Heat Exchangers 6q2lj

By: Baher EL Shaikh Mechanical Engineer EMetahnex

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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 .



Heat Exchanger Both sides single phase and process stream



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

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Reboiler One stream bottom stream from a distillation column and the other a hot utility or process stream 3



Code

Is recommended method of doing something

ASME BPV – TEMA 

Standard

is the degree of excellence required API 660-ASME B16.5–ASME B36.10M–ASME B36.19-ASME B16.9–ASME B16.11



Specifications

Is a detailed description of construction, materials,… etc Contractor or Owner specifications

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1- Channel Cover 2- Channel 3- Channel Flange 4- Partition 5- Stationary Tubesheet 6- Shell Flange 7- Tube

8- Shell 9- Baffles 10- Floating Head backing Device 11- Floating Tubesheet 12- Floating Head 13- Floating Head Flange 14 –Shell Cover 5

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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 8



Rear End Head Types

M - Type Fixed Tubesheet

S - Type Floating Head

T - Type Pull-Through Floating Head

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 U-Tube  Fixed

Heat Exchanger

Tubesheet Heat Exchanger

 Floating

Tubesheet Heat exchanger

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AES 11

AKT 12



Terminology



Design data



Material selection



Codes overview



Sample calculations



Hydrostatic test



Sample drawing

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ASME : American Society of Mechanical Engineers  TEMA : Tubular Exchanger Manufacturer Association  API : American Petroleum Institute  MAWP : Maximum Allowable Working Pressure  MDMT : Minimum Design Metal Temperature  PWHT : Post Weld Heat Treatment  NPS – DN – NB – NPT  Sch - BWG 

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

Heat Exchanger Data Sheet :



TEMA type



Design pressure



Design temperature



Dimensions / es



Tubes ( dimensions, pattern)

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Nozzles & Connections



Baffles (No. & Type)

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B 

A – Yield Strength



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

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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 19

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 :



Division 2: Alternative rules



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 



TEMA classes: 

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 

10 subsection

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Sample Calculations 

Shell thickness calculations under Internal Pressure:

PR t= + 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 : t Efficiency CA: Corrosion Allowance UT: Under Tolerance (if applicable)

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Sample Calculations 

Channel thickness calculations under Internal Pressure:

PR t= + 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 : t Efficiency CA: Corrosion Allowance UT: Under Tolerance (if applicable)

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Sample Calculations 

Body Flanges:

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Sample Calculations 

Body Flanges: 

Trial and error calculations 

Gasket seating conditions



Operating conditions



No. of bolts and size



Bolt circle diameter



Inside and outside diameters



Check min. and max. bolt spacing

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Detailed analysis of the flange 

Forces calculations



Moment calculations Stresses calculations



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Sample Calculations 

Precautions in body flanges design and installations:



Pairs of flanges

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Bolt holes shall straddle center line

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Corrosion Allowance



Cladding



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: 

Flange Rating (ASME B16.5)



Area replacement calculations



Nozzle neck thickness calculations



Impingement protection

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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 t  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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Baher EL Shaikh [email protected]

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