An upgrader is a facility that upgrades

bitumen Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term a ...

(extra heavy oil) into synthetic crude oil. Upgrader plants are typically located close to

oil sands Oil sands, tar sands, crude bitumen, or bituminous sands, are a type of unconventional petroleum deposit. Oil sands are either loose sands or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and wate ...

production, for example, the Athabasca oil sands in

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest T ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...

or the

Orinoco tar sands The Orinoco Belt is a territory in the southern strip of the eastern Orinoco River Basin in Venezuela which overlies the world's largest deposits of petroleum. Its local Spanish name is ''Faja Petrolífera del Orinoco'' (Orinoco Petroleum Belt). T ...

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

Processes

Upgrading means using

fractional distillation Fractional distillation is the separation of a mixture into its component parts, or fractions. Chemical compounds are separated by heating them to a temperature at which one or more fractions of the mixture will vaporize. It uses distillation ...

and/or chemical treatment to convert bitumen so it can be handled by oil refineries. At a minimum, this means reducing its viscosity so that it can be pumped through pipelines (bitumen is 1000x more viscous than light crude oil). However this process often also includes separating out heavy fractions and reducing sulfur, nitrogen and metals like nickel and vanadium. Upgrading may involve multiple processes: *

Vacuum distillation Vacuum distillation is distillation performed under reduced pressure, which allows the purification of compounds not readily distilled at ambient pressures or simply to save time or energy. This technique separates compounds based on differences i ...

to separate lighter fractions, leaving behind a residue with molecular weights over 400. * De-asphalting the vacuum distillation residue to remove the highest molecular weight alicyclic compounds, which precipitate as black/brown

asphaltene Asphaltenes are molecular substances that are found in crude oil, along with resins, aromatic hydrocarbons, and saturates (i.e. saturated hydrocarbons such as alkanes). The word "asphaltene" was coined by Boussingault in 1837 when he noticed tha ...

s when the mixture is dissolved in C₃–C₇

alkane In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in wh ...

s, leaving "de-asphalted oil" (DAO) in solution. A mixture of propane and butane will remove metallic compounds that would interfere with hydrotreating. * Cracking to break long chain molecules in the DAO into shorter ones. * Hydrotreating may also be employed to remove sulfur and reduce the level of nitrogen. Research into using

biotechnology Biotechnology is the integration of natural sciences and engineering sciences in order to achieve the application of organisms, cells, parts thereof and molecular analogues for products and services. The term ''biotechnology'' was first used ...

to perform some of these processes at lower temperatures and cost is ongoing.

References

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Processes

See also

References

Further reading