Compressed Air - Storage Volume
The storage volume for a compressed gas can be calculated by using Boyle's Law
p a V a = p c V c = constant (1)
where
p a = atmospheric pressure (14.7 psia, 101.325 kPa )
V a = volume of the gas at atmospheric pressure (cubic feet, m3 )
p c = pressure after compression (psi, kPa )
V c = volume of gas after compression (cubic feet, m3 )
Volume of free gas in a Storage Volume
The amount of free gas at atmospheric pressure in a given volume - like a cylinder storage - can be calculated my modifying (1)
V a = p c V c / p a (2)
Gas can be stored in high-pressure cylinders ranging to more than 6000 psig (410 bar) . Normal-pressure cylinders are in the range 2000 and 2500 psig (140 and 175 bar) and low-pressure cylinders are in the range 480 psig (34 bar).
Example - Volume of Air in a Cylinder Storage
Standard atmospheric volume of air compressed in a 1.76 cubic feet K-type cylinder at 2200 psig (2214.7 psia) can be calculated
V a = (2214.7 psia) (1.76 cu ft) / (14.7 psia)
= 265 (cu ft)
In other words - if air in a 1.76 cubic feet container is compressed to 2200 psig - the same air at atmospheric pressure will occupy 265 cubic feet .
Related Topics
• Gases and Compressed Air
Properties of air, LNG, LPG and other common gases. Pipeline capacities and sizing of relief valves.
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Compressed air is used for power tools, instrumentation, processing, breathing and medical purposes.
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Compressed Air vs. Free Air - Compression Ratio
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Rating of Air Compressors and Air Equipment
Common rating terms for air flow capacity are ICFM, FAD, ANR, SCFM or nl/min.
Types of Air Compressors
Reciprocating, rotary screw and rotary centrifugal air compressors.