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Compared with JB/T 7261-1994 "Technical Provisions of Aluminum Plate-fin Heat Exchanger", the main amendments of this standard are as follows:
——The design pressure was raised to 8.0MPa from less than 6.3MPa and the design temperature range was revised to -269℃~200℃from -270℃~150℃;
——The terms and definitions for plate-fin heat exchanger were added;
——The Pressure ratio in hydraulic and pneumatic test was revised from 1.5times and 1.25 to 1.3 times and 1.25 times to be in line with international manufacturing industry;
——Requirements to select the material according to standard JB/T 4734 and GB/T 3198 were added;
——"Design" in Chapter 5 was added;
——The content such as fluoroscopic inspection, correction of the inconsistent extant defect and remedial measures were added in the inspection and acceptance aspect;
——Content of clearness test, vacuum leak test and cubical expansion test in the previous standard was deleted;
——Content of installations and operation requirements was added.
In this standard, Annex A is normative; Annex B, Annex C and Annex D are informative.
This standard was proposed by and is under the jurisdiction of the National Technical Committee on Pressure Vessels of Standardization Administration of China (SAC/TC 262).
This standard was drafted and examined by the Subcommittee on Heat Exchanger of National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SC5).
Chief drafting organizations: Hangzhou Oxygen Plant Group co., ltd., Lanzhou Petroleum Mechinery Research Institute, Kaifeng Air Separation Group co., ltd., Sichuan Air Separation Equipment (Group) Company Ltd., Anshan Iron and Steel Company and China Special Equipment Inspection and Research Institute.
Chief drafting staffs: Yan Zhenhuang, Wang Jinhong, HongBaoling, Li Jianwei, Mao Yangping, Zeng Chuanyong, Zhou Wenxue, Tao Xianglun, Wang Jin, Jia Zhenwu, Zhang Yanfeng, Zhu Juxian, and Wang Weiguo.
Distribution condition for all previous edition of this Standard is:
——JB/TQ 258—76;
——JB/T 7261—1994.
Aluminum Plate-fin Heat Exchanger
鋁制板翅式熱交換器
1 Scope
This standard specifies the requirements of design, manufacture, inspection acceptance, installations, application and maintenance of Aluminum plate-fin heat exchanger (hereinafter referred to as heat exchange).
1.1 This standard is applicable to the heat exchanger with design pressure no greater than 8.0MPa. For the heat exchanger with design pressure greater than 8.0MPa, it may be designed and manufactured with reference to this standard when the buyer is agreed upon.
1.2 The design temperature range suitable to this standard is -269℃~20.
1.3This standard is applicable to the heat exchangers applied in the situation of air separation and liquification equipment (ASU), natural gas processing (NGP) and liquification (LNG), petrochemical engineering and mechanical power devices.
1.4 The pressure parts of heat exchanger which couldn't be determined by this standard, through the assessment and ratification of the National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China, may be designed by adopting the following methods:
a) The stress analysis (except the unit qualified for analysis design) including finite element method;
b) Replication experimental analysis (such as experimental stress analysis and replication hydraulic test);
c) The comparable structure which has been put into service shall be adopted to carry out the comparison empirical design.
2 Normative References
The following documents are indispensable to the application of this standard. For dated reference, subsequent amendments to, or revisions of, any of these publications do not apply. For undated references, the latest edition of the normative document referred to applies.
