Propane

Propane (/ˈproʊpeɪn/) is a three-carbon alkane with the molecular formula C3H8. It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel. Propane is one of a group of liquefied petroleum gases (LP gases). The others include butane, propylene, butadiene, butylene, isobutylene, and mixtures thereof. Propane (/ˈproʊpeɪn/) is a three-carbon alkane with the molecular formula C3H8. It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel. Propane is one of a group of liquefied petroleum gases (LP gases). The others include butane, propylene, butadiene, butylene, isobutylene, and mixtures thereof. Propane was discovered by the French chemist Marcellin Berthelot in 1857. It was found dissolved in Pennsylvanian light crude oil by Edmund Ronalds in 1864. Walter O. Snelling of the U.S. Bureau of Mines highlighted it as a volatile component in gasoline in 1910, which was the beginning of the propane industry in the United States. The volatility of these lighter hydrocarbons caused them to be known as 'wild' because of the high vapor pressures of unrefined gasoline. On March 31, 1912, The New York Times reported on Snelling's work with liquefied gas, saying 'a steel bottle will carry enough gas to light an ordinary home for three weeks'. It was during this time that Snelling, in cooperation with Frank P. Peterson, Chester Kerr, and Arthur Kerr, created ways to liquefy the LP gases during the refining of gasoline. Together, they established American Gasol Co., the first commercial marketer of propane. Snelling had produced relatively pure propane by 1911, and on March 25, 1913, his method of processing and producing LP gases was issued patent #1,056,845. A separate method of producing LP gas through compression was created by Frank Peterson and its patent granted on July 2, 1912. The 1920s saw increased production of LP gas, with the first year of recorded production totaling 223,000 US gallons (840 m3) in 1922. In 1927, annual marketed LP gas production reached 1 million US gallons (3,800 m3), and by 1935, the annual sales of LP gas had reached 56 million US gallons (210,000 m3). Major industry developments in the 1930s included the introduction of railroad tank car transport, gas odorization, and the construction of local bottle-filling plants. The year 1945 marked the first year that annual LP gas sales reached a billion gallons. By 1947, 62% of all U.S. homes had been equipped with either natural gas or propane for cooking. In 1950, 1,000 propane-fueled buses were ordered by the Chicago Transit Authority, and by 1958, sales in the U.S. had reached 7 billion US gallons (26,000,000 m3) annually. In 2004, it was reported to be a growing $8-billion to $10-billion industry with over 15 billion US gallons (57,000,000 m3) of propane being used annually in the U.S. The 'prop-' root found in 'propane' and names of other compounds with three-carbon chains was derived from 'propionic acid', which in turn was named after the Greek words protos (meaning first) and pion (fat). Propane is produced as a by-product of two other processes, natural gas processing and petroleum refining. The processing of natural gas involves removal of butane, propane, and large amounts of ethane from the raw gas, in order to prevent condensation of these volatiles in natural gas pipelines. Additionally, oil refineries produce some propane as a by-product of cracking petroleum into gasoline or heating oil. The supply of propane cannot easily be adjusted to meet increased demand, because of the by-product nature of propane production. About 90% of U.S. propane is domestically produced. The United States imports about 10% of the propane consumed each year, with about 70% of that coming from Canada via pipeline and rail. The remaining 30% of imported propane comes to the United States from other sources via ocean transport. After it is separated from the crude oil, North American propane is stored in huge salt caverns. Examples of these are Fort Saskatchewan, Alberta; Mont Belvieu, Texas; and Conway, Kansas. These salt caverns were hollowed out in the 1940s, and they can store 80,000,000 barrels (13,000,000 m3) or more of propane. When the propane is needed, much of it is shipped by pipelines to other areas of the United States. The North American standard grade of automotive use propane is rated HD 5. HD 5 grade has a maximum of 5 percent butane, but propane sold in Europe, has a max allowable amount of butane of 30 percent, meaning it's not the same fuel as HD 5. The LPG used as auto fuel and cooking gas in Asia and Australia, also has a very high content of butane. Propane is also shipped by truck, ship, barge, and railway to many U.S. areas.