Propane

When commonly sold as fuel it is also known as liquified petroleum gas (LPG or LP-gas) and is a mixture of propane with smaller amounts of propylene, butane and butylene, plus ethanethiol as an odorant to allow the normally odorless propane to be smelled.

It is used as fuel in cooking on many barbecues, portable stoves, and in motor vehicles. Propane powers some locomotives, buses, forklifts, and taxis and is used for heat and cooking in recreational vehicles and campers. In many rural areas of the U.S., propane is also used in furnaces, stoves, water heaters, laundry dryers, and other heat-producing appliances. 6.5 million American households use propane as their primary heating fuel.

Local delivery trucks called "bobtails" fill up large tanks that are permanently installed on the property (sometimes called pigs), or other service trucks exchange empty bottles of propane with filled bottles.

Another use of propane is the application as propellant for aerosol sprays, especially after the ban of CFCs. So called "green gas" used in many gas-powered BB or airsoft guns is merely propane as the propellant with 100% silicone oil added to lubricate gaskets. It is also used as a feedstock for the production of base petrochemicals in steam cracking.

U.S. industries using propane include glass makers, brick kilns, poultry farms, and other industries that need portable heat. Additionally, most of the entire U.S. chemical industry uses propane to power their huge facilities that crack or distill industrial chemical products.

Unlike natural gas, propane is heavier than air (1.5 times denser). 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.

Propane is the fastest growing fuel source in the Third World, especially in China and India. Its use frees up the huge rural populations from time-consuming ancient chores such as wood gathering and allows them more time to pursue other activities, such as increased farming or educational opportunties.

Propane is also being used increasingly more for vehicle fuels. In the U.S., 190,000 on-road vehicles use propane, and 450,000 forklifts use it for power. It is the third most popular vehicle fuel, behind gasoline and diesel. In other parts of the world, propane used in vehicles is known as autogas. About 9 million vehicles worldwide use autogas.

Propane is also instrumental in providing off-the-grid refrigeration, also called gas absorption refrigerators. Made popular by the Servel company, propane-powered refrigerators are highly efficient, do not require electricity, and have no moving parts. Refrigerators built in the 1930s are still in regular use, with little or no maintenance. (However, Servel refrigerators are subject to a 1998 CPSC recall for CO poisoning.) Today, the Unilever company is exploring the use of environmentally friendly propane as a refrigerant.

Source

Propane is not produced for its own sake, but as a byproduct of two other processes: natural gas processing and petroleum refining.

The processing of natural gas involves removal of propane and butane from the natural gas to prevent condensation of these liquids in natural gas pipelines. Additionally, oil refineries produce some propane as a by-product of production of gasoline or heating oil.

The supply of propane cannot be easily adjusted to account for increased demand because of the by-product nature of propane production. About 85% of U.S. propane is domestically produced.

The United States imports about 10-15% of the propane consumed each year. Propane is imported into the United States via pipeline and rail from Canada, and by tankers from Algeria, Saudi Arabia, Venezuela, Norway and the United Kingdom.

After it is produced, American propane is stored in two massive salt caverns located in Mont Belvieu, Texas, and Conway, Kansas. These salt caverns were hollowed out in the 1940s and can store up to 80 million barrels of propane, if not more. The exact storage capacity is not known. 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.

History

Propane was first identified as a volatile component in gasoline by Dr. Walter O. Snelling of the U.S. Bureau of Mines in 1910. Dr. Snelling established the first commercial propane vendor, American Gasol, in 1912.