90 % vol Rec at 675
F max
FBP 750
F max
Sulfur 0.3 % max
Gas oil recipe:
It is proposed to route all the FCCU’s Lt cycle oil make to this blend and
sufficient Kero to meet the sulfur specification, thus:
Let x lbs/CD be the amount of Kero in the blend, then:
lbs/CD sulfur in cycle oil = 2,380
lbs/CD sulfur in the Kero = 0.00004x
2,380 þ 0:00004x ¼ 0:003 438,000 þ x
ð
Þ
x ¼ 439,527 lbs=CD:
The resulting blend is shown in Table 46.
SG of blend = 0.856, which is within spec
ASTM distillation of blend is as follows:
10 % rec at 401
F
50 % rec at 473
F
90 % rec at 571
F
FBP 647
F
This meets the distillation spec.
Checking flash point : Kero flash point ¼ 0:77 ASTM 5 % temp À 150
ð
Þ
¼ 0:77 370 À 150
ð
Þ ¼ 169:4
F
The Lt cycle oil has an ASTM 5 % point higher than 370
F; therefore, blend flash
point will be >150
F which makes it within spec.
Table 45 Diesel product viscosity estimate
% vol
Visc at 100
F cSt
Visc index
Factor (index  % vol)
Gas oil
7.5
13.0
38
285
Diesel
92.5
4.0
48
4,440
Total
100.0
4,725
Table 46 Heating oil
blend recipe
Stream
MM lbs/CD
lbs/gal
BPCD
Lt cycle oil
0.438
7.63
1,366
Kerosene
0.440
6.70
1,563
0.878
7.13
2,929
Petroleum Products and a Refinery Configuration
119