HEAT EXCHANGERS m.ppt

PDEC

INDIAN OIL CORPORATION LTDPROCESS DESIGN ENGINEERING CELL(PDEC)

HEAT EXCHANGERS DESIGN &

MANUFACTURING FEATURESBY

M. BALA

1

PDEC CONTENT

• DEFINITION OF HEAT EXCHANGERS

• TYPES OF HEAT EXCHANGERS

• CLASSIFICATION OF SHEEL AND TUBE HEAT EXCHANGERS

• DIFFERENT TYPES OF HEAT TRANSFER EQUIPMENTS

2

PDEC CONTENT

• COMPONENTS OF SHELL AND TUBE HEAT EXCHANGERS

• NOMENCLATURE OF HEAT EXCHANGERS

• CONSTRUCTION OF HEAT EXCHANGERS

3

PDEC CONTENT

• CODES/ STANDARDS

• DESIGN OF HEAT EXCHANGERS

• MATERIAL IDENTIFICATION CHART

• SELECTION OF HEAT EXCHANGERS TYPES

4

PDEC CONTENT

• THERMAL DATA SHEET OF HEAT EXCHANGERS

• MECHANICAL DATA SHEET OF HEAT EXCHANGERS

• MANUFACTURING FEATURE

• MAINTENANCE OF HEAT EXCHANGERS

5

PDEC HEAT EXCHANGERS DESIGN

DEFINITION OF HEAT EXCHANGER:

A heat exchanger is a piece of equipment built for efficient heat transfer between a hot process stream and a cold process stream.

6


TYPES OF HEAT EXCHANGERS:

• Shell & Tube heat exchanger

• Plate heat exchanger

• Plate & Shell heat exchanger

7


SHELL AND TUBE HEAT EXCHANGER

Shell & tube heat exchangers consist of a series of tubes & cylindrical shell. One set of these tubes contains the fluid that must be either heated or cooled. The second fluid runs over the tubes i.e inside the shell that are being heated or cooled. A set of tubes is called the tube bundle.(as shown in Fig).

8


SHELL AND TUBE HEAT EXCHANGER

9

PDEC COMPLETE HEAT EXCHANGER

10


PLATE HEAT EXCHANGER

It is composed of multiple, thin, slightly separated plates that have very large surface areas and fluid flow passages for heat transfer.

• Much higher heat transfer co-efficient• Lower cost, low space requirement

11

PDEC PLATE HEAT EXCHANGERS

12


PLATE AND SHELL HEAT EXCHANGERS

• It is combines with plate heat exchanger and shell & tube heat exchanger technologies.

• High heat transfer, high pressure, high operating temperature

• Compact in size• Low fouling

13


PLATE AND SHELL HEAT EXCHANGERS

14


TYPE OF SHELL AND TUBE HEAT EXCHANGERS• Shell and Tube Heat Exchangers (STHEs) are the most

widely and commonly used unfired heat transfer equipment in the chemical process industries.

• Shell and tube heat exchanger may be classifiedBy construction andBy service

15

PDEC

HEAT EXCHANGERS NOMENCLATURE:

An STHE is divided into three parts mainly:

• The front head • The shell and • The rear head

16

HEAT EXCHANGERS DESIGN

PDEC

TEMA DESIGNATIONS FOR SHELL-AND-TUBE. HEAT EXCHANGERS

17

PDEC

HEAT EXCHANGERS NOMENCLATURE:

• There are five front head types: A, B, C, D and N.

• There are eight rear head types: L, M, N, P, S, T, V, and W which corresponding in practice to only three general construction types, namely fixed tube sheet, U-tube and floating head.

18


PDEC

Cont:

• Rear head ‘L’ is identical to a front head ‘A’ and rear head ‘M’ is identical to a front head ‘B’ while N is the same nomenclature.

• There are seven types of shell depending on fluid flows through a shell - E, F, G, H, J, K and X.

19



• CLASSIFICATION BY CONSTRUCTION It may be classified into three categories.

• Fixed-tube sheet heat exchanger

• U-tube heat exchanger

• Floating- head heat exchanger

20


FIXED-TUBE SHEET HEAT EXCHANGER

• A fixed-tube sheet heat exchanger has straight tubes secured at both ends to tube sheets welded to the shell.

• The construction may have removable channel covers (e.g. AEL), bonnet –type channel covers (e.g. BEM) or integral tube sheets (e.g. NEN)

21



Bonnet(StationaryHead)

StationaryTubesheet Support

BracketStationaryTubesheet

Bonnet(StationaryHead)

22



Advantages of this exchangers• The main advantage of a fixed-tube sheet

construction is low cost as it has the simplest construction.

