Pressure Vessels

1. Industry Definition & Scope

The Pressure Vessels industry encompasses the design, manufacturing, inspection, sale, and maintenance of all closed equipment and related systems designed to contain internal or external pressure (typically above 0.1 MPa gauge). These devices are critical in core industrial sectors such as energy, chemical, petrochemical, food, pharmaceutical, and aerospace. As essential special equipment for ensuring process flow, energy conversion, and substance storage, it is a key industry under stringent national safety regulation.

2. Main Product Categories

1. By Process Function

• Reaction Pressure Vessels (R): For physical or chemical reactions, e.g., reactors, synthesis towers, polymerization kettles, fermenters.

• Heat Exchange Pressure Vessels (E): For heat transfer between media, e.g., shell & tube heat exchangers, plate heat exchangers, coolers, condensers, evaporators.

• Separation Pressure Vessels (S): For fluid purification and component separation, e.g., separators, filters, absorption columns, scrubbers, drying towers.

• Storage Pressure Vessels (C, B for Spherical): For storing or holding gases, liquids, liquefied gases, e.g., air receivers, LNG storage tanks, liquid ammonia spheres, horizontal storage tanks.

2. By Pressure Level

• Low Pressure (L): 0.1 MPa ≤ p < 1.6 MPa

• Medium Pressure (M): 1.6 MPa ≤ p < 10.0 MPa

• High Pressure (H): 10.0 MPa ≤ p < 100 MPa

• Ultra-High Pressure (U): p ≥ 100 MPa

3. By Structural Form

• Spherical Vessels: e.g., LNG storage tanks, oxygen spheres. Uniform stress distribution, often used for large-scale storage.

• Cylindrical Vessels: The most common form (horizontal/vertical), comprising shell, heads (elliptical, dished, hemispherical), flanges, nozzles, supports.

• Combined Construction Vessels: e.g., jacketed vessels, multilayer vessels, strip-wound vessels.

4. By Application Sector

• Energy & Power: Nuclear reactor pressure vessels, steam generators, boiler drums, hydrotreaters, heat recovery steam generators (HRSG).

• Petrochemical: Catalytic cracking reactors, hydrocracking reactors, columns (distillation, extraction), various process tanks.

• Food & Pharmaceutical: Sterilizers, fermenters, mixing tanks, sanitary pressure vessels.

• Aerospace: Rocket propellant tanks, spacecraft life support system vessels.

• Civil & General: Air receivers, hyperbaric oxygen chambers, firefighting pressure vessels, accumulators.

3. Industry Chain Structure

Upstream:

• Raw Materials:

  • Metal Plates/Forgings: Pressure vessel steel plates (e.g., Q345R, SA516 Gr.70), stainless-steel plates (304/316L), clad plates, nickel alloys, heavy forgings (heads, flanges, shell courses).

  • Welding Consumables: Electrodes, wires, fluxes requiring excellent compatibility and performance.

  • Components: Safety valves, rupture disks, pressure gauges, level gauges, flanges, seals, insulation.

• Production & Testing Equipment: Plate rolling machines, edge preparation machines, heavy welding equipment (SAW, GTAW), heat treatment furnaces, NDT equipment (RT, UT, PT, MT), hydrostatic test pumps.

Midstream:

• Design Organizations: Entities holding pressure vessel design accreditation, performing stress analysis and detailed engineering.

• Manufacturers:

  • Integrated Heavy Equipment Makers: Capable of manufacturing thousand-ton reactors, nuclear equipment.

  • Specialized Pressure Vessel Factories: Focused on specific sectors or products (e.g., columns, heat exchangers, spheres).

  • Licensed Manufacturers: Must hold a Special Equipment Manufacturing License issued by national authorities.

• Inspection & Testing Agencies: Third-party inspection bodies (e.g., authorized inspection agencies), in-house QA/QC departments.

Downstream:

• End-User Industries:

  • Energy: Thermal, nuclear, hydro, wind, hydrogen.

  • Chemical & Petrochemical: Refining, ethylene, fertilizers, coal chemical, fine chemicals.

  • Metallurgy & Mining: Gas separation and storage.

