A
pressure vessel is an essential equipment in any gas plant. It is used to
hold gases or liquids at a pressure different from the ambient pressure. A
pressure vessel is in the shape of a closed, rigid container and the end
caps fitted to the cylindrical body are called heads.
Used as a boiler or a storage tank that contains liquids or gases, pressure
tanks are designed to operate at pressures above 15 psig. There are
different varieties of pressure tanks like high pressure vessels which
operates under greater than normal amounts of pressure. There are stainless
steel pressure vessels used as mixing, storage, jacketed and reactor tanks
in pharmaceutical production, food processing, brewery production and other
sanitary applications. Some pressure vessels have a series of gauges on the
outside of the tank to control the temperature of their contents. There are
other varieties designed to store volatile substances at high temperatures.
Major Parts of a Pressure Vessel
Design Standards of Pressure Vessels
For worker's safety and health, the safe design, operation, installation,
maintenance of pressure vessels depend on certain codes and standards. For
example, in the United States (which is also followed in other countries),
most of the pressure or storage vessels have been designed and constructed
with respect to one of the following two pressure vessel design codes:
- The ASME Code, or Section VIII (Division 1, 2 and 3) of the American
Society of Mechanical Engineers (ASME) "Boiler and Pressure Vessel
Code."
- The American Petroleum Institute (API) Standard 620 code which
provides rules for lower pressure vessels not covered by the ASME Code.
Other important codes are:
- BS 4994
- BS 5500
- CODAP
- Stoomwezen
- AD Merkblätter
- AS 1210
Health Hazards of Pressure Vessels
Pressure vessels have to work above 15 psig. There are many instances where
a slight difference in pressure can lead to cracking and damaging of the
vessels, which in turn can lead to leakage or rupture failures. A complete
rupture in the pressure vessel lead to the following:
- Blast effects caused by the sudden increase of the pressurized fluid
and
- For a leakage failure, the consequences can be
- Fragmentation damage and injury
For a leakage failure, the consequences can be
- Suffocation
- Poisoning
- Fire
- Explosion
- Chemical and thermal burns
Examples Of Pressure Vessel
- Industrial compressed air receivers
- Hot water storage tanks
- Diving cylinder
- Distillation towers
- Pneumatic reservoir
- Hydraulic reservoir
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- Rail vehicle air brake reservoir
- Road vehicle air brake reservoir
- Vessels used in piping and pipelines
- Storage tanks that operate nominally atmospheric pressure
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Applications Of Pressure Vessels
As seen from the above examples, it is evident that pressure vessels are
widely used in:
- Gas plants
- Mining
- Nuclear reactor vessel
- Oil refineries
- Petrochemical plants
- Habitat of a space ship
- Habitat of a submarine
Buyer's Guide
Specifications to consider for pressure vessels are as follows:
- Capacities
- Design pressure
- Design temperature
- Stand arrangements: floor mount or bench top
- Materials of construction: Machinable alloys like Monel, Inconel,
Stainless Steel, Hastelloy, Titanium, etc.
- Internal finish
- Process Contacting Seals: Viton, Teflon, Buna N, Kalrez
Pressure
Vessel