• Permits mechanical cleaning of the inside of the tubes as these are accessible after removal of the channel cover or bonnet.

23



• No leakage from the shell side fluid as there are no flanged joint.

Disadvantages of this exchangers• The outside of the tube can not be cleaned

mechanically as the bundle can not be removed from the shell.

• Due to this shell side fluid should be clean

24


U-TUBE HEAT EXCHANGER• As name implies, the tubes of a U-tube heat

exchanger are bent in the shape of a U. There is only one tube sheet in a U-tube heat exchanger.

25


U-TUBE HEAT EXCHANGERAdvantages of this exchangers• It permits the tube bundle to expand or

contract according to the differential stress set up due to free at one end.

• It permits the outside of the tubes cleaning as the tube bundle can be removed.

26


U-TUBE HEAT EXCHANGER Disadvantages of this exchangers• The inside of the tube cannot be cleaned

effectively.

• This exchangers should not be used for services which have dirty fluid inside the tubes.

27


U-TUBE HEAT EXCHANGER

• It places a very severe limitation on U-tube heat exchangers for refinery services, which usually have dirty streams on both the tube side and shell side. This is primarily the reason why U- tube heat exchangers are not generally used in oil refineries .

28


FLOATING- HEAD HEAT EXCHANGER•A Floating-heat exchanger is one where one tube sheet is fixed relative to the shell and the other is free to float within the shell.

29

PDEC HEAT EXCHANGERS DESIGN FLOATING- HEAD HEAT EXCHANGER•Advantages of the exchangers

This type of heat exchanger permits free expansion of the tube bundle

It permits cleaning of both the inside and outside of the tubes.

It is used for services where both the shell side and tube side fluids are dirty.

30


FLOATING- HEAD HEAT EXCHANGERFloating head exchanger is the most versatile construction.

•Disadvantages of this exchangersIt is more costlier than Fixed tube & U- tube exchangers due to: More components in this construction Shell diameter is larger than floating tube sheet.

31


FLOATING- HEAD HEAT EXCHANGER

Various types of floating head construction are:

• Pull through with backing device:TEMA type S• Pull through: TEMA type T• Outside- packed stuffing – box: TEMA type P • Outside-packed lantern ring: TEMA type W

32


• PULL THROUGH WITH BACKING DEVICE: TEMA type S

Most commonly used type in the chemical processing industries.

The floating head cover is secured against the floating tube sheet by bolting it to an ingenious device called split backing ring.

The floating head closure is located beyond the end of the shell and contained by a shell cover of a larger diameter.

33


Cont.For dismantling the heat exchanger, the shell

cover is removed first, then the split backing ring and finally the floating head cover after which the tube bundle can be removed from the stationary end.

For assembling the heat exchangers, the reverse order is followed.

34


PULL THROUGH WITH BACKING DEVICE: TEMA type S

35


Pull through: TEMA type T• The floating head cover is bolted directly to

the floating tube sheet so that a split backing ring is not required.

• The advantage of this type construction is that the tube bundle may be removed from the shell without removing either the shell or floating head cover.

36


Pull through: TEMA type T

• It is generally used for kettle re-boilers having a dirty heating medium where u-tube cannot be used.

• The shell diameter is the largest in this type of construction since floating head tube sheet with cover has to be removed through the shell. Hence, the cost is the highest in this type of construction.

37


• Pull through: TEMA type T

10

16

1521

6

4

3

Rear tubad end Shell Stationary Head end

38


OUTSIDE-PACKED STUFFING–BOX:TEMA TYPE P • In this construction, the shell side fluid is sealed

by ring of packing compressed within a stuffing- box by a follower ring.

• This construction is prone to leakage. Due to this, its usage is limited to shell side services, which are:

Non-hazardous and non-toxic services Moderate pressure and temperature (40

kg/cm² and 300ºc).39

PDEC HEAT EXCHANGERS DESIGN OUTSIDE- PACKED STUFFING – BOX: TEMA TYPE P

28

29

27

25

24

26

40


OUTSIDE-PACKED LANTERN RING: TEMA TYPE W

• The shell side and tube side fluids are sealed by separate ring of packing or O-ring and separated by a lantern ring provided with weep holes. Hence any leakage will be the outside.

• The width of the tube sheet necessarily has to be sufficient to accommodate the two packing rings and the lantern ring, plus the expansion margin.

