ASME U Stamp Certified Stacked Type Shell and Tube Heat Exchangers for Oil and Gas Industry

ASME U Stamp Certified Stacked Type Shell and Tube Heat Exchangers for Oil and Gas Industry​

YUHONG stacked heat exchanger is a highly efficient shell-and-tube heat exchange unit, characterised by the vertical stacking of two or more independent heat exchanger units, which are connected in series or in parallel and share a common shell or tube sheet structure. This design is particularly well-suited for processes involving large temperature differentials, multiple streams, or those requiring staged heat exchange. It enables a larger heat transfer area to be achieved within a limited footprint, significantly improving space utilisation and thermal efficiency. Its main features include a compact structure, high heat transfer coefficients, ease of modular design and installation, and the ability to flexibly configure flow combinations according to process requirements.

1. Design Parameters

Design pressure and temperature: To be determined in accordance with process requirements; the design must fully comply with the rules set out in ASME Code of Boilers and Pressure Vessels, Section VIII, Division 1 or Division 2.

Heat transfer area: The total area of a single unit or multiple stacked units must meet the requirements of the process heat load calculation.

Pressure Drop: Pressure drops in both the tube side and shell side must be controlled within the process-permissible range; hydraulic design may refer to TEMA (Tube-and-Shell Heat Exchanger Manufacturers Association) standards.

2. Material Requirements

The materials of all pressure-retaining components (shell, heads, tube sheets, heat exchange tubes, flanges, nozzles, etc.) must comply with the requirements listed in ASME Section II.

3. Manufacturing, Inspection and Testing

Manufacturing, inspection and acceptance must fully comply with the requirements of ASME Section VIII, Part 1 (or Part 2) and TEMA standards.

Welding: All welding procedure qualifications (PQR) and welder qualification records (WQR) must comply with the provisions of ASME Section IX.

Non-Destructive Testing (NDT):

Class A/B butt weld joints on major pressure-retaining components, such as the shell and heads, must undergo 100% radiographic testing (RT) or ultrasonic testing (UT) in accordance with the requirements of ASME Section V and the UG/UW sections.

Leak testing must be carried out on the connections between heat exchange tubes and tube sheets (whether expanded or welded), such as air tightness tests (ammonia leak tests) or other methods in accordance with ASME code requirements.

Pressure Testing: Upon completion, the equipment must undergo a hydrostatic test and/or a pneumatic test; the test pressure, holding time and medium must strictly comply with the provisions of ASME UG-99/UG-100.

Certification and Stamping: The equipment shall be manufactured by a manufacturer holding a valid ASME ‘U’ or ‘U2’ stamping authorisation certificate, and shall ultimately bear the ASME code stamp on the nameplate.

4.Applications

Petrochemicals and Refining: Used for feed preheating, product cooling, top-of-column condensation and bottom-of-column reboiling in units such as atmospheric and vacuum distillation, catalytic cracking, hydroprocessing and reforming. Must comply with supplementary industry standards such as API 660.

Chemical and Coal Chemical Industries: In processes such as ethylene, methanol, synthetic ammonia and coal-to-liquids, these units are used for syngas cooling and heat exchange for reactor feed and product streams.

Power Generation: Used in thermal power stations as high-pressure/low-pressure feedwater heaters, or in auxiliary cooling systems at nuclear power stations, where compliance with relevant nuclear power supplementary requirements is necessary.

Liquefied Natural Gas (LNG): Used for heat exchange involving cryogenic media in liquefaction, storage and regasification processes; materials must meet cryogenic impact toughness requirements (e.g. SA-516 Gr.70 N).

Marine and Offshore Engineering: Used for water cooling of main engine cylinder liners, lubricating oil cooling, and central cooling systems, etc., and must comply with the additional specifications of classification societies (e.g. ABS, DNV).

Refrigeration and Heating, Ventilation and Air Conditioning (HVAC): Used as evaporators and condensers in large-scale district cooling and heating plants or industrial refrigeration systems. Process fluid heating and cooling stages in industrial sectors such as papermaking, textiles and food processing.