heattransfer.xlsx

8/13/2019 HeatTransfer.xlsx

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Forced Convection reboiler

Instructions : Enter Data values in the BLUE cells. The result for each calculation

after the Enter key is pressed or move to a different cell.

Situation :

A fluid is vaporised in the tubes of a forced convection reboiler.

The calculations below calculate the local heat-transfer coefficient a

specified percentage of liquid vaporization.

Data Entry :

Physical Properties : Data Entry/Results

Boiling Point 234.00000

Density Liquid 2343.00000Density Vapour 1.23400

Viscosity Liquid 0.34500

Viscosity Vapour 0.03450

Conductivity Liquid 0.45400

Heat Capacity Liquid 1345.00000

Critical Pressure 56.00000

Percentage Liquid Vapourization 0.07000

Liquid Velocity at tube inlet 3.45670

Operating Pressure 0.78900

Tube inside Diameter (i.d) 25.00000

Local wall temperature 110.00000

Calculations :

Tube liquid velocity 3.21473

Reynolds No. Liquid 545805.41543

Heat transfer factor , Jh value 0.00456

Prandlt number, Pr 1.02208

convect ive c oeff ic ient , hfc 45524.87385

Lock hart-Martinelli two -phase parameter, Xn 3.37429

Convect ive boi l ing factor, fc 5.60000

convect ive boi l ing, h' fc 254939.29354




Use Mostin sk's cor reclation to estimate the nuc leate

boi l ing c oeff ic ient

Hnb : 43.75880

Nucleate boiling coeff ici ent, hnb 295269.16646

Reynolds No(liquid). * fc^1.25 4701894.43336Calculate with fs factor :

Suppression factor, fs 0.45000

Nucleate boiling coeff ici ent, h'nb 132871.12491

Effective heat-transfer co eff icient, hcb 387810.41845




will be recalculated on each cell value change,

a

Units

oC

kg/m3kg/m3

mNs/m2

mNs/m2

W/moC

kJ/kgoC

bar

%

m/s

bar

mmoC

m/s

Value based on calculated Rr,

W/m2oC

Value based on calculated Xn,

W/m2o

C




W/m2o

C

Value based on calculated Rr,

W/m2o

C

W/m2o

C



Pool Boiling - Heat Transfer

Instructions : Enter Data values in the BLUE cells. The result for each calculation


Situation :

A pool of Liquid is boiling.

Calculations below, calculate the heat-transfer coefficient.

From a surface at a specified surface temperature.

Data Entry : Data/Results Units

Physical Properties :

Pressure 3.00000 bar

Surface Temperature 130.00000

o

C

Physical Properties, from steam tables

Ts 120.00000oC

Density Liquid 975.00000 kg/m3

Density Vapour 1.20000 kg/m3

CpL 4350.00000 J/kgoC

Kl 0.68700 W/moC

uL 0.00023 Ns/m2

y 2198000.00000 J/kg

O 0.06700 N/m

pw 232200.00000 Ns/m2

Ps 28000.00000 Ns/m2

Calculations :

Foster-Zuber Correlation :

hb 24154.67873 W/m2o

C

Zuber Correlation :

Critical Flux,qc 1586510.68668 W/m2o

C

Actual flux 241546.78735 W/m2o

C

Is the Value Below Critical Flux Level ? (if

not re-calculate) A value of True indicatesit is. False means it is not.

TRUE



Pool Boiling - Heat Transfer

ill be recalculated on each cell value change,

130oC



Estimate Pressure drop

Instructions : Enter Data values in the BLUE cells. The result fo


Situation :

Exchanger Design to sub-cool condensate from a co

Calculations below are for the thermal design only.

Data Entry :

Condensate :

Temperature inlet

Temperature outlet

Flow-rate

Heat Capacity

DensityViscosity

Thermal Conductivity

Coolant :

Temperature inlet

Temperature outlet

Heat Capacity

Density

Viscosity

Thermal Conductivity

Temperature Correction factor, Ft

U

Tube Selection :

Outside Diameter

Inside Diameter

Length

Allow for tube-sheet thickness

Thermal conductivity of metalFouling coefficients

Tube sheet :

Triangular pitch

K1 value




n1

Head :

Shell inside bundle diameter

Baffle :

Baffle cut

Corrosive coolant, assigned to tube-side

Number of shell passes

Number of tube passes

Calculations :

Condensate Heat Load

coolant Flow

Mean Temp. Log.