41


OUTSIDE-PACKED LANTERN RING: TEMA TYPE W• This design is limited to 9.9 kg/cm² and 204ºc.

24

3

26

27

30

42

PDEC

CLASSIFICATION BY SERVICE It may be classified into four categories.• Single phase (both shell side and tube side)• Condensing (one side condensing and other

single phase)• Vaporizing ( one side vaporizing and the other

single phase)• Condensing/vaporizing (one side condensing and

the other vaporizing)


43

PDEC

DIFFERENT TYPES OF HEAT TRANSFER EQUIPMENTS

• Heat Exchanger: both side single phase process streams (that is not an utility).

• Cooler: One stream a process fluid and the other stream a cold utility, such as cooling water or air.

• .

44

PDEC

Cont.• Heater: One stream a process fluid and the other

stream a hot utility, such as stream or hot oil

• Condenser: One stream a condensing vapor and the other stream a cold utility, such as cooling water or air.

45

PDEC

Cont.• Chiller: One stream a process fluid being condensed at

sub-zero temperature and the other stream a boiling refrigerant or process stream (evidently cryogenic).

• Vaporizer: One stream a vaporizing liquid and the other a gas or a liquid.

• Re-boiler: One stream a bottom stream from a distillation column and other a hot utility (stream or hot oil) or a process stream.

46

PDEC RE-BOILER

47

PDEC

COMPONENT OF STHEs :

The principal components of an STHE are:

• Shell and Shell cover

• Tubes

• Channel and Channel cover48

PDEC


• Tube sheet

• Baffles

• Floating head cover

• Nozzles49

PDEC


The other components are,

• Tie-rods and spacers,

• Pass partition plates,

• Impingement plate,

50

PDEC


• Longitudinal baffles,

• Sealing strips, sliding strips, • Supports and foundation

51

PDEC

52

VARIOUS PARTS OF HEAT EXCHANGER

PDEC

1. Stationary Head-Channel

2. Stationary Head-Bonnet

3. Stationary Head Flange-channel Or Bonnet

4. Channel Cover

5. Stationary Head Nozzle

6. Stationary Tubesheet

7. Tubes

8. Shell

9. Shell Cover

10. Shell Flange-Stationary Head End

11. Shell Flange-Rear Head End

12. Shell Nozzle

13. Shell Cover Flange

14. Expansion Joint

15. Floating Tubesheet

16. Floating Head Cover

17. Floating Head Cover Flange

18. Floating Head Backing Device

19. Split Shear Ring

20. Slip-On Backing Flang

21. Floating Head Cover

22. Floating Tubesheet Skirt

23. Packing Box

24. Packing

25. Packing Gland

26. Lantern Ring

27. Tierods and Spacers

28. Transverse baffles or Support Plates

29. Impingement Plate

30. Longitudinal Baffle

31. Pass Partition

32. Vent Connection

53

VARIOUS PARTS OF HEAT EXCHANGER

PDEC

SHELL AND SHELL COVER:• The shell is cylinder in which tubes are contained

and serves to contain the shell side flowing stream and forms the outer casing of the tube bundle.

TUBE BUNDLE:• The tube bundle is the heart of the shell and tube

unit and comprises tubes, tube sheets, baffles, floating head cover, split ring. Tie rods, impingement plate, baffle, longitudinal baffle and sealing/sliding strips.

54

PDEC

TUBES:

• Tubes are most vital component of the heat exchangers.

• Tubes are two types, namely a) plain or bare and b) finned – external or internal

• Plain tubes are most common ones which are generally used in refineries

55

PDEC

Cont. • Tubes are usually defined by outer dia (OD)

and wall thickness (or BWG- Birmingham Wire Gauge).

• Wall thickness can be either minimum wall (when there is no under-tolerance, but only over tolerance), or average wall thickness (when there is both under tolerance and over tolerance).

56

PDEC

Cont. • The usual practice is to order tubes with

minimum wall thickness for carbon steel and low alloy steel tubes and with average wall thickness for non-ferrous and high-alloy steel tubes.

• Material of construction of tubes are- carbon steel, low and high alloy steels, special stainless steels, Admiralty brass and bronze, alloys of copper and nickel, Hastealloys and Tantalum. 57

PDEC

TUBE SHEETS: • The ends of the tubes fit into a common sheet

and are expanded against or welded to the shell to form a pressure tight seal which separates fluid in the shell and that in the tubes.

Tube sheet are two types

• Fixed/stationary tube sheet – A tube sheet fixed or welded to the shell.

