Page 226 - Chemical Process Equipment - Selection and Design

196 HEAT TRANSFER AND HEAT EXCHANGERS
TABLE 8.11. Overall Heat Transfer Coefficients in Air Coolers [U Btu/(hr)("F)(sqft of outside bare tube surface)]

Liquid Coolers Condensers
Heat-Transfer Heat-Transfer Heat-Transfer
Coefficient, Coefficient, Coefficient,
Material [Btu/(hr) (ft?PFIl Material [Btu/(hr)(ft2)PF)I Material [Btu/(hr)(ft%WI
Oils, 20" API 10-16 Heavy oils, 8-14"API Steam 140-150
200°F avg. temp 10-1 6 300°F avg. temp 6-10 Steam
300°F avg. temp 13-22 400°F avg. temp 10-16 10% noncondensibles 1 00-1 1 0
400°F avg. temp 30-40 Diesel oil 45-55 20% noncondensibles 95-1 00
Kerosene 55-60 40% noncondensibles 70-75
Oils, 30" API Heavy naphtha 60-65 Pure light hydrocarbons 80-85
150°F avg. temp 12-23 Light naphtha 65-70 Mixed light hydrocarbons 65-75
200°F avg. temp 25-35 Gasoline 70-75 Gasoline 60-75
300°F avg. temp 45-55 Light hydrocarbons 75-80 Gasoline-steam mixtures 70-75
400°F avg. temp 50-60 Alcohols and most Medium hydrocarbons 45-50
organic solvents 70-75 Medium hydrocarbons
Oils, 40" API wlsteam 55-60
150°F avg. temp 25-35 Ammonia 100-120 Pure organic solvents 75-80
200°F avg. temp 50-60 Brine, 75% water 90-110 Ammonia 100-110
300°F avg. temp 55-65 Water 120-140
400°F avg. temp 60-70 50% ethylene glycol
and water 100-120

Vapor Coolers
Heat-Transfer Coefficient [Btu/(hr)(*)PF)l
Material 10 psig 50 psig 100 psig 300 psig 500 psig
~
Light hydrocarbons 15-20 30-35 45-50 65-70 70-75
Medium hydrocarbons and organic solvents 15-20 35-40 45-50 65-70 70-75
Light inorganic vapors 10-15 15-20 30-35 45-50 50-55
Air 8-10 15-20 25-30 40-45 45-50
Ammonia 10-15 15-20 30-35 45-50 50-55
Steam 10-15 15-20 25-30 45-50 55-60
Hydrogen
100% 20-30 45-50 65-70 85-95 95-100
75% VOI 17-28 40-45 60-65 80-85 85-90
50% vol 15-25 35-40 55-60 75-80 85-90
25% vol 12-23 30-35 45-50 65-70 80-85
~
[Brown, Chem. Eng. (27 Mar. 1978)l.

TABLE 8.12. Overall Heat Transfer Coefficients in Condensers,
Btu/(hr)(sqft)("F)a
Liquid Coolants
Air Coolers
Vapor Coolant Btu/(hr)(sqft)("F)
Btu/(hr)
Vapor (bare sqft)("F)
Alcohol water 100-200
Dowtherm tall oil 60-80
Dowtherm Dowtherm 80-1 20 Ammonia 100-120
Hydrocarbons Freons 60-80
Hydrocarbons, light
80-1 00
high boiling under vacuum water 18-50
low boiling water 80-200 Naphtha, heavy 60-70
intermediate oil 25-40 Naphtha, light 70-80
kerosene water 30-65 Steam 130-140
kerosene oil 20-30 "Air cooler data are based on 50mm tubes with aluminum fins
naphtha water 50-75 16-18 mm high spaced 2.5-3 mm apart; coefficients based on bare tube
naphtha oil 20-40 surface. Excerpted from HEDH, 1983.
Organic solvents water 100-200
Steam water 400-1 000
Steam-organic azeotrope water 40-80
Vegetable oils water 20-50