PV Calculation

HYDROSTATIC TEST AND STRESS ANALYSISON SHELL AND TUBE HEAT EXCHANGER

Deepak SharmaB Tech , Punjab Technical University , India 2007

PROJECT

Submitted in partial satisfaction ofthe requirements for the degree of

MASTER OF SCIENCE

in

MECHANICAL ENGINEERING

at

CALIFORNIA STATE UNIVERSITY, SACRAMENTO

SUMMER2011

HYDROSTATIC TEST AND STRESS ANALYSISON SHELL AND TUBE HEAT EXCHANGER

A Project

by

Deepak Sharma

Approved by:

__________________________________, Committee ChairAkihiko Kumagai, Ph.D.

____________________________Date

ii

Student: Deepak Sharma

I certify that this student has met the requirements for format contained in the University

format manual, and that this project is suitable for shelving in the Library and credit is to be

awarded for the Project.

__________________________, Department Chair ________________Susan L. Holl, Ph.D Date

Department of Mechanical Engineering

iii

Abstract

of

THE HYDROSTATIC TEST AND THE STRESS ANALYSISON SHELL AND TUBE HEAT EXCHANGER

by

Deepak Sharma

The hydrostatic test is performed on a computer model of a heat exchanger to see if there

is any leakage in the heat exchanger. This test is performed on different parts separately based on

the calculations specified in the book of ASME SEC VIII DIV-1 2007 ED. Maximum allowable

pressure (MAWP) for different parts is determined and then is multiplied by a factor of 1.3. The

test is then performed on different parts based on those values continuously for 30 minutes. This

test easily tells where the leakage is which usually occurs in the joints which are welded. This test

is performed along with FEA before installing the heat exchanger. Once the CAD model is

developed, FEA is done to analyze the design thus saving money and time by reducing number of

prototypes. Through FEA we can optimize the size so as to reduce the weight of heat exchanger.

Through FEA we take a look at the entire design and understands how load is transferred between

parts and also where critical areas of design are located. Thus we can test a design before actually

building it, therefore saving the time and cost.

_______________________, Committee ChairAkihiko Kumagai, Ph.D.

_______________________Date

iv

ACKNOWLEDGMENTS

It is my distinct honor and proud privilege to acknowledge with gratitude to keen interest taken

by Professor Akihiko Kumagai, his ever-inspiring suggestions; constant supervision and

encouragement that made it possible to pursue and complete this project efficiently. Here I also

thank to the department of Mechanical Engineering and Department Chair Professor Susan L.

Holl who always guide me on proper way.

Finally I thank all the people who extended their support directly or indirectly to make this

project a complete success. In addition, it is a great pleasure to acknowledge the help of many

individuals without whom this project would not have been possible.

v

TABLE OF CONTENTS

Page

Acknowledgement............................................................................................................................v

List of Tables...................................................................................................................................ix

List of Figures..................................................................................................................................xi

1. INTRODUCTION........................................................................................................................1

2. HYDROSTATIC TEST................................................................................................................3

2.1 Test pressure determination for Tube side chamber...............................................................4

2.2 Test pressure determination for Shell side chamber...............................................................5

2.3 Determination of MAWP for Front Channel.........................................................................7

2.4 Determination of MAWP for Shell........................................................................................8

2.5 Determination of MAWP for Front Head............................................................................10

2.6 Determination of MAWP for Straight Flange on Front Head..............................................11

2.7 Determination of MAWP for Straight Flange on Rear Head...............................................12

2.8 Determination of MAWP for Rear Head..............................................................................13

2.9 Tube Side Nozzle (N1)........................................................................................................14

2.10 Shell side inlet Nozzle (N10).............................................................................................17

vi

2.11 Shell side inlet Nozzle (N11).............................................................................................19

2.12 Shell side outlet Nozzle (N12)...........................................................................................20



2.15 Tube side inlet Nozzle (N2)...............................................................................................26

2.16 Tube side inlet Nozzle (N3)...............................................................................................27

2.17 Tube side outlet Nozzle (N4).............................................................................................29



2.20 Shell side inlet Nozzle (N9)...............................................................................................35

2.21 Shell Side Flange................................................................................................................39

2.22 Shell Side Flange (front) - Flange hub...............................................................................43

2.23 Saddle.................................................................................................................................45

2.24 Pass Partition Plate.............................................................................................................52

2.25 Tubes..................................................................................................................................53

3. STRESS ANALYSIS.................................................................................................................56

3.1 Description of FEA on nozzle..............................................................................................56

3.2 Description of FEA on saddle..............................................................................................62

4. RESULTS...................................................................................................................................68

vii

4.1 Pressure summary for tube and shell....................................................................................68

4.2 Thickness on different parts of heat exchanger....................................................................69

4.3 Weight of heat exchanger.....................................................................................................70

4.4 Baffle....................................................................................................................................71

4.5 Study results of nozzle.........................................................................................................72

4.6 Study results of saddle..........................................................................................................73

5. CONCLUSION AND FUTURE SCOPE OF WORK................................................................74

5.1 Conclusion............................................................................................................................74

5.2 Future scope of work............................................................................................................74

References.......................................................................................................................................75

viii

LIST OF TABLES

Page

1. Table 2.1 Pressure on Tube side..........................................................................................4

2. Table 2.2 Pressure on Shell side..........................................................................................5

3. Table 3.1 Study properties of nozzle.................................................................................57

4. Table 3.2 Units...................................................................................................................57

5. Table 3.3 Material properties.............................................................................................58

6. Table 3.4 Structural Properties..........................................................................................58

7. Table 3.5 Load on nozzle...................................................................................................59

8. Table 3.6 Mesh information..............................................................................................59

9. Table 3.7 Study properties.................................................................................................62

10. Table 3.8 Units...................................................................................................................63

11. Table 3.9 Material Properties............................................................................................63

12. Table 3.10 Structural Properties........................................................................................64

13. Table 3.11 Load.................................................................................................................64

14. Table 3.12 Mesh Properties……………………………………………………………...65

15. Table 4.1 Pressure Summary for tube side........................................................................68

16. Table 4.2 Pressure Summary for Shell Side......................................................................69

17. Table 4.3 Thickness Summary..........................................................................................69

18. Table 4.4 Weight Summary of vessel................................................................................70

19. Table 4.5 Weight Summary of attachments......................................................................70

ix

20. Table 4.6 Baffle Summary.................................................................................................71

21. Table 4.7 Summary of FEA on nozzle..............................................................................72

22. Table 4.8 Summary of FEA on Saddle..............................................................................73

x

LIST OF FIGURES

Page1. Figure 2.1 Tube Side Inlet 1..............................................................................................14

2. Figure 2.2 Shell side Inlet N10..........................................................................................17

3. Figure 2.3 Shell side inlet N11..........................................................................................19

4. Figure 2.4 Shell side outlet N12........................................................................................20

5. Figure 2.5 Shell side outlet N13........................................................................................23

6. Figure 2.6 Shell side Outlet N14.......................................................................................24

7. Figure 2.7 Tube side inlet N2............................................................................................26

8. Figure 2.8 Tube side inlet N3............................................................................................27

9. Figure 2.9 Tube side outlet N4..........................................................................................29

10. Figure 2.10 Tube side outlet N5........................................................................................32

11. Figure 2.11 Tube side outlet N6........................................................................................33

12. Figure 2.12 Shell side inlet N9..........................................................................................35

13. Figure 2.13 Detail view of shell and tube heat exchanger.................................................38

14. Figure 2.14 Shell side flange.............................................................................................39

15. Figure 2.15 Closed view of shell and tube heat exchanger...............................................55

16. Figure 3.1 Stress in nozzle during FEA.............................................................................60

17. Figure 3.2 Displacement in nozzle during FEA................................................................61

18. Figure 3.3 Stress on Saddle during FEA...........................................................................66

19. Figure 3.4 Displacement in Saddle during FEA................................................................66

xi

xii

1

Chapter 1

INTRODUCTION

A heat exchanger is a device in which heat is transferred from one fluid to another. The

most commonly type used heat exchanger is shell and tube heat exchanger. One fluid runs inside

the tubes and the other one runs over it and thus heat is transferred from one fluid to another.

These types of heat exchangers are mostly used in oil refineries, refrigeration, power generation

etc. The main purpose in the heat exchanger design is to determine the overall cost of heat

exchanger.

The shell and tube heat exchanger was introduced in 1900s to meet the ever increasing

demand of the industry. During the course of the time it proved to be the best type of heat

exchanger used in the industry. Lots of improvements were done and various progresses has

been made especially in the calculation of true mean temperature difference in the tubes.

The objective of the project here is to design a shell and tube heat exchanger using the

given values which were calculated using specified pressure drops. So in this project I have

continued that work and designed the heat exchanger. Then certain tests are performed that is the

hydrostatic test and stress analysis. These tests are performed before the installation of heat

exchanger thus helping in reducing the time and money. Hydrostatic test is performed to check

the leakage in the system. It involves more calculations and some new factors like nozzle

schedule etc are used which are commonly used in the modern industries. Stress analysis or finite

element analysis is performed to determine the strength of the material involved in the heat

exchanger.