58

PDEC

Welded tube to tube sheet joints are usuallyemployed for severe condition such as high pressure (say, in excess of 80 kg/cm²) or when handling toxic or inflammable fluids where leakage is not permitted.

Floating tube sheet:• A tube sheet which can move to allow for

expansion or contraction of the tubes relative to the shell.

59

PDEC

• Tube sheet thickness can vary from 25 mm for low-pressure low shell dia. to 300 mm for high pressure & large shell

• Depending on the severity of the situation, tubes are either expanded into grooves in the tube sheet or welded to theme to tube sheet

Baffles: • It serve to support the tubes as well as to impart a

sufficiently shell side velocity to yield a satisfactory heat transfer co-efficient.

60

PDEC

• Baffles are held securely in place by a combination of tie rods and spacers.

• The length of spacers is equal to the baffle spacing.

• The outside diameter of the baffle has to be less than the inside diameter of the shell to permit insertion of the tube bundle into the shell and removal of the bundle from the shell.

61

PDEC

• A plate which is placed transversely along the centre line of the shell and is employed to divide the shell into two or more compartments is called longitudinal baffle.

• A single longitudinal baffle from one tube sheet to just sort of the other tube sheet produce on ‘F’ shell i.e. a shell with two shell passes.

LONGITUDINAL BAFFLES:

62

PDEC

• A pair of sliding strips is provided at the bottom of floating head tube bundles for their insertion and removal to and from the shell.

• A sufficient number of sealing strips is required to be inserted in the gap between the shell and outer most tubes in floating head tube bundles to minimize leakage of the shell

SLIDING AND SEALING STRIPS:

63

PDEC

IMPINGEMENT PLATE: • The inlet nozzle is provided with a plate

which is used to protect the uppermost tubes located just below the shell side inlet nozzle against direct impingement by the shell side fluid is called an impingement plate.

CHANNEL, CHANNEL COVER & PASS PARTITION PLATES:

• Channel is the inlet and outlet chambers for the fluids flowing through the tubes.

64

PDEC

• A channel may either be of a bonnet const. where a dished end is welded to channel barrel or a flanged channel cover.

• Pass partition plates are the plate in the channel which make the fluid in the tubes flow through one set of tubes and back through another set. They fit tightly into grooves in the tube sheet and channel cover in order to eliminate the possibility of leakage of the tube side fluid from one pass to the next.

65

PDEC PASS PARTITION ARRANGEMENT FOR TUBE PASSES

66

PDEC

CODES/STANDARDS:• API 660 - Shell & tube heat exchangers for general

refinery services.

• ASME Section VIII – Pressure Vessels for Shell thickness cal., Welding & Testing

requirements.

• TEMA(Tubular Exchanger Manufacturers Association) for design of STHEs

67

PDEC

TEMA: There are three classes of TEMA;• Class-R Refinery Service• Class-B Chemical Process service• Class-C General service

LIMITATION OF TEMA:• Inside diameter of shell is 2540 mm• A design pressure of 211 kg/cm2

68

PDEC

BASIC FORMULA:

The basic formula for heat transfer is, Q = A* U*△T Where, Q = Total heat to be transferred, Kcal/hr A = Required effective heat exchanger surface, based on the tube

O.D , m2U= Overall heat transfer co-efficient,Kcal/hr-m2-c

69

PDEC

Cont.△T = effective mean temperature difference, OC

For exchangers where the flow of the hot and cold fluids is true counter or concurrent, △T is equal to the log mean temperature difference (LMTD)

In most commercial exchangers, the use of shell baffles and multiple tube passes causes the flow to be partially counter current and

70

PDEC

Cont. partially concurrent flow. For this mixed flow △T is obtained by

applying a correction factor (F) to the calculated LMTD for a counter current flow arrangement i.e.

△T (effective) = LMTD * F ( F= < 1.0) Where,

71

LMTD =△Th - - △Tc

Ln (Ln (△Th / / △Tc )

PDEC

Cont.Where, △Th = T1 - t2

△Tc = T2 - t1

T1 = Inlet temp. of hot fluid

T2 = Outlet temp. of hot fluid

t 1 = Inlet temp. of cold fluid

t 2 = Outlet temp. of cold fluid 72

PDEC

Cont. The value of correction factor “F” is obtained from TEMA

chart. “F” is plotted as a function of “P” and “R” . Where” and “R”

P = Temp. effectiveness or efficiency of exch. = ( t of cold fluid) / ( t of hot & cold fluid inlet temp.)△ △