  • Food & Beverage: Brewing, dairy, beverage processing.

  • Pharmaceutical & Biotech: Bioreactors, clean-in-place vessels.

  • Transportation: CNG/LNG vehicle cylinders, ship tanks.

• Engineering Procurement & Construction (EPC) Contractors: Major purchasers responsible for entire plant construction.

• Installation & Maintenance Service Providers: Responsible for field erection, periodic inspection, and repair.

4. Core Industry Characteristics & Barriers

1. Stringent Regulatory & Standards Regime

• Mandatory Oversight: In China, governed by the Special Equipment Safety Law and the Regulation for Safety Technology Supervision of Stationary Pressure Vessels (TSG 21).

• Codes & Standards: Must comply with GB/T 150 (Pressure Vessels) series, and international codes like ASME Boiler & Pressure Vessel Code (USA), Pressure Equipment Directive (PED, EU), JIS (Japan).

• Licensing: All activities (design, manufacture, installation, inspection, filling) require administrative permits.

2. High Technology Intensity & Complexity

• Design & Analysis: Requires detailed stress analysis (Finite Element Analysis) to ensure safety under all operating conditions.

• Materials Science: Demands expertise in material behavior under high temperature, pressure, and corrosive environments (creep, fatigue, hydrogen embrittlement).

• Manufacturing Processes: Involves complex techniques like precision forming, specialized welding (thick-section, dissimilar metals), heat treatment (stress relieving, PWHT), and NDT.

• Extreme Service Conditions: Often operates under extremes: high temperature, cryogenic, high pressure, severe corrosion, radiation.

3. Paramount Safety & Reliability Requirements

• Severe Failure Consequences: Failures can lead to catastrophic explosions, fires, or toxic releases.

• Quality Assurance Systems: Mandatory implementation of rigorous QA systems for full traceability.

• Lifecycle Management: Closed-loop management from design, manufacturing to operation, inspection, and decommissioning.

5. Development Trends

1. Scale-up & Modularization: Drive for efficiency leads to larger process units and consequently, mega-vessels. Modular fabrication aids transport and site assembly.

2. Higher Parameters & Extreme Service: Advancing technology for vessels in more severe conditions (higher T/P, aggressive media like acetic acid, HF).

3. Lightweighting & New Materials: Using high-strength steels to reduce wall thickness; applying composites, titanium alloys.

4. Smart Manufacturing & Digital Delivery:

   • Adopting smart tech (robotic welding, digital workshops).

   • Promoting 3D model-based digital delivery, providing operable "digital twin" assets to owners.

5. Green & Energy Efficient: Developing high-efficiency heat exchangers; applying Leak Detection and Repair (LDAR) technologies.

6. Emerging Markets (e.g., Hydrogen): High-pressure hydrogen storage (Type IV cylinders), liquid hydrogen tanks, water electrolyzers represent new growth frontiers.

6. Key Challenges & Opportunities

Challenges:

• High Technical Barriers: Key technologies in advanced materials, design software, and special processes are still dominated by foreign firms.

• Intense Market Competition: Overcapacity and cut-throat price competition in mid-to-low end markets.

• Significant Cost Pressure: Volatility in raw material (specialty steel) prices and rising labor costs.

• Heavy Safety Liability: Manufacturers bear lifelong quality responsibility with extremely high safety risks.

• Severe Talent Shortage: Lack of experienced senior design, welding, and inspection engineers and technicians.

Opportunities:

• National Strategic Demand: The "Dual Carbon" goals drive high-end demand from new energy (hydrogen, energy storage), nuclear power, and coal chemical upgrade projects.

• Accelerated Import Substitution: Localization of key equipment (e.g., LNG core equipment, hydrogenation reactors) is a clear trend and policy direction.

• Globalization & BRI: The cost-technology synergy of Chinese manufacturing aids in capturing overseas EPC project markets.

• Installed Base Renewal & Retrofits: Vast number of in-service equipment reaching design life, creating a huge market for replacement, retrofits, and inspection services.

• Service & Aftermarket Extension: Transitioning from manufacturing to full lifecycle services (design, repair, inspection, life assessment) for higher profitability.