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-- 作者： max123
-- 发布时间： 2005/02/07 01:28am
http://www.engineeringpage.com/info/he/typU.html TYPICAL OVERALL HEAT TRANSFER COEFFICIENTS (U - VALUES)
Shell and Tube Heat Exchangers Hot Fluid Cold Fluid U [W/m2C]
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Heat Exchangers Water Water 800 - 1500
Organic solvents Organic Solvents 100 - 300
Light oils Light oils 100 - 400
Heavy oils Heavy oils 50 - 300
Reduced crude Flashed crude 35 - 150
Regenerated DEA Foul DEA 450 - 650
Gases (p = atm) Gases (p = atm) 5 - 35
Gases (p = 200 bar) Gases (p = 200 bar) 100 - 300
Coolers Organic solvents Water 250 - 750
Light oils Water 350 - 700
Heavy oils Water 60 - 300
Reduced crude Water 75 - 200
Gases (p = atm) Water 5 - 35
Gases (p = 200 bar) Water 150 - 400
Gases Water 20 - 300
Organic solvents Brine 150 - 500
Water Brine 600 - 1200
Gases Brine 15 - 250
Heaters Steam Water 1500 - 4000
Steam Organic solvents 500 - 1000
Steam Light oils 300 - 900
Steam Heavy oils 60 - 450
Steam Gases 30 - 300
Heat Transfer (hot) Oil Heavy oils 50 - 300
Heat Transfer (hot) Oil Gases 20 - 200
Flue gases Steam 30 - 100
Flue gases Hydrocarbon vapours 30 -100
Condensers Aqueouos vapours Water 1000 - 1500
Organic vapours Water 700 - 1000
Refinery hydrocarbons Water 400 - 550
Vapours with some non condensibles Water 500 - 700
Vacuum condensers Water 200 - 500
Vaporisers
Steam Aqueouos solutions 1000 - 1500
Steam Light organics 900 - 1200
Steam Heavy organics 600 - 900
Heat Transfer (hot) oil Refinery hydrocarbons 250 - 550
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Air Cooled Exchangers Process Fluid U [W/m2C] --------------------------------------------------------------------------------
Water 300 - 450
Light organics 300 - 700
Heavy organics 50 - 150
Gases 50 - 300
Condensing hydrocarbons 300 - 600
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Immersed coils Coil Pool U [W/m2C] --------------------------------------------------------------------------------
Natural circulation Steam Dilute aqueouos solutions 500 - 1000
Steam Light oils 200 - 300
Steam Heavy oils 70 - 150
Aqueouos solutions Water 200 - 500
Light oils Water 100 - 150
Agitated Steam Dilute aqueouos solutions 800 - 1500
Steam Light oils 300 - 500
Steam Heavy oils 200 - 400
Aqueouos solutions Water 400 - 700
Light oils Water 200 - 300
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Jacketed vessels Jacket Vessel U [W/m2C] --------------------------------------------------------------------------------
Steam Dilute aqueouos solutions 500 - 700
Steam Light organics 250 - 500
Water Dilute aqueouos solutions 200 - 500
Water Light organics 200 - 300
-- 作者： max123
-- 发布时间： 2005/02/07 01:29am
TYPICAL FOULING FACTORS: COOLING WATER - Fouling Factors in [m2K/W]
Conditions cooling water < 50 ° C
cooled fluid < 120 ° C cooling water > 50 ° C
cooled fluid > 120 ° C
Water velocity v < 1 m/s v > 1 m/s v < 1 m/s v > 1 m/s
Type of Water
Sea 0.00009 0.00009 0.00018 0.00018
Brackish 0.00035 0.00018 0.00053 0.00035
Cooling tower with inhibitor 0.00018 0.00018 0.00035 0.00035
Cooling tower without inhibitor 0.00053 0.00053 0.00088 0.00070
City grid 0.00018 0.00018 0.00035 0.00035
River mimimum 0.00018 0.00018 0.00035 0.00035
River average 0.00053 0.00035 0.00070 0.00035
Engine jacket 0.00018 0.00018 0.00018 0.00018
Demineralized or distilled 0.00009 0.00009 0.00009 0.00009
Treated Boiler Feedwater 0.00018 0.00009 0.00018 0.00018
Boiler blowdown 0.00035 0.00035 0.00035 0.00035 -------------------------------------------------------------------------------- SEVERAL FLUIDS - Fouling Factors in [m2K/W]
Group Fluid Fouling Factor
Oil Gasoil 0.00009
Transformer 0.00018
Lubrication 0.00018
Heat Transfer oil 0.00018
Hydraulic 0.00018
Gas and Vapour Hydrogen 0.00176
Engine exhaust 0.00176
Steam 0.00009
Steam with oiltraces 0.00018
Cooling fluid vapours with oil traces 0.00035
Organic solvent vapours 0.00018
Compressed air 0.00035
Natural gas 0.00018
Stable top products 0.00018
