Page 192 - Chemical process engineering design and economics

174 Chapter 4

Table 4.4 Summary of Heat-Exchanger Approach Temperature Differ-
ences and Pressure Drops

3
Heat-Exchanger Heat- Approach Pressure Drop , bar
Transfer Temperature
3
Fluid Difference , °C
Shell Tube
Chiller (H) c Brine 3.0 - 5.0 b
Cooler (H) Water 5.0 - 50.0
Air 5.0 - 50.0 0.0012
Condenser (H or V) Water 10.0-50.0 0.1
(I) Air 5.0 - 50.0 0.0012
Heater (H) d 10.0-50.0 0.1
Superheater (H) d 50.0- 100.0 0.05 - 0.6 0.05-
0.6

Reboiler or Vapor-
izer
Kettle (H) d 10.0-50.0 negligible 6 0.1
Thermosyphon (V) d 20.0 - 60.0 0.1 0.2 - 0.6

Interchanger (H) Process 10.0-50.0
Fluid

Liquids
Average Viscosity, cp Pressure Drop
Shell or Tube, bar
(psi)

<1.0 0.34 (5.0)
1.0-10.0 0.48 (7.0)
>10.0 0.70(10)

Gases
Pressure, bar Pressure Drop
Shell or Tube, bar

High Vacuum 0.004 - 0.008
<1.7 0.035
>1.7 5.0 to 10.0% of the
inlet pressure

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