GB/T 151-2026Heat exchangers (English PDF)

1.6 Shell-and-tube heat exchangers exceeding the range of

1.5 shall be constructed in accordance with this document.

1.7 This document does not apply to the following heat exchangers.

a) Heat exchangers heated by direct flame;

b) Flue-type waste heat boilers;

c) Heat exchangers in nuclear power plants that pose a risk of failure due to neutron radiation damage;

d) Non-metallic heat exchangers;

e) Heat exchangers for which there are separate national or industry standards in the refrigeration and air conditioning industry.

1.8 The scope of heat exchangers is defined as follows:

a) Heat exchanger connection to external tubing. 1) The first bevel face of a welded joint; 2) The first threaded joint face of a threaded joint; 3) The first flange sealing face of a flange joint; 4) The first sealing face of a special connector or fitting connection.

b) Pressure-bearing heads, flat covers, and their fasteners for tubes, manholes, handholes, etc.

c) Welds connecting non-pressure-bearing components to pressure-bearing components.

d) Non-pressure-bearing components directly connected to the heat exchanger, such as supports and gaskets.

e) Overpressure relief devices installed on the heat exchanger.

3.2 Heat exchange area

3.2.1 calculated heat transfer area It refers to the outer surface area calculated based on the outer diameter of the heat exchange tube, after deducting the length of the heat exchange tube that does not participate in heat exchange. NOTE. The unit of nominal heat transfer area is square meters (m2).

3.2.2 nominal heat transfer area The area after calculating the heat transfer area, round it to the nearest integer. NOTE. The unit of nominal heat transfer area is square meters (m2).

3.3 nominal length LN The length of the heat exchange tubes in a shell-and-tube heat exchanger. NOTE. When the heat exchange tube is a straight tube, the nominal length is the length of the straight tube. When the heat exchange tube is a U-shaped tube, the nominal length is the length of the straight section of the U-shaped tube. The unit of nominal length is meters (m).

3.4 Tube side and shell side

3.4.1 tube side tube hole diameters and allowable deviations of grade II fit precision. Non-ferrous metal tube bundles of which the heat exchange tubes are of grade II precision as specified in NB/T 47019 (all parts), and the tube sheet pore diameter and allowable deviations adopt grade II fit precision.

3.9 strength expansion An expansion joint of which the expansion joint strength between the heat exchange tubes and the tube sheet must meet the design requirements for axial (tensile or compressive) mechanical and thermal loads of the heat exchange tubes and ensure sealing performance.

3.10 light expansion A slight expansion joint to eliminate gaps between heat exchange tubes and tube sheet holes.

3.11 strength weld A weld of which the welded connection strength between the heat exchange tubes and the tube sheet must meet the design requirements for axial (tensile or compressive) mechanical and thermal loads of the heat exchange tubes and ensure sealing performance.

3.12 seal weld A weld only ensuring that there is no leakage at the connection between the heat exchange tubes and the tube sheet.

3.13 tubes welded to backside of tubesheet A weld of which the heat exchange tubes and tube sheet are joined on the shell side by butt welds to form either a butt joint or a lock-bottom joint.

5.1 General rules

5.1.1 Heat exchangers shall comply with the provisions of this clause and shall adhere to relevant national laws, regulations, and safety technical specifications. Shell-and- tube heat exchangers constructed in accordance with the requirements of this document shall meet the basic safety requirements of TSG

21.The declaration of conformity to the standard shall be in accordance with Annex A.

5.1.2 Shell-and-tube heat exchangers shall comply with the provisions of this document. Other structural types of heat exchangers shall comply with the relevant requirements of NB/T 10938, NB/T 11026, NB/T 47004.1, NB/T 47004.2, NB/T 47006, NB/T 47007 and NB/T 47048.

5.1.3 In addition to meeting the requirements of this document, shell-and-tube heat exchangers or pressure-bearing components made of non-ferrous metals such as aluminum, copper, nickel, titanium, and zirconium shall also meet the relevant requirements of JB/T 4734, JB/T 4755, JB/T 4756, NB/T 11270, and NB/T 47011.

5.1.4 The design and manufacturers of heat exchangers shall establish and effectively operate a sound quality management system.

5.1.5 The materials, design, manufacture, installation, modification, maintenance and use of heat exchangers within the scope of TSG 21 shall be subject to the management of the special equipment safety supervision and management department.

5.1.6 For heat exchangers or pressure-bearing components that cannot be designed and calculated according to GB/T 150.3-2024, this document and the relevant referenced standards, the design can be carried out according to the method specified in

5.1.6 of GB/T 150.1-2024.

5.1.7 For heat exchangers that exceed the structural type specified in

5.1.2 and for which no national or industry standards have been established, the research and development unit shall formulate enterprise standards and publicize them to the public in accordance with relevant regulations.

5.1.8 When a heat exchanger uses high-efficiency heat transfer elements or a high- efficiency heat transfer structure, its performance can be tested by a testing organization with testing capabilities in accordance with the provisions of GB/T 27698 (all parts).

5.2 Qualifications and responsibilities

5.2.1 Qualifications For heat exchangers within the scope of TSG 21, the design and manufacturers shall hold the corresponding special equipment production license.

