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This standard is developed in accordance with the rules given in GB/T 1.1-2009 Directives for standardization - Part 1: Structure and drafting of standards.
This standard was revised by reference to ISO 13706:2011 Petroleum, petrochemical, and natural gas industries-Air-cooled heat exchangers, and API 661-2013 Petroleum, petrochemical, and natural gas industries - Air-cooled heat exchangers.
This standard replaces NB/T 47007-2010 Air-cooled heat exchangers. The following main technical changes have been made with respect to NB/T 47007-2010:
——Some terms are added or revised;
——The requirements for testing the heat transfer performance of single finned tube are specified;
—— The technical requirements for "Inlaid finned tube" are added;
——The method for evaluating the energy efficiency of air-cooled heat exchanger is added.
This standard was proposed by and is under the jurisdiction of the National Technical Committee 262 on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262).
The previous edition of this standard is as follows:
——NB/T 47007-2010.
Air-cooled heat exchangers
1 Scope
This standard specifies the design, materials, manufacturing, inspection and acceptance requirements of forced-draught and induced-draught air-cooled heat exchangers (hereinafter referred to as "air-cooled exchangers") and their energy efficiency evaluation methods.
1.1 This standard is applicable to air-cooled exchangers with design pressure not higher than 35MPa.
1.2 The design temperature range to which this standard is applicable shall be determined according to the allowable service temperature of materials.
1.3 The following air-cooled exchangers are beyond the scope of this standard:
a) Those with their headers made of aluminum or other non-ferrous metal;
b) Those with special professional standards (such as refrigeration and air conditioning industry).
1.4 Scope of air-cooled exchanger
1.4.1 Tube bundle
a) The first flange sealing surface of the connection between the header and the external pipeline;
b) The first threaded joint of the connection between the header and the external pipeline.
1.4.2 Structure
Steel structure above the bottom plate of structure column.
1.4.3 Fan
The first joint of motor junction box and fan pneumatic control air source.
1.4.4 Louvers
The first joint of louver pneumatic control air source.
1.5 For the pressure parts whose structural dimension cannot be determined according to this standard, the following methods may be adopted for design after being evaluated and approved by the National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China:
a) Analysis and design (except the units that have obtained the qualification of analysis and design);
b) Confirmatory hydraulic test;
c) Comparative experience design by the comparable structure that have been used.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 150.1-2011 Pressure vessels - Part 1: General requirements
GB/T 150.2-2011 Pressure vessels - Part 2: Materials
GB/T 150.3-2011 Pressure vessels - Part 3: Design
GB/T 150.4-2011 Pressure vessels - Part 4: Fabrication, inspection and testing, and acceptance
GB/T 151-2014 Heat exchangers
GB/T 28712.6-2012 Type and basic parameters of heat exchanger - Part 6: air cooled heat exchanger
GB/T 27698.6-2011 Test method for the performance of heat exchangers and heat exchange element - Part 6: Fing tube for air-cooled heat exchangers
GB/T 16507.4-2013 Water-tube boilers - Part 4: Strength calculation of pressure parts
GB/T 196 General purpose metric screw threads - Basic profile (GB/T 196-2003, ISO 724:1993, MOD)
GB/T 197 General purpose metric screw threads - Tolerances (GB/T 197-2018, ISO 965-1:2013, MOD)
GB/T 230.1 Metallic materials - Rockwell hardness test - Part 1: Test method
GB/T 231.1 Metallic materials - Brinell hardness test - Part 1: Test method (GB/T 231.1-2018, ISO 6506-1:2014, MOD)
GB/T 699 Quality carbon structure steels
GB/T 700 Carbon structural steels GB/T 700-2006, ISO 630:1995, NEQ)
GB/T 985.1 Recommended joint preparation for gas welding, manual metal arc welding, gas-shield arc welding and beam welding
GB/T 985.2 Recommended joint preparation for submerged arc welding
GB/T 1171 Classical V-belt for general drive
GB/T 1231 Specifications of high strength bolts with large hexagon head, large hexagon nuts, plain washers for steel structures
GB/T 1566 Square and rectangular thin keyways (GB/T 1566-2003, ASME B18.25.1M:1996, NEQ)
GB/T 1567 Square and rectangular thin keys (GB/T 1567-2003, ASME B18.25.1M:1996, NEQ)
GB/T 3077 Alloy structure steels
GB/T 3190 Wrought aluminium and aluminium alloy - Chemical composition
GB/T 6892 Wrought aluminium and aluminium alloys extruded profiles for general engineering
GB/T 3767 Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Engineering methods for an essentially free field over a reflecting plane (GB/T 3767-2016, ISO 3744:2010, IDT)
GB/T 3880.1 Wrought aluminium and aluminium alloy plates, sheets and strips for general engineering - Part 1: Technical conditions of delivery
GB/T 4437.1 Aluminium and aluminium alloy extruded tubes - Part 1: Seamless tubes