Liquid Cooling Fluid 0.00018
Organic heat transfer fluids 0.00018
Salts 0.00009
LPG, LNG 0.00018
MEA and DEA (Amines) solutions 0.00035
DEG and TEG (Glycols) solutions 0.00035
Stable side products 0.00018
Stable bottom products 0.00018
Caustics 0.00035
Vegetable Oils 0.00053 -------------------------------------------------------------------------------- REFINERY FLUIDS - Fouling Factors in [m2K/W]
Crude - wet,
(bearing salty water)
Temperature 0 to 95 ° C 95 to 160 ° C 160 to 260 ° C > 95 ° C
Velocity
< 0.6 m/s 0.00053 0.00088 0.00105 0.00123
0.6 m/s to 1.2 m/s 0.00035 0.00070 0.00088 0.00106
> 1.2 m/s 0.00035 0.00070 0.00070 0.00088
Crude - dry
Temperature 0 to 95 ° C 95 to 160 ° C 160 to 260 ° C > 95 ° C
Velocity
< 0.6 m/s 0.00053 0.00053 0.00070 0.00088
0.6 m/s to 1.2 m/s 0.00035 0.00035 0.00053 0.00070
> 1.2 m/s 0.00035 0.00035 0.00035 0.00053
Products Gasoline 0.00018
Naphtha and Light Distillates 0.00018
Kerosene 0.00018
Light gas oil 0.00035
Heavy gas oil 0.00053
Heavy fuel oils 0.00088
Asphalt and residuum 0.00176
Cracking and
Coking Units streams Overhead vapors 0.00035
Light cycle oil 0.00035
Heavy cycle oil 0.00053
Light coker gas oil 0.00053
Heavy coker gas oil 0.00070
Bottom slurry (> 1.5 m/s) 0.00053
Bottom liquid products 0.00035
Catalytic Reforming,
Hydrocracking,
Hydrodesulfurization (HDS) Reformer charge 0.00035
Reformer effluent 0.00018
Hydrocracker charge and effluent 0.00035
Recycle gas 0.00018
HDS charge and effluent 0.00035
Overhead vapors 0.00018
Liquid product > 50 API 0.00018
Liquid product 30 to 50 API 0.00035
Light Ends
processing streams Overhead vapors and gases 0.00018
Liquid products 0.00018
Absorption oils 0.00035
Alkylation trace acid streams 0.00053
Reboiler streams 0.00053
Lube oil processing streams 0.00053
Feed stock 0.00035
Solvent feed mix 0.00035
Solvent 0.00018
Extract 0.00035
Raffinate 0.00018
Asphalt 0.00088
Wax slurries 0.00053
Refined lube oil 0.00018
-- 作者： max123
-- 发布时间： 2005/02/07 01:32am
http://www.engineeringpage.com/info/he/HEside.html FLUID ALLOCATION: CHOICE BETWEEN SHELL OR TUBE SIDE Introduction
The choice of the allocation of the fluid to the shell side or tube side can have a significant impact on the performance, economics and maintainability of a heat exchanger. For most design work a balanced decision is required as the considerations can lead to opposite preferences. Some general guidelines are provided underneath: Fouling
There are many mechanisms of fouling. Allocating the most fouling fluid to the tube side will be more favourable as mechanical cleaning of the inside of the tubes wil be much easier. As the allowable velocity in the tubes is usually higher than at the shell side and a high fluid velocity causes attrition of the deposits, it is possible to reduce fouling by design. Mechanical Design Pressure
It will be more econamical to put the medium with the highest maximum allowable working pressure at the tube side. If the shell side needs to be designed for a high pressure the wall thickness will increase making the heat exchanger more expensive. Corrosion
If you need an expensive corrosion resistant material it will be more economical to place the corrosive fluid in the tubes as this will reduce the costs of the shell material or cladding. High Viscosity or Low Flowrates
To obtain an economic design high heat transfer coefficients are required. As heat transfer coefficients are much higher for turbulent flow this is the most important aspect to look into. For a highly viscous medium or a low flowrate turbulent flow can be obtained easier at the shell side. If the Reynolds number at the shell side is below 200, however, it will probably be cheaper to allocate this fluid to the tube side and use a high number of tube passes.
Use the thermal rating calculation routine to do trial and error runs and get an economical design.
-- 作者： Shaw
-- 发布时间： 2005/02/07 02:10am
有用，但很难记住。[size=6]文字[/size][color=#006400]文字[/color]
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