GB 150"Steel Pressure Vessels"
GB/T 228 "Metallic Materials-Tensile Testing at Ambient Temperature" (GB/T 228—2002, ISO 6892: 1998(E), EQV)
GB/T 229 "Metallic materials-Charpy Pendulum Impact Test Method" (GB/T 229—2007, ISO 148-1: 2006, MOD)
GB/T 232 "Metallic Materials-Bend Test" (GB/T 232-1999, ISO 7438: 1985, EQV)
GB/T 1804"General tolerances-Tolerances for Linear and Angular Dimensions without Individual Tolerance Indications" (GB/T 1804—2000, ISO 2768-1: 1989, EQV)
GB/T 2624.1-2006 "Measurement of Fluid Flow by Means of Pressure Differential Devices Inserted in Circular Cross-section Conduits Running Full-Part 1: General Principles and Requirements" (GB/T 2624.1—2006, ISO 5167-1: 2003, IDT)
GB/T 2624.2—2006 "Measurement of Fluid Flow by Means of Pressure Differential Devices Inserted in Circular Cross-section Conduits Running Full - Part 2: Orifice Plates"(GB/T 2624.2—2006, ISO 5167-2: 2003, IDT)
GB/T 2624.3—2006 "Measurement of Fluid Flow by Means of Pressure Differential Devices Inserted in Circular Cross-section Conduits Running Full -Part 3: Nozzles and Venturi nozzles" (GB/T 2624.3—2006, ISO 5167-3: 2003, IDT)
GB/T 2624.4—2006 "Measurement of Fluid Flow by Means of Pressure Differential Devices Inserted in Circular Cross-section Conduits Running Full-Part 4: Venturi Tubes" (GB/T 2624.4—2006, ISO 5167-4: 2003, IDT)
GB/T 3190"Wrought Aluminum and Aluminum Alloys-Chemical Composition Limits" (GB/T 3190—2008, ISO 209: 2007(E), MOD)
GB/T 3191—1998"Extrusion Rods and Bars of Aluminum and Aluminum Alloy"
GB/T 3195—2008"Aluminum and Aluminum Alloys Drawn Round Wire"
"Aluminum and Aluminum-alloy Foil"
GB/T 3246.1"Wrought Aluminum and Aluminum Alloys Products Inspection Method for Structure"
GB/T 3246.2"Wrought Aluminum and Aluminum Alloys Products Inspection Method for Macrostructure"
GB/T 3880.1-2006 “Wrought Aluminum and Aluminum Alloy Plates, Sheets and Strips for General Engineering-Part 1: Technical Conditions of Delivery"
GB/T 3880.2-2006 “Wrought Aluminum and Aluminum Alloy Plates, Sheets and Strips for General Engineering-part 2: Mechanical Properties"
GB/T 3880.3-2006 “Wrought Aluminum and Aluminum Alloy Plates, Sheets and Strips for General Engineering -part 3: Tolerances on Forms and Dimensions"
GB/T 4436 “Wrought Aluminum and Aluminum Alloy Tubes-Dimensions and Deviations”
GB/T 4437.1-2006 “Aluminum and Aluminum Alloy Extruded Tubes-Part 1: Seamless Tubes"
GB/T 6892-2006 "Wrought Aluminum and Aluminum Alloys Extruded Profiles for General Engineering"
GB/T 6893-2000 "Aluminum and Aluminum Alloy Cold Drawn (rolled) Seamless Tubes"
GB/T 8063-1994 "Designation of Cast Nonferrous Metals and Their Alloys" (GB/T 8063—1994, ISO 2092, NEQ)
GB/T 9438-1999 "Aluminum Alloy Casting" (GB/T 9438—1999, ASTM B26/B26M: 1992, NEQ)
GB/T 10858-2008 "Aluminum and Aluminum Alloy Wires and Rods"
GB/T 13384"General Specifications for Packing of Mechanical and Electrical Product"
GB/T 16474"Wrought Aluminum and Aluminum Alloy—Designation System" (GB/T 16474-1996, ANSIH35.1: 1993, EQV)
GB/T 16475 "Temper Designation System for Wrought Aluminum and Aluminum Alloy" (GB/T 16475-2008, ISO 2107: 2007, MOD)
JB/T 4730.2-2005 "Nondestructive Testing of Pressure Equipments-Part 2: Radiographic Testing"
JB/T 4730.3-2005 "Nondestructive Testing of Pressure Equipments-Part 3: Ultrasonic Testing"
JB/T 4730.5-2005 "Nondestructive Testing of Pressure Equipments-Part 5: Penetrant Testing"
JB/T 4734 "Aluminum Welded Vessels"
HG/T 20592~20635-2009 "Steel Pipe Flanges, Gaskets and Bolting
YS/T 69-2005 "Aluminum Alloy Composite Sheet for Brazing"
TSG R0004-2009 "Supervision Regulation on Safety Technology for Stationary Pressure Vessel"
3 General Provisions
3.1 Not only the requirements stipulated in this standard, but also those in the current relevant ones of the nation shall be complied with in the design, manufacture, inspection, acceptance, installation, operation and maintenance of heat exchanger.
