heat exchangers (Shell & Tube)

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Heat Exchangers


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Heat ExchangersHeat exchangers are one of the most common pieces of

equipment found in all plants.

Heat Exchangers are components that allow the

transfer of heat from one fluid (liquid or gas) to another

fluid.

In a heat exchanger there is no direct contact betweenthe two fluids. The heat is transferred from the hot fluid

to the metal isolating the two fluids and then to the

cooler fluid.


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Types of Heat Exchangers


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Double-Pipe Exchanger


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Double Pipe

Simplest type has one tube inside another - innertube may have longitudinal fins on the outside

However, most have a

number of tubes in the outertube - can have very many tubes

thus becoming a shell-and-tube


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Shell-and-Tube Heat Exchanger


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Shell-and-Tube Heat Exchangers are the most

important type of HE.

It is used in almost every type of industry.

This type of heat exchanger consists of a set of

tubes in a container called a shell.

The fluid flowing inside the tubes is called thetube side fluid and the fluid flowing on the outside

of the tubes is the shell side fluid.


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Main Components of Shell-and-Tube

Heat Exchangers


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Some common heat-exchanger

terms Tube side: Inside the tubes.

Shell side: Outside the tubes, between the

tubes and the shell. Tube sheet A thick plate provided with holes

(one per tube) in which the tubes are fixed.

Tube bundle Consists of tubes, tube sheet and

baffle plates Shell A cylinder of plate in which the tube bundle

is placed


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TEMA Heat

Exchangers


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Shell and Tube Heat Exchangers

Construction Fixed Tube-sheet type

U-tube type

Floating Head type


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Front head type

A-type B-type

B

Channel and removable cover Bonnet (integral cover)

A


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Shell type

E-type

F shell

E F

One-pass shell Two-pass

shell

Longitudinal baffle


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More shell types

G and H shells normally only used for horizontal thermosyphonreboilers

J and X shells if allowable pressure drop can not be achieved in an Eshell

J

HG

X

Split flow Double split flow

Divided flow Cross flow

Longitudinal

baffles


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Low-finned Tubes

Flat end to go into tube sheet andintermediate flat portions for bafflelocations

Available in variety of metals includingstainless steel, titanium and inconels


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Plate and frame

Plates hung vertically andclamped in a press or frame.

Gaskets direct the streamsbetween alternate plates andprevent external leakage

Plates made of stainless steel or

higher quality material Plates corrugated to give points

of support and increase heattransfer


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Plate Heat Exchanger


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Chevron Washboard

Plate typesCorrugations on plate

improve heat transfer

give rigidity

Many points of

contact and atortuous flow path


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General view of

plate exchanger

Plate exchanger

normally refersto a gasketedplate- and-frameexchanger

Flo A angement ithin a


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Flow Arrangement within aPHE

Alternate plates (often same plate types inverted)

Gaskets

arranged for

each stream to

flow betweenalternate plates


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Air-Cooled or Fin-Fan

Exchanger


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Air-cooled exchanger

Air blown across finned tubes (forceddraught type)

Can suck air across (induced draught)

Finned tubes


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ACHE bundle


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Spiral Heat Exchanger


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Spiral Heat Exchangers Spiral heat exchangers can be used in most applications in the

chemical process industry

In many difficult applications where fouling and plugging are

problems, a standard shell and tube design may not be

effective

While a spiral heat exchanger often has a higher initial cost, it

may provide a lower life cycle cost due to lower fouling rates

and ease of maintenance


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A spiral heat exchanger is composedof two long, flat plates wrappedaround a mandrel or center tube,

creating two concentric spiralchannels

In a spiral heat exchanger, the hotfluid flows into the center of the unitand spirals outward toward the outer

plates while at the same time, the coldfluid enters the periphery and spiralinward, exiting at the center


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heat exchangers (Shell & Tube)

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