GB/T 4437.2 Aluminium and aluminium alloy extruded tubes - Part 2: Seam tubes
GB/T 4662 Rolling bearings - Static load ratings (GB/T 4662-2012, ISO 76:2006, IDT)
GB/T 5777 Seamless steel pipe and tubing - methods for ultrasonic testing (GB/T 5777-2008, ISO 9303:1989, MOD)
GB/T 6391 Rolling bearings - Dynamic load ratings and rating life GB/T 6391-2010, ISO 281:2007, IDT)
GB/T 6479 Seamless steel tubes for high-pressure for chemical fertilizer equipments
GB/T 5310 Seamless steel tubes and pipes for high pressure boiler
GB/T 6893 Aluminium and aluminium alloys cold drawn (rolled) seamless tubes
GB/T 9948 Seamless steel tubes for petroleum cracking
GB/T 10412 Grooved pulleys for classical and narrow V-belts (system based on datum width) (GB/T 10412-2002, ISO 4183:1995, MOD)
GB/T 10413 Grooved pulleys for narrow V-belts (system based on effective width) (GB/T 10413-2002, ISO 5290:2001, MOD)
GB/T 12730 Narrow V-belt for general drive
GB/T 10715 Belt drives - V-ribbed belts, joined V-belts and V-belts including wide section belts and hexagonal belts - Electrical conductivity of antistatic belts: Characteristics and methods of test (GB/T 10715-2002, ISO 1813:1998, MOD)
GB/T 13575.1 Classical and narrow V-belt drives - Part 1: System based on datum width
GB/T 13575.2 Classical and narrow V-belt drives - Part 2: Effective system
GB 19761-2009 Minimum allowable values of energy efficiency and energy efficiency grades for fan
GB/T 13296 Seamless stainless steel tubes for boiler and heat exchanger
GB/T 2882 Nickel and nickel alloy tube
GB/T 3625 Titanium and titanium alloy tube for condensers and heat exchangers
GB/T 8890 Seamless copper alloy tube for heat-exchanger
GB/T 13306 Plates
GB/T 13487 Synchronous belts for general drive
GB/T 8923.1 Preparation of steel substrates before application of paints and related products - Visual assessment of surface cleanliness - Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings
GB/T 13912 Metallic coatings - Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods (GB/T 13912-2002, ISO 1461:1999, MOD)
GB 18613 Minimum allowable values of energy efficiency and energy efficiency grades for small and medium three-phase asynchronous motors
GB 50009 Load code for the design of building structures
GB 50011 Code for seismic design of buildings (with Explanation of provisions)
GB 50017 Standard for design of steel structures (with Explanation of provisions)
GB 50018 Technical code of cold-formed thin-wall steel structures
GB 50205 Code for acceptance of construction quality of steel structures
JB/T 4711 Coating and packing for pressure vessels transport
JB/T 10562 Technical specification for general purposes axial fans
NB/T 47013.1-2015 Nondestructive testing of pressure equipments - Part 1: General requirements
NB/T 47013.2-2015 Nondestructive testing of pressure equipments - Part 2: Radiographic testing
NB/T 47013.3-2015 Nondestructive testing of pressure equipments - Part 3: Ultrasonic testing
NB/T 47013.4-2015 Nondestructive testing of pressure equipments - Part 4: Magnetic particle testing
NB/T 47013.5-2015 Nondestructive testing of pressure equipments - Part 5: Penetrant testing
NB/T 47013.6-2015 Nondestructive testing of pressure equipments - Part 6: Eddy current testing
NB/T 47014 Welding procedure qualification for pressure equipment
NB/T 47015 Welding specification for pressure vessels
YB/T 050 YNK gear reducer for metallurgical equipment
TSG Z6002 Examination rules for welding operators of special equipment
TSG Z8001 Examination rules for non-destructive testing inspectors of special equipment
TSG 21 Supervision regulation on safety technology for stationary pressure vessel
3 Terms and definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
pressure
gauge pressure, unless otherwise specified
3.2
working pressure
maximum pressure possibly reaching within the tube bundles of an air-cooled exchanger under normal working condition
3.3
design pressure
maximum pressure set within the air-cooled exchanger tube bundles, which shall be taken as the design load condition together with the corresponding design temperature and shall not be less than the working pressure
3.4
calculated pressure
pressure used to determine the calculated thickness of the pressure part of the air-cooled exchanger tube bundle at the corresponding design temperature, including the static pressure of liquid column
3.5
test pressure
pressure on the header top during pressure-tight test or leakage test
3.6
design temperature
mental temperature set for pressure parts of the tube bundle under normal working conditions
3.7
minimum design air temperature
specified inlet air temperature that is used for winterization
3.8
metal temperature
average temperature of the pressure parts of air-cooled exchanger tube bundle along section thickness
3.9
minimum design metal temperature
lowest metal temperature at which pressure-containing parts can be subjected to design pressure under various possible conditions expected during operation
3.10
critical process temperature
temperature related to important physical properties of a process stream (such as freezing point, bubble point, dew point, cloud point, etc.)
