Page 140 - Synthetic Fuels Handbook

126 CHAPTER FOUR

Syncrude has moved away from fluid coking as the only upgrading option for tar sand
bitumen. The process begins with diluted bitumen fed into the diluent recovery units where
water is removed and naphtha is recovered to be recycled through extraction. The resulting
dry bitumen is fed to the fluid coker, the LC-Finer (a hydrocracker), and the vacuum distil-
lation unit (VDU) for further processing.
Light and heavy gas oils are distilled off in the vacuum distillation unit and sent to
hydrotreaters. The remaining bitumen is sent to the LC-Finer and coking unit. Light
and heavy gas oils are formed in the LC-Finer, through the use of a catalyst to add
hydrogen, and sent to hydrotreaters. The remaining bitumen is sent to the coking unit.
Naphtha, light gas oil, and heavy gas oil are produced in the coker, through chemical
reaction using hot coke, and sent to hydrotreaters. As before, the end result is a syn-
thetic crude oil but the makeup of the synthetic crude oil can be varied in response to
the market demand.
In comparison to a conventional crude oil (Brent), the Syncrude sweet blend has lower
sulfur and no resid (as shipped); it contains significantly less naphtha-range material and
more middle distillate and vacuum gas oil (Table 4.5).

TABLE 4.5 Comparison of Brent Crude Oil and Syncrude
Sweet Blend
Brent Sweet blend
Gravity, °API 38.6 31.8
Sulfur, wt % 0.3 0.1
C -minus 2.9 3.4
4
C –350°F 28.6 15.0
5
350–650°F 29.6 44.0
650–1050°F 29.8 37.6
1050°F and above 9.1 0.0
Generally, sweet synthetic crude oil makes up the majority of the synthetic crude oil
market but sour synthetic crude oil is also available. Suncor markets a range of sour syn-
thetic blends, each tailored to meet specific refinery processing capabilities. One such
synthetic crude oil is a blend of hydrotreated coker naphtha with nonhydrotreated coker
distillate and coker heavy gas oil.
Suncor’s sour synthetic crude oil is a blend of hydrotreated coker naphtha with straight-
run distillate and straight-run vacuum gas oil. Other blends can also be made available, each
with its own processing characteristics. While these sour crude blends still contain no resid
fraction, they are generally sold to medium and heavy sour crude refineries.
Husky Oil started up a heavy conventional crude upgrader in 1990 using a combination
of ebullated-bed hydroprocessing and delayed coking technologies. Their sweet synthetic
crude is traded as Husky Sweet Blend (HSB). The Athabasca Oils Sands Project (AOSP)
started producing sweet synthetic crude in 2003 called Premium Albian Synthetic (PAS)
using ebullated-bed hydroprocessing technology.

4.8 THE FUTURE

For future tar sand development, the Government of the Province of Alberta, Canada, announced
a standard royalty formula for the oil sands industry, have embraced the principles and, to a large
degree, put into the practice the fiscal recommendations of the National Task Force on Oil Sands