The first chapter deals with the brief introduction of the heat exchanger. The second

chapter deals with the hydrostatic test. In this chapter various calculations have been made taking

2

each part separately. In the third chapter stress analysis on the saddle is done keeping in mind

given load conditions. The fourth chapter deals with stress analysis on the nozzle showing various

displacement that occur on it when the given load is applied on it.

3

Chapter 2

HYDROSTATIC TEST

To start with first we have to decide the NPS (nominal pipe size). NPS is a set of standard

pipe sizes used for low or high pressure and temperature. It was set up by American Standards

Association in 1927.Pipe size is specified according to two variables

NPS for diameter

Schedule for wall thickness

Now for the given schedule, the wall thickness remains the same but the outside diameter

of the pipe increases. And for the given NPS , the outside diameter remains the same but the wall

thickness increases with the schedule. The pipe outside diameter and wall thickness is obtained

according to the NPS and schedule of the pipe. Based on this theory the nozzle summary,

pressure summary, thickness summary is calculated.

A hydrostatic test is a test in which leaks are found in the pipelines of the pressure vessel

such as heat exchanger. Hydro testing of pipes are done to ensure there is no leaks and to expose

defective materials such as corrosive materials which are not visible to the naked eye. Hydrostatic

test is very important to ensure the proper functioning of the heat exchanger under the industrial

conditions.

ASME (American Society of Mechanical Engineers) requires hydrostatic test to ensure

that the heat exchanger is intact and all the parts are tight enough to withstand the high pressure

and temperature. According to the ASME the test should be performed at 1.3 times the

MAWP(maximum allowable working pressure). According to ASME the test should be

performed at higher pressure but mostly tests are performed at 1.3 times the MAWP. The test is

4

performed for 30 minutes to ensure there is no leakage. The test is performed on tubes and shell

sides separately in such a way that leaks can be determined easily.

After the test is over, inspection is done to ensure there is no leakage in any part of the

heat exchanger. This inspection is done at a pressure equal to test pressure divided by1.3.

hydrostatic test is performed every 2 years for high pressure heat exchanger and every 5 years for

low pressure heat exchanger.

Calculations

2.1 Test pressure determination for Tube side chamber

Shop hydrostatic test gauge pressure is 845 psi at 70 °F (the chamber MAWP = 650 psi)

The shop test is performed with the vessel in the horizontal position.

Table 2.1 Pressure on Tube side

Identifier

Local test

pres(psi)

Test liquid

static head

psi

UG-99

stress

ratio

UG-99

pressure

factor

Stress during

test psi

Allowable

test stress

psi

Stress

excessive?

Front Head

(1)

846.358 1.358 1 1.30 18,891 34,200 No

Straight

Flange on

846.358 1.358 1 1.30 21,410 34,200 No

Front

Channel

846.358 1.358 1 1.30 21,410 34,200 No

Tubes 846.272 1.272 1 1.30 3,707 23,400 No

Front

Tubesheet

846.358 1.358 1 1.30 See tubesheet report

TS Inlet

(N1)

846.597 1.597 1 1.30 23,719 48,600 No

TS Inlet

Aux1 (N2)

846.428 1.428 1 1.30 3,764 48,600 No

TS Inlet

Aux2 (N3)

846.428 1.428 1 1.30 3,764 48,600 No

TS Outlet

(N4)

845.217 0.217 1 1.30 23,681 48,600 No

TS Outlet

Aux1 (N5)

845.196 0.196 1 1.30 3,758 48,600 No

TS Outlet

Aux2 (N6)

845.196 0.196 1 1.30 3,758 48,600 No

Identifier

Local test

pressure

psi

Test

liquid

static

head

UG-99

stress

ratio

UG-99

pressure

factor

Stress

during test

psi

Allowab

le test

stress

psi

Stress

excess

ive?

5

Notes:

Front Head limits the UG-99 stress ratio.

PL stresses at nozzle openings have been estimated using the method described

in PVP-Vol. 399, pages 77-82. (3) VIII-2, AD-151.1(b) used as the basis for

nozzle allowable test stress.

The zero degree angular position is assumed to be up, and the test liquid height is

assumed to the top-most flange.

The test temperature of 70 °F is warmer than the minimum recommended

temperature of 10 °F so the brittle fracture provision of UG-99(h) has been met.

2.2 Test pressure determination for Shell side chamber

Hydrostatic test gauge pressure is 845 psi at 70 °F (the chamber MAWP = 650 psi) The

shop test is performed with the vessel in the horizontal position.

Table 2.2 Pressure on Shell side

6

Tubes 846.272 1.272 N/A 1.30 NI NI NI

Front

Tubesheet

846.358 1.358 1 1.30 See tubesheet report

Shell Side

Flange (front)

846.358 1.358 1 1.30 42,6

82

51,300 No

SS Inlet

(N9)

845.217 0.217 1 1.30 23,6

81

48,600 No

SS Inlet

Aux1 (N10)

845.196 0.196 1 1.30 3,75

8

48,600 No

SS Inlet

Aux2 (N11)

845.196 0.196 1 1.30 3,75

8

48,600 No

SS Outlet

(N12)

846.597 1.597 1 1.30 23,7

19

48,600 No

SS Outlet

Aux1 (N13)

846.428 1.428 1 1.30 3,76

4

48,600 No

SS Outlet

Aux2 (N14)

846.428 1.428 1 1.30 3,76

4

48,600 No

Notes:

Shell limits the UG-99 stress ratio.

NI indicates that test stress was not investigated.

PL stresses at nozzle openings have been estimated using the method described

in PVP-Vol. 399, pages 77-82. (4) VIII-2, AD-151.1(b) used as the basis for

nozzle allowable test stress.

The zero degree angular position is assumed to be up, and the test liquid height

is assumed to the top-most flange.

The test temperature of 70 °F is warmer than the minimum recommended

temperature of 10 °F so the brittle fracture provision of UG-99(h) has been

met.

7

2.3 Determination of MAWP for Front Channel

Component: Cylinder

Material specification: SA-516 70 (II-D p. 18, ln. 22)

Material is impact test exempt per UG-20(f)

UCS-66 governing thickness = 0.625 in

Internal design pressure: P = 650 psi @ 400°F

Static liquid head:

Pth = 1.3582 psi (SG=1.0000, Hs=37.6250", Horizontal test head)

Corrosion allowance: Inner C = 0.0000"

Outer C = 0.0000" Design MDMT = -20.00°F

No impact test performed

Rated MDMT = -20.00°F

Material is not normalized

Material is not produced to Fine Grain Practice

PWHT is not performed

Radiography: Longitudinal joint - Full UW-11(a) Type 1

Left circumferential joint - Full UW-11(a) Type 1

Right circumferential joint - Full UW-11(a) ype 1

Estimated weight: New = 421.7529 lb corr = 421.7529 lb

Capacity: New = 78.4174 gal corr = 78.4174 gal

ID = 31.0000"

Length Lc = 24.0000" t = 0.6250"

8

Design thickness, (at 400.00°F) UG-27(c)(1)

t = P*R/(S*E - 0.60*P) + Corrosion

= 650.00*15.5000/(20000*1.00 - 0.60*650.00) + 0.0000

= 0.5138" (2.1)

Maximum allowable working pressure, (at 400.00°F) UG-27(c)(1)

P = S*E*t/(R + 0.60*t) – Ps

=

=

20000*1.00*0.6250 / (15.5000 + 0.60*0.6250) - 0.0000

787.4016 psi (2.2)

Maximum allowable pressure, (at 70.00°F) UG-27(c)(1)

P = S*E*t/(R + 0.60*t)

= 20000*1.00*0.6250 / (15.5000 + 0.60*0.6250)

= 787.4016 psi (2.3)

% Extreme fiber elongation - UCS-79(d)

= (50 * t / Rf) * (1 - Rf / Ro)

= (50 * 0.6250 / 15.8125) * (1 - 15.8125 / ∞)

= 1.9763 % (2.4)

2.4 Determination of MAWP for Shell

Component: Cylinder


Material is impact test exempt per UG-20(f)



9

Static liquid head:


Corrosion allowance:

Inner C = 0.0000"

Outer C = 0.0000"

Design MDMT = -20.00°F No impact test performed

Rated MDMT = -20.00°F Material is not normalized



Radiography: Longitudinal joint - Full UW-11(a) Type 1

Left circumferential joint - Full UW-11(a) Type 1

Right circumferential joint - Full UW-11(a) Type 1



ID = 31.0000"

Length Lc = 96.0000" t = 0.6250"



= 650.00*15.5000/(20000*1.00 - 0.60*650.00) + 0.0000

= 0.5138" (2.5)

10


P = S*E*t/(R + 0.60*t) - Ps

=

=

20000*1.00*0.6250 / (15.5000 + 0.60*0.6250) - 0.0000

787.4016 psi (2.6)


P = S*E*t/(R + 0.60*t)

= 20000*1.00*0.6250 / (15.5000 + 0.60*0.6250)

= 787.4016 psi (2.7)


= (50 * t / Rf) * (1 - Rf / Ro)

= (50 * 0.6250 / 15.8125) * (1 - 15.8125 / ∞)

= 1.9763 % (2.8)

2.5 Determination of MAWP for Front Head

Component: Ellipsoidal Head

Material Specification: SA-516 70 (II-D p.18, ln. 22)

Straight Flange governs MDMT

Internal design pressure: P = 650 psi @ 400 °F

Static liquid head:

Ps= 0 psi (SG=1, Hs=0" Operating head)

Pth= 1.3582 psi (SG=1, Hs=37.625" Horizontal test head)

Corrosion allowance: Inner C = 0" Outer C = 0"

11

Design MDMT = -20°F

No impact test performed

Rated MDMT = -20°F

Material is not normalized

Material is not produced to fine grain practice


Do not Optimize MDMT / Find MAWP

Result Summary

The governing factor is internal pressure

Minimum thickness = 0.0625” + 0” = 0.0625”

Design thickness due to internal pressure = 0.5054”

Maximum allowable working pressure (MAWP) = 803.21 psi

Maximum allowable pressure (MAP) = 803.21 psi

The head internal pressure design thickness is 0.5054".