R

S

Adjust the FT, U values at the initial Data Entry Stage Above :

Mean Temperature

Provisional Area

Area of one tube

Number of tubes

Bundle diameter, Db

Shell diameter, Ds

Choose nearest standard pipe size

Tube-side coefficient :

Mean water temperature

Tube cross-sectional area

Tubes per passTotal flow area

Coolant mass velocity

Coolant linear velocity

Heat Coefficient, hi




Check with Calculated value using equation.....

Re

Pr

Ratio Tube Length/Tube inside diameter

Correction factor, jh

hi

Choose lower value

Shell-side coefficient :

Baffle spacing

Tube pitch

Cross-flow area

Mass Velocity, Gs

Equivalent Diameter

Shell side temperature – mean

Re

Pr

Correction factor, jh

Shell side coefficient, hs

Estimate Wall Temperature :

Mean Temperature Difference across all resistances.

across condensate film

Mean Wall Temperature

Overall Coefficient,Uo

Check the Uo value for correctness.

Pressure Drop :

Tube-side :




Correction factor, Jf

Pressure Drop =

Check if pressure drop is acceptable else change parameters to




each calculation will be recalculated on each cell value change,

denser.

Data/Result Units

92.00000oC

50.00000oC

15000.00000 kg/hr

3.05000 kJ/kgoC

850.00000 kg/m0.37000 mNs/m

0.23000 W/moC

22.00000oC

45.00000oC

4.56700 kJ/kgoC

1001.00000 kg/m

0.34560 mNs/m2

0.67800 W/moC

0.98700 Fig 12.19

595.00000 W/moC Fig 12.1

28.00000 mm

18.00000 mm

5.05000 m

5.00000 m

65.00000 W/mo

C5976.00000 W/m

oC

1.25000

0.24900 from tube sheet.




2.20700 from tube sheet.

75.00000 mm

18.00000 % of baffle

1.00000

2.00000

533.75000 kW

5.08135 kg/s

31.55227

1.82609

0.32857

31.14209

28.80535 m

0.43982 m2

65.49306

349.67718 mm

424.67718 mm

User input here

33.50000oC

254.46900 mm

32.746530.00833 m

2

609.78800 kg/s m

0.60918 m/s

3201.41514 W/moC




31759.79160

2.32796

277.77778

0.00370

a ue ase on

calculated Pr, tube

passes values.

5849.76371 W/moC without viscosity correctio

3201.41514

84.93544 mm

35.00000 mm

0.00721 m2

577.57838 kg/s m

19.88140 mm

71.00000oC

31035.31552

4.90652

0.00378

Value based on

calculated Pr, tubepasses values.

2306.14573 W/moC without viscosity correctio

37.50000oC

9.67523oC

61.32477oC

693.32712 W/m2oC




0.00400

Value based on

calculated Pr, tube

passes values.

4230.62980 N/m Neglect viscosity correctio

recalculate.....




n

n




n term



Estimate Heat Transfer Co-effic

Instructions : Enter Data values in the BLUE cells. The result for each calculation will be


Situation :

Estimate Heat Transfer Co-efficient of steam on the inside and outside of

Calculations below estimate the Heat Transfer Co-efficient inside and out

Data Entry : Data / Results

Vertcal Tubes

Outside diameter 35.00000

Inside diameter 30.00000

Length 4.05000

Steam Condensate Flow Rate 0.02800Pressure Condensate forms 4.00000

Saturation Temp. 125.67000

Liquid Density 1005.00000

Vapour Density 1.85000

Liquid heat transfer 0.87650

Liquid Viscosity 0.45300

Prc 1.56000

Condensation Coefficient for vertical tubes, outside 0.18900

Condensation Coefficient for vertical tubes, inside 0.18760

Calculations :

Vertical tube loading 0.25465

Reynolds No.,Re 2248.54666

Condensation outside tube 6028.58292

Condensation inside the tube

Vertical tube loading 0.29709

Reynolds No.,Re 2623.30443

Condensation inside tube 5983.92675

Using Boyko-Kruzhilin Method




Cross-Sectional Area of Tube 0.00071

Fluid velocity, total condensation

Fluid velocity, Ut 0.03941

Reynolds,Re 2623.30443

Heat transfer coefficient, liquid, h'i 403.61983

Heat transfer coefficient, condensation, hc 4905.51044

Which value is lager? H'i or hc 4905.51044




recalculated on each cell value change,

he heat exchanger tubes.

ide the tubes.

