524
The Chemistry and Technology of Petroleum
19.4.4 HeAvy oIl treAtIng ProCess
The heavy oil treating (HOT) process is a catalytic cracking process for upgrading heavy feedstocks, such as topped crude oils, vacuum residua, and solvent deasphalted bottoms (Table 19.5),
using a fluidized bed of iron ore particles. The main section of the process consists of three fluidized
reactors, and separate reactions take place in each reactor (cracker, regenerator, and desulfurizer):
Fe O Asphaltene constituents coke Fe O Oil Gas in the
3 4
3 4
+
Æ
+
+
/
(
cra acker)
3
2
3 4
2
FeO H O Fe O H in the
+
Æ
+ (
)
cracker
Coke /Fe O O
FeO CO CO in the
3 4
2
2
3
+
Æ
+
+
(
)
regenerator
FeO SO
CO FeS CO in the
+
+
Æ
+
2
2
3
3
(
)
regenerator
3
5
3
2
3 4
2
FeS O
Fe O
SO in the
+
Æ
+
(
)
desulfurizer
In the cracker, heavy oil cracking and the steam-iron reaction take place simultaneously under
the conditions similar usual to thermal cracking. Any unconverted feedstock is recycled to the
cracker from the bottom of the scrubber. The scrubber effluent is separated into hydrogen gas, liquefied petroleum gas (LPG), and liquid products that can be upgraded by conventional technologies
to priority products.
In the regenerator, coke deposited on the catalyst is partially burned to form carbon monoxide
in order to reduce iron tetroxide and to act as a heat supply. In the desulfurizer, sulfur in the solid
catalyst is removed and recovered as molten sulfur in the final recovery stage.
19.4.5 r2r ProCess
The R2R process is a fluid catalytic cracking process for the conversion of heavy feedstocks (Table
19.6; Heinrich and Mauleon, 1994; Inai, 1994).
In the process, the feedstock is vaporized upon contacting hot regenerated catalyst at the base of
the riser and lifts the catalyst into the reactor vessel separation chamber (Figure 19.4) where rapid
disengagement of the hydrocarbon vapors from the catalyst is accomplished by both a special solids
separator and cyclones. The bulk of the cracking reactions takes place at the moment of contact and
continues as the catalyst and hydrocarbons travel up the riser. The reaction products, along with
a minute amount of entrained catalyst, then flow to the fractionation column. The stripped spent
catalyst, deactivated with coke, flows into the Number 1 regenerator.
TABLE 19.5
Feedstock and Product Data for the HOT Process
Feedstock
Arabian Light
Vacuum Residuum
API
7.1
Sulfur, % w/w
4.2
Carbon residue, % w/w
21.6
Products
Light naphtha (C5-180°C, C5-355°F), vol.%
15.2
Heavy naphtha (180°C–230°C, 355°F–445°F), vol.%
8.2
Light gas oil (230°C–360°C, 445°F–680°F), vol.%
2.3
Heavy gas oil (360°C–510°C, 680°F–950°F), vol.%
28.2
The Chemistry and Technology of Petroleum
19.4.4 HeAvy oIl treAtIng ProCess
The heavy oil treating (HOT) process is a catalytic cracking process for upgrading heavy feedstocks, such as topped crude oils, vacuum residua, and solvent deasphalted bottoms (Table 19.5),
using a fluidized bed of iron ore particles. The main section of the process consists of three fluidized
reactors, and separate reactions take place in each reactor (cracker, regenerator, and desulfurizer):
Fe O Asphaltene constituents coke Fe O Oil Gas in the
3 4
3 4
+
Æ
+
+
/
(
cra acker)
3
2
3 4
2
FeO H O Fe O H in the
+
Æ
+ (
)
cracker
Coke /Fe O O
FeO CO CO in the
3 4
2
2
3
+
Æ
+
+
(
)
regenerator
FeO SO
CO FeS CO in the
+
+
Æ
+
2
2
3
3
(
)
regenerator
3
5
3
2
3 4
2
FeS O
Fe O
SO in the
+
Æ
+
(
)
desulfurizer
In the cracker, heavy oil cracking and the steam-iron reaction take place simultaneously under
the conditions similar usual to thermal cracking. Any unconverted feedstock is recycled to the
cracker from the bottom of the scrubber. The scrubber effluent is separated into hydrogen gas, liquefied petroleum gas (LPG), and liquid products that can be upgraded by conventional technologies
to priority products.
In the regenerator, coke deposited on the catalyst is partially burned to form carbon monoxide
in order to reduce iron tetroxide and to act as a heat supply. In the desulfurizer, sulfur in the solid
catalyst is removed and recovered as molten sulfur in the final recovery stage.
19.4.5 r2r ProCess
The R2R process is a fluid catalytic cracking process for the conversion of heavy feedstocks (Table
19.6; Heinrich and Mauleon, 1994; Inai, 1994).
In the process, the feedstock is vaporized upon contacting hot regenerated catalyst at the base of
the riser and lifts the catalyst into the reactor vessel separation chamber (Figure 19.4) where rapid
disengagement of the hydrocarbon vapors from the catalyst is accomplished by both a special solids
separator and cyclones. The bulk of the cracking reactions takes place at the moment of contact and
continues as the catalyst and hydrocarbons travel up the riser. The reaction products, along with
a minute amount of entrained catalyst, then flow to the fractionation column. The stripped spent
catalyst, deactivated with coke, flows into the Number 1 regenerator.
TABLE 19.5
Feedstock and Product Data for the HOT Process
Feedstock
Arabian Light
Vacuum Residuum
API
7.1
Sulfur, % w/w
4.2
Carbon residue, % w/w
21.6
Products
Light naphtha (C5-180°C, C5-355°F), vol.%
15.2
Heavy naphtha (180°C–230°C, 355°F–445°F), vol.%
8.2
Light gas oil (230°C–360°C, 445°F–680°F), vol.%
2.3
Heavy gas oil (360°C–510°C, 680°F–950°F), vol.%
28.2