Upgrading

Upgrading is a process that converts raw bitumen to synthetic crude oil.

Bitumen that is open pit mined is first treated to remove all water, sand, and other particulates. However, this feedstock is very heavy¹ and cannot be processed by most existing refineries. Instead, they must be upgraded to “synthetic crude oil” prior to refining.

Upgrading is performed in two stages, known as primary and secondary refining. Primary refining aims to break apart the long carbon chains (known as cracking) to create shorter, lighter hydrocarbons. This can be done by either carbon rejection or hydrogen addition. The choice between the two is largely economic in nature. Hydrogen addition offers higher yields at higher costs and is preferential when the price of crude is high. Secondary refining removes impurities such as sulphur, nitrogen, and heavy metals.

Context

The need to upgrade the heavy crude from the oil sands renders bitumen derived petroleum products  more energy intensive than conventional crude. Some estimates suggest that bitumen products have 3.2-4.5 times more GHG emissions per barrel than conventional crude from North America². With growing energy needs of developing nations and dwindling conventional crude supplies, issues such as upgrader efficiency and economy will need to be addressed in political, environmental, and economic fields. The energy contained in the oil sands is immense, and sufficient upgrader technology will be necessary to utilize the resource to its fullest potential.

Scientific research is currently underway to achieve 2-3 fold improvements in upgrading efficiency. With respect to climate effects, carbon capture and storage (CCS) is seen as a potential method to reduce environmental impact. For example, the Shell Quest CCS Project aims to capture 35% of the emissions from the Scotford Upgrader in Edmonton, Alberta when online².