DESIGN OF SHELL AND TUBE HEAT

EXCHANGER

Bahan Perkuliahan Perpindahan Panas

Dr. H.M. Djoni BUSTAN

TEMAstandard designation system for

shell-and-tube heat exchangers.

(From Saunders, 1988, with permission.)

Type B-E-M Shell and Tube Heat Exchanger (TEMA)

Single-tube-pass baffled single-pass-shell shell-and-tube heat exchanger designed to give essentially counterflow conditions. The toroidal expansion joint in the center of the shell accommodates differential thermal expansion between the tubes and the shell.

U-tube single-pass-shell shell-and-tube heat exchanger.

Type U-Tube Shell and Tube Heat Exchanger (TEMA)

Two-pass baffled single-pass-shell Shell and Tube Heat Exchanger.

Type A-E-T Shell and Tube Heat Exchanger (TEMA)

Heat exchanger similar to that of( c) except for the floating head used to accommodate differential thermal expansion between the tubes and the shell.

Type B-E-WShell and Tube Heat Exchanger (TEMA)

Heat exchanger that is similar to the heat exchanger in (d) but with a different type of floating head.

Type B-E-S Shell and Tube Heat Exchanger (TEMA)

Single-tube-pass baffled single-pass-shell shell-and-tube heat exchanger with a packed joint floating head and double header

sheets to assure that no fluid leaks from one fluid circuit into the other.

Type C-E-M Shell and Tube Heat Exchanger (TEMA)

Shell Picture

Shell Picture

Shell and Tube Heat Exchanger Picture

Tube Picture

Shell and Tube Heat Exchanger

THERMAL DESIGN FEATURES

SizeOutside Diameter

mm in

Small 15.875 to 25.4 to 1

Medium 25.4 to 50.8 1 to 2

Large 50.8 to 76.2 2 to 3

Most widely used 19.05 – 25.4 ¾ – 1

8

5

THERMAL DESIGN FEATURES

Tube outside diameter mm 15.88 19.05 25.40 31.75

in 1 1¼

Tube Thickness

Carbon and low-alloy steels mm 1.65 2.11 2.77 3.40

in 0.065 0.083 0.109 0.134

b.w.g. 16 14 12 10

Stainless steels, aluminium, copper and nickel alloys

mm 1.24 1.65 2.11 2.77

in 0.049 0.065 0.083 0.109

b.w.g. 18 16 14 12

Minimum tube pitch

Clean service (300 or 600) mm 19.84 23.81 31.75 39.69

in 1¼ 1

Fouling service (450 and 900) mm 22.22 25.40 31.75 39.69

in 1 1¼ 1

85

43

3225

1615

169

87

169

TYPICAL DIAMETERS, THICKNESS AND PITCH ARRANGEMENT OF TUBES

THERMAL DESIGN FEATURESTUBE LENGTH

The maximum tube length for removable bundle exchangers may be restricted to about 9 m, with a maximum bundle weight of about 200 tons.

The maximum tube length for fixed tubesheet exchangers is less important but may be limited to about 15 m.

Tube Length

mm ft

The sizes which are often regarded as standard for both straight and U–tubes

2438 8

3658 12

4877 16

6096 20

7315 24

THERMAL DESIGN FEATURES

Pitch pattern Pitch angleNature of shell-side fluid Flow regime

triangular 300 clean all

rotated triangular 600 cleanNowadays, never used –300 best

square 900 fouling turbulent

rotated square 450 fouling laminar

Fewer costly alloy or clad components are needed if the corrosive fluid isinside the tubes.

Fluid Properties, Fluid AllocationData sifat-sifat fisika fluida harus seakurat mungkin, tetapi karena umumnya sifat fisika campuran harus dihitung atau di-estimasi, tidak ada nilai pasti dalam menentukan true film temperature.

Corrosion

This can be minimized by placing the fouling fluid in the tubes to allowbetter velocity control; increased velocities tend to reduce fouling

Fouling

For high-temperature services requiring expensive alloy materials, feweralloy materials, fewer alloy components are needed when the hot fluid is placed on the tubeside.

Temperature

Placing a high-pressure stream in the tubes will require fewer (more costly) high-pressure components.

Pressure

For the same pressure drop, higher heat-transfer coefficients are obtained on the tube-side.

