|
Hydrotreating
technology for FCC Feed
R
& D Background
FCC,
one of the main refining technologies in China, has been
the core operation of domestic refineries. According to
statistics, FCC capacity is over 35% of the total domestic
oil capacity. Many FCC units have been designed to be RFCC
type so that they can process certain part of poor quality
VGO (such as CGO, DAO, etc) and residue in order to get
higher light oil yield and economic profits. If metal
contents and carbon residue in FCC feedstock are too high,
FCC units will have to be operated under more severe
conditions, which not only accelerates coke deposit in
catalysts, increase capacity of regenerator and catalyst
loss, but also render poor gasoline quality. Higher S
content in feedstock will lead to high sulfur in FCC
gasoline/diesel and regenerator flue gas.
Advantages
of FCC feedstock pre-hydrotreatment
-
Improve
crackability, decrease FCC operation severity,
-
Improve
product slates, increase selectivity to target
products,
-
Decrease
dry gas and coke yields,
-
Decrease
S content in target products
-
Decrease
SOx and NOx in regenerator flue
gas
-
FCC
can process high sulfur heavy feedstock.
Typical
operating conditions:
Typical
results
Effects
of pre-hydrotreating to FCC operation
|
S
removal rate of pre-hydrotreating |
0 |
90% |
98% |
99% |
|
Density/g×
cm-3 |
0.9271 |
0.9090 |
0.9013 |
0.8944 |
|
S/m% |
2.6 |
0.25 |
0.06 |
0.02 |
|
N/m
g× g-1 |
880 |
500 |
450 |
400 |
|
MCR/m% |
0.4 |
0.25 |
0.1 |
0.1 |
|
Ni+V/m
g× g-1 |
1 |
<1 |
<1 |
<1 |
|
Product
slates/m% |
|
|
|
|
|
C3+C4 |
16.3 |
17.6 |
18.7 |
19.9 |
|
Full
range gasoline |
48.3 |
51.5 |
52.5 |
53.6 |
|
Diesel(LCO) |
16.7 |
15.7 |
15.0 |
14.0 |
|
Clarified
oil |
9.0 |
6.6 |
5.9 |
5.2 |
|
Coke |
5.4 |
5.0 |
4.7 |
4.4 |
|
Conversion/v% |
74.3 |
77.7 |
79.1 |
80.8 |
|
Properties
of main products |
|
|
|
|
|
Gasoline
RON |
93.2 |
93.0 |
92.9 |
92.7 |
|
MON |
80.5 |
80.8 |
81.1 |
81.0 |
|
Cetane
number of diesel |
25.7 |
25.7 |
26.4 |
26.5 |
|
S
content in products/m g× g-1 |
|
|
|
|
|
Gasoline |
3600 |
225 |
55 |
18 |
|
Diesel |
29700 |
3400 |
900 |
300 |
|
Clarified
oil |
57800 |
11000 |
3000 |
1100 |
|
Coke |
30300 |
5700 |
1554 |
516 |
|
SOx
（ml/l） |
2030 |
410 |
120 |
42 |
Commercial
and pilot plant results of poor CGO pre-hydrotreating
|
Capacity |
Commercial |
Commercial |
Pilot
plant |
|
Feed |
Pipeline
CGO |
Gudao
V3 and CGO mix |
Mix
of Saudi middle V4, CGO and DAO |
|
Operating
conditions |
|
|
|
|
Inlet
pressure/MPa |
6.0 |
7.0 |
8.0 |
|
Temperature/℃ |
340(reactor
inlet) |
384 |
380 |
|
Catalyst |
CH-20 |
3966 |
FZC-22/3936 |
|
LHSV/h-1 |
1.03 |
0.81 |
0.52 |
|
H2/oil(v/v) |
1250:1 |
600:1 |
800:1 |
|
Property |
Feed |
Effluent |
Feed |
Effluent |
Feed |
Effluent |
|
Density/g×
cm-3 |
0.8919 |
- |
0.9205 |
0.8889 |
- |
- |
|
Boiling
range(ASTM D-1160)/℃ |
219~491 |
- |
255~558 |
192~556 |
- |
- |
|
S/m
g× g-1 |
8860 |
400 |
10000 |
61 |
21300 |
1500 |
|
N/m
g× g-1 |
4502 |
1848 |
3985 |
1144 |
2314 |
830 |
|
Basic
N/m g× g-1 |
1560 |
434 |
－ |
- |
- |
- |
|
MCR/% |
0.09 |
0.02 |
0.61 |
0.07 |
3.09 |
0.55 |
|
S
removal/% |
95.5 |
99.4 |
93.0 |
|
N
removal/% |
59.0 |
71.3 |
64.1 |
|
MCR
removal/% |
77.8 |
88.5 |
82.2 |
Typical
heavy oil pre-hydrotreating unit--feedstock properties
| Density/g/cm3 |
0.9268 |
| Boiling
range (D-1160)/℃ |
|
| IBP/10% |
322/400 |
| 30%/50% |
431/454 |
| 70%/90% |
495/574 |
| EBP |
705 |
| S/m% |
2.21 |
| N/m
g/g |
1310 |
| MCR/m% |
1.57 |
| Metal/m
g/g： |
|
| Fe |
0.15 |
| Ni |
0.82 |
| V |
0.79 |
Typical
heavy oil pre-hydrotreating unit—effluents properties
| Fraction/℃ |
<180 |
180～385 |
>385 |
| density(20℃)/g/cm3 |
0.7703 |
0.8681 |
0.8877 |
| Boiling
range/℃： |
|
|
|
| IBP/10% |
62/85 |
172/254 |
392/410 |
| 30%/50% |
98/126 |
301/323 |
431/445 |
| 70%/90% |
146/168 |
337/351 |
479/536 |
| EBP |
183 |
367 |
602 |
| S/m
g/g |
|
～200 |
～350 |
| N/m
g/g |
|
～100 |
～200 |
| Cetane
index(D4737-96a) |
|
48.8 |
|
| BMCI |
|
|
31.9 |
|
