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196 Applied Process Design for Chemical and Petrochemical Plants

2
(hr)(ft )(°F)/Btu, the service overall coefficient is 331 Heat Transfer Rate—Simplified Method
2
Btu/(hr)(ft )(°F).
5. The overall temperature difference is 10–18°F, depend- For W T 12.7 lb/sec circulation, the following values are
ing on fouling. Vacuum operation on the steam side is obtained:
indicated.
2
h L 162 Btu/(hr) (ft )(°F)
h tp / h L 2.4 (at x 0.4, x E 0.16)
2
h tp 386 Btu/(hr) (ft )(°F)

1.0 } Figure 10-118
2

E 0.5 GT 27.8 lb/(sec) (ft )

0.75
2
h b 900 Btu/(hr) (ft )(°F) at t w t s 5.0°F and data of
Fair’s reference 9.
L BC h 1 L cd h v
hp
L t
See Figure 10-110 for length designations.

2
h p h v 0.75 19002 386 1061 Btu>1hr2 1ft 21°F2
For the inside surface of 285 ft , the vaporization is
2
h p A1t w t s 2 11,06121285215.02
4.35 lb>sec
196.9213,6002
Figure 10-120. Summary of information for Example 10-19. (Used by
permission: Fair, J. R. Chemical Engineering, July 8, 1963, Part 1.
©McGraw-Hill, Inc. All rights reserved.)
Table 10-31
Stepwise Calculations for C 3 Splitter Reboiler,
Example 10-19
Increment 1 2 3 4 5 6 7 8 Exit

Incr. vaporization, x 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.035
vaporization, x 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.385 0.385
0.08 0.20 0.35 0.50 0.66 0.83 1.01 1.25 1.32
1 3 X tt
0.58 0.42 0.35 0.31 0.28 0.25 0.23 0.20 0.19
R L
16.25 12.98 11.54 10.74 10.08 9.40 9.00 8.60 8.28
tp
2 2.70 4.80 7.00 9.60 12.2 15.5 19.0 22.5 25.0
1.23 1.65 2.07 2.50 2.90 3.28 3.60 3.95 . . .
h tp /h L
198 266 333 403 467 529 580 636 . . .
h tp
900 900 900 900 900 900 900 900 . . .
h b
_

1.0 1.0 1.0 1.0 1.0 0.80 .070 0.50 . . .
1098 1166 1233 1303 1367 1249 1210 1085 . . .
h p
Incr. length, ft 1.15 1.08 1.02 0.97 0.92 1.01 1.04 0.81 . . .
length, ft 1.15 2.23 3.25 4.22 5.14 6.15 7.19 8.00 . . .
p, psf 19.96 35.37 48.56 60.46 71.30 82.72 94.09 102.97 146.57
Pressure Balance
Outlet psf Inlet psf
Static 89.99 Static (8.0 ft) 198.40
Friction, tubes 10.88 Friction, piping 30.80
Friction, exit 36.30 (Required extra) 21.03
Acceleration 9.40 146.57
146.57
Used by permission: Fair, J. R. Petroleum Refiner, V. 39, No. 2, p. 105, ©1960. Gulf Publishing Company. All rights reserved.