Shell and Tube Heat Exchanger

Shell and Tube Heat ExchangerShell and Tube Heat Exchanger

Frank FaulkenbergFrank Faulkenberg

Jimmy HuserJimmy Huser

John SnodgrassJohn Snodgrass

Eric BushEric Bush

David GilesDavid Giles

ME 414: Thermal Fluids

Problem StatementProblem Statement

Design a heat exchanger to meet the Design a heat exchanger to meet the customer requirements for heat customer requirements for heat

transfer and maximum dimensions, transfer and maximum dimensions, while optimizing the weight and while optimizing the weight and

pressure losses in both the tube and pressure losses in both the tube and shell sides.shell sides.

Project DefinitionProject Definition

Chemical Specifications:Chemical Specifications:• Temperature must be reduced from 40°C to Temperature must be reduced from 40°C to

25°C25°C• Mass flow rate is 120,000 kg/hrMass flow rate is 120,000 kg/hr• Material properties closely approximate that of Material properties closely approximate that of

waterwater Cooling Water Specifications:Cooling Water Specifications:

• Treated city water at 20°CTreated city water at 20°C• Mass flow rate is not fixedMass flow rate is not fixed• Exit temperature is function of designExit temperature is function of design

Customer RequirementsCustomer Requirements

Must cool the chemical from 40 C to 25 CMust cool the chemical from 40 C to 25 C Heat exchanger length can not exceed 7mHeat exchanger length can not exceed 7m Heat exchanger shell diameter can not Heat exchanger shell diameter can not

exceed 2mexceed 2m Minimize heat exchanger shell and tube Minimize heat exchanger shell and tube

weight hence the costweight hence the cost Minimize heat exchanger pressure dropMinimize heat exchanger pressure drop

AnalysisAnalysis

MatlabMatlab

Used to run code Used to run code that takes the that takes the input variables that input variables that affect exchanger affect exchanger performance and performance and returns numerical returns numerical values for the values for the performance of the performance of the exchangerexchanger

MinitabMinitab

Used to statistically Used to statistically analyze the results analyze the results from Matlab to from Matlab to narrow down the narrow down the input variables to input variables to those that have the those that have the greatest affect of greatest affect of exchanger exchanger performance.performance.

First TrialFirst Trial

Total heat exchanger weight = 4384.68 kgTotal heat exchanger weight = 4384.68 kg

Desired Heat Transfer Rate = 2088969 WDesired Heat Transfer Rate = 2088969 W

Calculated Heat Transfer Rate = 2084742 WCalculated Heat Transfer Rate = 2084742 W

Difference = 4227.48 WDifference = 4227.48 W

Desired-to-Calculated Ratio = 1.00 Desired-to-Calculated Ratio = 1.00

Shell Side Delta-P = 9875.34 Pa Shell Side Delta-P = 9875.34 Pa

Tube Side Delta-P = 134.48 Pa Tube Side Delta-P = 134.48 Pa

Analyzing dataAnalyzing data

GoodGood

• Light in weightLight in weight

• Good pressure drops Good pressure drops

• Achieved desired-to-calculated ratioAchieved desired-to-calculated ratio

Analyzing dataAnalyzing data

BadBad• Further inspection shows that this design is Further inspection shows that this design is

impossible.impossible.

Inlet (°C) Outlet (°C)

Tube 40 25

Shell 20 32

•Shell side outlet cannot be greater than the tube side outlet for a parallel heat exchanger.

•For parallel flow, a shell mass flow rate of ~400000 kg/hr must be used to satisfy this condition

Second TrialSecond Trial

Parallel flowParallel flow No bafflesNo baffles About 4 meters in lengthAbout 4 meters in length

Analyzing DataAnalyzing Data

Good:Good: Yielded very low weightYielded very low weight Very low pressure dropsVery low pressure drops Desired heat transferDesired heat transfer

Bad:Bad: Impossible design in realityImpossible design in reality Structurally unsound, tubes would sagStructurally unsound, tubes would sag

Critical Parameter Flow DownCritical Parameter Flow Down

14 parameters14 parameters

7 factor DOE7 factor DOE

4 factor DOE4 factor DOE

Initial ParametersInitial Parameters

Tube lengthTube length Tube diameter Tube diameter

(OD)(OD) Shell diameter (ID)Shell diameter (ID) Mass Flow Rate of Mass Flow Rate of

cooling watercooling water Pipe layout Pipe layout Baffle SpacingBaffle Spacing Shell materialShell material

Tube materialTube material Shell thicknessShell thickness Tube thicknessTube thickness Flow configuration Flow configuration

