Upgrader

An upgrader is a facility that upgrades bitumen (extra heavy oil) into synthetic crude oil. Upgrader plants are typically located close to oil sands production, for example, the Athabasca oil sands in Alberta, Canada or the Orinoco tar sands in Venezuela.

Processes

Upgrading means using fractional distillation and/or chemical treatment to convert bitumen so it can be handled by oil refineries. At a minimum, this means reducing the bitumens viscosity with naphthenic solvents so that it can be pumped through pipelines (bitumen is 1000x more viscous than light crude oil). However this process often also includes some kind of cracking process, as well as separating different fractions and reducing sulfur, nitrogen and metals like nickel and vanadium. Upgraders typically consists multiple refinery units and have many variations depending on the required product. Products of an Upgrader can be: diluted bitumen, synthetic crude oil (SCO), or refined products (gas oils, distillates and naphtha). Partial upgrading is also possible, where the heavy and sour bitumen viscosity is improved just enough to reduce or eliminate the diluent needs.

Upgrading may involve multiple processes:

• Vacuum distillation 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 asphaltenes when the mixture is dissolved in C₃–C₇ alkanes, leaving "de-asphalted oil" (DAO) in solution. A mixture of propane and butane will remove metallic compounds that would interfere with hydrotreating. ^[1]
• Cracking to break long chain molecules into shorter ones. Delayed cokers, and Ebullated bed reactor hydrocrackers ("LC-Finer") are most commonly utilized for cracking.
• Hydrotreating may also be employed to remove sulfur and reduce the level of nitrogen.

Research into using biotechnology to perform some of these processes at lower temperatures and cost is ongoing.

See also

• Canadian Centre for Energy Information
• History of the petroleum industry in Canada (oil sands and heavy oil)
• Scotford Upgrader
• Syncrude
• Suncor
• Visbreaker

References

1. Study of Selected Petroleum Refining Residuals (PDF). United States Environmental Protection Agency. August 1996. p. 107. Archived from the original (PDF) on June 2, 2011.

Further reading

• University of Alberta Tutorial on Upgrading of Oilsands Bitumen