Pressure vessel

Pressure vessel

1. Pressure vessel

2. PVaredesignedtooperatesafelyat:
Specificpressure
Specifictemperature
FailureofPV:EXAMPLE
Design Pressure
Design Temperature

3. Example
•Reactors,
•Separationcolumns,
•Flashdrums,
•Heatexchangers,
•Surgetanks,and
•Storagevessels.
PVConsistof:
Shell:Cylindrical
Head:EllipticalorHemisphericalattheends(Peters)

4. Basic data required by PV Design Engineer
Functionof PV
Materials Processed (Liquid, Gas)
Operatingtemperature and pressure
Materials of PV
Dimensionsand orientation of PV
Vessel headsTypes
Openingsand connections required
Specificationof internal fittings

5. Firedpressurevessels
ItisaPVwhichiscompletelyorpartiallyexposedto
fire(Burnersorcombustiongases)
Boiler:Generatingsteam
Thermaloilheater
Un-firedpressurevessels
AsperI.S.2825categories
Anypressurevesselwhichisnotexposedtofired.
Pressurizedtanksstoring:Air,NitrogenAmmoniaor
NaturalGas

6. USES
•Industrial compressed airreceivers
•Domestic hot water storage tanks
•Diving cylinders
•Distillation towers
•Pressure reactors
•Autoclaves
Vessels in:
•Mining operations
•Oil refineries
•Petrochemical plants
•Nuclear reactor vessels
•Submarine
•Space ship
Reservoirs
•Pneumatic reservoirs
•Hydraulic reservoirs under pressure
•Rail vehicle airbrake reservoirs
•Road vehicle airbrake reservoirs
Storage vesselsfor
liquefied gases
•Ammonia,
•Chlorine,
•Propane,
•Butane and
•LPG

7. Unfired pressure vessels
•Closedmetalcontainer,intendedforthestorage
andtransportofanycompressedgaswhichis
subjectedtointernalpressure>Patm
•Capacityof1000Litreandabove

8. IS 2825-1969
PVaredesignedaccordingtoNational,
Inter-Nationalcodes.IS2825-1969.
The Indian standards code :
•Design procedure for welded PVs Ferrous
material. ( Pi=1 to 00 kgf/cm2)
PV do not come under scope of this code
•Small PV with di< 150 mm & V=500 Liters
•Nuclear PV, Steam Boilers, water storage tanks.

9. Components of UFPV
•Pressure vessel shell
•End closure
•Nozzles and Opening
•Flanged Joints
•Vessel support

10. Welded PV
Shell
Head
Head

11. CategoryA:
•LongitudinalweldwithinmainShell,communicatingchamber
andNozzles
•WeldinFormedheadORFlathead
•Circumferentialweldconnectingendclosertomainshell
CategoryB:CircumferentialweldwithinmainShell,
communicatingchamberorNozzles
CategoryC:Weldconnectingflangesandflatheadstomainshell,
formedheadandnozzles
CategoryD:WeldconnectingCommunicatingChambersand
NozzlestotheMainshell.
•Category of welded joints : A, B, C, & D
•Idea @ Location and not @ types of weld.

12. Codes for unfired PV
I. S. 2825-1969 categories Bureau of Indian standard
η=
Strength of he plate
Strength of welded joint

13. Classification of UPV
03 classes of vessel according to IS code 2825-1969

14. Pressures subjected by UPV
(P
mw)=Working pressure:
Maximum pressure to which UPV is subjected in operation.
(P
i)=Design Pressure: At which PV is designed Pi=(1.05)* P
mw
To calculate shell thickness, Nozzle, opening calculations
(P
ht)=Hydrostatic test pressure:
At which UPV is tested before put into operation P
ht= (1.3)* P
i
ASME / IS code DIN code
σall=Sult/3 σ
all=s
yt/1.5
Allowable stresses(σ
t
=σ
all
)
Pressures

15. C not required C required
Material:
HighAlloysteeland
Non-ferrous
Material:
CI, Carbon steel:
C= 1.5 mm
t>30mm
Severe corrosion conditions:
C = 3 mm
Corrosionallowance(C)
Theadditionalthicknessprovidedtoshelltotakeintoaccount
thecorrosionofplateofPVbychemicalattack,rustingetc.

16. Shell Thickness Design:
σ
all=
??????????????????
2??????????????????
[d=di+t]
t =
????????????????????????
2σ
all
????????????−????????????
[t
s=t+c]

17. Stresses in Vessel
A] Circumferential direction stress: Due to Pi (??????&#3627408481;)
σ
t=+
????????????(????????????+??????)
2??????
t=ts-c

18. •B) Longitudinal direction: ( ????????????)= (????????????1)+????????????2+(????????????3)
1) Due to Pi
(????????????1)= +
????????????(????????????)
4??????
2) Weight of vessel contents (Vertical)
(????????????2)= +
??????
??????????????????
=+
??????
??????????????????+????????????
3) Bending
????????????3)= +
??????
??????
Z=+
??????????????????+??????
2
??????
4

19. C) Pipe lines (σs)
??????&#3627408480;=
2??????
??????(????????????+??????)
2
??????
Equivalent resultant stress
????????????=??????&#3627408481;
2
+????????????
??????
−??????&#3627408481;????????????+3??????&#3627408480;
2
.
.

27. End Closures
•Flat Head
•Formed Head
1.Plain formed heads
2.Tor spherical
3.Semi-Ellipsoidal
4.Hemispherical
5.Conical heads

28. Classification according to the shape:
i. Convex heads
Semi-spherical head
Elliptical head
Dished head (spherical head with hem)
Spherical head without hem
ii. Conical heads
Conical head without hem
Conical
iii. Flat heads

29. Flat Head
t
h= 0.7d
i
??????
??????
??????
??????????????????
+ c
End closure: Small Diameter vessel
Manhole cover: Low pressure vessel
Cover: Small openings

30. Plain Formed Head
t
h= 0.4d
i
??????
??????
??????
??????????????????
+ c
Knuckle radius:
r
ic≥ 0.1d
i
Straight Flat length:
S
f=3 t
hto 20 mm( Larger)
Horizontal cylindrical storage vessel at P
atm
Bottom head for vertical cylindrical vessel on concrete slab
(D< 7 m)
Minimum forming: Economical

31. Tori spherical Dished Head
t
h=
??????
????????????????????????
??????
2??????
????????????????????????−0.2??????
??????
+
c
Stress Concentration Factor
K
f= 0.253+
????????????
??????
????????????
Crown Radius
Rc=0.5d
i ≤ R
c≤ 1d
i
r
ic=0.06 R
cK
f=1.77
th=
0.88??????????????????
??????
??????
????????????????????????−0.1??????
??????
+ c
S
f=3 t
hto 20 mm( Larger)
V
h=0.08467 di
3
mm
3
Excluding SfPortion
Local stresses at discontinuities

36. Stress intensifier factor
K
f=
1
6
2+??????
1
2
K1= Ration of major and minor axis=2
Kf=1
t
h=
??????
????????????
??????
2??????????????????????????????−0.2??????
??????
+ c
r
ic≥ 0.1 d
i
V
h=0.0131 di
3
mm
3
Excluding SfPortion
Semielliptical Head
S
f=3 t
hto 20 mm( Larger)

37. •Strongestinallformedheads.
•UsedforHPvessels
•Moreformingrequiredsomorecost
Hemispherical Head
S
f=3 t
hto 20 mm( Larger)

38. Bottomheadtoremovedrainage
Conical Head
S
f=3 t
hto 20 mm( Larger)

39. Attachments oh head to shell
•Flat heads
•Formed heads

40. Openings in PV:
Inlet/OutletPipeconnections.
Manhole(380mm)
•Opening designed by Area compensation method
•Area removed = Reinforced by EQUAL C/S AREA not Volume

41. Support
Lug-Support Skirt-Support

42. Saddle-Support