3.2 Scope
The scope of heat exchange covered by this standard includes heat exchanger body and the pressure parts integral to the body and has been defined in the following scope.
3.2.1 Connection of the heat exchanger to outer ducts:
a) The bevel end surface of the first layer of girth joint connected by welding;
b) The first flange sealing surface connected by flanges;
c) The joint end surface of screw thread connected by screw thread;
d) The first sealing surface connected by special connecting pieces or tubes.
3.2.2 For the parts beyond the welded joints between the non pressure parts and the pressure parts, such as stiffening ring, supporter and lifting lug, shall be in accordance with those specified in this standard or the corresponding standards.
3.2.3 The overpressure relief devices shall be directly connected on the heat exchanger according to the requirements as specified in Annex B of GB 150 and the accessories connected on the heat exchanger meters shall be in accordance with those specified in this standard.
3.3 Terms and definitions
The following terms and definitions set by JB/T 4734 are applicable to this standard.
3.3.1 Plate-fin heat exchanger
The heat exchanger is composed of the accessories such as block (core), header, nozzle and supporter. Each story of layer of the fluid is composed of heat transfer fin, parting sheet and side bar and is installed with inlet and outlet of fluid on specific positions; then the inlet and outlet headers of the fluid being considered are respectively adopted to include each layer of the inlet and outlet and nozzles are welded. Figure 3.1 is the schematic diagram of multi-strand flow heat exchanger.
Figure 3.1 Schematic Diagram Multi-strand Flow Heat Exchanger
3.3.2 Block (core)
It is superposed and brazed with passages of all fluids. Each layer is composed of parting sheet (or cap sheet), heat transfer fin (or distributor fin) and side bar as is shown in Figure 3.2.
Figure 3.2 Schematic Diagram of Basic Block (core) Structure
3.3.3 Heat transfer fin
It is the primary part of heat exchanger and the heat transfer process is mainly finished through the heat conduction of heat transfer fin as well as the convection heat transfer between the heat transfer fin and fluid.
3.3.4 Distributor fin
It shoulders mail the steering function for the fluid inlet and outlet, and it is generally multi-orifice heat transfer fin.
3.3.5 Side bar
It is the primary part of heat exchanger, which are dispersed over the margins of heat exchanger and acts to seal and support each layer of passage.
3.3.6 Parting sheet
It is the metal sheet between two layers of heat transfer fins, also called composite sheet; it covers a layer of brazing alloy on the surface of parent metal and when it is brazed, the alloy is melt and the heat transfer fin, side bar and sheet are welded together.
3.3.7 Cap sheet
It is the parting sheet located at the outermost side of the heat exchanger block (core), also called cover plate.
3.3.8 Dummy layer
It is the layer which is set on the top and bottom of the block (core) to connect with the ambient atmosphere for heat exchange resistance according to the requirements of strength, heat isolation and manufacture process. (And it is called the process layer).
3.3.9 Dead area
It refers to the area where the heat transfer fin or distributor fins are connected or unconnected without media flowing.
3.3.10 Layer arrangement
The layer arrangement manners may be classified into single banking, double banking and single and multiple banking.
3.3.10.1 Single banking
When single banking is carried out, every hot layer shall be arranged with a cold layer, see Figure 3.3 a).
