Description

Bitumen

Asphalt is a sticky, black and highly viscous liquid or semi-solid form of petroleum. It may be

found in natural deposits or may be a refined product; it is a substance classed as a pitch. Until

the *0th century, the term asphaltum was also used. The word is derived from the Greek

\'asphaltos\' which in turn was borrowed from an Eastern word.

The primary use (*0%) of asphalt/bitumen is in road construction, where it is used as the glue or

binder mixed with aggregate particles to create asphalt concrete. Its other main uses are

for bituminous waterproofing products, including production of roofing felt and for sealing flat

roofs.

The terms asphalt and bitumen are often used interchangeably to mean both natural and

manufactured forms of the substance. In American English, asphalt (or asphalt cement) is the

carefully refined residue from the distillation process of selected crude oils. Outside the United

States, the product is often called bitumen. Geological terminology often prefers the

term bitumen. Common usage often refers to various forms of asphalt/bitumen as "tar", such as

at the La Brea Tar Pits. Another term for asphalt/bitumen, now rather archaic, is "pitch".

Naturally occurring asphalt/bitumen is sometimes specified by the term "crude bitumen". Its

viscosity is similar to that of cold molasses while the material obtained from the fractional

distillation of crude oil boiling at **5 °C (**7 °F) is sometimes referred to as "refined bitumen".



5.1 Bitumen-based fuel

Fuel specifically developed for industrial use. The most known bitumen-based fuel

is Orimulsion, an emulsion of natural bitumen from Orinoco Belt and fresh water, which was

developed by Intevep.

Raw bitumen has an extremely high viscosity, between 8 to *0 API degrees, at ambient

temperatures, rendering it unusable for use in electrical power stations. Bitumen can be modified

by mixing it with fresh water and a small amount of phenol-based surfactant. The resulting

mixture has properties similar to conventional fuel oil.

A newer version of bitumen-based fuel has replaced the original version with an alcoholbased

surfactant, making it easier to transport the fuel and eliminating the health concerns

associated with the phenol group of surfactants.

Bitumen-based fuel is currently used as a commercial boiler fuel in power plants

in Canada, Japan, Lithuania, and China). Commonly available air pollutant control technology

can limit emissions from Orimulsion to levels considered Best Available Control Technology, as

defined by the United States Environmental Protection Agency.