% Extreme fiber elongation

= (75*t / Rf)*(1 - Rf / Ro)

= (75*0.625 / 5.5825)*(1 - 5.5825 / ∞)

= 8.3968% (2.9)

The extreme fiber elongation exceeds 5 percent. Heat treatment may be required.

2.6 Determination of MAWP for Straight Flange on Front Head

Design thickness, (at 400.00°F)


= 650.00*15.5000/(20000*1.00 - 0.60*650.00) + 0.0000

12

= 0.5138" (2.10)

Maximum allowable working pressure, (at 400.00°F)

P = S*E*t/(R + 0.60*t) - Ps

= 20000*1.00*0.6250 / (15.5000 + 0.60*0.6250) - 0.0000

Maximum allowable pressure, (at 70.00°F)

P = S*E*t/(R + 0.60*t)

= 20000*1.00*0.6250 / (15.5000 + 0.60*0.6250)

= 787.4016 psi (2.12)

% Extreme fiber elongation

= (50 * t / Rf) * (1 - Rf / Ro)

= (50 * 0.6250 / 15.8125) * (1 - 15.8125 / ∞)

= 1.9763 % (2.13)

2.7 Determination of MAWP for Straight Flange on Rear Head



= 650.00*15.6158/(20000*1.00 - 0.60*650.00) + 0.0000

= 0.5177" (2.14)


P = S*E*t/(R + 0.60*t) – Ps

13

=

=

20000*1.00*0.5177 / (15.6158 + 0.60*0.5177) - 0.0000

650.1148 psi (2.15)


P = S*E*t/(R + 0.60*t)

= 20000*1.00*0.5177 / (15.6158 + 0.60*0.5177)

= 650.1148 psi (2.16)


= (50 * t / Rf) * (1 - Rf / Ro)

= (50 * 0.5177 / 15.8746) * (1 - 15.8746 / ∞)

= 1.6306 % (2.17)

2.8 Determination of MAWP for Rear Head

Design thickness for internal pressure, (Corroded at 400 °F) UG-32(d)(1)

t = P*D/(2*S*E - 0.2*P) + Corrosion

= 650*31.2316/(2*20,000*1 - 0.2*650) + 0

= 0.5092" (2.18)

The head internal pressure design thickness is 0.5092".

Maximum allowable working pressure, (Corroded at 400 °F) UG-32(d)(1)

P = 2*S*E*t/(D + 0.2*t) - Ps

=

=

2*20,000*1*0.5092/(31.2316 +0.2*0.5092) - 0

650.04 psi (2.19)

14

The maximum allowable working pressure (MAWP) is 650.04 psi.

Maximum allowable pressure, (New at 70 °F) UG-32(d)(1)

P = 2*S*E*t/(D + 0.2*t) - Ps

=

=

2*20,000*1*0.5092/(31.2316 +0.2*0.5092) - 0

650.04 psi (2.20)

The maximum allowable pressure (MAP) is 650.04 psi.


= (75*t / Rf)*(1 - Rf / Ro)

= (75*0.5177 / 5.5682)*(1 - 5.5682 / ∞)

= 6.9731%

The extreme fiber elongation exceeds 5 percent. Heat treatment may be required.

Results

The governing condition is internal pressure

Minimum thickness = 0.0625” + 0” = 0.0625”

Design thickness due to internal pressure = 0.5092”

Maximum allowable working pressure(MAWP) = 650.04”

Maximum allowable pressure (MAP) = 650.04 psi

15

2.9 Tube Side Nozzle (N1)

Figure 2.1 Tube Side Inlet 1

Calculations for internal pressure 650 psi @ 400 °F

Nozzle is impact test exempt to -155 °F per UCS-66(b)(3) (coincident ratio = 0.12371).

Nozzle UCS-66 governing thk: 0.625 in

Nozzle rated MDMT: -155 °F

Nozzle required thickness per UG-27(c)(1)

trn = P*Rn/(Sn*E - 0.6*P)

= 650*2.6125/(20,000*1 - 0.6*650)

= 0.0866 in (2.21)

Required thickness tr from UG-37(a)

tr = P*R/(S*E - 0.6*P)

= 650*15.5/(20,000*1 - 0.6*650)

= 0.5138 in (2.22)

Area required per UG-37(c)

Allowable stresses: Sn = 20,000, Sv = 20,000 psi fr1 = lesser of 1 or Sn/Sv = 1

16

fr2 = lesser of 1 or Sn/Sv = 1

A = d*tr*F + 2*tn*tr*F*(1 - fr1)

=

=

5.225*0.5138*1 + 2*0.7*0.5138*1*(1 - 1)

2.6844 in2 (2.23)

Area available from FIG. UG-37.1

A1 = larger of the following= 0.5812 in2

= d*(E1*t - F*tr) - 2*tn*(E1*t - F*tr)*(1 - fr1)

= 5.225*(1*0.625 - 1*0.5138) - 2*0.7*(1*0.625 - 1*0.5138)*(1 - 1)

= 0.5812 in2

= 2*(t + tn)*(E1*t - F*tr) - 2*tn*(E1*t - F*tr)*(1 - fr1)

= 2*(0.625 + 0.7)*(1*0.625 - 1*0.5138) - 2*0.7*(1*0.625 - 1*0.5138)*(1 - 1)

= 0.2948 in2 (2.24)

A2 = smaller of the following= 1.9169 in2

= 5*(tn - trn)*fr2*t

= 5*(0.7 - 0.0866)*1*0.625

= 1.9169 in2

= 5*(tn - trn)*fr2*tn

= 5*(0.7 - 0.0866)*1*0.7

= 2.1469 in2 (2.25)

17

A41 = Leg2*fr2

= 0.8752*1

= 0.7656 in2

Area = A1 + A2 + A41

= 0.5812 + 1.9169 + 0.7656

= 3.2637 in2 (2.26)

As Area >= A the reinforcement is adequate.

Allowable stresses in joints UG-45(c) and UW-15(c)

Groove weld in tension: 0.74*20,000 = 14,800 psi

Nozzle wall in shear: 0.7*20,000 = 14,000 psi

Inner fillet weld in shear: 0.49*20,000 = 9,800 psi

2.10 Shell side inlet Nozzle (N10)

Figure 2.2 Shell side Inlet N10


18






= 650*0.39/(20,000*1 - 0.6*650)

= 0.0129 in (2.27)


tr = P*Ro/(S*E + 0.4*P)

=

=

650*3.3125/(20,000*1 + 0.4*650)

0.1063 in (2.28)

This opening does not require reinforcement per UG-36(c)(3)(a)

UW-16(d) Weld Check

tmin = lesser of 0.75 or tn or t = 0.135 in

t1(min) or t2(min) = lesser of 0.25 or 0.7*tmin = 0.0945 in

t1(actual) = 0.7*Leg = 0.7*0.1875 = 0.1312 in

The weld size t1 is satisfactory.

t2(actual) = 0.106 in


t1 + t2 = 0.2372 >= 1.25*tmin

19

The combined weld sizes for t1 and t2 are satisfactory.

UG-45 Nozzle Neck Thickness Check

Wall thickness per UG-45(a): tr1 = 0.0319 in (E =1)

Wall thickness per UG-45(b)(1):tr2 = 0.1253 in

Wall thickness per UG-16(b): tr3 = 0.0815 in

Standard wall pipe per UG-45(b)(4): tr4 = 0.1179 in

The greater of tr2 or tr3: tr5 = 0.1253 in

The lesser of tr4 or tr5: tr6 = 0.1179 in

Required per UG-45 is the larger of tr1 or tr6 = 0.1179 in

Available nozzle wall thickness new, tn = 0.154 in

The nozzle neck thickness is adequate.