73

P =t2 - t1

T1 - t1

PDEC

Cont. Where, R = Heat capacity rate ratio. = wc / Wc

74

R =T1 - T2

t2 - t1

PDEC

BASIS OF DESIGN PRESSURE:• Maximum pump shut of pressure, or• 25 psi or 10% greater than the maximum operating pressure in

PSIG

BASIS OF DESIGN TEMPERATURE:

• The minimum design temp is normally set a 25oC above the maximum operating temp at the exchanger

75

PDEC

DESIGN OF STHEs:

The design of shell and tube heat exchangers comprises two distinct activities

are:• Thermal design and

• Mechanical design

76

PDEC

Thermal design:

• In thermal design, the heat exchangers is sized, which means that all the principal construction parameters such as shell type and diameter, number of tubes, tube OD and thickness, tube length, tube pitch, number of tube passes, baffle spacing & cut and nozzles sizes are determined.

77

PDEC

Basic aims of a thermal designer are: 1.Produce a thermal design that has a low overall cost.• Overall cost = initial cost + operating cost• Initial cost is evidently the fixed cost or first cost of the

heat exchangers• Operating cost = pumping cost + maintenance cost +

down time cost

78

PDEC

Cont.: • Maintenance cost= periodically cleaning cost + anti - foulant

cost + any repair or replace. Cost.2. Utilize allowable pressure drop as fully as possible.• Higher the velocity of the fluid higher will be the heat transfer

co-efficient.• Higher heat transfer co-efficient will be higher pressure drop.

79

PDEC

Cont.: • Higher heat transfer co-efficient will tend to reduce

first cost of the exchangers. • Higher pressure drop will tend to increase the

operating cost of the exchangers• Thus a very important goal for a good thermal design

is the best utilization of the allowable pressure drop

80

PDEC

REQUIRED DATA FOR THERMAL DESIGN : Process dept. have to furnish the following data for thermal design of heat

exchangers:

• Name of the fluids• Flow rate of the fluids• Inlet & outlet temperature of the fluids• Operating pressure of the fluids

81

PDEC

Cont. • Allowable pressure drop Generally 0.5 to 0.7 kg/cm2 per shell for liquid 0.05 to 0.02 kg/cm2

per shell for gases • Fouling refers- accumulation and deposition of living organisms and

certain non-living materials on the surface• Properties of fluids like – Specific gravity/ density, thermal conductivity,

viscosity and specific heat.

82

PDEC

Cont.• Heat release profile for two phase flow – it is a plot of heat duty and weight fraction

vapor versus temperature and is an essential part of the process data sheet.• Heat exchanged i.e. heat duty

83

Process data sheet of HE 1.pdf...

PDEC

Cont. • Selection of heat exchanger type i.e Fixed tube, U-tube or

Floating head tube exchangers (i.e AES, BEM )etc.

• Placement of Fluids Generally low flow rate fluid is placed on the shell side .This

facilitates provision of adequate turbulence by increasing number of baffles

84

PDEC

Cont. Cooling water which is likely to deposit scales is generally placed on

tube side for facilitating mechanical cleaning of tubes from inside In general highly befouling fluids that need frequent mechanical

cleaning of heat exchangers are usually placed on tube side Highly corrosive fluids are preferably placed on tube side

85

PDEC

Cont. Fluids with very high operating pressure are preferably placed on tube side• Line sizes: Generally line size match with nozzle sizes• Preferred tube size: OD: Commonly used OD 19.05/ 25.4 mm Tube thick.: Commonly used thk.2 / 2.5 mm Length: Commonly used length 6000 / 9000 mm

86

PDEC

Cont.

• Maximum shell diameter As per TEMA ID is 2540 mm As per engineering practice, For floating & U-tube exchangers: Shell ID 1400-1500 mm For fixed tube heat exchanger: No limitation

87

PDEC

Cont.

• Corrosion allowance

Tube: As per TEMA no corrosion allowance is applied in tube Shell: Depends on services and materials of construction. Generally 1.5 to 3 mm is used

depending on materials.

88

PDEC

Cont.

• Velocity –In-general very high velocity lead to erosion. For liquid- minimum recommended velocity in s tube side is 0.9 m/s while

maximum is 2.4 m/s. Shell side velocity is from 0.6 t0 1.5 m/sFor gases – maximum tube side velocity is 35 m/s

89

PDEC

Cont.

• Type of shell As per TEMA, there are seven types of shells like E, F, G, H, J, K & X.

• Tube lay out pattern There are 4 types of tube lay out pattern.

90

PDEC

Rotated Triangular- Not Used when mechanically cleaning is required

Triangular- Not Used when mechanically cleaning is required.

