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Heat Exchangers Design and Construction. By kamal Nashar. Introduction:. Shell and tube heat exchangers are one of the most common equipment found in all plants. How it works?. What are they used for?. Classification according to service. Heat Exchanger. - PowerPoint PPT Presentation
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Heat Exchangers Design and
Construction
By kamal Nashar
1
Shell and tube heat exchangers are one of the most common equipment found in all plants
Introduction:
How it works?
2
What are they used for?
Heat Exchanger
Cooler
Heater
Condenser
Reboiler
Both sides single phase and process stream
One stream process fluid and the other cooling water or air
One stream process fluid and heating utility as steam
One stream condensing vapor and the other cooling water or air
One stream bottom stream from a distillation column and the other a hot utilityor process stream
Classification according to service .
3
Code
Design codes:
Standard
Specifications
Is recommended method of doing something
ASME BPV – TEMA
is the degree of excellence requiredAPI 660-ASME B16.5–ASME B36.10M–ASME B36.19-ASME B16.9–ASME B16.11
Is a detailed description of construction, materials,… etc Contractor or Owner specifications
4
Main Components
2- Channel3- Channel Flange4- Pass Partition5- Stationary Tubesheet6- Shell Flange7- Tube
8- Shell9- Baffles 10- Floating Head backing Device11- Floating Tubesheet12- Floating Head13- Floating Head Flange14 –Shell Cover
1- Channel Cover
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TEMAHeat Exchanger
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TEMA Heat Exchanger Front Head Type
A - Type B - Type C - Type
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TEMA Heat Exchanger Shell Type
E - Type F - Type
J - TypeK - Type
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TEMA Heat Exchanger Rear End Head Types
M - Type S - Type T - TypeFixed Tubesheet Floating Head Pull-Through
Floating Head
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Classification:
U-Tube Heat Exchanger
Fixed Tubesheet Heat Exchanger
Floating Tubesheet Heat exchanger
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Example
AES
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AKT
Example
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Terminology Design data
Material selection
Codes overview
Sample calculations
Hydrostatic test
Sample drawing
Heat Exchangers Mechanical Design
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ASME TEMA API MAWP MDMT PWHT NPS – DN – NB – NPT Sch - BWG
Terminology
14
Design Data Heat Exchanger Data Sheet :
Design pressure
Design temperature
Dimensions / passes Tubes ( dimensions, pattern) Nozzles & Connections
TEMA type
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Baffles (No. & Type)
Material Selection
MaterialSelection
Strength
Corrosion Resistance
Fabricability
Cost&
Availability
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Strength
A – Yield Strength
B – Tensile Strength
C – Rupture point
AB
C
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Creep Strength a slow plastic strain increased by time and temperature
(time and temperature dependant) for stressed materials
Fatigue Strength The term “fatigue” refers to the situation where a
specimen breaks under a load that it has previously withstood for a length of time
Toughness The materials capacity to absorb energy, which, is
dependant upon strength as well as ductility
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Strength
ASME code Overview
ASME BPV code
Sec.I Power Boilers
Sec.II Materials
Sec.III Nuclear Fuel Containers
Sec.IV Heating Boilers
Sec. V Non Destructive Examination
Sec. VI Operation of heating boilers
Sec. VII Operation of power boilers
Sec. VIII Pressure vessels
Sec. IX Welding and Brazing
Sec. X Fiber-Reinforced plastic PV
Sec. XI Inspection of nuclear power plant
Sec. XII Transport tanks
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ASME code overview Sec. II: Materials
Part A : Ferrous material specifications
Part B : Non-Ferrous material specifications
Part C : Specifications of welding rods, electrodes and filler metals
Part D : Properties
Sec. VIII: Rules of construction of pressure vessels
Division 1 : 3 Subsections + mandatory Annex + non mandatory Annex
Division 2: Alternative rules
Division 3 : Alternative rules of high pressure
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ASME code overview
TEMA code overview TEMA classes:
Class R: Generally severe requirements for petroleum
and related processing applications
Class C: Generally moderate requirements of commercialand general processing applications
Class B: Chemical Process service
TEMA subsections 10 subsection
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Sample Calculations Shell thickness calculations under Internal Pressure:
t : Min. Required Shell Thickness P : Design Pressure of Shell Side S: Max. Allowable Stress of Shell Material R: Shell Inside Radius (corroded conditions) E : Joint Efficiency CA: Corrosion Allowance UT: Under Tolerance (if applicable)
PR .SE – 0.6 P
+ CAt = + UT
23
Sample Calculations Channel thickness calculations under Internal Pressure:
t : Min. Required Channel Thickness P : Design Pressure of Tube Side S: Max. Allowable Stress of Channel Material R: Channel Inside Radius (corroded conditions) E : Joint Efficiency CA: Corrosion Allowance UT: Under Tolerance (if applicable)
PR .SE – 0.6 P
+ CAt = + UT
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Sample Calculations Body Flanges:
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Sample Calculations Body Flanges:
Trial and error calculations Gasket seating conditions
No. of bolts and size Bolt circle diameter Inside and outside diameters
Check min. and max. bolt spacing
Detailed analysis of the flange Forces calculations Moment calculations Stresses calculations
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Operating conditions
Sample Calculations Precautions in body flanges design and installations:
Pairs of flanges Bolt holes shall straddle center line
Corrosion Allowance
Bolts shall be multiple of 4
Bolting shall be allowed to be removed from either side
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Calculated thickness not include the RF
Cladding
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Sample Calculations Nozzles and standard flanges:
Flange Rating (ASME B16.5)
Nozzle neck thickness calculations
Area replacement calculations
Sample
Impingement protection
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Sample CalculationsTubesheet:
• Tubesheet is the principal barrier between shell side and tube side
• Tubes shall be uniformly distributed
• Tubesheet thickness shall be designed for both sides
• Tubesheet shall be designed for bending stresses and shear stresses
• Corrosion allowance
• Made from around flat piece of metal with holes drilled for the tubes
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Sample CalculationsTubesheet:
• Tubesheet thickness for bending
T: Effective tubesheet thickness
S: Allowable stress
P: Design pressure corrected for vacuum if applicable at the other side
η: Ligament efficiency
For Square pattern
For Triangular pattern
G: Gasket effective diameter
F: Factor
31
Sample CalculationsTubesheet:
• Tubesheet thickness for Shear:
T: Effective tubesheet thickness
DL: Effective diameter of the tube center parameter DL=4A/C
C: Perimeter of the tube layout A: Total area enclosed by the Perimeter C
P: Design pressure
S: Allowable stress
do: Outside tube diameter
32
Tube-to-Tubesheet jointExpanded
Seal welded
Strength welded
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Hydrostatic Test
Test pressure : 1.3 X MAWP
Test Procedure
Gasket change
34
Sample drawing
Construction drawing is the design output
Sample drawing 1 Sample drawing 2