been revised in recent years, such as elliptical heads, vessel flanges, pipe flanges, manholes, hand holes, supports, etc. Therefore, the content of this standard has also been adjusted accordingly with reference to these standards. 2. If other standards have special provisions, this standard will no longer repeat their contents, such as welding structures in GB151, equipment flanges, pipe flanges, etc.
3. Appropriate adjustments have been made to some vocabulary, clauses, numerical values, illustrations, etc. in terms of accuracy and strictness in light of actual conditions. 4. Added "Foreword", "Equipment Lifting Ears", "Grounding Plates", and "Segmentation Boundaries of Overlimit Containers". Appendices A and B of this standard are appendices to this standard. Appendices C and D of this standard are indicative appendices. This standard is proposed and managed by the National Chemical Equipment Design Technology Center. This standard is edited by China Huatai Engineering Company. The main drafters of this standard: Wang Kai, Qiao Haixing, Zhang Zhenhua, Wei Xiaolian 302
HG20583-1998 "Steel Chemical Container Structural Design Regulations" is a supplement and concretization of the structural design aspects of GB150-1998 "Steel Pressure Vessels" in light of the specific conditions of chemical container design. The scope of application, referenced standards and definitions of this regulation, unless otherwise specified, are the same as GB150-1998 "Steel Pressure Vessels". Pressure Vessels》.
1.0.1 These regulations apply to general structures in the design of steel chemical containers. 1.0.2 These regulations do not include special structures or special structures (such as towers and heat exchangers, etc.) that have been specified in special standards. 303
2 Cylinders, heads and their connections
The cylinder or jacket is usually made of steel plate rolled and welded, and the nominal diameter is based on the inner diameter. For small-diameter containers, steel pipes can generally be used as cylinders, and the nominal diameter should comply with the provisions of GB9019. 2.2 Seals
2.2.1 Standard elliptical heads should be used as the head type for medium and low pressure vessels, and they should be selected according to JB/T4737 and JB/T4729 standards. If necessary, dish-shaped, folded-edge conical heads and other heads can also be used, and they should be selected according to the corresponding standards. 2.2.2 Spherical cap heads are generally only used as intermediate heads or end heads for two independent pressurized spaces. For its use under various diameters, please refer to Figure 2-1, and it should be designed in accordance with GB150 "Steel Pressure Vessels". o
Without reinforcement
With reinforcement
Container diameter
Figure 2-1 Application scope of spherical cap heads
2.2.3 Pressure vessels with larger diameters (generally DN4000mm) can use welded heads. 2.2.4 When a pressure vessel adopts a conical head to meet the process production requirements, the conical head without folded edge should be designed in accordance with GB150 "Steel Pressure Vessels", which is suitable for the semi-cone top angle of the cone α<30°. When α>30°, the large end must use a transition folded edge, and when 45<α≤60°, the small end must use a transition folded edge. Use a folded edge structure with a transition section. The folded edge conical head is recommended and selected according to JB/T4738~4739 standards. 2.2.5 For vertical containers placed on the ground or steel frame platform, the bottom of which only bears the dead weight of the liquid, a flat plate can be used as its bottom head, and the thickness of the head is determined by calculation.