5.2.2 Responsibilities

5.2.2.1 Responsibilities of users or design clients Users or design clients shall fulfill the following responsibilities.

a) The user or design client of the heat exchanger shall submit Design Requirements (UDS) to the designer in a formal written form, which shall include at least the following. 1) The main standards and specifications upon which the design is based; 2) The operating parameters (including working pressure, working temperature range, cyclic load conditions, liquid level, tube load, and cyclic load, etc.); 3) The site of use and its natural conditions (including ambient temperature, seismic fortification intensity, wind load, and snow load, etc.); 4) Medium composition and properties; 5) Expected service life; 6) Geometric parameters and nozzle orientation; 7) Potential for overpressure during heat exchanger service and its causes; 8) Bundle grade; 9) Other necessary conditions required for design.

b) Users or design clients of heat exchangers shall adhere to the following guidelines. 1) Consider the potential overpressure risk of the heat exchanger; 2) When the pressure source originates outside the pressure vessel and is reliably controlled, the overpressure relief device does not need to be directly installed on the heat exchanger. When process or environmental factors prevent the installation of an overpressure relief device, a system safety design method with reliability no less than that of the overpressure relief device shall be adopted to prevent overpressure in the pressure vessel; 3) Users shall confirm that the overpressure relief device is correctly installed in the designated position before the heat exchanger is first operated.

5.2.2.2 Responsibilities of the designer The designer of a heat exchanger shall have at least the following responsibilities.

a) Responsible for the correctness and completeness of the design documents;

b) Provide the client with the design documents specified in section

5.3.7 of GB/T 150.1-2024;

c) The general design drawings of heat exchangers within the jurisdiction of TSG 21 shall bear the special design stamp for special equipment (photocopies are invalid);

d) The risk assessment report issued by the designer to the heat exchanger user complies with the requirements of Annex F of GB/T 150.1-2024;

e) All design documents for shell-and-tube heat exchangers shall be retained for their designed service life. The retention requirements for design documents of other types of heat exchangers shall be in accordance with the relevant standards.

5.2.2.3 Responsibilities of the manufacturer The heat exchanger manufacturer shall have at least the following responsibilities.

a) The manufacturer shall manufacture in accordance with the requirements of the design documents. If modifications to the original design are necessary, written consent from the original designer shall be obtained, and the modified parts shall be documented in detail.

b) Before manufacturing heat exchangers, the manufacturer shall develop a comprehensive quality plan. This plan shall at least include the manufacturing process control points, inspection items, and acceptance criteria for the heat exchanger or components.

c) During and after the manufacturing process of the heat exchanger, the inspection department of the manufacturer shall conduct various inspections and tests on the heat exchanger in accordance with the provisions of this document, design documents and quality plan, issue corresponding reports, and be responsible for the accuracy and completeness of the reports.

5.3.1 Design conditions

5.3.1.1 The user or design client of the heat exchanger shall submit the process design conditions to the designer in formal written form, which shall include at least the following.

a) Operational data, including flow rate, gas phase fraction, non-condensable gas components and fractions, temperature, pressure, heat load, etc.;

b) Physical property data, including the composition and density of the medium, specific heat, viscosity, thermal conductivity, and other characteristics;

c) Allowable resistance drops;

d) Others, including operational flexibility, operating conditions, installation requirements (geometric parameters, nozzle orientation), etc.

5.3.1.2 The data sheet for shell-and-tube heat exchangers is shown in Table B-1 of Annex B.

5.3.2 Type selection and calculation

5.3.2.1 The following factors shall be considered when selecting a heat exchanger.

a) The type of heat exchanger and heat transfer element shall be selected appropriately. The basic parameters shall be determined to meet the requirements of safety, reliability, and heat transfer;

b) Economic considerations shall be taken into account, and materials shall be selected appropriately;

c) It shall meet the requirements for heat exchanger installation, operation, and maintenance.

5.3.2.2 Calculations for heat transfer without phase change in shell-and-tube heat exchangers are provided in Annex B. When necessary, fluid-induced vibrations shall also be considered for shell-and-tube heat exchangers. Calculations for fluid-induced vibrations are provided in Annex C. Physical property data for common fluids are provided in Annex D. Fouling thermal resistance is provided in Annex E. Thermal conductivity of metals is provided in Annex F.

5.3.3 Energy efficiency requirements

5.3.3.1 The heat exchanger process calculation shall be optimized, so as to improve heat exchange efficiency and meet process design conditions and energy efficiency requirements.

5.3.3.2 When the heat transfer driving force is small, the short-circuit flow ratio is large, the space is limited, or the equipment is large, it is advisable to adopt high-efficiency heat transfer elements or high-efficiency heat transfer structures, rationally select tube bundle grades, and set up short-circuit protection structures.

5.3.3.3 The energy efficiency testing and evaluation methods for shell-and-tube heat exchangers are described in B.12.

5.4.1 Load

5.4.1.1 The following loads shall be evaluated during the design process.

a) Internal pressure, external pressure, or maximum pressure difference;

b) Forces caused by different thermal expansion amounts;

c) Hydrostatic pressure of the liquid column. When the hydrostatic pressure of the liquid column is less than 5% of the design pressure, it is negligible.

5.4.1.2 When necessary, the following loads shall also be evaluated.

a) The self-weight of the heat exchanger and the gravitational load of the internal medium under normal operating conditions or pressure resistance test conditions;

b) The gravitational loads on auxiliary equipment and insulation materials, linings, tubes, escalators, platforms, etc.;

c) The wind load, seismic load, snow load;

d) The reaction force of supports and other types of bearings;

e) The force that connects tubes and other components;

f) The forces caused by temperature gradients;

g) The impact loads, including impact loads caused by rapid pressure fluctuations and reaction forces caused by fluid impacts;

h) The forces exerted during transportation or hoisting.

5.4.2 Design pressure or calculated pressure The determination of design pressure or calculated pressure shall comply with the following provisions.