Detailed Production Process of Cryogenic Pressure Vessels

 

Detailed Production Process of Cryogenic Pressure Vessels

Cryogenic pressure vessels are specialized equipment extensively used in the chemical, petroleum, and energy industries, primarily for storing and transporting liquefied gases. Their production process is meticulous and complex, involving several critical steps. Below is the primary production process for cryogenic pressure vessels:

store and transport liquefied gases

1. Design and Material Selection: The design of cryogenic pressure vessels must comply with relevant safety standards and regulations, such as ASME and GB. The design considerations include the vessel's working pressure, temperature, volume, and the characteristics of the contained medium. Material selection is crucial, typically involving steels with excellent cryogenic properties, such as 9% nickel steel, to ensure good mechanical performance at extremely low temperatures.

2. Cutting and Forming: Once the materials pass inspection, they are cut according to the design drawings to form the required plates and pipes. The plates are then rolled into cylindrical shapes using a rolling machine and welded to create cylindrical or spherical vessels. Additional forming processes, such as stamping and spinning, might be required for complex structures.

3. Welding: Welding is a critical step in manufacturing cryogenic pressure vessels, requiring strict control of welding parameters to ensure weld quality. Methods such as argon arc welding (TIG welding) are commonly used. Post-welding, non-destructive testing (NDT), such as X-ray inspection and ultrasonic testing, is conducted to ensure no cracks, pores, or other defects.

4. Heat Treatment: Post-welding, the vessel undergoes stress-relief heat treatment to improve the microstructure of the welded areas, enhancing their corrosion resistance and mechanical properties. The heat treatment process includes preheating, holding, and cooling stages, which must be meticulously followed according to the procedure.

5. Internal and External Surface Treatment: The vessel's internal and external surfaces are cleaned to remove scale, welding slag, and other impurities. Subsequently, anti-corrosion treatments such as rust-proof painting or coating extend the vessel's service life.

6. Assembly and Pressure Testing: The components are assembled into a complete vessel, including installing flanges, nozzles, safety valves, and other accessories. Finally, pressure testing, typically hydrostatic and helium leak testing, is conducted to verify the vessel's sealing and strength.

7. Final Inspection and Delivery: After passing all tests, the cryogenic pressure vessel undergoes a final quality inspection. Once confirmed to be free of issues, it is packaged and ready for delivery.

The above outlines the production process for cryogenic pressure vessels. Each step requires precise operation and stringent control to ensure product quality and safety. Adjustments and optimizations may be made in actual production based on specific circumstances, but the basic process remains broadly consistent.