91

PDEC

Square- When mechanically cleaning is required

Rotated square- When mechanically cleaning is required

92

PDEC

• Tube Pitch; center to center distance between two adjacent tubes.

For triangular & rotated triangular pattern tube pitch is 1.25 times the tube OD

For square or rotated square pattern tube pitch is generally (OD+6mm)

93

PDEC

Final decision on exchanger type depends on many factors but the table given below is only for guide lineShell side fluid Tube side fluid Type of exchanger

Clean Dirty Clean Dirty

Yes - Yes - Fixed tube sheet or U-tube with triangular pitch

Yes - - Yes Fixed tube sheet or floating head with triangular pitch

- Yes Yes - U-tube or floating head with square pitch

- Yes - Yes Floating head with square pitch

SELECTION OF HEAT EXC.TYPE BASIS ON SERVICES

94

PDEC

THERMAL DESIGN OF HEAT EXCHANGERS IS DONE BY

• HTRI (Heat Transfer Research Institute) Soft ware, USA

95

PDEC

THERMAL DATA SHEET OF HEAT EXCHANGER:

• Heat exchanger thermal specification sheet is divided into three parts,

General information of exchangers

Performance of exchangers

Construction of exchangers

96

THERMAL DATA SHEET.pdf

PDEC

• MECHANICAL DESIGN:

Detailed calculations are carried out to determine the dimensions of various components such as tube sheets,girth flanges, shell , shell barrel, channel, channel barrel,Baffle plate, floating head dish, etc and a complete bill of materials and engineering drawings such as bundles assembly and setting plan drawings are generated.

97

PDEC

Generally there are two types of baffles• Plate type - Single segmental

- Double segmental - Triple segmental

Baffles:

98

PDEC

PLATE TYPE BAFFLES:

99

PDEC

ROD TYPE BAFFLE-

Entire heat transfer area is effective

Tube bundle is vibration free

No stagnation of flow, uniform flow

Pressure drop minimum

100

PDEC

ROD TYPE BAFFLE:

101

PDEC

BAFFLE SPACING:

• Center to center line distance between adjacent baffles is called baffle spacing

• Minimum spacing as per TEMA is one fifth of the shell ID or 51 mm whichever is greater.

102

PDEC

BAFFLE SPACING:

• For example if shell inside diameter = 1000 m Then 1/5th = 1000/5 = 200 mm

• So spacing should be 200 mm

• Maximum spacing is usually the shell ID

103

PDEC

BAFFLE CUT: • It is the segment opening heights expressed as a

percentage of the shell inside diameter . Baffle cuts are :• Horizontal- This is used for single pass shell for

minimizing the accumulation of deposit at the bottom.

104

PDEC

BAFFLE CUT: • Vertical - This is used for two pass shell for ease of fabrication and bundle assembly, as well as for condenser.

• Recommended baffle cut is from 20% to 35%

105

PDEC

Baffle or support plate thickness should be as per below table (R-4.41 of TEMA)

Shell ID Plate thickness

Unsupported tube length between central baffles

610 mm & under

Over 610 - 914 mm

Over 914 - 1219 mm

Over 1219 - 1524mm

Over 1525mm

152 – 356 3.2 4.8 6.4 9.5 9.5

381 - 711 4.8 6.4 9.5 9.5 12.7

735 - 965 6.4 7.5 9.5 12.7 15.9

991 - 1524 6.4 9.5 12.7 15.9 15.9

1549 - 2540 9.5 12.7 15.9 19.1 19.1

BAFFLE PLATE THICKNESS :

106

PDEC

Tie rod and spacers shall be provided to retain all baffles and tube support plates securely in position.

Number and size of the tie rods will be as per below table (R-4.71 of TEMA)

Nominal shell diameter in mm

Tie rod diameter in mm Minimum number of tie rod

152 - 381 9.5 4

406 – 686 9.5 6

711 – 838 12.7 6

864 – 1219 12.7 8

1245 – 1524 12.7 10

1549 - 2540 15.9 12

TIE ROD AND SPACERS:

107

PDEC

Material Identification chart:

