Transcript Heat Exchangers Design and Construction

Chemicoz
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Shell and tube heat exchangers are one of the
most common equipment found in all plants
How it works?
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Classification according to service .
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Heat Exchanger
Both sides single phase and process stream
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Cooler
One stream process fluid and the other cooling water or air
Heater
One stream process fluid and heating utility as steam
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Condenser
One stream condensing vapor and the other cooling water or air
Reboiler
One stream bottom stream from a distillation column and the other a hot utility
or process stream
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Code
Is recommended method of doing something
ASME BPV – TEMA
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Standard
is the degree of excellence required
API 660-ASME B16.5–ASME B36.10M–ASME B36.19-ASME B16.9–ASME B16.11
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Specifications
Is a detailed description of construction, materials,… etc
Contractor or Owner specifications
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Channel Cover
Channel
Channel Flange
Pass Partition
Stationary Tubesheet
Shell Flange
Tube
8- Shell
9- Baffles
10- Floating Head backing Device
11- Floating Tubesheet
12- Floating Head
13- Floating Head Flange
14 –Shell Cover
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Front Head Type
A - Type
B - Type
C - Type
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Shell Type
E - Type
J - Type
F - Type
K - Type
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Rear End Head Types
M - Type
Fixed Tubesheet
S - Type
Floating Head
T - Type
Pull-Through
Floating Head
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U-Tube Heat Exchanger
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Fixed Tubesheet Heat Exchanger
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Floating Tubesheet Heat exchanger
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AES
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AKT
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Terminology
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Design data
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Material selection
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Codes overview
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Sample calculations
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Hydrostatic test
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Sample drawing
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ASME
TEMA
API
MAWP
MDMT
PWHT
NPS – DN – NB – NPT
Sch - BWG
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Heat Exchanger Data Sheet :
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TEMA type
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Design pressure
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Design temperature
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Dimensions / passes
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Tubes ( dimensions, pattern)
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Nozzles & Connections
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Baffles (No. & Type)
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Strength
Cost
&
Availability
Material
Selection
Corrosion
Resistance
Fabricability
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B
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A – Yield Strength
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B – Tensile Strength
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C – Rupture point
A
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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ASME code Overview
Sec.I Power Boilers
Sec.II Materials
Sec.III Nuclear Fuel Containers
Sec.IV Heating Boilers
ASME
BPV
code
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
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Sec. II: Materials
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Part A : Ferrous material specifications
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Part B : Non-Ferrous material specifications
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Part C : Specifications of welding rods, electrodes and filler metals
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Part D : Properties
Sec. VIII: Rules of construction of pressure vessels
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Division 1 :
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Division 2: Alternative rules
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Division 3 : Alternative rules of high pressure
3 Subsections + mandatory Annex + non mandatory Annex
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ASME code overview
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TEMA code overview
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TEMA classes:
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Class R: Generally severe requirements for petroleum
and related processing applications
Class C: Generally moderate requirements of commercial
and general processing applications
Class B: Chemical Process service
TEMA subsections
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10 subsection
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Sample Calculations
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Shell thickness calculations under Internal Pressure:
t=
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PR
. + CA + UT
SE – 0.6 P
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)
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Sample Calculations
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Channel thickness calculations under Internal Pressure:
t=
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PR
. + CA + UT
SE – 0.6 P
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)
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Sample Calculations
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Body Flanges:
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Sample Calculations
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Body Flanges:
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Trial and error calculations
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Gasket seating conditions
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Operating conditions
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No. of bolts and size
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Bolt circle diameter
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Inside and outside diameters
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Check min. and max. bolt spacing
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Detailed analysis of the flange
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Forces calculations
Moment calculations
Stresses calculations
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Sample Calculations
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Precautions in body flanges design and installations:
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Pairs of flanges
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Bolt holes shall straddle center line
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Corrosion Allowance
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Cladding
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Bolts shall be multiple of 4
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Bolting shall be allowed to be removed from either side
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Calculated thickness not include the RF
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Sample Calculations
 Nozzles and standard flanges:
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Flange Rating (ASME B16.5)
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Area replacement calculations
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Nozzle neck thickness calculations
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Impingement protection
Sample
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Sample Calculations
Tubesheet:
• Tubesheet is the principal barrier between shell side and tube side
• Made from around flat piece of metal with holes drilled for the tubes
• 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
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Sample Calculations
Tubesheet:
• 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
G: Gasket effective diameter
F: Factor
For Square
pattern
For Triangular
pattern
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Sample Calculations
Tubesheet:
• 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
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Tube-to-Tubesheet joint
Expanded
Strength welded
Seal welded
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Hydrostatic Test
 Test pressure : 1.3 X MAWP
 Test Procedure
 Gasket change
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Sample drawing
Construction drawing is the design output
Sample drawing 1
Sample drawing 2
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