20


Figure 2.3 Shell side inlet N11





Limits of reinforcement per UG-40

Parallel to the vessel wall: (Rn + tn + t )= 1.225 in

Normal to the vessel wall outside: 2.5*(tn - Cn) + te = 0.3375 in (2.29)



= 650*0.39/(20,000*1 - 0.6*650)

= 0.0129 in (2.30)


tr = P*Ro/(S*E + 0.4*P)

21

=

=

650*3.3125/(20,000*1 + 0.4*650)

0.1063 in (2.31)


UW-16(d) Weld Check



t1(actual) = 0.7*Leg = 0.7*0.1875 = 0.1312 in




t1 + t2 = 0.2372 >= 1.25*tmin


2.12 Shell side outlet Nozzle (N12)

Figure 2.4 Shell side outlet N12

22







= 650*2.6125/(20,000*1 - 0.6*650)

= 0.0866 in (2.32)


tr = P*R/(S*E – 0.6*P)

= 650*15.5/(20,000*1 – 0.6*650)

= 0.5138 in (2.33)


Allowable stresses: Sn = 20,000, Sv = 20,000 psi fr1 = lesser of 1 or Sn/Sv = 1


A = d*tr*F + 2*tn*tr*F*(1 - fr1)

=

=

5.225*0.5138*1 + 2*0.7*0.5138*1*(1 - 1)

2.6844 in2 (2.34)


23



= 5.225*(1*0.625 - 1*0.5138) - 2*0.7*(1*0.625 - 1*0.5138)*(1 - 1)

= 0.5812 in2


= 2*(0.625 + 0.7)*(1*0.625 - 1*0.5138) - 2*0.7*(1*0.625 - 1*0.5138)*(1 - 1)

= 0.2948 in2 (2.35)



= 5*(0.7 - 0.0866)*1*0.625

= 1.9169 in2


= 5*(0.7 - 0.0866)*1*0.7

= 2.1469 in2 (2.36)

A41 = Leg2*fr2

= 0.8752*1

= 0.7656 in2 (2.37)

Area = A1 + A2 + A41

= 0.5812 + 1.9169 + 0.7656

24

= 3.2637 in2 (2.38)







Figure 2.5 Shell side outlet N13







= 650*0.39/(20,000*1 - 0.6*650)

= 0.0129 in (2.39)


25

tr = P*Ro/(S*E + 0.4*P)

=

=

650*3.3125/(20,000*1 + 0.4*650)


UW-16(d) Weld Check



t1(actual) = 0.7*Leg = 0.7*0.1875 = 0.1312 in




t1 + t2 = 0.2372 >= 1.25*tmin



Figure 2.6 Shell side Outlet N14

26







= 650*0.39/(20,000*1 - 0.6*650)

= 0.0129 in (2.41)


tr = P*Ro/(S*E + 0.4*P)

=

=

650*3.3125/(20,000*1 + 0.4*650)

0.1063 in (2.42)


UW-16(d) Weld Check



t1(actual) = 0.7*Leg = 0.7*0.1875 = 0.1312 in




t1 + t2 = 0.2372 >= 1.25*tmin

27


28

2.15 Tube side inlet Nozzle (N2)

Figure 2.7 Tube side inlet N2







= 650*0.39/(20,000*1 - 0.6*650)

= 0.0129 in (2.43)


tr = P*Ro/(S*E + 0.4*P)

=

=

650*3.3125/(20,000*1 + 0.4*650)

0.1063 in (2.44)


29

UW-16(d) Weld Check



t1(actual) = 0.7*Leg = 0.7*0.1875 = 0.1312 in




t1 + t2 = 0.2372 >= 1.25*tmin


2.16 Tube side inlet Nozzle (N3)

Figure 2.8 Tube side inlet N3





30



= 650*0.39/(20,000*1 - 0.6*650)

= 0.0129 in (2.45)


tr = P*Ro/(S*E + 0.4*P)

=

=

650*3.3125/(20,000*1 + 0.4*650)

0.1063 in (2.46)


UW-16(d) Weld Check



t1(actual) = 0.7*Leg = 0.7*0.1875 = 0.1312 in




t1 + t2 = 0.2372 >= 1.25*tmin


31

2.17 Tube side outlet Nozzle (N4)

Figure 2.9 Tube side outlet N4







= 650*2.6125/(20,000*1 - 0.6*650)

= 0.0866 in (2.47)


tr = P*R/(S*E - 0.6*P)

= 650*15.5/(20,000*1 - 0.6*650)

= 0.5138 in (2.48)

32


Allowable stresses: Sn = 20,000, Sv = 20,000 psi



A = d*tr*F + 2*tn*tr*F*(1 - fr1)

=

=

5.225*0.5138*1 + 2*0.7*0.5138*1*(1 - 1)

2.6844 in2 (2.49)




= 5.225*(1*0.625 - 1*0.5138) - 2*0.7*(1*0.625 - 1*0.5138)*(1 - 1)

= 0.5812 in2


= 2*(0.625 + 0.7)*(1*0.625 - 1*0.5138) - 2*0.7*(1*0.625 - 1*0.5138)*(1 - 1)

= 0.2948 in2 (2.50)



= 5*(0.7 - 0.0866)*1*0.625

= 1.9169 in2

33


= 5*(0.7 - 0.0866)*1*0.7

= 2.1469 in2 (2.51)

A41 = Leg2*fr2

= 0.8752*1

= 0.7656 in2 (2.52)

Area = A1 + A2 + A41

= 0.5812 + 1.9169 + 0.7656

= 3.2637 in2 (2.53)


UW-16(d) Weld Check



t1(actual) = 0.7*Leg = 0.7*0.875 = 0.6125 in

The weld size t1 is satisfactory. t2(actual) = 0.5625 in

The weld size t2 is satisfactory. t1 + t2 = 1.175 >= 1.25*tmin





34








Limits of reinforcement per UG-40

Parallel to the vessel wall: (Rn + tn + t )= 1.225 in

Normal to the vessel wall outside: 2.5*(tn - Cn) + te = 0.3375 in



= 650*0.39/(20,000*1 - 0.6*650)

35

= 0.0129 in (2.54)


tr = P*Ro/(S*E + 0.4*P)

=

=

650*3.3125/(20,000*1 + 0.4*650)

0.1063 in (2.55)


UW-16(d) Weld Check



t1(actual) = 0.7*Leg = 0.7*0.1875 = 0.1312 in




t1 + t2 = 0.2372 >= 1.25*tmin


36









= 650*0.39/(20,000*1 - 0.6*650)

= 0.0129 in (2.56)


tr = P*Ro/(S*E + 0.4*P)

=

=

650*3.3125/(20,000*1 + 0.4*650)

0.1063 in (2.57)

37


UW-16(d) Weld Check


t1(actual) = 0.7*Leg = 0.7*0.1875 = 0.1312 in




t1 + t2 = 0.2372 >= 1.25*tmin


38


Figure 2.12 Shell side inlet N9







= 650*2.6125/(20,000*1 - 0.6*650)

= 0.0866 in (2.58)


Tr = P*R/(S*E – 0.6*P)

= 650*15.5/(20,000*1 – 0.6*650)

= 0.5138 in (2.59)


Allowable stresses: Sn = 20,000, Sv = 20,000 psi

39



A = d*tr*F + 2*tn*tr*F*(1 - fr1)

=

=

5.225*0.5138*1 + 2*0.7*0.5138*1*(1 - 1)

2.6844 in2 (2.60)




= 5.225*(1*0.625 - 1*0.5138) - 2*0.7*(1*0.625 - 1*0.5138)*(1 - 1)

= 0.5812 in2


= 2*(0.625 + 0.7)*(1*0.625 - 1*0.5138) - 2*0.7*(1*0.625 - 1*0.5138)*(1 - 1)

= 0.2948 in2 (2.61)



= 5*(0.7 - 0.0866)*1*0.625

= 1.9169 in2


= 5*(0.7 - 0.0866)*1*0.7

40

= 2.1469 in2 (2.62)

A41 = Leg2*fr2

= 0.8752*1

= 0.7656 in2 (2.63)

Area = A1 + A2 + A41

= 0.5812 + 1.9169 + 0.7656

= 3.2637 in2 (2.64)


UW-16(d) Weld Check



t1(actual) = 0.7*Leg = 0.7*0.875 = 0.6125 in

The weld size t1 is satisfactory. t2(actual) = 0.5625 in

The weld size t2 is satisfactory. t1 + t2 = 1.175 >= 1.25*tmin


The nozzle neck thickness is adequate.

41

Figure 2.13 Detail view of shell and tube heat exchanger

Here is the detail view of shell and tube heat exchanger. This heat exchanger is designed

based on the heat exchanger designed earlier using specified pressure drop. Total number of

nozzles in this heat exchanger is 10. Numbers of Baffles used are 4.this heat exchanger designed

covers less space on floor and is more cost efficient.

