Tuesday, August 31, 2010

Propane undergoes combustion reactions in a similar fashion to other alkanes. In the presence of excess oxygen, propane burns to form water and carbon dioxide.

    C3H8 + 5 O2 → 3 CO2 + 4 H2O + heat

    propane + oxygen → carbon dioxide + water

When not enough oxygen is present for complete combustion, incomplete combustion occurs when propane burns and forms water, carbon monoxide, carbon dioxide, and carbon.

    2 C3H8 + 7 O2 → 2 CO2 + 2 CO + 2 C + 8 H2O + heat

    Propane + Oxygen → Carbon Dioxide + Carbon Monoxide + Carbon + Water

Unlike natural gas, propane is heavier than air (1.5 times as dense). In its raw state, propane sinks and pools at the floor. Liquid propane will flash to a vapor at atmospheric pressure and appears white due to moisture condensing from the air.

When properly combusted, propane produces about 50 MJ/kg. The gross heat of combustion of one normal cubic meter of propane is around 91 megajoule

Propane is nontoxic; however, when abused as an inhalant it poses a mild asphyxiation risk through oxygen deprivation. Commercial products contain hydrocarbons beyond propane, which may increase risk. Commonly stored under pressure at room temperature, propane and its mixtures expand and cool when released and may cause mild frostbite.

Propane combustion is much cleaner than gasoline combustion, though not as clean as natural gas combustion. The presence of C–C bonds, plus the multiple bonds of propylene and butylene, create organic exhausts besides carbon dioxide and water vapor during typical combustion. These bonds also cause propane to burn with a visible flame.

Greenhouse gas emissions factors for propane are 62.7 kg CO2/ mBTU or 1.55 kg of CO2 per litre or 73.7 kg/GJ.

Sunday, August 29, 2010

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 produced, North American propane is stored in huge salt caverns located in Fort Saskatchewan, Alberta; Mont Belvieu, Texas and Conway, Kansas. These salt caverns were hollowed out in the 1940s, and they can store 80 million or more barrels of propane. When the propane is needed, most of it is shipped by pipelines to other areas of the Midwest, the North and the South, for use by customers. Propane is also shipped by barge and rail car to selected U.S. areas.

Saturday, August 28, 2010

The 1920s saw increased production of LP gas, with the first year of recorded production totaling 223,000 gallons in 1922. In 1927, annual marketed LP gas production reached one million gallons, and by 1935, the annual sales of LP gas had reached 56 million gallons. 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 gallons annually. In 2004 it was reported to be a growing $8-billion to $10-billion industry with over 15 billion gallons 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".

Friday, August 27, 2010

Propane was first identified as a volatile component in gasoline by Dr. Walter O. Snelling of the U.S. Bureau of Mines in 1910. 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 the New York Times reported on Dr. Snelling's work with liquefied gas and that "...a steel bottle will carry enough [gas] to light an ordinary home for three weeks."

It was during this time that Dr. Snelling, in cooperation with Frank P. Peterson, Chester Kerr and Arthur Kerr, created ways to liquefy the LP gases during the refining of natural gasoline. Together they established American Gasol Co., the first commercial marketer of propane. Dr. 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 patented in 1912.

Thursday, August 26, 2010


Propane is a three-carbon alkane, normally a gas, but compressible to a transportable liquid. It is derived from other petroleum products during oil or natural gas processing. It is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves and residential central heating.

A mixture of propane and butane, used mainly as vehicle fuel, is commonly known as liquefied petroleum gas (LPG or LP gas). It may also contain small amounts of propylene and/or butylene. An odorant such as ethanethiol or thiophene is added so that people can easily smell the gas in case of a leak.