Units

mm

mm

m

kg/sbar

oC

kg/m3

kg/m3

W/moC

mNs/m2

estimated value required calculations

are below

estimated value required calculationsare below

kg/s m

W/mo

kg/s m

W/mo




m

m/s

W/moC

W/moC

W/moC



Flooding Tubes Condenser

Instructions : Enter Data values in the BLUE cells. The result for each calculation will b


A condenser is fitted to a distillation column. Determine/Check if

flooding of the vertical tubes will occur during operation.

Data Entry :

Flow Rate Top Product 2908.00000 kg/h

Reflux Ratio 3.80000

No. Vertical Tubes Condenser 220.00000

Tubes Internal diameter 40.00000 mm

Condenser Pressure 3.50000 bar

Density Top product @ Boiling point

Liquid Density 890.00000 kg/mVapour Density 3.20000 kg/m

Calculations :

Vapour Flow 21228.40000 kg/h

Liquid Flow 11050.40000 kg/h

Total Area Tubes 0.27646 m

Vapour Velocity 6.66549 m/s

Liquid Velocity 0.01248 m/s

Check 1 4.06312

Check 2 2.59143

Tubes will not flood if Check 1 < Check 2. A

True value indicates flooding will not occur. (

A False value indicates flooding will occur)

FALSE



Flooding Tubes Condenser

e recalculated on each cell value change,



Condenser - Thermal Design

Instructions : Enter Data values in the BLUE cells. The result for each calculatio


Situation :

Condenser Design. Vapours are totally condensed. Thermal Design

Data Entry :

Condenser Duty for Design : 48000.00000

Condenser Operating Pressure : 8.00000

Saturated Vapour in Temperature 75.00000

Completion Temperature 57.00000

Condensing Coefficient 1700.00000

Ave. Molecular weight of Vapours 76.00000

Ave. Molecular weight of Mixtures 70.00000

Vapour Enthalpy 897.00000

Condensate Enthalpy 305.00000

Cooling Water Temperature 35.00000

Allowed Temperature Rise 5.00000

Heat Capacity of Water 4.18000

Outside Diameter of Tubes : 25.00000

Inside Diameter of Tubes : 21.56000

Length of Tubes : 5.00000

Vapours Totally Condensed Yes

Subcooling Required No

Vapour Viscosity 0.00560

Overall Heat Transfer Coefficient : 904.00000

Shell-Side Fluid properties :

Viscosity : 0.24000

Density : 609.00000Conductivity : 0.15678

Density of water @ required temp. 1095.00000

Fouling Factors : 6000.00000

kw 75.00000




Head Type : Pull through

Select baffle spacing = shell diameter, 45% cut

Clearance 105.00000

Assume pressure drop value cal. Use inlet flow,

neglect viscosity. Value as a percentage. 65.00000

Viscosity of Water : 0.89000

Calculations :

Amount of Heat Transferred from Vapour : 7893.33333

Cooling Water Flow : 377.67145

Mean Temperature Difference :

R = 3.60000

S = 0.12500

Horizontal Exchanger, Condensation in the shell

Number of tube passes 4.00000

Temperature Correction Factor, Ft 0.98000

Log mean temperature difference 27.99880Mean Temperature Difference : 27.43882

initial Area 318.21930

Surface area of 1 tube 0.39270

Number of tubes 810.33879

Pitch 1.25000

Use Square pitch, Pt 31.25000

Value for K1 0.15800

Value for n1 2.26300

Tube bundle diameter, Do 1089.83545

Number of Tubes in Centre Row 34.87473

Shell-Side Coefficient

Mean Temperature Difference :