3.3.10.2 Double banking
Every hot layer is alternate with two cold layers or every cold layer is alternate with two hot layers, see Figure 3.3).
3.3.10.3 Single and multiple banking
In addition to the hot layer and cold layer adjointly arranged, there is also the situations that that a hot layer is alternate with two cold layers or a cold layer is alternate With two hot layers on the same block (core), see diagram 3.3 c).
A—Cold layer; B—Hot layer
a) Schematic Diagram of Layer Single Banking
A—Cold layer; B—Hot layer
b) Schematic Diagram of Layer Double Banking
A—Cold layer; B—Hot layer
c) Schematic Diagram of Layer Single and Multiple Banking
Figure 3.3 Schematic Diagram of Layer Arrangement
3.3.11 Header
The header is generally formed by welding the header body, nozzle, header with ends and flange (or nozzle cap) together.
3.3.11.1 Header body
It refers to the semi circular cylinder parts of the header.
3.3.11.2 Header with ends
It refers to the parts connected at both ends of the header body.
3.3.11.3 Nozzle
It refers to the pipeline for the fluid in and out header.
3.3.11.4 Nozzle cap
It refers to the parts which seal the nozzle when the pressure test or nitrogen sealing is carried out.
3.3.12 Composite block
It refers to the block (core) which is parallel welded together with two or more blocks (core) and the Figure 3.4 is the block (core) which is connected together by parallel welding method.
Figure 3.4 Structure Drawing of Heat Exchanger Block Composed by Multi-block (core)
3.3.13 Manifolded exchanger
It is formed by connecting two or more heat exchangers according to different pipe arrangement form (parallel connection or series connection) as shown in Figure 3.5.
Figure 3.5 Schematic Diagram of Manifolded Exchanger Formation
3.4 General Requirements
3.4.1 Design pressure
3.4.1.1 The heat exchanger is composed of several pressure layers (same or different pressure). The most harsh pressure combination that may occur in operation shall be taken into consideration in design.
3.4.1.2 The design pressure of each layer shall not be less than the maximum layer working pressure.
3.4.1.3 When the heat exchanger is installed in the pressure vessel, ambient design pressure of heat exchanger shall be provided by the buyer and the heat exchanger shall be able to bear the action of the internal and external pressure difference.
3.4.1.4 When the heat exchanger is installed in the vacuum vessel, the maximum working pressure of corresponding layers shall be affirmed and determined by the buyer.
3.4.1.5 When the heat exchanger is designed under external pressure, the maximum internal and external pressure difference that may occur in normal operating conditions shall be taken into consideration.
3.4.1.6 When the heat exchanger is operated in vacuum state, the design pressure of vacuum layer shall be considered according to the bore external pressure and when the safety control device is installed, the design pressure is taken with the minimum value of 1.25 times of the maximum internal and external pressure difference and the 0.1MPa; when no safety control device is installed, it shall be taken as 0.1MPa.
3.4.2 Design temperature
3.4.2.1 The increase of internal thermal stress shall not exceed the ultimate strength of material and the maximum recommended allowable temperature difference is 50℃between the aluminum heat exchanger layers (on the same section) in the steady state; However, for the fluid with phase change and instant circulation, the recommended temperature difference shall be 20℃~30℃.
3.4.2.2 When the design temperature is not greater than 65℃, the aluminum alloy with magnesium content of more than 3% shall not be adopted.
3.4.2.3 The design temperature shall not be less than the maximum temperature attained by the parts metals under operating conditions. For the metal Temperature of below 0℃, the design temperature shall be -269℃at the lowest.
3.4.2.4 When the metal temperatures of heat exchanger parts are different under operating conditions, the maximum temperature shall be complied with to design. In any case, the metal surface temperature of parts shall not exceed the allowable service temperature of material.