2.2.6 When a thin flat plate is used as the top cover of the container, the top cover with a diameter of DN≥1600mm should generally consider setting a steel section to increase rigidity. The thickness of the top cover and the specifications of the steel section should be determined by calculation. 2.2.7 When there are many pipes on the head with a small diameter, the overall thickness of the head can be increased to improve strength and rigidity. 304
2.3 Connection of the head
The corner welds connecting the compressed spherical cap head, the non-folded edge conical head and the cylinder or flange must adopt a full penetration structure. 2.3.1
When the head is connected to the flange, the height of its straight edge should meet the requirements of Figure 2-2. If the standard head cannot meet this requirement, the following measures can be taken: 1. Increase the straight edge height, but the maximum height shall not be greater than 1.5 times the straight edge height of the standard head (the non-standard straight edge height value shall be indicated in the detailed table of the design drawing); 2. Add a short section between the head and the flange. ≥2S and not less than 13mm Figure 2-2 Head straight edge quotient 3. Vessel flange, gasket, bolt (column) 3.1 Vessel flange 3.1.1 For vessels without airtight requirements, angle steel can be used as flange. The number of bolts on the angle steel flange is generally a multiple of 4. 3.1.2 Pressure vessel flanges shall be selected according to JB4701~4703 standards. 3.1.3 Sealing surface type The sealing surface type of the vessel flange can generally be selected by referring to Appendix A. However, if the engineering design stipulates otherwise, the engineering regulations shall apply. 1
2 When using concave-convex or grooved container flanges, the grooved or concave surface of the vertical container flange must face upward, and the grooved or concave surface of the flange-connected horizontal container flange should be located on the cylinder. Determination of nominal pressure
The pressure level of the selected container flange should not be lower than the allowable working pressure of the flange material at the working temperature. 1
2 The nominal pressure selected for the vacuum system container flange should generally be no less than 0.6MPa (excluding when selected according to the vacuum flange standard). 3.2 GasketsbzxZ.net
3.2.1 Gasket types and selection
1 Non-metallic gaskets should be used for normal pressure, low pressure and medium temperature: metal gaskets or gaskets with metal (metal-clad gaskets, spiral wound gaskets) should be used for high temperature <≥350℃) and high pressure (≥6.4MPa). When the temperature and pressure fluctuate, it is advisable to use gaskets with good resilience or a certain self-tightening effect.
2The wound gasket has good compressibility and resilience, excellent sealing performance, and is suitable for use under general conditions. It is especially suitable for medium and low pressure flange sealing under conditions of stress relaxation, temperature and pressure fluctuations, shock and vibration. However, it should be noted that the hook should be tightened evenly and avoid over-tightening. The structural types of the seal are: basic type, with inner ring, with outer ring, and with inner and outer rings. The functions of the ring are as follows: (1) Outer ring: It plays the role of centering and limiting the outward expansion of the gasket when it is under pressure. The thickness is generally 3.2mm, and it is mostly made of low carbon steel. (2) Inner ring: It can prevent the gasket from being squeezed and deformed inward when it is under pressure, and at the same time prevent the steel belt and filler from entering the container to contaminate the material. After the inner ring is installed, the gap between the flanges is reduced, thereby reducing fluid stagnation and preventing eddy currents. It can also reduce the occurrence of corrosion in corrosive media. The thickness is generally 3.2mm, and it is mostly made of low carbon steel. If stainless steel is required, the thickness is taken as 2.5mm. (3) Inner and outer rings: In addition to the comprehensive performance of the inner and outer rings mentioned above, they also play a role in axially limiting excessive extrusion of the metal belt. In addition, the reduction of the gasket specific pressure is prevented.
3 Asbestos rubber sheet is the most commonly used non-metallic gasket, suitable for the connection of water, steam, air and other inert gases with low temperature and pressure and small fluctuations that are not often disassembled. Asbestos rubber sheet should comply with GB3985 "Asbestos Rubber Sheet" standard. When selecting, the brand should be indicated in the remarks column (generally XB350 is used. XB350 is suitable for P≤2.5MPa, ≤300℃, and XB200 is suitable for P≤0.6MPa, t≤150C) (At present, asbestos rubber gaskets have been gradually eliminated abroad and replaced with flexible graphite, ceramic fiber, etc.). Oil-resistant asbestos rubber sheets should comply with the GB539 "Oil-resistant asbestos rubber sheets" standard and are generally suitable for t≤200C occasions. 4 When the medium is ethylene oxide, asbestos-containing gaskets shall not be used. 5 When operating under vacuum, asbestos rubber gaskets are not allowed to be used as flange gaskets. Generally, rubber washers or other types of gaskets (such as 306
spiral wound gaskets) are used.
