Gravity of the distillate ¼ 26
API 7:48 lbs=gal
ð
Þ :
Weight of distillate ¼ 17, 340 Â 7:48 Â 1:75 ¼ 226, 981 lbs=h:
Percent weight distillate on feed ¼ 65%
Referring to Fig. 7 in this chapter, the soaking volume factor (SVF) corresponding
to a 9 % conversion with a distillate content of 65 % is 0.135.
The heater coil is divided into the following sections:
Temp in,
F
Temp out,
F
Section 1
Convection side
500
700
2
Heater side
700
760
3
”
760
820
4
Soaker side
820
840
5
”
840
860
6
”
860
880
7
”
880
900
8
”
900
920
Feed In
600 psig Steam
500°F
700°F
840°F
880°F
860°F
760°F
920°F
800°F
Convection Side
Soaker side
Section 7
Section 8
Section 6
900°F
Section 5
Section 1
Section 4
Section 2
Section 3
Heater Side
Cracked
Effluent
Out
Fig. 17 Temperature profile across the thermal cracker heater
558
D.S.J. Jones