Prediction of Flash Reference Line
From Distillation Reference Lines
8
8
9
10
11
12
7
7
6
6
5
5
4
4
Slope of Flash Reference Line (FRL)
°F/%
3
3
Slope of Crude Assay (TBP) Distillation Reference Line °F/F%
F l a s h
v s
C r u d e
A s s a y
( T B P )
F l a s h
v s
C r u d e
A s s a y
( T B P )
F l a s h
v s
C r u d e
A s s a y
( T B P )
2
2
1
1
0
0
0
20
40
60
Prediction of FRL
50% Point
Δt′
50 (DRL-FRL)
**Δt′ (Flash/
Δt′(Assay Dist.)
t′ 50 50 DRL<300 DRL<300°F
t′ 50 50 DRL>300 DRL>300°F
t′ 50 DRL<300°F
t′ 50 DRL>300°F
8
9
10
11
12
7
6
5
4
3
Slope of Crude Assay (TBP) Distillation Reference Line °F/%
Prediction of Flash Curve
from its Reference Line
Crude Assay (TBP) Distillation
2
1
0
0
10
20
30
NOTE: * Flash and distillation reference lines (FRL and DRL) are straight lines through the 10%
and 70% points. The temperature of the 50% points refer to these reference lines.
** Δt′ is the deparature of the actual flash and distillation curves from their respective
reference lines. While the individual (Δt′)’s may be either plus or minus, the ratio
is always positive.
40
50
60
Percent off
70
80
90
100 110 120
0.8
0.6
0.4
0.2
0
Reference:
S. D. Maxwell, “Data on Hydrocarbons”
pp 222-228, Van Hostrand Company.
New York, 1950.
Fig. 7 EFV–TBP correlation – Maxwell method
Introduction to Crude Oil and Petroleum Processing
21