(counter, parallel)(counter, parallel) Pipe layout anglePipe layout angle Number of TubesNumber of Tubes Tube PitchTube Pitch

11stst DOE DOE



cooling watercooling water Pipe layout Pipe layout Baffle SpacingBaffle Spacing Shell materialShell material

7 factor MEPs7 factor MEPsM

ean o

f Q_7

0.0146050.010795

1800000

1500000

1200000

0.963930.71247 7.07255.2275

38.33328.333

1800000

1500000

1200000

10 0.6000.402

212

1800000

1500000

1200000

Tube_OD_7 Shell_ID_7 tube_len_7

mdot_shell_7 sqr_tri_7 baffle_space_7

shell_mat_7

Main Effects Plot (data means) for Q_7

22ndnd DOE DOE



cooling watercooling water


ean o

f Q

0.0146050.010795

1800000

1650000

1500000

1350000

1200000

0.963930.71247

7.07255.2275

1800000

1650000

1500000

1350000

1200000

38.33328.333

Tube_OD Shell_ID

Tube_Length mdot_shell

Main Effects Plot (data means) for Q


ean o

f DP_sh

ell

0.0146050.010795

12000

10000

8000

0.963930.71247

7.07255.2275

12000

10000

8000

38.33328.333

Tube_OD Shell_ID


Main Effects Plot (data means) for DP_shell


ean o

f w

eig

ht

0.0146050.010795

7000

6000

5000

4000

0.963930.71247

7.07255.2275

7000

6000

5000

4000

38.33328.333

Tube_OD Shell_ID


Main Effects Plot (data means) for weight


ean o

f DP_tu

be

0.0146050.010795

1000

800

600

400

0.963930.71247

7.07255.2275

1000

800

600

400

38.33328.333

Tube_OD Shell_ID


Main Effects Plot (data means) for DP_ tube

4-factor Interaction Plots4-factor Interaction Plots

Tube_OD

Tube_Length

mdot_shell

Shell_ID

0.963930.71247 7.07255.2275 38.33328.33315000

10000

500015000

10000

500015000

10000

5000

0.0107950.014605

Tube_OD

0.712470.96393

Shell_ID

5.22757.0725

Tube_Length

Interaction Plot (data means) for DP_shell

Pareto ChartsPareto ChartsTe

rm

Effect

ABCD

ABC

BCD

ABD

ACD

BC

AB

AC

BD

CD

AD

B

C

A

D

500040003000200010000

1202

A Tube_ODB Shell_IDC Tube_LengthD mdot_shell

Factor Name

Pareto Chart of the Effects(response is DP_shell, Alpha = .10)

Lenth's PSE = 596.751

Final DesignFinal Design1 shell pass1 shell pass 1 tube pass1 tube pass

Shell material = AlShell material = Al Tube material = AlTube material = Al

Mdot_shell = 120000 kg/hrMdot_shell = 120000 kg/hr Mdot_tube = 120000 kg/hrMdot_tube = 120000 kg/hr

Shell_ID = 0.8382 mShell_ID = 0.8382 m Tube_OD = 12.7 mmTube_OD = 12.7 mm

Shell_th = 19.05 mmShell_th = 19.05 mm Tube_th = 20 BWGTube_th = 20 BWG

Baffle spacing= 0.6*Shell_IDBaffle spacing= 0.6*Shell_ID Tube pitch = 1.4*Tube_ODTube pitch = 1.4*Tube_OD

Baffle cut = 25%Baffle cut = 25% 30° Triangular layout30° Triangular layout

Expected PerformanceExpected Performance

Total heat exchanger weight Total heat exchanger weight 48684868 kg kg

Desired Heat Transfer Rate 2088969 WDesired Heat Transfer Rate 2088969 W

Calculated Heat Transfer Rate 2095309 WCalculated Heat Transfer Rate 2095309 W

Difference Difference -6340 W -6340 W

Desired-to-Calculated Ratio 1.00 Desired-to-Calculated Ratio 1.00

Shell Side Delta-P Shell Side Delta-P 9228 Pa 9228 Pa

Tube Side Delta-P Tube Side Delta-P 556 Pa 556 Pa

ReferencesReferences

[1] Jones, Luke. “Minitab tutorial.”[1] Jones, Luke. “Minitab tutorial.”

[2] Toksoy, John. “Heat Exchanger Project – [2] Toksoy, John. “Heat Exchanger Project – fall 2006.”fall 2006.”

[3] Toksoy, John. “TFD-HE4 Log Mean [3] Toksoy, John. “TFD-HE4 Log Mean Temperature Difference.” fall 2006Temperature Difference.” fall 2006

Documents

Shell and Tube Heat Exchanger