Coil
section
Exit
temp
F
Duty
MMBtu/h
Sq.ft. of
coil
Volume of
coil cuft
Cumulative
volume cuft
K T /
K 800
4
840
12.275
1,227
135.0
861.2
3.02
5
860
5.682
568
62.5
923.7
5.0
6
880
21.739
2,174
239.1
1,162.8
7.3
7
900
13.855
1,386
152.5
1,315.3
9.0
8
920
11.634
1,163
127.9
1,443.2
10.2
Total
184.226
1,443.2
Temperature versus volume of coil is plotted over each coil section and is given
in Fig. 19. The plot of coil volume above 800
F versus the K T /K 800 ratio is also
plotted in Fig. 20. The area under the curve developed in Fig. 20 is calculated and
then divided by the throughput in terms of BPSD gives the SVF for the conversion.
Thus,
Area under the curve of Fig: 20 ¼
ð 920
800
K T =K 800 Â coil vol
¼ 3, 867
allow 10% for the steam ¼ 3, 480
then calculated SVF ¼
3, 480
25, 500
¼ 0:136
which compares well with the estimate for a 9 % conversion originally used.
500
600
700
800
Temperature °F
Total Volume = 1443 Cu ft
900
1000
1600
1400
1200
1000
800
600
400
200
Coil Volume Cu ft
Coil Outlet
Fig. 19 Coil temperature versus coil volume
Upgrading the Bottom of the Barrel
563