Pressure Vessel Types, Jackets, Inspection & Design Pressure
1. Types of heads for pressure vessels
- Hemispherical head
- Torispherical (flanged and dished) head
- Ellipsoidal (2:1 elliptical) head
- Conical head
- Flat head
2. Weld joint efficiency factor (E)
Indicates the quality and reliability of welds in pressure vessels.
Ranges from 0.7 to 1.0 depending on joint type and inspection level.
3. Maximum Working Pressure (MWP) & Design Pressure
MWP: Highest internal pressure during normal operation.
Design pressure: Higher than MWP (typically 5–10% more) to ensure a safety margin.
5. Classification of pressure vessels (internal pressure)
- Thin-walled vessels (t < D/10)
- Thick-walled vessels (t ≥ D/10)
- Horizontal and vertical vessels
6. Classification of reaction vessels
- Jacketed and non-jacketed vessels
- Agitated and non-agitated vessels
- Pressurized and non-pressurized vessels
7. Components of an agitation system
- Impeller
- Shaft
- Bearings
- Baffles
- Motor and drive system
8. Types of jackets
- Conventional jacket
- Limpet coil jacket
- Half-coil jacket
- Dimple jacket
9. Applications of chemical process equipment
- Reactors for chemical synthesis
- Heat exchangers for cooling/heating
- Distillation columns for separation
- Storage vessels for liquids and gases
- Pressure vessels for reactions
10. Selection of storage vessels for toxic/combustible liquids
- Use non-corrosive and leak-proof materials
- Provide pressure relief systems
- Ensure ventilation and inert gas blanketing
- Select underground or double-wall tanks for added safety
11. Advantages of codes and standards
- Ensures safety and reliability
- Provides uniform design practices
- Facilitates regulatory compliance
- Enhances interchangeability of components
12. Disadvantages of codes and standards
- Can be rigid and less flexible
- May increase cost of design and fabrication
- Not always up-to-date with new technology
- Requires strict documentation and inspection
13. Important mechanical properties of materials
- Tensile strength
- Yield strength
- Hardness
- Toughness
- Ductility
- Fatigue resistance
14. Choosing design pressure (static conditions)
Consider liquid head due to static fluid height.
Add a safety margin (5–10%) above static pressure.
15. Methods for equipment inspection
- Visual inspection
- Ultrasonic testing
- Radiographic testing
- Hydrostatic testing
- Magnetic particle testing
- Dye penetrant testing
17. Neat sketches of jackets
Dimple jacket – for uniform heating/cooling.
Limpet coil jacket – for high-pressure fluids.
(Provide hand-drawn diagrams in exam)
18. Materials for construction of reaction vessels
- Carbon steel
- Stainless steel (SS-304, SS-316)
- Alloy steels (Hastelloy, Inconel)
- Glass-lined steel
- Non-metallics like FRP (for corrosion resistance)
19. Need for reinforcement in pressure vessels
To compensate for material loss due to openings (nozzles, manholes).
Ensures structural strength and safety.
20. Methods of reinforcement
- Reinforcement pads or rings around openings
- Using thicker shell plates locally
- Welded collars or sleeves
- Integrally reinforced nozzles