42

2.21 Shell Side Flange

Figure 2.14 Shell side flange

Flange calculations for Internal Pressure + Weight Only

Gasket details from facing sketch 1(a) or (b), Column II

Gasket width N = 1.0497 in b0 = N/2 = 0.5249 in

Effective gasket seating width, b = 0.5*b01/2 = 0.3622 in

G = (OD of contact face) - 2b = 32.375 in

hG = (C - G)/2 = (35 - 32.375)/2 = 1.3125 in hD = R + g1/2 = 1 + 1/2 = 1.5 in

43

hT = (R + g1 + hG)/2 = (1 + 1 + 1.3125)/2 = 1.6563 in

Hp = 2*b*3.14*G*m*P

= 2*0.3622*3.14*32.375*1.5603*650

= 74,686.02 lbf

H = 0.785*G2*P

= 0.785*32.3752*650

= 534,813.75 lbf

HD = 0.785*B2*P

= 0.785*312*650

= 490,350.25 lbf

HT = H - HD

= 534,813.8 - 490,350.3

= 44,463.5 lbf (2.65)

Wm1 = H + Hp

= 534,813.8 + 74,686.02

= 609,499.75 lbf (2.66)

Wm2 = 3.14*b*G*y

= 3.14*0.3622*32.375*5,500

= 202,511.91 lbf (2.67)

Required bolt area, Am = greater of Am1, Am2 = 24.37999 in2

44

Am1 = Wm1/Sb = 609,499.8/25,000 = 24.38 in2

Am2 = Wm2/Sa = 202,511.9/25,000 = 8.1005 in2

Total area for 20- 1.5 in dia bolts, corroded, Ab = 28.1 in2

W = (Am + Ab)*Sa/2

= (24.38 + 28.1)*25,000/2

= 655,999.88 lbf (2.68)

MD = HD*hD = 490,350.3*1.5 = 735,525.4 lb-in

MT = HT*hT = 44,463.5*1.6563 = 73,642.7 lb-in

HG = Wm1 - H = 609,499.8 - 534,813.8 = 74,686 lbf

MG = HG*hG = 74,686*1.3125 = 98,025.4 lb-in

Mo = MD + MT + MG = 735,525.4 + 73,642.7 + 98,025.4 = 907,193.4 lb-in

Mg = W*hG = 655,999.9*1.3125 = 860,999.8 lb-in (2.69)

The bolts are adequately spaced so the TEMA RCB-11.23 load concentration factor does not

apply.

Stresses at operating conditions - VIII-1, Appendix 2-7

f = 1

L = (t*e + 1)/T + t3/d

= (3*0.1931 + 1)/1.838313 + 33/67.032

= 1.261815 (2.70)

45

SH = f*Mo/(L*g12*B)

= 1*907,193.4/(1.261815*12*31)

= 23,192 psi (2.71)

SR = (1.33*t*e + 1)*Mo/(L*t2*B)

= (1.33*3*0.1931 + 1)*907,193.4/(1.261815*32*31)

= 4,562 psi (2.72)

ST = Y*Mo/(t2*B) - Z*SR

= 10.6729*907,193.4/(32*31) - 5.5058*4,562

= 9,587 psi (2.73)

Allowable stress Sfo = 20,000 psi

Allowable stress Sno = 20,000 psi

ST does not exceed Sfo

SH does not exceed Min[ 1.5*Sfo, 2.5*Sno ] = 30,000 psi

SR does not exceed Sfo

0.5(SH + SR) = 13,877 psi does not exceed Sfo

0.5(SH + ST) = 16,390 psi does not exceed Sfo

Stresses at gasket seating - VIII-1, Appendix 2-7

SH = f*Mg/(L*g12*B)

= 1*860,999.8/(1.261815*12*31)

46

= 22,011 psi (2.74)

SR = (1.33*t*e + 1)*Mg/(L*t2*B)

= (1.33*3*0.1931 + 1)*860,999.8/(1.261815*32*31)

= 4,330 psi (2.75)

ST = Y*Mg/(t2*B) - Z*SR

= 10.6729*860,999.8/(32*31) - 5.5058*4,330

= 9,099 psi (2.76)

Allowable stress Sfa = 20,000 psi

Allowable stress Sna = 20,000 psi

ST does not exceed Sfa

SH does not exceed Min[ 1.5*Sfa, 2.5*Sna ] = 30,000 psi

SR does not exceed Sfa

0.5(SH + SR) = 13,170 psi does not exceed Sfa

0.5(SH + ST) = 15,555 psi does not exceed Sfa

Flange rigidity per VIII-1, Appendix 2-14

J = 52.14*V*Mo/(L*E*g02*KI*h0)

= 52.14*0.3008*907,193.4/(1.2618*27,900,000*0.6252*0.3*4.4017)

= 0.7836226 (2.77)

The flange rigidity index J does not exceed 1; satisfactory.

47

2.22 Shell Side Flange (front) - Flange hub

Component: Flange hub


Material impact test exemption temperature from Fig UCS-66 Curve D = -48 °F

Fig UCS-66.1 MDMT reduction = 17.8 °F, (coincident ratio = 0.8220296)

Rated MDMT is governed by UCS-66(b)(2)



Static liquid head:

Not Considered

Corrosion allowance: Inner C = 0.0000" Outer C = 0.0000"


Rated MDMT = -55.00°F Material is normalized

Material is produced to Fine Grain Practice


Radiography: Longitudinal joint - Seamless No RT

Left circumferential joint - N/A

Right circumferential joint - Full UW-11(a) Type 1



ID = 31.0000"

Length Lc = 2.0000"

t = 0.6250"


48


= 650.00*15.5000/(20000*1.00 - 0.60*650.00) + 0.0000

= 0.5138" (2.78)


P = S*E*t/(R + 0.60*t) - Ps

=

=

20000*1.00*0.6250 / (15.5000 + 0.60*0.6250) - 0.0000

787.4016 psi (2.79)


P = S*E*t/(R + 0.60*t)

= 20000*1.00*0.6250 / (15.5000 + 0.60*0.6250)

= 787.4016 psi (2.80)


= (50 * t / Rf) * (1 - Rf / Ro)

= (50 * 0.6250 / 15.8125) * (1 - 15.8125 / ∞)

= 1.9763 % (2.81)

2.23 Saddle

Saddle material:A36

Saddle construction is: Web at edge of rib

Saddle allowable stress: Ss = 24,000 psi

Saddle yield stress: Sy = 36,000 psi

49

Saddle distance to datum: 17.0625 in

Tangent to tangent length: L = 133.2 in

Saddle separation: Ls = 70.6875 in

Vessel radius: R = 16.125 in

Tangent distance left: Al = 43.45 in

Tangent distance right: Ar = 19.0625 in

Tubesheet distance left: Atsl = 15.6 in

Saddle height: Hs = 28.125 in

Saddle contact angle: θ = 120°

Wear plate thickness: tp = 0.25 in

Wear plate width: Wp = 7 in

Wear plate contact angle: θw = 132°

Web plate thickness: ts = 0.25 in

Base plate length: E = 32 in

Base plate width: F = 6 in

Base plate thickness: tb = 0.375 in

Number of stiffener ribs: n = 3

Largest stiffener rib spacing: di = 15.375 in

Stiffener rib thickness: tw = 0.25 in

Saddle width: B = 5 in

Anchor bolt size & type: 1 inch series 8 threaded

50

Anchor bolt material: SA-193 B8

Anchor bolt allowable shear: 18,800 psi

Anchor bolt corrosion allowance: 0 in

Anchor bolts per saddle:4

Base coefficient of friction: µ = 0.45

Weight on left saddle: operating corr = 5,104 lb, test new = 7,568 lb

Weight on right saddle: operating corr = 1,646 lb, test new = 2,731 lb

Weight of saddle pair = 180 lb

51

Notes:

(1) Saddle calculations are based on the method presented in "Stresses in Large Cylindrical

Pressure Vessels on

Two Saddle Supports" by L.P. Zick.

(2) If CL of tube sheet is located within a distance of Ro/2 to CL of saddle, the shell is assumed

stiffened as if tube sheet is a bulk head.