6 In situations where trace amounts of fibers are not allowed to mix into the medium, such as aviation gasoline or aviation kerosene, asbestos rubber sheets and other fibrous gaskets should not be used, but spiral wound gaskets with expanded graphite or polytetrafluoroethylene as fillers should be used. 7 When gaskets are used in situations where hydrogen sulfide stress corrosion occurs, the metal material of the gasket should be stainless steel containing Ti. 8 For gaskets in hydrogen-containing devices, if metal gaskets, wound gaskets or metal-clad gaskets are used, the hydrogen resistance and corrosion resistance of the metal materials used should be equal to or higher than the sealing surface materials. 9 In order to improve the sealing performance of metal flat gaskets and metal-clad gaskets, 0.4mm thick expanded graphite tape can be attached to both sides of the gasket. The gasket coefficient after attachment can be m=2, Y=5.9MPa. 10 Polytetrafluoroethylene has excellent corrosion resistance and self-lubrication, and is a good sealing material. Its types include polytetrafluoroethylene raw tape wrapped with asbestos rubber sheet, polytetrafluoroethylene sheet, polytetrafluoroethylene wound gasket and polytetrafluoroethylene wrapped gasket. The higher the operating temperature, the lower the applicable pressure, and the maximum temperature is less than or equal to 250℃. 11 High-strength graphite gasket is a new type of asbestos-free gasket, which can be used in high temperature (up to 450~650℃, mainly depending on the metal core plate material), low temperature (up to 70℃), high pressure (up to 6.3MPa) and corrosive media. The gasket is composed of a punched metal core plate and expanded graphite particles (see Figure 3-1), and its thickness T is 1.5mm and 3mm.
12 Octagonal or elliptical cross-section
Punched metal core plate
Expanded graphite particles
Figure 3-1
Ring metal gaskets are used in high temperature (t≥450～600℃), medium and high pressure (2.0～35MPa) occasions, and have the characteristics of reliable sealing and reusability. Due to the processing problems of rings and grooves, it is generally used for sealing high-temperature and high-pressure parts with a nominal diameter of DN<900mm.
13 Coated gasket (referred to as coated gasket)
This type of gasket is divided into two types: metal coated gasket and non-metal coated gasket. (1) Metal coated gasket: It is a gasket formed by wrapping a non-metallic material with a soft and thin metal sheath. It can be used to seal certain liquids and gases at higher temperatures (<450℃) and pressures (≤6.4MPa). The most widely used is the flat metal coated gasket. The advantage of this semi-metal coated gasket is that it is easier to compress than a metal gasket and has better recovery. The material of the metal sheath is usually low carbon steel, copper, aluminum, monel alloy and stainless steel. Non-metallic materials are mostly asbestos sheets, and other materials such as glass fiber, polytetrafluoroethylene, porcelain fiber, expanded graphite, etc. can also be used.
(2) Non-metallic gasket: It is a gasket with complementary properties made of asbestos rubber sheet, asbestos sheet, metal mesh and corrugated metal sheet as filling core material, and then covered with polytetrafluoroethylene sleeve. It is characterized by sufficient elasticity and flexibility, as well as good corrosion resistance, and can ensure good sealing even when used on low-pressure flanges. The operating pressure is less than or equal to 4.OMPa, and the operating temperature is less than or equal to 150℃.
3.2.2 Gasket specifications and dimensions and requirements for the roughness of flange sealing surface 1 The specifications and dimensions of non-metallic soft gaskets, spiral wound gaskets and metal-clad gaskets for pressure vessel flanges shall be selected according to JB47044706 standard, and spiral wound gaskets can also be selected according to GB4622 "Spiral Wrap Gasket" standard. 2 Gaskets for pipe flanges shall be selected according to HG20606~20611 and HG20627~20632 standards. 3 The specifications and dimensions of metal toothed gaskets shall be selected in accordance with the standard JB88 "Metal toothed gaskets for flanges with concave and convex sealing surfaces". 4 The elliptical and octagonal ring gaskets shall be selected in accordance with the standards HG20612 and HG20633. 307
5 The specifications and dimensions of lens-type gaskets for pipe flanges shall be selected in accordance with the standards JB90 "Metal gaskets for flanges with lens-type sealing surfaces" or JB2776~2777 "Lens gaskets".