3.4.2.5 The metal temperature of parts may be attained by heat transmission calculation or measured on the heat exchanger in the same applied working condition or determined according to the medium temperature. For the heat exchanger in different working condition, it shall be designed according to the harsh working conditions group; the pressure and temperature values in the working conditions shall be indicated in the drawing or corresponding technical provisions.
3.4.3 Fluid medium
The media characteristics used in the operational process shall be restricted. The fluid shall be clean and free of corrosive action to the aluminum alloy; generally the corrosion allowance is not taken into consideration. The media which can easily be scale formed, settled and block the heat exchanger shall be controlled.
3.4.4 Load
The following loads shall be taken into consideration in design:
a) Internal pressure, external pressure or the maximum pressure difference;
b) The static pressure of fluid liquid column;
c) The deadweight load of heat exchanger and the gravity load of build-in material under the normal working condition or pressure test state;
d) The gravity loads of auxiliary facilities, heat insulating materials and pipes;
e) Wind load and earthquake load;
f) The counterforce of supporter, lug and other types of supports;
g) The acting force of connecting pipe and other parts;
h) The acting force due to the difference of temperature gradient or thermal expansion quantity;
i) The impact load including pressure rapid fluctuation;
j) The counter force of shock, such as counter force due to the fluid shock etc.;
k) The acting force when it is transported or hoisted.
3.4.5 Additional thickness
The additional thickness shall be determined according to Formula (3.1);
C=C1+C2 (3.1)
Where:
C——the additional thickness, mm;
C1——the thickness tolerance of aluminum products, which shall be specified by the requirements in GB/T 3880.3 and GB/T 4436, mm;
C2——the corrosion allowance, which shall be specified according to the requirements in 3.4.3, C2=0.
3.5 Allowable stress
This standard specifies that the allowable stress values of pressure parts for the aluminum product, such as header, nozzle, flange, side bar and cap sheet shall be determined according to those specified in JB/T 4734 or according to the mechanical property and safety factor as provided by the corresponding standards; for the materials of pressure parts, such as heat transfer fin and parting sheet, it shall be determined by dividing the tensile strength value as specified in GB/T 3198and YS/T 69 by the safety factor 4~6.
3.6 Welded joint factor
The welded joint factor φ shall be determined according to the welding method and welded joint mode of pressure parts as well as the linear scale of nondestructive test:
a) For the butt joint of both sides welding and the full penetration butt joint equivalent to the both sides welding:
The 100%nondestructive test φ=0.95;
Partial nondestructive test φ=0.8.
b) The joint of single welded butt joint (stoolplate is closely clung to the base metal along the seam root full length):
100 % nondestructive test φ=0.90;
Partial nondestructive test φ=0.8.
When the welded joint couldn't be carried out with nondestructive test due to structure, full penetration structure shall be adopted for the welded joint and the welded joint coefficient is generally not greater than 0.6.
3.7 Pressure test
Pressure test shall be carried out after the heat exchanger is manufactured. The manner, requirements and test pressure of pressure test shall be indicated in the drawing.
The pressure test is generally adopted with hydraulic test and the testing liquid shall be carried out according to those specified in 6.2.
For the heat exchanger which is not allowed to have residual liquid or the hydraulic test couldn't be carried out with full liquid due to structure may be adopted with the pneumatic test. The heat exchanger to carry out pneumatic test and leakage test shall be in accordance with those specified in 6.2.
3.7.1 Test pressure
The minimum value of test pressure shall be in accordance with the following requirements and the upper limit of test pressure shall be in accordance with the restricts of stress check as specified in 5.1.8.2.
3.7.1.1 Internal pressure layer
Hydraulic test pressure:
(3.2)
Pneumatic test pressure:
(3.3)
Air tight test pressure:
pT=1.0p (3.4)
Where:
pT——the test pressure, MPa;
p——the design pressure, MPa;
[σ]——the allowable stress of material for heat exchanger at test temperature, MPa;
[σ]t——the allowable stress of materials for heat exchanger at design temperature, MPa.