Longitudinal stress between saddles (Weight ,Operating, right saddle loading and geometry

govern)

S1 = +- 3*K1*Q*(L/12) / (π*R2*t)

= 3*0.3706*1,646*(133.2/12) / (π*15.81252*0.625)

= 41 psi

Sp = P*R/(2*t)

= 650*15.5/(2*0.625)

= 8,060 psi (2.82)

Maximum tensile stress S1t = S1 + Sp = 8,101 psi

Maximum compressive stress (shut down) S1c = S1 = 41 psi

Tensile stress is acceptable (<=1*S*E = 20,000 psi)

Compressive stress is acceptable (<=1*Sc = 15,071 psi)

Longitudinal stress at the left saddle (Weight ,Operating)

Le = 2*(Left head depth)/3 + L + 2*(Right head depth)/3

= 2*8.375/3 + 133.2 + 2*8.3171/3

= 144.3281 in (2.83)

52

w = Wt/Le = 6,750/144.3281 = 46.77 lb/in

Bending moment at the left saddle:

Mq = w*(2*H*Al/3 + Al2/2 - (R2 - H2)/4)

= 46.77*(2*8.375*43.45/3 + 43.452/2 - (16.1252 - 8.3752)/4)

= 53,272.9 lb-in (2.84)

S2 = +- Mq*K1'/ (π*R2*t)

= 53,272.9*9.3799/ (π*15.81252*0.625)

= 1,018 psi (2.85)

Sp = P*R/(2*t)

= 650*15.5/(2*0.625)

= 8,060 psi (2.86)

Maximum tensile stress S2t = S2 + Sp = 9,078 psi

Maximum compressive stress (shut down) S2c = S2 = 1,018 psi

Tensile stress is acceptable (<=1*S = 20,000 psi)

Compressive stress is acceptable (<=1*Sc = 15,071 psi)

Tangential shear stress in the shell (left saddle, Weight ,Operating)

Qshear = Q - w*(a + 2*H/3)

= 5,104 - 46.77*(43.45 + 2*8.375/3)

= 2,810.79 lbf (2.87)

53

S3 = K2.2*Qshear/(R*t)

= 1.1707*2,810.79/(15.8125*0.625)

= 333 psi (2.88)

Tangential shear stress is acceptable (<= 0.8*S = 16,000 psi)

Circumferential stress at the left saddle horns (Weight ,Operating)

S4 = -Q/(4*t*(b+1.56*Sqr(Ro*t))) - 3*K3*Q/(2*t2)

= -5,104/(4*0.625*(5+1.56*Sqr(16.125*0.625))) - 3*0.0503*5,104/(2*0.6252)

= -1,191 psi (2.89)

Circumferential stress at saddle horns is acceptable (<=1.5*Sa = 30,000 psi)

The wear plate was not considered in the calculation of S4 because the wear plate width is not at

least {B +1.56*(Rotc)0.5} =9.9524 in

Ring compression in shell over left saddle (Weight ,Operating)

S5 = K5*Q/((t + tp)*(ts + 1.56*Sqr(Ro*tc)))

= 0.7603*5,104/((0.625 + 0.25)*(0.25 + 1.56*Sqr(16.125*0.875)))

= 726 psi (2.90)

Ring compression in shell is acceptable (<= 0.5*Sy = 16,250 psi)

Saddle splitting load (left, Weight ,Operating)

Area resisting splitting force = Web area + wear plate area

Ae = Heff*ts + tp*Wp

= 5.375*0.25 + 0.25*7

= 3.0938 in2 (2.91)

54

S6 = K8*Q / Ae

= 0.2035*5,104 / 3.0938

= 336 psi (2.92)

Stress in saddle is acceptable (<= (2/3)*Ss = 16,000 psi)

Shear stress in anchor bolting, one end slotted

Maximum seismic or wind base shear = 0 lbf

Thermal expansion base shear = W*µ = 5,194 * 0.45= 2,337.3 lbf

Corroded root area for a 1 inch series 8 threaded bolt = 0.551 in2 ( 4 per saddle )

Bolt shear stress = 2,337.3/(0.551*4) = 1,060 psi

Anchor bolt stress is acceptable (<= 18,800 psi)

Web plate buckling check (Escoe pg 251)

Allowable compressive stress Sc is the lesser of 24,000 or 8,870 psi: (8,870)

Sc = Ki*π2*E/(12*(1 - 0.32)*(di/tw)2)

= 1.28*π2*29E+06/(12*(1 - 0.32)*(15.375/0.25)2)

= 8,870 psi (2.93)

Allowable compressive load on the saddle

be = di*ts/(di*ts + 2*tw*(b - 1))

= 15.375*0.25/(15.375*0.25 + 2*0.25*(5 - 1))

= 0.6578 (2.94)

Fb = n*(As + 2*be*tw)*Sc

55

= 3*(1.1875 + 2*0.6578*0.25)*8,870

= 40,351.84 lbf (2.95)

Saddle loading of 7,658 lbf is <= Fb; satisfactory.

Primary bending + axial stress in the saddle due to end loads (assumes one saddle slotted)

σb = V * (Hs - xo)* y / I + Q / A

= 0 * (28.125 - 13.3353)* 3.2917 / 14.87 + 5,104 / 10.5448

= 484 psi (2.96)

The primary bending + axial stress in the saddle <= 24,000 psi; satisfactory.

Secondary bending + axial stress in the saddle due to end loads (includes thermal

expansion, assumes one saddle slotted)

σb = V * (Hs - xo)* y / I + Q / A

= 2,337.3 * (28.125 - 13.3353)* 3.2917 / 14.87 + 5,104 / 10.5448

= 8,135 psi (2.97)

The secondary bending + axial stress in the saddle < 2*Sy= 72,000 psi; satisfactory.

Saddle base plate thickness check (Roark sixth edition, Table 26, case 7a)

where a = 15.375, b = 5.75 in

tb = (β1*q*b2/(1.5*Sa))0.5

= (2.2393*40*5.752/(1.5*24,000))0.5

= 0.2864 in (2.98)

The base plate thickness of 0.375 in is adequate.

Foundation bearing check

56

Sf = Qmax / (F*E)

= 7,658 / (6*32)

= 40 psi (2.99)

Concrete bearing stress < 750 psi ; satisfactory.

57

2.24 Pass Partition Plate

Minimum Front Pass Partition Plate Thickness

Front tube side pressure drop: q = 1 psi

Front pass plate material: SA-516 70 (II-D p. 18, ln. 22)

Front pass plate allowable stress: S = 20,000 psi

Front pass plate dimension: a = 30.9375 in

Front pass plate dimension: b = 33.75 in

Front pass plate thickness, new: T = 0.5625 in

Front pass plate corrosion allowance: C = 0.0625 in

Front pass plate fillet weld leg size, new 0.25 in

From TABLE RCB-9.131 t = 0.5

From TABLE RCB-9.132, three sides fixed, a/b = 0.9167, B = 0.2624

t = b*(q*B/(1.5*S))1/2 + C

= 33.75*(1*0.2624/(1.5*20,000.00))1/2 + 0.0625

= 0.1623 in (2.100)

The pass partition plate thickness of 0.5625 in is adequate.

Pass partition minimum weld size = 0.75*t + C/0.7= 0.1641 in

The pass partition fillet weld size of 0.25 in is adequate.

58

2.25 Tubes

Component: Tubes

Material specification: SA-179 Smls tube (II-D p. 6, ln. 11)

Material is impact test exempt per UCS-66(d) (NPS 4 or smaller pipe)


External design pressure: Pe = 650 psi @ 400°F

Static liquid head:


Corrosion allowance: Inner C = 0.0000" Outer C = 0.0000"


Rated MDMT = -155.00°F Material is not normalized




Capacity: New = 0.1193 gal corr = 0.1193 gal OD = 0.7500"

Length Lc = 80.0000" t = 0.0850"

Design thickness, (at 400.00°F) Appendix 1-1

t = P*Ro/(S*E + 0.40*P) + Corrosion

=

=

650.00*0.3750/(13400*1.00 + 0.40*650.00) + 0.0000

0.0179" (2.101)

59

Maximum allowable working pressure, (at 400.00°F) Appendix 1-1

P = S*E*t/(Ro - 0.40*t) - Ps

=

=

13400*1.00*0.0744 / (0.3750 - 0.40*0.0744) - 0.0000

2886.6765 psi (2.102)

Maximum allowable pressure, (at 70.00°F) Appendix 1-1

P = S*E*t/(Ro - 0.40*t)

=

=

13400*1.00*0.0744 / (0.3750 - 0.40*0.0744)

2886.6765 psi (2.103)

External Pressure, (Corroded & at 400.00°F) UG-28(c)

L/Do = 80.0000/0.7500 = 50.0000

Do/t = 0.7500/0.033147 = 22.6263

From table G: A = 0.002230

From table CS-1: B = 11030.3105 psi

Pa = 4*B/(3*(Do/t))

= 4*11030.3105/(3*(0.7500/0.033147))

= 650.0004 psi

Design thickness for external pressure Pa = 650.0004 psi

= t + Corrosion = 0.033147 + 0.0000 = 0.0331"

Maximum Allowable External Pressure, (Corroded & at 400.00°F) UG-28(c)

L/Do = 80.0000/0.7500 = 50.0000

Do/t = 0.7500/0.0744 = 10.0840 (2.104)

From table G: A = 0.010996

60

From table CS-1: B = 12939.5146

psi

Pa = 4*B/(3*(Do/t))

= 4*12939.5146/(3*(0.7500/0.0744))

= 1710.8915 psi (2.105)

Figure 2.15 Closed view of shell and tube heat exchanger

61

Chapter 3

STRESS ANALYSIS

Stress analysis is a part of engineering that decides the stress in the given part when it is

subjected to a particular type of load. That means it tells us whether that particular part can

withstand that particular or different types of load or not. Stress analysis is required for different

types of materials like those involved in heat exchangers, tunnels etc. it is a very important factor

considering the design of the various mechanical parts.

