North American Heavy Oil, Oil Sands, and Oil Shale Resources

A schematic of a fluid coker is shown in Figure 5-2 [25]. The four components of the
fluid coker (boiler, burner, fluid coker, and scrubber) allow for good heat integration
and control over product quality. The scrubber allows initial product fractionation
before the products are sent to the finishing unit. The capital costs for fluid coking are
comparable to those of delayed coking, but the overall cost per barrel is higher because
energy is consumed during coke circulation in the fluid coker [17].
Figure 5-2. Schematic of a fluid coker.
Products
Scrubber
Fluid Coker
Hot coke
Cold coke
Boiler
Burner
Flue-gas treatment
Steam
Source: D. G. Hammond et al., Review of FLUID COKING and FLEXICOKING Technologies, 2003
Another coking process that adds a gasification step to reduce natural gas consumption
is called Flexicoking. In Flexicoking, part of the coke is gasified to synthesis gas
(syngas). The syngas can be used as a low-quality fuel or cleaned up for hydrogen
recovery. Hydrogen can subsequently be used in the hydrogen addition step for
nitrogen or heavy metal removal. Some studies have shown that the capital cost for
Flexicoking units are comparable to capital expenditures for delayed coking, while
other studies report capital costs for Flexicoking that are 30-50% higher and operating
costs that are 25-30% higher [17,18] than for comparable delayed coking facilities.
These claims have not been verified for the upgrading of oil sands bitumen.
These processes have been used to maximize liquid yields while minimizing gas and
coke formation. The products from fluid coking and Flexicoking are the same as those
from delayed coking except for the quantity of coke produced. For both fluid coking
and Flexicoking, the gross coke yield is about 24-35 wt% on a fresh feed basis. Since
some of the coke is utilized for process heating requirements, the net coke yield is
about 70-85 wt% of the gross coke yield [17,18].
5.4.4 Fluid Catalytic Cracking
FCC is the mainstay of most refinery operations. However, this technology has not yet
been used in large commercial operations for upgrading heavy oil residues or bitumen.
The process is similar to that of thermal cracking but uses catalysts [18]. Preheated
feed is sprayed into the base of a vertical pipe where it contacts hot, fluidized catalyst.
The hot catalyst serves two purposes: it vaporizes the heavy oil feed and it catalyzes the
cracking reactions that reduce the molecular weight of the feed to that of medium API
oil.
There are Flexicoking units
around the world for upgrading
heavy oil residues, but thus
far, none have been used for
upgrading oil sand bitumen.
The percentage by weight of
a component in a mixture is
commonly abbreviated as wt%.
Catalytic cracking increases the
proportion of gasoline produced
by cracking naptha to lighter
products in the presence of
catalysts.
Utah Heavy Oil Program Unconventional Oils Research Report
September 2007 Upgrading and Refining 5.9