Description of parts

Carbon steel Alloy steel Stainless Steel

Shell SA516Gr60/70 SA387GR5CL2 SA240Gr316

Shell cover barrel SA516Gr60/70 SA387GR5CL2 SA240Gr316

Shell cover bonnet SA516Gr60/70 SA387GR5CL2 SA240Gr316

Channel SA516Gr60/70 SA387GR5CL2 SA240Gr316

Channel cover SA105 SA182GrF5 SA182Gr316

Tubes SA179 SA213GrT5 SA213Gr316

Tubes sheet SA266Gr.2 SA336GrF5 SA240Gr316

Baffles SA516Gr60/70 SA387 Gr5CL2 SA240Gr316

Floating Head Dish SA266Gr.2 SA336GrF5 SA336Gr316

Girth Flanges SA266Gr.2 SA336GrF5 SA336Gr316

108

PDEC

Material Identification chart:

Description of parts

Carbon steel Alloy steel Stainless Steel

Nozzles Neck SA106GrB SA335GrP5 SA312Gr316

Nozzles Flanges SA105 SA182GrF5 SA182Gr316

PAD SA516Gr60/70 SA387GR5CL2 SA240Gr316

Backing Ring SA105 SA336GrF5 SA336Gr316

Tie Rods SA516Gr60/70 SA387GR5CL2 SA240Gr316

Partition Plate SA516Gr60/70 SA387GR5CL2 SA240Gr316

Impingement plate SA516Gr60/70 SA387GR5CL2 SA240Gr316

Sealing strips SA516Gr60/70 SA387GR5CL2 SA240Gr316

Spacers SA179 SA213GrT5 SA213Gr316

Saddle plate SA516Gr60/70 SA387GR5CL2 SA240Gr311

109

PDEC

MECHANICAL DATA SHEET OF EXCHANGER:• This is required for procurement of heat

exchangers.

110

Mechanical Data sheet .pdf

PDEC

• DESIGN SOFTWARE:

• PV ELITE and Microprotol software are being used worldwide

• Microprotol By EU Research, France

• PV- Elite by COADE taken over by Intergraph, USA

111

PDEC

DRAWINGS AND ASME CODE DATA REPORT:• Drawings for approval and changeThe manufacturer shall submit for purchaser’s

approval three(3) prints of an outline drawing showing nozzle sizes and locations, overall dimensions, support and weight.

It is anticipated that a reasonable number of minor drawing changes may be required at that time.

112

MANUFACTURING FEATURES

PDEC

Cont.Any changes may cause additional expense

chargeable to the purchaser.Purchaser’s approval of drawings does not relieve

the manufacturer of resposibility for compliance with the standard and applicable ASME code requirements.

The manufacturer shall not make any changes on the approved drawings without express agreement of the purchaser.

113


PDEC

Cont.Any changes may cause additional expense

chargeable to the purchaser.Purchaser’s approval of drawings does not relieve

the manufacturer of responsibility for compliance with the standard and applicable ASME code requirements.

The manufacturer shall not make any changes on the approved drawings without express agreement of the purchaser.

114


PDEC

Cont.Shop detail drawings are for internal use by the

fabricator, it may be furnished to the purchaser upon request.

• Drawings for recordAfter approval of drawings manufacturer furnished 3 set

of drawings along with all documents to the purchaser

+115


PDEC

• Proprietary rights to drawingsThe drawings and the design indicated by the

manufacturer are to be considered the property of the manufacturer and are not to be used or reproduced without his permission, except by the purchaser for his own internal use.

• ASME code data reportsAfter completion of fabrication and inspection of

ASME code stamped exchangers, the manufa. shall furnish 3 set of ASME data report.

116


PDEC

INSPECTION: There are two yepes of inspection:• Manufacturer’s Inspection• Purchaser’s Inspection

• Manufacturer’s InspectionInspection and testing of units will be provided by

the manufacturer unless otherwise specified.

117


PDEC

The manufacturer shall carry out the inspection required by the ASME code and also inspection by state and local codes .

• Purchaser’s InspectionThe purchaser shall have the right to make

inspection during fabrication and to witness any test.

Inspection by the purshaser shall not relieve the manufacturer of his responsibilities.

118


PDEC

PREPARATION FOR SHIPMENT:• CleaningInternal and external surfaces are to be free from

loose scale and other foreign material that is readily removable by hand or power brushing

• DrainingWater, oil or other liquids used for cleaning or

hydro-static testing are to be drained from all units before shipment. 119


PDEC

• Flange protectionAll exposed machined contact surfaces shall be

coated with a removable rust preventative.All threaded connections are to be suitably plugged.

• Damage protectionThe exchangers and any spare parts are to be

suitably protected to prevent damage during shipment.

120


PDEC

GUARANTEES: It may be given on the basis of• Performance and• Defective parts• Performance GuaranteeThe manufacturer shall guarantee thermal

performance and mechanical design of a heat exchanger, when operated at the design conditions specified by the purchaser in his order.