The main purpose of the stress analysis is to determine the strength of the material or a

collection of materials that in turn are used in different bodies like heat exchangers automobiles

etc . The material’s maximum tensile strength, fatigue and other factors are noted down and then

the given force is applied to check whether the tensile strength, fatigue are less than that of the

material.

There is one more important factor considered and that one is factor of safety. It defines

the capacity of the system beyond the actual given load that is how much the system is stronger

than it usually is for a given particular load. In that case factor of safety comes into place.

Numerically it is defined as

Factor of safety = Material strength Design Load

Factor of safety is different for different mechanical components. For example in case of

heat exchangers it is taken as 3.5 – 4. Now here we are doing the FEA analysis on different parts

of the heat exchanger separately. First we are performing on the test on nozzle.

62

3.1 Description of FEA on nozzle

Nozzle Finite element analysis (FEA) is done to calculate the stresses and flexibility of

the meshing of the nozzle and shell. This also calculates the given number of loads on the nozzle

and estimates its functioning over wide range of operating conditions. This also is done to

increase the safety of the equipment. Below are the steps which we do while doing the stress

analysis:-

Step 1

Table 3.3 Study properties of nozzle

Study name Study 1

Analysis type Static

Mesh Type: Solid Mesh

Solver type FFE Plus

Inplane Effect: Off

Soft Spring: Off

Inertial Relief: Off

Thermal Effect: Input Temperature

Zero strain temperature 298.000000

Units Kelvin

This step includes the general properties of the material chosen. These are the steps that are

performed while doing the finite element analysis of any part. Each value has to be filled out

according to its characteristics.

Step 2

63

Table 3.4 Units

Unit system: SI

Length/Displacement mm

Temperature Kelvin

Angular velocity rad/s

Stress/Pressure N/m^2

This table tells us the system of units used. The system used here is SI system and the units are

chosen accordingly.

Step 3

Table 3.5 Material properties

No. Body Name Material Mass Volume

1 Solid Body 1(CirPattern1)

SA516 Steel 26.937 kg 0.00343146 m^3

2 SolidBody 1(Cut-Extrude2)

SA516 Steel 193.166 kg 0.0246071 m^3

The material chosen here is SA 516 steel. This is chosen because it is the most cost

effective and it withstands the given loads without any failure.

Step 4Table 3.6 Structural Properties

Property Name Value Units Value Type

Elastic modulus 2e+011 N/m^2 Constant

Poisson's ratio 0.26 NA Constant

Shear modulus 7.93e+010 N/m^2 Constant

Mass density 7850 kg/m^3 Constant

64

Tensile strength 4e+008 N/m^2 Constant

Yield strength 2.5e+008 N/m^2 Constant

This table tells here the general properties of the SA 516 steel like what is its yield

strength, Poisson’s ratio etc.

Step 5

Table 3.7 Load on nozzle

Load name Selection set Loading type Description

Force-1 <Shell1-1, Nozzle-1>

on 2 Face(s) apply normal force 4.48 N using uniform distribution

Sequential Loading Load acting tangentially

The loading on the nozzle is sequential loading that is it is acting uniformly from all sides

as can be seen in the figure 3.16.

Step 6Table 3.8 Mesh information


Mesher Used: Standard mesh

Automatic Transition: Off

Smooth Surface: On

Jacobian Check: 4 Points

Element Size: 37.615 mm

Tolerance: 1.8807 mm

Quality: High

65

Number of elements: 9720

Number of nodes: 19469

Time to complete mesh(hh;mm;ss): 00:00:06

Computer name: MT6

This table clearly tells the type of mesh and number of nodes in nozzle while performing

the test. The time effectiveness can also be seen from the fact that after all the values were put in,

it took only 6 sec to complete the analysis. Thus this test clearly reduces the time from design to

production.

Figure 3.16 Stress in nozzle during FEA

As we can see in the figure there is no red region in any part of the nozzle. So nozzle can

withstand the given load .

66

Figure 3.17 Displacement in nozzle during FEA

There is small red portion in the bottom as can be seen in the figure. But when we see the

corresponding values on the right hand side, we find that they are vey less. It is approximately

equal to 0.0000139mm which is very less and can be neglected.

67

3.2 Description of FEA on saddle

Stress analysis on the saddle is done to predict the stress distributions in the heat

exchanger. FEA is used where number of saddles is two or more. The saddle should be designed

to meet two loading conditions:-

Primary load failures

Secondary/fatigue failures

The first one includes the excessive distortion due to pressure more than the given

pressure. This is an important factor and should be kept in mind while designing the saddle.

The second one includes the crack that can occur in the saddle due to excessive pressure

or due to ageing of the material.

Below are the steps which we do while doing the stress analysis:-

Step 1

Table 3.9 Study properties

Study name Study 1

Analysis type Static


Solver type FFE Plus

Inplane Effect: Off

Soft Spring: Off

Inertial Relief: Off

68

Thermal Effect: Input Temperature

Zero strain temperature 298.000000

Units Kelvin

This step includes the general properties of the material chosen. These are the steps that are

performed while doing the finite element analysis of any part. Each value has to be filled out

according to its characteristics.

Step 2

Table 3.10 Units

Unit system: SI

Length/Displacement mm

Temperature Kelvin

Angular velocity rad/s

Stress/Pressure N/m^2

This table tells us the system of units used. The system used here is SI system and the units are

chosen accordingly.

Step 3

Table 3.11 Material Properties

No. Body Name Material Mass Volume

1 SolidBody 1(Boss-Extrude4)

SA 516Steel 39.2619 kg 0.00500151 m^3

69

The material chosen here is SA 516 steel. This is chosen because it is the most cost

effective and it withstands the given loads without any failure.

Step 4

Table 3.12 Structural Properties

Property Name Value Units Value Type

Elastic modulus 2e+011 N/m^2 Constant

Poisson's ratio 0.26 NA Constant

Shear modulus 7.93e+010 N/m^2 Constant

Mass density 7850 kg/m^3 Constant

Tensile strength 4e+008 N/m^2 Constant

Yield strength 2.5e+008 N/m^2 Constant

This table tells here the general properties of the SA 516 steel like what is its yield

strength, Poisson’s ratio etc.

Step 5

Table 3.13 Load

Load name Selection set Loading type Description

Force-1 <Bracket> on 1 Face(s) apply normal force 23314 N using uniform distribution

Sequential Loading

70

The loading on the saddle is sequential loading that is it is acting uniformly from all sides

as can be seen in the figure 3.16.

Step 6

Table 3.14 Mesh Properties


Mesher Used: Standard mesh

Automatic Transition: Off

Smooth Surface: On

Jacobian Check: 4 Points

Element Size: 0.94752 in

Tolerance: 0.047376 in

Quality: High

Number of elements: 7875

Number of nodes: 16077

Time to complete mesh(hh;mm;ss): 00:00:04

Computer name: MT6

This table clearly tells the type of mesh and number of nodes in saddle while performing

the test. The time effectiveness can also be seen from the fact that after all the values were put in,

it took only 4 sec to complete the analysis. Thus this test clearly reduces the time from design to

production.

71

Figure 3.18 Stress on Saddle during FEA

The stresses during performing the FEA can be seen in the picture. It is clearly

seen that is very few red zone that is very few danger zones and that can be neglected.

Figure 3.19 Displacement in Saddle during FEA

72

The displacement analysis is done and it is clearly seen in the picture that there

are very few red zones in the saddle. When we check the values corresponding to the red

zones, they are found to be very less and can be neglected.

73

Chapter 4

RESULTS

All the results that came above after doing the hydrostatic test proves that this heat

exchanger will work very well in the given conditions. Hydrostatic test is a must for long

functioning of the heat exchanger. This test is performed on different parts separately and based

on that test full result summary is given below in the tables:-

4.1 Pressure summary for tube and shell

Table 4.1 Pressure Summary for tube side

IdentifierP

Design

( psi)

T Design(°F)

MAWP ( psi)

MAP ( psi)

MAEP ( psi)

Teexternal(°F)

MDMT (°F)

MDMT Exemption

Total Corrosio

n

Allowance

ImpactTest

Front Head 650.0 400.0 803.2 803.2 0.00 400.0 -20 Note 1 0.000 No

Straight Flange 650.0 400.0 787.4 787.4 N/A 400.0 -20 Note 2 0.000 No

Front Channel 650.0 400.0 787.4 787.4 N/A 400.0 -20 Note 2 0.000 No

Front Tubesheet 650.0 400.0 796.0 928.3 680.7 400.0 -20 Note 3 0.125 No

Tubes 650.0 400.0 2886. 2886. 1710. 400.0 -155 Note 4 0.000 No

TS Inlet (N1) 650.0 400.0 650.0 650.0 N/A 400.0 -54 Note 5 0.019 No

TS Inlet Aux1 650.0 400.0 650.0 650.0 N/A 400.0 -155 Note 6 0.019 No

TS Inlet Aux2 650.0 400.0 650.0 650.0 N/A 400.0 -155 Note 6 0.019 No

TS Outlet (N4) 650.0 400.0 650.0 650.0 N/A 400.0 -54 Note 5 0.019 No

TS Outlet Aux1 650.0 400.0 650.0 650.0 N/A 400.0 -155 Note 6 0.019 No

TS Outlet Aux2 (N6)

650.0 400.0 650.00

650.00

N/A 400.0 -155 Note 6 0.019 No

The MAWP for different parts of the heat exchanger are calculated and are as shown in

the table. It is now multiplies by 1.3 to perform the hydrostatic test.