3.7.1.2 External pressure layer
Hydraulic test pressure:
pT=1.3p (3.5)
Pneumatic test pressure:
pT=1.25p (3.6)
Leakage test:
pT=1.0p (3.7)
Where:
pT——The test pressure, MPa;
p——The design pressure, MPa;
3.7.1.3 The pressure test with special requirements
For the heat exchanger which bears alternate load or is applied in special situations, the hydraulic test pressure shall be suitably raised and the specific requirements shall be carried out according to those specified in the drawing.
3.8 Drawing
The outside drawing of product provided by the manufactory shall be equipped with all the data that is required for the buyer examination and mainly includes:
a) Physical dimension, material thickness, model specification, heat interchanging area, layer volume, support and weight;
b) The designation specification of material and the heat transfer fin type of applied heat transfer fin;
c) Position of nozzle and flange, connection details and types of all fluids if necessary;
d) Manufacturing and testing data, range and position of nondestructive test, test pressure and welding seam identification.
4 Materials
The materials for heat exchanger shall be taken into consideration with the operating conditions (such as design temperature, design pressure, media characteristics and operating feature), manufacture process and inspection requirements of heat exchanger as well as the economical rationality; it shall also be provided with favorable corrosion resisting property, mechanical property, welding property, shaping property and other processing properties and physical properties. For the specified, the relevant requirements as specified in JB/T 4734, GB/T 3198 and YS/T 69 shall be taken as the reference.
5 Design
5.1 Header
5.1.1 When the header nozzle is connected with the external aluminum alloy pipe, welded structure shall be adopted. Please see Figure 5.1 a) for the details.
5.1.2 When the header nozzle is connected with the external pipe, flanged connection shall be adopted. Please see Figure 5.1 b) for the structure.
5.1.3 The header nozzle and external heterogeneous metal pipe (rustless steel or copper) shall be adopted with welded structure. Please see Figure 5.1 c) for the details.
Figure 5.1 Header Structure Schematic Diagram
5.1.4 The arrangement form (see Figure 5.2 for the typical arrangement plan) of header/nozzle.
Figure 5.2 Typical Header/Nozzle Form
5.1.5 Symbol explanation:
B——the transverse width of composite header rectangular bottom surface, mm;
C——the additional value of wall thickness, mm;
Di——the internal diameter of semicircle cylinder, mm;
di——the internal diameter of nozzle, mm ;
Dp——the calculated diameter of slab-shaped header with end, for the circular slab, it is internal diameter and for the non circular slab, it is minor axis;
F——the calculated resultant force on the interior section from nozzle to header, N;
Fr——the allowable resultant force on the interior section from nozzle to header, N;
Fx——the component force on the interior section of x direction from nozzle to header, N;
Fy——the component force on the interior section of Y direction from nozzle to header, N;
Fz——the component force on the interior section of Z axis direction from nozzle to header, N;
h1, h2——the folding height of slab composite header, mm;
h——the height of transitional short piece, mm;
H——the height of slab composite header, mm;
L——the longitudinal width of rectangular bottom surface for the composite header, mm;
M——the calculated resultant moment on the interior section from nozzle to header, N·m;
Mr——the allowable resultant moment on the interior section from nozzle to header, N·m;
Mx——the component moment on the interior section of x direction from nozzle to header, N·m;
My——the component moment on the interior section of Y axis direction from the nozzle to header, N·m;
Mz——the component moment on the interior section of Z axis direction from nozzle to header, N·m;
p——the design pressure, MPa ;
Ri——the internal radius of header body, mm;
Foreword I
1 Scope
2 Normative References
3 General Provisions
4 Materials
5 Design
6 Fabrication, Inspection and Acceptance
7 Installation and Operation
Annex A (Normative) Test Methods of Heat Exchanger Performance
Annex B (Informative) Welded Joint Type
Annex C (Informative) Preparation Method of Heat Exchanger Type
Annex D (Informative) Application Instruction of Heat Exchanger