Shell-Side = 66.00000

Tube -Side = 37.50000




Tube Wall Temperature, Tw 50.84471

Mean Temperature Condensate 58.42235

Vapur density @ mean vapour temperature 21.85841

Tube loading, condensate flow per unit length 0.00329

Average No. of tubes in a vertical row 23.24982

Mean coefficient for a tube bundle, hc 1449.15973

CHECKED ASSUMED value :

close enough to assume value of 1500

Tube-Side Coefficient

Tube Cross-Sectional Area 0.07396

Tube Velocity 4.66344

water inside coefficient 16356.99945

Overall Coefficient 872.94773

Repeat trial if the obtained Overall Coefficient

Shell-Side Pressure Drop

Shell inside diameter 1194.83545

Cross-flow Area, As 0.28553

Mass flow-rate, based on inlet conditions, Gs 46.69738

Equivalent diameter, de 24.73592

Reynolds Number, Re 206268.34380

Correction factor, jf 0.02100

Us 2.13636

Pressure Drop Shell Side 11010.35105

Re 123702.61360

correction factor jf 0.00320




neglect viscosity friction factor 401827.88395




will be recalculated on each cell value change,

is only calculated.

kg/hr

bar oC

oC

W/m2 oC

KJ/kg

KJ/kg

oC

oC

KJ/kg

mm

mm

m

mNs/m2

W/m2 oC “Typical Overall heat transfer coefficients” sheet

mNs/m2

kg/m3

W/moC

kg/m3

W/m2 oC

W/moC




mm

mNs/m

kW

kg/s

Value based on

calculated S, tube

passes values.

o

CoC

m2

m2

(value from “Tube pitch Constants” sheet)



mm (value from “Tube pitch Constants” sheet)

oC

oC




oC

oC

kg/m3

kg/s m

W/moC

m2

m/s

W/moC

W/moC

mm

m2

kg/sm2

mm

Value based on

calculated Re value.

m/s

N/m2

Value based on

calculated Re value.




N/m2



Tube pitch Constants

Equations for Triangular and Square patterns :

Nt = K1(Db /do)n

1

Db = do(Nt /K1)1/n

1

Triangular pitch

Equation : pt= 1.25do

No. Passes 1 2 4 6 8

K1 0.319 0.249 0.174 0.0743 0.0365

n1 2.142 2.207 2.285 2.499 2.675

Square pitch

Equation : pt= 1.25do

No. Passes 1 2 4 6 8

K1 0.215 0.156 0.158 0.0402 0.0331

n1 2.207 2.291 2.263 2.617 2.643



Typical Overall heat transfer c

Typical Overall heat transfer coef

Shell and Tube Exchangers

Hot Fluid

Coolers Organic Solvents

Light Oils

Heavy oils

Gases

Organic Solvents

Water

Gases

Heat Exchangers Water

Organic Solvents

Light Oils

Heavy oils

Gases

Heaters Steam

Steam

Steam

Steam

Steam

Dowtherm

Dowtherm

Flue Gases

Flue

Condensers Aqueous Vapours

Organic Vapours

Organics

Vacuum Condensers

Vaporisers Steam

Steam

Steam

Air-Cooled Exchangers

Process Fluid

Water




Light Organics

Heavy Organics

Gases, 5-10 bar

10-30 bar

Condensing HydroCarbons

Immersed Coils

Coil

Natural Circulation

Steam

Steam

Steam

Aqueous Solutions

Light Oils

AgitatedSteam

Steam

Steam

Aqueous Solutions

Light Oils

Jacketed Vessels

Jacket

Steam

SteamWater

Water




ficients

Cold Fluid U (W/m2 oC)

Water 250-750

Water 350-900

Water 60-300

Water 20-300

Brine 150-300

Brine 600-1200

Brine 15-250

Water 800-1500

Organic Solvents 100-300

Light Oils 100-400

Heavy Oils 50-300

Gases _10 – 50

Water 1500-4000

Organic Solvents 500-1000

Light Oils 300-900

Heavy Oils 60-450

Gases 30-300

Heavy Oils 50-300

Gases 20-200

Steam 30-100

Hydrocarbon Vapours 30-100

Water 1000-1500

Water 700-1000

Water 500-700

Water 200-500

Aqueous Solutions 1000-1500

Light Organics 900-1200

Heavy Organics 600-900

300-450




300-700

50-150

50-100

100-300

300-600

Pool

Dilute Aqueous Solutions 500-1000

Light Oils 200-300

Heavy Oils 70-150

Water 200-500

Water 100-150

Dilute Aqueous Solutions 800-1500

Light Oils 300-500

Heavy Oils 200-400

Water 400-700

Water 200-300

Vessel

Dil. Aqueous Soln. 500-700

Light Organics 250-500Dil. Aqueous Soln. 200-500

Light Organics 200-300

heattransfer.xlsx

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