74

Table 4.2 Pressure Summary for Shell Side

IdentifierP

Design( psi)

T Desig

n(°F)

MAWP ( psi)

MAP ( psi)

MAEP ( psi)

Teextern

al(°F

MDMT (°F)

MDMT Exemption

Total Corrosi

on

All

ImpactTest

Front 650.0 400.0 680.79 991.73 796.01 400.0 -20.0 Note 3 0.125 No

Shell 650.0 400.0 787.40 787.40 N/A 400.0 -20.0 Note 2 0.000 No

Straight 650.0 400.0 650.11 650.11 N/A 400.0 -20.0 Note 8 0.000 No

Rear Head 650.0 400.0 650.04 650.04 0.00 400.0 -20.0 Note 7 0.000 No

Tubes 650.0 400.0 1710.8 1710.8 2886.6 400.0 N/A N/A 0.000 No

Shell Side 650.0 400.0 749.18 749.18 0.00 400.0 -55.0 Note 9 0.000 No

Shell Side 650.0 400.0 787.40 787.40 N/A 400.0 -55.0 Note 10 0.000 No

Saddle 650.0 400.0 650.00 N/A N/A N/A N/A N/A N/A N/A

SS Inlet 650.0 400.0 650.00 650.00 N/A 400.0 -155 Note 6 0.019 No

SS Inlet 650.0 400.0 650.00 650.00 N/A 400.0 -155 Note 6 0.019 No

SS Outlet 650.0 400.0 650.00 650.00 N/A 400.0 -54.0 Note 5 0.019 No

SS Outlet 650.0 400.0 650.00 650.00 N/A 400.0 -155 Note 6 0.019 No

SS Outlet 650.0 400.0 650.00 650.00 N/A 400.0 -155 Note 6 0.019 No

SS Inlet 650.0 400.0 650.00 650.00 N/A 400.0 -54.0 Note 5 0.019 No

The MAWP for different parts of the heat exchanger are calculated on the shell side and

are as shown in the table. It is now multiplies by 1.3 to perform the hydrostatic test. After

performing the test it was found that there is no leakage in the system.

4.2 Thickness on different parts of heat exchanger

Table 4.3 Thickness Summary

ComponentIdentifier

Material Diameter(in)

Length(in)

Nominal t(in)

Design t(in)

JointE

Load

Front Head SA-516 70 31.00 ID 8.38 0.6250 0.5054 1.000 Internal

Straight Flange on Front Head SA-516 70 31.00 ID 2.00 0.6250 0.5138 1.000 Internal

Front Channel SA-516 70 31.00 ID 24.00 0.6250 0.5138 1.000 Internal

Front Tubesheet SA-516 70 37.25 OD

3.70 3.7000 3.6176 1.000 Unknown

Tubes SA-179 Smls tube

0.7500 OD

80.00 0.0850 0.0331 1.000 External

75

Shell SA-516 70 31.00 ID 96.00 0.6250 0.5138 1.000 Internal

Straight Flange on Rear Head SA-516 70 31.23 ID 2.00 0.5177 0.5177 1.000 Internal

Rear Head SA-516 70 31.23 ID 8.32 0.5092 0.5092 1.00 Internal

Here is the summary of thickness of different parts of the heat exchanger. The material used here

is SA 51670. Each dimension like length, breadth etc are calculated on every part.

4.3 Weight of heat exchanger

Table 4.4 Weight Summary of vessel

ComponentWeight ( lb) Contributed by Vessel Elements

MetalNew*

MetalCorroded*

Insulation & Supports

Lining Piping+ Liquid

OperatingLiquid

TestLiquid

Front Head 240.97 240.97 0.00 0.00 0.00 0.00 195.26Front Channe l 409.56 409.56 0.00 0.00 0.00 0.00 656.52Front Tubesheet 911.67 880.87 0.00 0.00 0.00 0.00 0.00Shell 1,674.82 1,674.82 0.00 0.00 0.00 0.00 1,971.90Tubes 2,601.00 2,601.00 0.00 0.00 0.00 0.00 493.61Rear Head 197.83 197.83 0.00 0.00 0.00 0.00 199.25Saddle 180.00 180.00 0.00 0.00 0.00 0.00 0.00TOTAL: 6,215.84 6,185.04 0.00 0.00 0.00 0.00 3,516.53

This table tells us the total weight of the heat exchanger. When we add all the values it

comes out to be 6962 lb .

Table 4.5 Weight Summary of attachments

ComponentWeight ( lb) Contributed by Attachments

Body Flanges Nozzles & Flanges

PackedBeds

Trays & Supports

Rings &

VerticalLoads

76

ClipsNew Corroded New Corroded

Front Head 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00Front Channe l 0.00 0.00 134.94 134.37 0.00 0.00 0.00 0.00Front 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00Shell 339.24 339.24 134.94 134.37 0.00 137.40¹ 0.00 0.00Rear Head 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00TOTAL: 339.24 339.24 269.88 268.75 0.00 137.40 0.00 0.00

Vessel operating weight, Corroded: 6,930 lb

Vessel operating weight, New: 6,962 lb

Vessel empty weight, Corroded: 6,930 lb

Vessel empty weight, New: 6,962 lb

Vessel test weight, New: 10,479 lb

Vessel center of gravity location - from datum - lift condition

Vessel Lift Weight, New: 6,961 lb

Center of Gravity: 67.77"

4.4 Baffle

Table 4.6 Baffle Summary

Baffle

Name

Distance from

Front Tubesheet (in) Cut Direction

Cut Distance from

Center (in) Baffle Weight

(lb)

Baffle

#1

17.500 Downwards 6.200 34.349

Baffle

#2

35.000 Upwards 6.200 34.349

77

Baffle

#4

52.500 Downwards 6.200 34.349

Baffle

#3

70.000 Upwards 6.200 34.349

For better efficiency the baffles should be cut accordingly as shown in the table. The

distance of the baffles from the tubesheet is specified accordingly with their direction of cut.

4.5 Study results of nozzle

Table 4.7 Summary of FEA on nozzle

Name Type Min Location Max Location

Stress1 VON: von Mises Stress

2.12762 N/m2

Node: 8470

(-827.723 mm,

342.867 mm,

208.502 mm)

847.1 N/m2

Node: 19227

(-566.039 mm,-0.00328805 mm,-401.287

Displacement1

URES: Resultant Displacement

6.84308e-012 mm

Node: 5042

(-566.039 mm,

-6.85283e-012 mm,

401.287 mm)

1.34909e-005 mm

Node: 15863

(-326.784 mm,

-3.582e-005 mm,

-409.224 mm)

As the diagram clearly indicates that the min stress is 2.12762 N/m2 and the maximum

stress is 847.1 N/m2 and the colour in the diagram is blue which clearly shows that nozzle will

work perfectly in the given working conditions when max stress is applied.

78

4.6 Study results of saddle

Table 4.8 Summary of FEA on Saddle

Name Type Min Location Max Location

Stress1 VON: von Mises Stress

165.412 N/m2

Node: 7112

(-5.64706 in,

0 in,

-2.5 in)

3.15364e+007 N/m2

Node: 15894

(0.473022 in,

11.7122 in,

-3.5639 in)

Displacement1 URES: Resultant Displacement

0 mm

Node: 1362

(-16 in,

0 in,

-3 in)

0.255345 mm

Node: 280

(8.70051 in,

13.8879 in,

-3.56437 in)

The maximum stress in case of saddle is 3.15364 N/m2 and the minimum stress is

165.412 N/m2 and it works perfectly fine under the given load conditions.

79

Chapter 5

CONCLUSION AND FUTURE SCOPE OF WORK

5.1 Conclusion

Both Hydrostatic test and Stress analysis proves that the new shell and tube heat

exchanger which is designed using specified pressure drops can be used in the industry. The

calculations done in the hydrostatic test is based on the ASME SEC VIII DIV-1 2007 ED. The

overall cost of this heat exchanger would be approximately $ 19000. There was no specific

leakage found during the hydrostatic test performed separately on different parts. The hydrostatic

test performed should never exceed 1.3 times the MAWP. During the FEA there is a slight

displacement both in nozzle and saddle which looks alarming but actually the red zone

corresponds to a very low value which can be neglected.

5.2 Future scope of work

The hydrostatic test performed here is only limited to coolant being hot water and fluid to

be cooled is steam. New set of calculations has to be performed when using different fluids.

Other tests have to be performed before the installation of heat exchanger where leakage is not an

issue as this test is performed where leakage is a major issue. There was a fiber elongation which

exceeds 5 percent, so heat treatment might be needed. In addition to the FEA performed field test

should be done before the installation of heat exchanger.

REFERENCES

80

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82

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