3.11
specified minimum tube-wall temperature
critical process temperature plus a safety margin
3.12
test temperature
metal temperature of the air-cooled exchanger header during pressure-tight test or leakage test
3.13
exposure temperature
temperatures imposed by external heat sources on mechanical and instrumentation components
3.14
bare tube surface
total area of the outside surfaces of the tubes, based on the length measured between the outside faces of the header tubesheets
3.15
finned surface
total area of the outside surface on a finned tube exposed to air, based on the length measured between the outside faces of the header tubesheets
3.16
calculated thickness
thickness calculated according to formulas in each clause of this standard, excluding additional thickness. If necessary, the thickness required by other loads (see 4.3) shall also be taken into account
3.17
design thickness
sum of calculated thickness and corrosion allowance
3.18
nominal thickness
thickness obtained by rounding the sum of steel thickness and negative deviation of steel thickness up to steel standard specification, namely the thickness marked on the drawings
3.19
available thickness
thickness obtained by deducting the nominal thickness and negative deviation of material thickness
3.20
seal-welded
tube-to-tubesheet joint weld applied between the tubes and tubesheets for the sole purpose of reducing the potential for leakage
3.21
strength-welded
tube-to-tubesheet joint welded so that the strength meets the design requirements for axial (tensile or compressive) tube mechanical and temperature difference loads, with sealing performance guaranteed
3.22
strength-expansion
Tube-to-tubesheet joint expanded so that the strength meets the design requirements for axial (tensile or compressive) tube mechanical and temperature difference loads, with sealing performance guaranteed
3.23
light-expansion
slight expansion for the purpose of eliminating the gap between the tube and the tubesheet hole
3.24
unit
one or more items arranged in a continuous structure
3.25
bay
one or more tube bundles, serviced by two or more fans, including the structure, plenum and other attendant equipment
Note: Figure 1 shows typical bay arrangements.
3.26
forced-draught air-cooled exchanger
air-cooled exchanger designed with the tube bundles located on the discharge side of the fan (see Figure 1)
3.27
induced-draught air-cooled exchanger
air-cooled exchanger designed with the tube bundles located on the suction side of the fan (see Figure 2)
3.28
item
one or more tube bundles for an individual service
3.29
item number
purchaser's identification number for an item
3.30
hydrogen service
services that contain hydrogen at a partial pressure exceeding 700 kPa absolute
4 General
4.1 The design, manufacturing, inspection and acceptance of air-cooled exchangers shall not only meet the requirements of this standard, but also meet those of relevant laws, regulations and rules issued by the state.
4.2 Qualification
4.2.1 Designers and manufacturers of air-cooled exchangers shall have sound quality management system.
4.2.2 Manufacturers of air-cooled exchanger products and their finned tubes and fans shall obtain corresponding "Safety Registration Certificate for Air-cooled Heat Exchanger Products".
4.3 Loads
4.3.1 The following loads shall be considered for designing air-cooled exchanger pressure parts:
a) Design pressure;
b) Static pressure of liquid column, which may be negligible if it is less than 5% of the design pressure.
4.3.2 The following loads shall be considered for designing steel structure of air-cooled exchanger:
a) gravity load of materials;
b) gravity load of equipment;
c) dynamic load of platform and ladder;
d) dynamic load;
e) thermal thrust;
f) earthquake load;
g) wind load;
h) snow load;
i) test load.
4.4 Allowable stress of pressure parts
The allowable stress of steel and stud material at different temperatures shall be selected in accordance with GB/T 150.
4.5 Welded joint coefficient
In air-cooled exchanger header, the welds (longitudinal welds) between tubesheet/plug sheet and top/bottom plates, and the welds (edge welds) between end plate and tubesheet, plug sheet, top and bottom plates shall be treated as Class A welds specified in GB 150.1-2011.
If double-sided or single-sided welding is adopted for the welds of air-cooled exchanger box, the welded joint coefficient of butt weld of fillet joint shall be selected according to the following requirements:
a) In the case of single-sided welding:
100% non-destructive testing: φ=0.9;
Local non-destructive testing: φ=0.8;
When the welded joint cannot be subjected to non-destructive testing: φ=0.6.
b) In the case of double-sided welding:
100% non-destructive testing: φ=1.0;
Local non-destructive testing: φ=0.85;
When the welded joint cannot be subjected to non-destructive testing: φ=0.6.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 General
5 Type, structure and model
6 Materials
7 Design
8 Manufacture
9 Inspection and acceptance
10 Nameplate, painting and transport package
11 Supplementary requirements
Annex A (Informative) Quotation and documentation
Annex B (Informative) Recommended practices
Annex C (Informative) Calculation of removable cover plate and removable bonnet header
Annex D (Informative) Checklist and data sheets
