Page 128 - Applied Process Design For Chemical And Petrochemical Plants Volume III

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94 Applied Process Design for Chemical and Petrochemical Plants

Table 10-17 Table 10-18
Approximate Overall Heat Transfer Coefficient, U* Approximate Overall Heat Transfer Coefficient, U
Condensation
Use as a guide to the order of magnitude and not as limits to any value.
Coefficients of actual equipment may be smaller or larger than the values
Process Side (Hot) Condensing Fluid (Cold)
listed.
Hydrocarbons (light) Water 100—160
Condensing
Hydrocarbons w/ inerts (traces) Water 30—75
2
Hot Fluid Cold Fluid U, Btu/hr (ft )(°F) Organic vapors Water 070—160
Water vapor Water 150—340
Steam (pressure) Water 350—750 Water vapor Hydrocarbons 060—150
Steam (vacuum) Water 300—600 Exhaust steam Water 280—450
Saturated organic solvents Water 100—200 Hydrocarbons (light) Refrigerant 045—110
near atmospheric Organics (light) Cooling brine 050—120
Saturated organic solvents, Water, brine 050—120 Gasoline Water 065—130
vacuum with some Ammonia Water 135—260
noncondensable Hydrocarbons (heavy) Water 40—75
Organic solvents, Water, brine 20—80 Dowtherm vapor Liquid organic 075—115
atmospheric and high
Vaporization
noncondensable
Aromatic vapors, Water 05—30
Process Side (Vaporized) Heating Fluid
atmospheric with
noncondensables
Hydrocarbons, light Steam 090—210
Organic solvents, vacuum Water, brine 10—50
Hydrocarbons, C4—C8 Steam 075—150
and high noncondensables
Hydrocarbons, C3—C4 (vac) Steam 045—175
Low boiling atmospheric Water 080—200
Chlorinated HC Steam 090—210
High boiling hydrocarbon, Water 10—30
HCl solution (18—22%) Steam 120—240
vacuum
Chlorine Steam 130—220
Heaters Coils in Tank
Steam Water 250—750 Coil Fluid Tank Fluid
Steam Light oils 050—150
Steam Heavy oils 10—80 Steam Aqueous sol’n. (agitation) 140—210
Steam Organic solvents 100—200 Steam Aqueous sol’n. (no agitation) 060—100
Steam Gases 05—50 Steam Oil-heavy (no agitation) 10—25
Dowtherm Gases 04—40 Steam Oil-heavy (agitation) 25—55
Dowtherm Heavy oils 08—60 Steam Organics (agitation) 090—140
Flue gas Aromatic HC and 05—15 Hot water Water (no agitation) 35—65
steam Hot water Water (agitation) 090—150
Hot water Oil-heavy (no agitation) 06—25
Evaporators
Heat transfer oil Organics (agitation) 25—50
Salt brine Water (agitation) 050—110
Steam Water 350—750
Water (cooling) Glycerine (agitation) 50—75
Steam Organic solvents 100—200
Steam Light oils 080—180
Steam Heavy oils 25—75
(vacuum)
Water Refrigerants 075—150 Film Coefficients with Fluid Inside Tubes, Forced
Organic solvents Refrigerants 030—100
Convection
Heat Exchangers (No Change of Phase)
Useful dimensionless groups for heat transfer calculation
Water Water 150—300 are 70
Organic solvents Water 050—150 Symbol Name Function
Gases Water 03—50
Light oils Water 060—160 Gz Graetz number wc/kL
Heavy oils Water 10—50 Gr Grashof number D g t/ 2
3 2
Organic solvents Light oil 20—70 Nu Nusselt number h D/k
Water Brine 100—200 Pe Peclet number DG c/k
Organic solvents Brine 30—90
Gases Brine 03—50 Pr Prandtl number c /k
Organic solvents Organic solvents 20—60 Re Reynolds number DG/ , or, D u /
Heavy oils Heavy oils 08—50 Sc Schmidt number / k d
St Stanton number h/cG
Used by permission: Pfaudler, Inc., Bul. SB 95-500-1, ©1984.