Extraction is where bitumen is separated from the sand. The slurry is fed into Primary Separation Vessels (PSVs), where the bitumen floats to the surface as froth. Tumblers are also used.
Before heading to the Upgrader, the froth is diluted with naphtha and put into either inclined plate settlers or through centrifuges to remove water and solids. Over 99% of the naphtha is recovered and recycled back to the extraction plant.
Middlings, which remain suspended in the middle of the vessel, are fed through smaller versions of the PSVs to recover additional bitumen.
Primary Separation Vessel (PSV)
The remaining material consists of sand, water, clay, fine silts and residual bitumen, and is known as tailings. Tailings are pumped by pipeline to one of several settling basins on site. These settling basins, or tailings ponds, are the source of the recycled water used in the bitumen extraction process. Over 85% of the water used at Syncrude is from these facilities. We are also actively pursuing a suite of technologies which will assist us in reclaiming tailings more quickly. Learn more here.
We regularly achieve bitumen recovery rates exceeding 90%. Incremental increases can translate into significant economic and production benefits, while reducing the amount of bitumen that enters the tailings ponds. Specific initiatives are underway to improve our processes and develop the new generation of extraction technologies.
The Aurora mine – located about 40 kilometres north of our Mildred Lake site – is a model for oil sands efficiency and smart energy use. Hot water, reclaimed from waste heat produced at the Mildred Lake upgrader, is sent via pipeline to the Aurora mine where it is used to extract the bitumen from the oil sand. This results in a substantial reduction in the energy that would otherwise be required to heat the water. The cooler water is then returned, along with the bitumen, to the upgrader at Mildred Lake. Here, the bitumen in processed into crude oil and the water reheated and again returned to the Aurora.