Fluid Properties, Location

Pressure Drop

Higher heat-transfer rates are generally obtained by placing a viscous fluid on the shellside.

Viscosity

Generally, the toxic fluid should be placed on the tubeside, using a double tubesheet to minimize the possibility of leakage.

Toxic and Lethal Fluids

Placing the fluid with the lower flowrate on the shellside usually results in a more economical design.

Flowrate

TUBE PITCH ARRANGEMENTS

Pitch

300

TRIANGULAR (300)

THERMAL DESIGN FEATURES

Pitch

600

ROTATED TRIANGULAR (600)

THERMAL DESIGN FEATURES

TUBE PITCH ARRANGEMENTS

Pitch

SQUARE (900)

THERMAL DESIGN FEATURES

TUBE PITCH ARRANGEMENTS

ROTATED SQUARE (600)

Pitch

450

THERMAL DESIGN FEATURES

TUBE PITCH ARRANGEMENTS

TYPICAL TUBE PASS LAYOUTSNumber of

passes

Type 1 Type 2 Type 3Stationary end Rear end Stationary end Stationary endRear end Rear end

2

4

2

1 1

2

Full lines indicate gasket pattern at stationary and rear ends.Indicates plane of U bendsIndicates acceptable arrangement for longitudinal baffle (F-, G- and H- type shells)

2

121

34

3

4

21

3 4

21

3 4

2

1

3

4

2

1

4

3

62

1

3

4

21

34

21

4 3

21

345

6

1

6

3

4

2

55 6 5 6 5

6

21

3456

THERMAL DESIGN FEATURES

TYPICAL TUBE PASS LAYOUTSNumber of

passes

Type 1 Type 2 Type 3Stationary end Rear end Stationary end Stationary endRear end Rear end

8

21

5 6

2134 2

1

10

1

1

347

8

256

1256

8

347

34

785 6

78

34

765

8

2

1

34

7 65

8

10

2354

678 9

1

52

10

43

87

96

1

5

2

10

4 3

8 7

9

6

2

3

76

10

1

4

85

9

1

4

6

5

9

23

7 8

10

1

4

6

5

9

23

7 8

10

THERMAL DESIGN FEATURES

CROSS–BAFFLE ARRANGEMENTS

Single segmental

w

w

1 2

1 1

22

Double segmental

1 2

1 122

w

w

w Floating-head support plates

THERMAL DESIGN FEATURES

(w denotes baffle window)

CROSS–BAFFLE ARRANGEMENTS

Triple segmental

1 2

No-tubes-in-window

(NTIW)

1 2w

13

12

w

ww

w

w

w

w 3

int

2 2 w w

w intint = intermediate suport

THERMAL DESIGN FEATURES

(w denotes baffle window)

BAFFLE EDGE ORIENTATION

THERMAL DESIGN FEATURES

Service Baffle edge Notes

Single phase – clean Either – horizontal more common

–

Single phase – fouling Vertical Prevents dirt settlement

Condensing Vertical Enables condensate to flow freely

Vaporising Either Horizontal prevents stratification

THERMAL DESIGN THERMAL DESIGN FEATURESFEATURES

Exchanger Exchanger typetype

More More commoncommon

Permissible but less Permissible but less commoncommon

Fixed Fixed tubesheettubesheet

1, 2, 4, 6, 81, 2, 4, 6, 8 3, 5, 10, 12, 14, etc.3, 5, 10, 12, 14, etc.

U-tubeU-tube 2, 42, 4 6, 86, 8

Floating headFloating head Lantern ringLantern ring 1, 21, 2(1)(1) – –

Outside packedOutside packed 2, 4, 6, 82, 4, 6, 8 1, 3, 10, etc. 1, 3, 10, etc. (2)(2)

Split backing ring & pull Split backing ring & pull throughthrough

1, 2, 4, 6, 8 1, 2, 4, 6, 8 (3)(3) 10, 12, 14, etc.10, 12, 14, etc.

Notes:

(1) Tubeside nozzles must be at stationary end for two passes.

(2) Means to accommodate rear-end nozzle movement with odd number of passes.

(3) Bellows or gland required at floating-head end for one pass.

TYPICAL TUBE PASS NUMBERSTYPICAL TUBE PASS NUMBERS