Week-2, Lecture-9 Types of Shell and

Tube exchangers
Shabina Khanam
Associate Professor
Department of Chemical Engineering

1
 Shell and Tube Heat Exchanger
Since shell and tube heat exchangers can be constructed with a very large
heat transfer surface in a relatively small volume, fabricated from alloy steels
to resist corrosion and be used for heating, cooling and for condensing a very
wide range of fluids, they are the most widely used form of heat transfer
equipment.

A shell-and-tube exchanger consists of a bundle of tubes contained in a

cylindrical shell. The tubes may be permanently positioned inside the shell
(fixed tube-sheet exchanger) or may be removable for ease of cleaning and
replacement (floating-head or U-tube exchanger).
 Shell and Tube Heat Exchanger
For variety of industrial services where large heat transfer surfaces
are required, shell and tube heat exchangers are commonly used.
S&T accounted for 85% of new exchangers supplied to oil-refining,
chemical, petrochemical and power companies.

Why?
• Can be designed for almost any duty with a very wide range of temperatures
and pressures
• Can be built in many materials
• Many suppliers
• Repair can be by non-specialists
• Design methods and mechanical codes have been established from many
years of experience
 Scope of Shell and Tube Heat Exchanger
• Maximum pressure
– Shell 300 bar (4500 psia)
– Tube 1400 bar (20000 psia)
• Temperature range
– Maximum 600oC (1100oF) or even 650oC
– Minimum -100oC (-150oF)
• Fluids
– Subject to materials
– Available in a wide range of materials

• Size per unit 100 - 10000 ft2 (10 - 1000 m2)

Classification of Shell and Tube Heat Exchanger
For variety of industrial services where large heat transfer surfaces are
required, shell and tube heat exchangers are commonly used. These heat
exchange equipment can be fabricated from wide range of materials of
construction. The exchanger consists of number of parallel tubes, ends of
which are mounted in the tube sheet and entire tube bundle is enclosed in a
close fitting cylindrical shell.

Shell is usually a cylindrical casing through which one of fluid flows in one or
more passes. It is commonly made of carbon steel Standard heat exchanger
tubes which are used in many industrial processes may be of various sizes
and lengths. The tube that is placed in the tube bundle inside shell are either
rolled or welded to the tube sheet.
Classification of Shell and Tube Heat Exchanger
A variety of different internal constructions are used in shell-and-tube exchangers,
depending on the desired heat transfer and pressure drop performance and the
methods employed to reduce thermal stresses, to prevent leakages, to provide for
ease of cleaning, to contain operating pressures and temperatures, to control
corrosion, to accommodate highly asymmetric flows, and so on. Shell-and-tube
exchangers are classified and constructed in accordance with the widely used
TEMA (Tubular Exchanger Manufacturers Association) standards.

Fixed tube sheet

External floating head
U-tube Internal floating head
Classification of Shell and Tube Heat Exchanger

Fixed tube sheet

• No provision for differential

expansion
• Limited to temperature
differences up to about 90◦C
Classification of Shell and Tube Heat Exchanger

U-Tube

Limited in use to
relatively clean fluids
Classification of Shell and Tube Heat Exchanger
Internal Floating Head

• More versatile than fixed head and U-tube

exchangers
• Suitable for high-temperature differentials
• Easier to clean and can be used for fouling
liquids
• Clearance between the outermost tubes in
the bundle and the shell is made greater
Classification of Shell and Tube Heat Exchanger
External Floating Head

• Floating-head joint is located outside the

shell, and the shell sealed with a sliding
gland joint.
• Because of the danger of leaks through the
gland, the shell-side pressure in this type is
usually limited to about 20 bar, and
flammable or toxic materials should not be
used on the shell side.
Classification of Shell and Tube Heat Exchanger
Front end
Stationary
head types
Classification of Shell and Tube Heat Exchanger

Rear end
Head types
 Features of shell–and–tube heat exchangers
Type of design Fixed tube U- tube Packed Internal Outside- Pull –
sheet lantern–ring floating head packed through
floating head (split backing floating floating
ring) head head
TEMA rare – head L,M or N U W S P T
type
Relative cost B A C E D E
increases from A
(least expensive)
through E (most
expensive)
Provision for Expansion Individual Floating head Floating head Floating Floating
differential joint in shell tubes free head head
expansion to expand
Removal bundle No Yes Yes Yes Yes Yes
Replacement No Yes Yes Yes Yes Yes
bundle possible
13
 Features of shell–and–tube heat exchangers
Type of design Fixed tube U- tube Packed Internal Outside- Pull –
sheet lantern–ring floating head packed through
floating head (split backing floating floating
ring) head head
Individual tubes Yes Only those Yes Yes Yes Yes
replaceable in outside
row
Tube cleaning by Yes Yes Yes Yes Yes Yes
chemicals inside
and outside
Interior tube Yes Special Yes Yes Yes Yes
cleaning tools
mechanically required
Exterior tube cleaning mechanically:
Triangular pitch No No No No No No
Square pitch No Yes Yes Yes Yes Yes
14
 Features of shell–and–tube heat exchangers
Type of design Fixed tube U- tube Packed Internal Outside- Pull –
sheet lantern–ring floating head packed through
floating head (split backing floating floating
ring) head head
Hydraulic – jet cleaning:
Tube interior Yes Special Yes Yes Yes Yes
tools
required
Tube exterior No Yes Yes Yes Yes Yes
Number of tubes No practical Any even Limited to one No practical No practical No
passes limitations number or two passes limitations limitations practical
possible limitations
Internal gaskets Yes Yes Yes No Yes No
eliminated

15
 References
1 Backhurst, J.R. and Harker J.H., “Coulson and Richardson Chemical Engineering”,
Vol. II, 5th Ed., 2002, Butterworth-Heinemann.
2 Sinnott, R.K., “Coulson and Richardson’s Chemical Engineering Series: Chemical
Engineering Design”, Vol. VI, 4th Ed., 2005, Elsevier Butterworth-Heinemann.
3 Serth, R.W., “Process Heat Transfer: Principles and Applications” 2007, Elsevier Ltd.
4 Shah, R.K. and Sekulic, D.P., “Fundamentals of heat Exchanger Design”, 2003, John
Wiley & Sons.
 Summary of the video
 Shell and tube heat exchanger is discussed.
 Scope of shell and tube exchanger is described.
 Types of shell and tube exchangers with respective limitations are
discussed.
 TEMA designations of shell and tube exchangers are shown.

17
Thank You!

18