Liquefied gases are a gaseous compound or mixture that is converted to a liquid when compressed or cooled. They are stored under pressure and transported by a transport trailer, tank car, or tanker ship. Depending on the amount of vapor pressure, they are transported and stored in a refrigerated or non-refrigerated container. For example, propane, butane, ammonia, and natural gas can be stored and transported at ambient temperatures. However, liquefied natural gas (LNG), hydrogen and nitrogen have a much higher vapor pressure so they must be stored or transported in a refrigerated container.
Liquefied gases have many uses for everyday life. Propane and natural gas are used to heat residential homes and businesses as well as fueling private vehicles and fleets. Refrigerants are used for cooling food, homes, and automobiles. Ammonia is used in fertilizing applications in the agricultural industry. A host of other liquefied gases (ethylene, propylene, benzene, butadiene, and toluene) are used to manufacture a large number of consumer and commercial products. Other examples include oxygen, carbon dioxide, chlorine, methyl chloride, nitrogen, oxygen, argon, carbon dioxide, hydrogen, helium, and many other specialty gases.
Liquefied gases are considered volatile since they are sensitive to temperature and pressure changes. Most are thinner than water so pumping them can be challenging. Any increases in ambient temperature or pressure losses in the piping system can cause a liquefied gas to change from a liquid to a vapor. In contrast, any decreases in the ambient temperature or increases in pressure will result in a change to a liquid form. While vapor is mandatory for a compressor application, it is important to keep the liquefied gas in the liquid phase in a pump application; the absence of vapor eliminates cavitation and maximizes pump performance. Corken sliding vane and turbine pumps are engineered to handle thin, volatile, liquids so they are great choices for moving liquefied gases.
When the piping system for a liquefied gas application does not provide adequate net positive suction head (NPSH), a reciprocating gas compressors is the best choice. Tank car unloading and underground tank applications with top unloading connecitons are a few examples where a reciprocating compressor should be applied.
For more information on Corken’s compression and pumping solutions for the liquefied gas market, click on one of the links below: