Lecture 8_MDPE_Design of Nozzles & Flange.pdf

Lecture 8_MDPE_Design of Nozzles & Flange.pdf
Introduction :
Concept of internal & external design pressure, design stress & design temperature,
Different types of equipments, Static & rotary equipments, Different types of static
equipments, Various mechanical properties of material, Different methods of
fabrication, Different types of welding joints, Joint efficiency, Radiography.
04
2 Mechanical design of Pressure vessel:
Introduction of ASME Code sec-VIII, DIV-I & IS-2825, Classification of pressure vessel as
per IS-2825,Mechanical design of Shell: shell subjected to internal pressure, Graphical
& analytical method for Shell subjected to external pressure, design of shell for
external pressure with & without stiffening ring, Different types of head, their selection
criteria, Mechanical design of heads: Heads subjected to internal pressure, Graphical
& analytical method for heads subjected to external pressure, Different types of
Nozzles, their selection criteria, Design of nozzle pipe, Design of reinforcement pad by
area for area method, Different types of flanges, Different types of standard flanges,
their important features & selection criteria, Different

1. Mechanical Design of Process Equipment
(3170514)
JileshM. Pandya
Assistant Professor,
Chemical Engineering Department,
V. V. P. Engineering College, Rajkot.

2. 1Introduction:
Conceptofinternal&externaldesignpressure,designstress&designtemperature,
Differenttypesofequipments,Static&rotaryequipments,Differenttypesofstatic
equipments,Variousmechanicalpropertiesofmaterial,Differentmethodsof
fabrication,Differenttypesofweldingjoints,Jointefficiency,Radiography.
04
2MechanicaldesignofPressurevessel:
IntroductionofASMECodesec-VIII,DIV-I&IS-2825,Classificationofpressurevesselas
perIS-2825,MechanicaldesignofShell:shellsubjectedtointernalpressure,Graphical
&analyticalmethodforShellsubjectedtoexternalpressure,designofshellfor
externalpressurewith&withoutstiffeningring,Differenttypesofhead,theirselection
criteria,Mechanicaldesignofheads: Headssubjectedtointernalpressure,Graphical
&analyticalmethodforheadssubjectedtoexternalpressure,Differenttypesof
Nozzles,theirselectioncriteria,Designofnozzlepipe,Designofreinforcementpadby
areaforareamethod,Differenttypesof flanges,Differenttypesofstandardflanges,
theirimportantfeatures&selectioncriteria,Differenttypesofflangefacings&their
selectioncriteria,Differenttypesofgaskets,theirselectioncriteria,Designofring
flange.
20
:: Content ::

3. 3MechanicaldesignofReactionVessel:
Mechanicaldesignofshell,head,Jacket,coil,agitator,nozzle,bodyflange,etc.,Differenttypesof
agitators&theirselectioncriteria,Differenttypesofagitatorshaftsealingsystem&theirselectioncriteria,
Differenttypesofpowertransmissionsystem,Determinationofpowerrequiredforagitation,shaftdiameter,
bladethickness,etc.,Differenttypesofjackets&theirselectioncriteria,Selectionbetweencoil&jacket.
06
4MechanicaldesignofStorageTank:
ClassificationofstoragetankasperIS-803,Capacityofstoragetank,itsdiameter&height,Designofshell
andbottomplateforstoragetank,DesignofSelfsupportedconicalroof,Designofstructuredsupported
conicalroofasperAPI620,Selectionofcolumn,girdersandrafters,Roofcurbangel,Floatingroof.
05
5MechanicaldesignofShell&TubeHeatExchangers:
MechanicaldesignofShell,tube,tubesheet,head,channelshell,,etc.ofshell&tubeheatexchanger.
05
6MechanicaldesignofVerticaltalltower(DistillationColumn):
Mechanicaldesignofshell,head,traysupport,nozzle,bodyflange,forVerticaltalltower,Determinationof
shellthicknessesatvariousheightsfortraytower&packedtowerincaseofinternal&externalpressure,
Differenttypesoftraysupports&theirselectioncriteria,designofhorizontalstructuralmemberwith
peripheryringtypepackingsupport.
08
7Supports:
Differenttypesofsupports,Mechanicaldesignofbracketsupport,skirt,support&saddlesupport.
06

4. Chapter: 2 Designing of Pressure Vessel
Nozzles
oropeningsareprovidedin
pressurevesseltofacilitateinput&outputof
materialtomeasuretemperature,pressureor
levelandtofacilitatecleaningasman-hole,
hand-holeordrain.
Nozzlemaybelocatedon shell,headoron
jacket.
Duringinstallationofnozzleonshell,heador
jacket;itcreatesstressconcentrationinthe
vicinityofhole.
Inorderto minimizethesestresses,itis
preferredtouseopeningwitheither circular,
ellipticalorobroundshape.
Beforeconnectingnozzletovesselwall, holes
areprovided(made)tovessel;whichcreates
adiscontinuityinthevesselwall.

5. Duetopressure,stressconcentration
inducedinthevicinityofthevesselwall.
Incaseofcircularhole,theshellissubjected
toeitherinternalorexternalpressure.
Thestressdevelopedatholeisabout 2.5
timescircumferentialstressdevelopedinthe
shell.
Thisstressaroundtheholecanbereduced
byincreasingthethicknessofvesselinthis
area.
Thethicknessanbeincreasedby attaching
aPAD/DISCaroundthebore/holewith
thehelpofcontinuouswelding.
ThisPAD/DISCistermedas REINFORCEMENT
PAD/REINFORCEMENTDISC.
Dimensionofreinforcementpad/disccan
befoundoutby AREAFORAREAMETHOD .
Nozzle
Reinforcement
Pad

6. Areaforwhichcompensationisrequiredcanbecalculatedasunder:
'
*
SitDA
D
i
=I.D.ofNozzle
t
s
'=calculated/giventhicknessofshell,headorjacket
Ifthereinforcementisprovidedintheboundary“ ABCD”,thenmaximum
reinforcementisgivenwithminimummaterial.
ii
DrAB 2*4
StH 5.2
1
Horizontallimitforreinforcement
H
1
=verticallimitforreinforcement
t
s
'=actualthicknessofshell
(ifcompensationisprovided)
ntH 5.2
1
H
1
=verticallimitforreinforcement
t
s
'=actualthicknessofshell
(ifcompensationisprovidedby
combinationofReinforcementpad&nozzle)
Areaavailableforcompensationis,
iOS
AAAA 

7. A
S
=Compensationprovidedbyadditional
thicknessofShell
Vertical limit of Reinforcement Pad
 
CttdA
SSiS 
'
*
A
o
=Compensationprovidedbyadditional
thicknessofnozzleexternaltovessel
 
CttHA
nnO

'
1
*
A
i
=Compensationprovidedbyadditional
thicknessofnozzleexternaltovessel
 
CtHA
ni
2*2
1

t
S
&t
n
aretheactualthicknessofshell,headornozzle
t
S
’&t
n
’arethecalculatedminimumthicknessofshell,
headornozzle
Thus,additionalcompensationarea
requiredis,
 
iOSC
AAAAA 
 
tdDA
OC *
D=OutsidediameterofReinforcementPad
d
O
=OutsidediameterofNozzlepipe
t=thicknessofnozzle

8. TypesofNozzle
IntegratedNozzle:ItisanintegralpartofShell,Heador
Jacket.
Itismadebycutting&shapingofmetaltoobtainthe
desiredcontourofnozzle.
Ductilematerialispreferredforthistype.
FabricatedNozzle:Thesearetheshortpiecesof
standard/fabricatedpipe.
Pieceofpipeisattachedtothevesselwallbywelding.
Ringflangeisattachedtotheotherendofthepipeby
welding.
Itisusedforthelowandmediumpressureservice.
FormedNozzle: Usually,weldedneckflange isan
internalpartofnozzle.
Theyareformedby forgingorrolling.
Thesenozzlesareavailableindifferentsizes.

9. PROBLEM: 11
Anozzlehavinganinsidediameter 400mmisfabricated
fromSA–516Gr70Plate.Itisattachedby weldingtothe
vesselshellthathasaninsidediameter 1500mm.Internal
designpressureofshellis10kgf/cm
2
.Designtemperatureis
300C.VesselShellisalsofabricatedfromSA516Gr70
Plate.Checkwhetherthisnozzlerequiresreinforcementpad
ornot.Ifrequirethendetermineitsdimensions.Maximum
allowablestressofmaterialatdesigntemperatureis 612.4
kgf/cm
2
.Takeweldjointefficiencyfactoras 0.85forboth
shell&nozzle.Corrosionallowanceis1.5mmanddensityof
materialis7830kg/m
3
.

10. SOLUTION PROBLEM: 11

11. SOLUTION PROBLEM: 11

12. SOLUTION PROBLEM: 11

13. SOLUTION PROBLEM: 11

14. SOLUTION PROBLEM: 11

15. PROBLEM: 12
Examinethe datagivenbelowto evaluatetherequirementof
reinforcementpadforthenozzleopeninginthecylindricalshell.
O.D.OfShell=2m
Maximumworkingpressurewithintheshell=3.5MN/m
2
ThicknessofShell=0.05m
CorrosionAllowance=3mm
Jointefficiencyforshell&nozzle=1
MOCforshell,nozzle&reinforcementpad=IS2002
Allowablestressofmaterial=96MN/m
2
Densityofmaterial=7800kg/m
3
O.D.OfNozzle=0.25m
Nozzlewallthickness=0.016m
Lengthofnozzle=100mm

16. SOLUTION PROBLEM: 12

17. SOLUTION PROBLEM: 12

18. SOLUTION PROBLEM: 12

19. SOLUTION PROBLEM: 12

20. SOLUTION PROBLEM: 12

21. SOLUTION PROBLEM: 12

22. FlangeDesign
Non–standardflangerequiresproperdesign.
Inactualpractice,the useofstandardpipeandflangeareusually
fabricatedfrom12”standardpiperatherthan24”.
Ringtypeflangeiswidelyusedasa STANDARDFLANGE .
ForGasket,thedimensioncanbecalculatedby:
Selectpropergasketfromthestandardgasketchart.
Selectthickness&gasketfactor(m)ofgasket.
Decidethevalueof insidediameterofgasket (“d
i
”)basedoninside
diameterandthicknessofshell(pipe).
Calculateoutsidediameterofgasket(d
O
).
Becauseofdifferenttypesofflangefacings&gasket; totalwidthofgasketis
notfullyutilized.
Also,boltloadisappliedon oneside,createsdeflectioninflange;hence
totalwidthofgasketdoesnotbarethetotalload,butsome effectivepartis
bearingtheload.

1.
.



mPY
mPY
d
d
i
O

23. Now,b
O
=basicgasketseatingwidthfordifferenttypesofflange
facing&gasketand b=effectivegasketseatingwidth.
Ifb
O
¼inch,thenb=b
O
&ifb
O
¼inch,thenb=(b
O
)
0.5
/2.
“G”becomesthe meandiameter ofgasketcontactfaceforthe
caseb
O
¼inch.
Ifb
O
¼inch,thenG=[O.D.ofgasket]–(2*b) .
Foradesigningofflange;itisdividedintotwoclasses.
1.Looseflange…
2.Internalflange…
Foradesigningof looseflange,variousaxialforcesonaflange
createsbendingmoment.
Totalbendingmoment createdattheoperatingconditionisgiven
by;
GTDO
MMMM 

24. GTDO MMMM 
Bending moment created by force “h
D
”
Bending moment created by force “h
T
”
Bending moment created by force “h
G
”







2
BC
h
D
DT hHh 
2
2








GB
C
h
T
4
2 GBC
h
T


HWh
G








2
GC
h
G
Where, C = Bolt Circle Diameter, B = Inside Diameter of Flange, G = Mean Diameter of Gasket, b
O
¼ inch

25. Minimumflangethickness(t)foralooseflangeisgivenbytheequation:
..
**
max
AC
f
CMY
t
B
F

Where,M
max
=MaximumbendingmomentgreaterthanM
O
.
M
O
=Totalbendingmomentactingonflangeatoperatingcondition.
M
a
=Bendingmomentactingonflangeatboltinguporatatmosphericcondition.
f
fo
=Maximumallowabledesignstressofflangematerialatoperatingcondition.
f
fa
=Maximumallowabledesignstressofflangematerialatoperatingcondition.
C
f
=BoltpitchCorrectionFactor







fa
fo
a
f
f
MM
max







2
GC
WM
a


















1
log
7169.566845.0
1
1
2
10
2
K
KK
K
Y
2
1
2








td
B
C
S
F
B
A
O. D. of Flange
I. D. of Flange

26. Chemical Engineering Department,
V. V. P. Engineering College, Rajkot