121


PDEC

Cont.

This guarantee shall extend for a period of twelve months after shipping date.

The thermal guarantee shall not be applicable to exchangers where the thermal perfomance rating was made by the purhaser.

122


PDEC

• Defective parts Guarantee

The manufacturer shall repair or replace any parts proven defective within the guarantee period.

Finished materials and accessories purchased from other manufacturers, including tubes are warranted only to the extent of the original manufacturer’s warranty to the heat exchanger.

123


PDEC

MANUFACTURES OF HEAT EXCHANGER:

• M/s Aero-therm Products

• M/s Hindustan Radiators

• M/s Unique Chemo-plant Equipments

• M/s Larsen & Toubro

124

PDEC

MANUFACTURES OF HEAT EXCHANGER:

• M/s Hindustan Dorr Oliver Ltd

• M/s Godrej

• M/s Precision Engineering.

• M/s Universal Heat Exchangers

125

PDEC

MAINT. OF HEAT EXCHANGERS

126

PDEC ROUTINE MAINTENANCE

OPERATIONAL PROBLEMS

• Decline in heat transfer efficiency / high pressure drop

• Scaling, fouling, choking, etc.,

• Internal Leak

Causing contamination between shell and tube fluids

127

PDEC ROUTINE MAINTENANCE

OPERATIONAL PROBLEMS

• Gasket Leaks

Due to thermal shock during start-up, shutdowns & Upsets

• Tube Leaks

Tube failure due to fatigue, ageing & corrosion

BLINDING THE EQUIPMENTS

128

PDEC

• Why ?

(During a shutdown, in the presence of air and liquid water, often dew point water, the sulfides convert to polythionic acid which causes inter-granular Stress Corrosion Cracking to Austenitic steels)

• Materials prone for SCC

(Austenitic SS tube bundles - SS 304, SS310, SS316, SS321, SS347)

PASSIVATION

129

PDEC

• When ? Before Opening of the equipments

• Solution Soaked with a solution of DM Water, Sodium

Carbonate (2%) and Sodium Nitrate (0.5%) for about 8 hours.

PASSIVATION

130

PDEC

• Opening the covers of heat exchangers• Removing of bundle Bundle Extractor or Puller

131

PDEC

• Chemical Cleaning Shell - Fixed Tube Sheet Bundle Vacuum Condensers, Ejector Condensers,

Reboilers 0.5% concentration HCl with inhibitor

circulation for 8 hours Hot water wash Branded chemicals Online by wash water circulation

EXCHANGER CLEANING

132

PDEC

• Kero -bath soaking Crude vacuum, Asphalt services• Hydroblasting (For Tube exteriors) Water jet at a pressure of 300 - 600 Kg/Sq.cm (Up to 35000 psi / 2500 bar)

133

PDEC Hydro-blasting (For Tube exteriors)

Before Cleaning After Cleaning

134

PDEC Hydro-lancing (For Tube interiors)

Manual Operation Power Lancing135

PDEC Hydro-lancing (For Tube interiors)

Before Cleaning After cleaning

136

PDEC

• Gasket Replacement

A gasket is a compressible material, or combination of materials, which when clamped between two stationary members prevents the passage of the media across those members.

• Gasket Selection Tem. of the media to be contained,

Corrosive nature of the application and Criticality of the application

137

PDEC

• GASKET CLASSIFICATION CAF (Compressed asbestos fiber)

250 deg. C, 30 bar, Water, steam and for non-critical applications

138

PDEC

• GASKET CLASSIFICATION IJA (Iron Jacketed Asbestos)

High Temperature applications Sheet Metal - SS, Brass, Monel , Al, In-conel Filler - Asbestos, PTEF, Grafoil

139

PDEC

• GASKET CLASSIFICATION Spiral Wound Gasket (SPWD)

(SPWD) with Asbestos filled & Inner Ring (13mm) & Outer Nose (4 mm width) 260 – 650 C

Winding - SS 410, 304, 316, Monel, InconelFiller - CAF(360oC), PTFE(260oC),

Graphite(550oC), Ceramic(650oC)

140

PDEC

TUBE BUNDLE RETUBING• More number of tubes plugged • Not possible to clear the tubes• Scaling & poor heat transfer• After average life of the bundle• Frequent failures

141

PDEC

TUBE BUNDLE RETUBING• Full or Partial• WhereAt Bundle Shop or at Position

142

PDEC

THANK YOU

143

Documents

HEAT EXCHANGERS m.ppt