also stored in refrigerated specially designed vessels in the refineries. Its storage is near its bubbling temperature at almost atmospheric pressures.
As it is expected from process plant point of view, a storage vessel is not pumped completely dry when emptied. The vapours above the remaining liquid will expand to fill the void space at the liquids vapour pressure at storage temperature. As the vessels fill, vapours are compressed into smaller void space until the set pressure on the relief system is reached. Some filling losses are associated with the liquid expansion into the vessel. The vapors emitted from storage vessel relief valves are generated in two ways:
Vapours which are generated by liquid vaporization stored in storage vessel.
Storage vessel vapours forced out during filling operations (Displacement losses)
The vaporization and displacement losses are basically sources of BOG generations of interest for gas processing activities. Essentially, there are two types of storage classifications, above ground and underground. Categories include; Atmospheric, Low pressure (0 to 17 KPa), Medium pressure (17 to 100 KPa), High Pressure (at Pressures above 100 KPa) [2] and underground.
Atmospheric are cylindrically designed tanks for content storage at atmospheric pressure. They range from small shop-welded tanks to field-erected tanks. They are bolted tanks and, usually, rectangular welded tanks are also used