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
or the Orinoco tar sands
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 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:
to separate lighter fractions, leaving behind a residue with molecular weights over 400.
the vacuum distillation residue to remove the highest molecular weight alicyclic
compounds, which precipitate as black/brown asphaltene
s when the mixture is dissolved in C3
s, leaving "de-asphalted oil" (DAO) in solution. A mixture of propane and butane will remove metallic compounds that would interfere with hydrotreating.
to break long chain molecules in the DAO into shorter ones.
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.
* Canadian Centre for Energy Information
* History of the petroleum industry in Canada (oil sands and heavy oil)
* Scotford Upgrader
University of Alberta Tutorial on Upgrading of Oilsands Bitumen