6 The thickness of non-metallic soft gaskets is generally selected according to the diameter of the container: for nominal diameter DN≤450mm, thickness 8=2mm; for nominal diameter DN>450mm, thickness =3mm. 7 The thickness of metal flat gaskets is generally 3~6mm. 8 The roughness requirements of various gaskets on flange sealing surfaces are shown in Table 3-1. Table 3-1
Gasket category
Gasket name
Flange sealing surface
Surface roughness
Metal gasket
Serrated
Semi-metallic sealing gasket
Metal clad
Asbestos rubber sheet
Bolt (column)
3.3.1 Equal-length studs for pressure vessel flanges shall be selected in accordance with JB4707 standard. Polytetrafluoroethylene sealing gasket
Rubber sheet
Plate gasket
Clad gasket
Flexible graphite
3.3.2 For the materials of connecting bolts (columns) and nuts for austenitic alloy steel flanges, when the working temperature t≤100℃, carbon steel is generally allowed to be used. When the working temperature is 100℃2 Gasket specifications and dimensions and requirements for the roughness of flange sealing surfaces 1 The specifications and dimensions of non-metallic soft gaskets, spiral wound gaskets and metal clad gaskets for pressure vessel flanges shall be selected according to the JB47044706 standard, and spiral wound gaskets may also be selected according to the GB4622 "Spiral Wrap Gasket" standard. 2 Gaskets for pipe flanges shall be selected according to the HG20606~20611 and HG20627~20632 standards. 3 The specifications and dimensions of metal toothed gaskets shall be selected according to the JB88 "Metal toothed gaskets for flanges with concave and convex sealing surfaces". 4 Oval and octagonal ring gaskets shall be selected according to the HG20612 and HG20633 standards. 307
5 The specifications and dimensions of lens-type gaskets for pipe flanges shall be selected according to the JB90 "Metal gaskets for flanges with lens-type sealing surfaces" or JB2776~2777 "Lens Gaskets" standards.
6 The thickness of non-metallic soft gaskets is generally selected according to the diameter of the container: for nominal diameter DN≤450mm, thickness8=2mm; for nominal diameter DN>450mm, thickness=3mm. 7 The thickness of metal flat gaskets is generally 3~6mm. 8 The roughness requirements of various gaskets on flange sealing surface are shown in Table 3-1. Table 3-1
Gasket category
Gasket name
Flange sealing surface
Surface roughness
Metal gasket
Serrated
Semi-metallic sealing gasket
Metal package
Asbestos rubber sheet
Bolt (column)
3.3.1 Equal-length studs for pressure vessel flanges shall be selected in accordance with JB4707 standard. PTFE gasket
Rubber sheet
Plate gasket
Pack gasket
Flexible graphite
3.3.2 For the connecting bolts (columns) and nuts of austenitic alloy steel flanges, when the working temperature t≤100℃, carbon steel is generally allowed to be used. When the working temperature is 100℃2 Gasket specifications and dimensions and requirements for the roughness of flange sealing surfaces 1 The specifications and dimensions of non-metallic soft gaskets, spiral wound gaskets and metal clad gaskets for pressure vessel flanges shall be selected according to the JB47044706 standard, and spiral wound gaskets may also be selected according to the GB4622 "Spiral Wrap Gasket" standard. 2 Gaskets for pipe flanges shall be selected according to the HG20606~20611 and HG20627~20632 standards. 3 The specifications and dimensions of metal toothed gaskets shall be selected according to the JB88 "Metal toothed gaskets for flanges with concave and convex sealing surfaces". 4 Oval and octagonal ring gaskets shall be selected according to the HG20612 and HG20633 standards. 307
5 The specifications and dimensions of lens-type gaskets for pipe flanges shall be selected according to the JB90 "Metal gaskets for flanges with lens-type sealing surfaces" or JB2776~2777 "Lens Gaskets" standards.
6 The thickness of non-metallic soft gaskets is generally selected according to the diameter of the container: for nominal diameter DN≤450mm, thickness8=2mm; for nominal diameter DN>450mm, thickness=3mm. 7 The thickness of metal flat gaskets is generally 3~6mm. 8 The roughness requirements of various gaskets on flange sealing surface are shown in Table 3-1. Table 3-1
Gasket category
Gasket name
Flange sealing surface
Surface roughness
Metal gasket
Serrated
Semi-metallic sealing gasket
Metal package
Asbestos rubber sheet
Bolt (column)
3.3.1 Equal-length studs for pressure vessel flanges shall be selected in accordance with JB4707 standard. PTFE gasket
Rubber sheet
Plate gasket
Pack gasket
Flexible graphite
3.3.2 For the connecting bolts (columns) and nuts of austenitic alloy steel flanges, when the working temperature t≤100℃, carbon steel is generally allowed to be used. When the working temperature is 100℃
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