Refer to Table 40. The RVP of the finished product is determined by a bubble
point calculation in which the C 4 is an unknown x and the RVP is set at 7 psia and
100
F. Thus:
Calculating for butane addition to make 7 psia RVP:
6:287 þ x ¼ 3:804 þ 8:57x
x ¼ 0:328
¼ 0:328 Ä 6:287 þ 0:328
ð
Þ
¼ 0:0495
C 4 will be 4.95 mol% or 4.0 vol% of total product gasoline.
Table 36 Balance over isom/alky plants
Stream
lbs/CD
lbs/Gal
BPCD
Routing
In
Unsats ex FCCU
340,201
1,736
Butanes ex sats
355,263
1,760
Total in
695,464
4.74
3,496
Out
C 3 ex FCCU
35,980
203
LPG pool
nC 4 ex Sats
125,763
616
Gasoline/LPG
nC 4 ex FCCU
25,107
123
Gasoline/LPG
Alkylate
506,101
2,054
Gasoline
Total out
692,951
5.51
2,996
Table 35 Gasoline grades
and blending specifications
Premium grade
Regular grade
Octane research clear
90
82
Ried vapor pressure (min)
7 psia
7 psia
Volatility ASTM
50 % vol distilled (min)
275
F
175
F
60 % vol distilled (max)
300
F
210
F
95 % vol distilled (max)
400
F
325
F
Table 37 Premium gasoline grade blend
BPCD
% vol
ON(RES) clear
Octane factor
Alkylate
2,054
26.7
97
0.26
Heavy cracked naphtha
1,695
22.0
89
0.20
Light cracked naphtha
1,000
13.0
94
0.12
Reformate
1,951
25.3
91
0.23
Light str run naphtha
1,000
13.0
69
0.09
Total
7,700
100.0
90
0.90
Petroleum Products and a Refinery Configuration
111