Blog: Basics of Pressure Vessel Design & Analysis

Introduction

Pressure vessels are precision-engineered containers designed to operate under extreme pressure and temperature conditions. They come in various shapes and sizes, adapting to diverse industry needs, including storage, chemical processes, and material transportation. Pressure vessel failures may result in loss of life, health hazards and property damage. Vessels have openings of various diameters to accommodate manholes, handholds, and nozzles, which lead to high stress concentrations that may lead to vessel failure.

This Blog summarizes pressure vessel design, material selection, stress analysis, safety measures, and adherence to industry standards.

Vessel Design & Analysis Process

The design process for pressure vessels is a collaborative effort between designers, engineers and fabricators. The Critical Design Factors for Pressure Vessels includes:

1. 1. Material Selection
      Choosing the right material is fundamental to pressure vessel design. Material options range from common carbon steel to exotic alloys, influenced by factors such as the substance, operating temperature, and pressure fluctuations.
   2. Design Codes and Standards
      Adhering to industry codes and standards is essential. Codes like ASME Boiler and Pressure Vessel Code (B&PV) provide guidelines for design, fabrication, inspection, and testing, ensuring safety and compliance.
   3. Design Pressure and Temperature
      Accurately determining maximum pressure and temperature during the vessel’s operational life is critical, influencing material selection, wall thickness, and overall design.
   4. Stress Analysis
      Comprehensive stress analysis ensures the vessel can withstand internal pressures without deformation or rupture, often employing Finite Element Analysis (FEA) for simulations. The various types of loads include:

       

      • Design pressure
      • Dead loads
      • Wind loads
      • Earthquake loads
      • Temperature or Transient Temperature loads
      • Piping loads
      • Impact or cyclic loads
   5. Wall Thickness
      Calculating required wall thickness factors in material stress, design pressure, and vessel geometry, ensuring structural integrity.
   6. Nozzle and Flange Design
      Precision nozzle and flange design is essential for maintaining structural integrity and preventing leaks at connection points.
   7. Fatigue Analysis
      Fatigue is one of the most frequent causes of failure in pressure vessels. A vibrating component often leads to fatigue – which eventually leads to equipment malfunction, or catastrophic failure. We perform Fatigue Analysis to ASME Boiler & Pressure Vessel Code.
   8. Safety – ensured using various methods:
      • Material Testing: Rigorous testing ensures material quality and strength.
      • Welding Inspection: Meticulous welding procedures and inspections prevent defects.
      • Hydrostatic Testing: Testing validates vessel integrity under elevated pressure conditions.
      • Relief Devices: Pressure relief valves protect against overpressure.
   9. Regular Inspections:
      • Routine maintenance to detect wear and tear.
      • Quality Assurance and Documentation
        Detailed records of the design process, material specifications, inspection results,
        and operational history ensure compliance and support informed decisions.

    

2. Conclusion

   Pressure vessel design demands precision, safety, and compliance with established standards. Well-designed vessels guarantee safety and efficiency. Whether you’re an experienced engineer or new to the field, understanding pressure vessel design contributes to safer and more efficient industrial operations.

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3. Read More

   – Design by Analysis v Design by Rule
   – Description of Finite Element Analysis (FEA)
   – Stress Analysis of Thin Walled Vessels

   O’Donnell Consulting Engineers Performs Pressure Vessel Design & Analysis for Clients in Various Industries.