section 2 design of process vessels chapter 2 panorama
Post on 21-Dec-2015
260 views
TRANSCRIPT
![Page 1: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/1.jpg)
Section 2 Design Section 2 Design of Process Vesselsof Process Vessels
Chapter 2 Chapter 2 PanoramaPanoramaChapter 2 Chapter 2 PanoramaPanorama
![Page 2: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/2.jpg)
1.Conception of Vessels:1.Conception of Vessels:
Process Vessels are the various Process Vessels are the various equipments in the chemical equipments in the chemical process.process.
2.1 Structure and 2.1 Structure and
ClassificationClassification of Vesselsof Vessels
2.1 Structure and 2.1 Structure and
ClassificationClassification of Vesselsof Vessels
![Page 3: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/3.jpg)
2.2.Structure of vessels:Structure of vessels:
![Page 4: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/4.jpg)
3.3.Classification of vessels:Classification of vessels:
i. According to pressure and its typei. According to pressure and its type
(1)Internal Pressure Vessel(1)Internal Pressure Vessel
—— —— vessels where the media pressure vessels where the media pressure
inside the vessel is larger than that outsideinside the vessel is larger than that outside
(gauge pressure).(gauge pressure).
![Page 5: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/5.jpg)
Low pressure vessel (L):
0.1≤P < 1.6 MPa
Medium pressure vessel (M):
1.6 ≤P < 10 MPa
High pressure vessel (H):
10 ≤ P < 100 MPa
Ultra-high pressure vessel (U):
P ≥100 MPa
![Page 6: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/6.jpg)
(2)External Pressure Vessel
——the media pressure inside the vessel the media pressure inside the vessel is lower than that outsideis lower than that outside
(gauge pressure). When the pressure(gauge pressure). When the pressure inside the vessel is less than 0.1 MPa (absolute pressure), such vessels are called Vacuum Vessel.
![Page 7: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/7.jpg)
ii. According to temperature Normal temperature vessel -20< T ≤200℃ Medium temperature vessel —— between normal T & high T vessels Low temperature vessel < -20 ℃ High temperature vessel —— where the wall temperature is above the creep temperature.
![Page 8: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/8.jpg)
High temperature vessel
Carbon steel & Low-alloy steel T> 420 ℃ Alloy steel (Cr-Mo steel) T> 450 ℃ Austenite stainless steel (Cr-Ni) T> 550 ℃
![Page 9: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/9.jpg)
iii. According to management
Grade (I)
Grade (II)
Grade (III)
Factor
P, P*V
Media toxic and combustible
importance Degree of danger:
I < II < III
![Page 10: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/10.jpg)
2.2
Basic code and
Common Standard for
Design of Pressure Vessels1.Conditions: i. The maximum working pressure
Pw≥ 0.1 MPa
(neglecting the net pressure of liquid )
![Page 11: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/11.jpg)
ii. Internal diameter Di (equal the maximum
dimension or size in the non-circular
sections) ≥ 0.15m, and V ≥ 0.025 m3
iii. With the medium as gas or liquefied gas,
or liquid whose maximum working
T ≥ standard b.p. (boiling point )
![Page 12: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/12.jpg)
2.Basic Code and Common Standard:
i. 《 Security Technique Supervising Rules for
Pressure Vessel 》 1999
ii. GB 150 — 1998
《 Steel Pressure Vessel 》 iii. GB 151 — 1999
《 Tubular Heat Exchanger 》 iv. JB 4710 — 2000
《 Steel Tower Vessel 》
![Page 13: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/13.jpg)
2.3 Standardization of Pressure Vessel Parts
1.Significance of Standardization:i. It consolidates and harmonizes the various activities in the manufacture and social life.ii. It’s the important means to organize the modernization production.
![Page 14: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/14.jpg)
iii. It’s the important component in scientific
management.
iv. Development of new products,
assures the interchangeability and common- usability
Convenient to use and maintain.
v. It’s helpful in the interchange of international
science & technology, culture and economy.
![Page 15: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/15.jpg)
2. Chemical Vessels and Standards of Equipments Components:
Cylinder Heads Vessel Flange Pipe Connecting (Nozzle) Flange
![Page 16: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/16.jpg)
Support Stiffening Ring
Manhole Handhole
Sight (level) Glass Liquid Leveler (LG)
Expansion joint
Heat Exchanger Tube Tray
Float (floating) Valve (FV)
Bubble (bubbling) cap Packing etc.
![Page 17: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/17.jpg)
3.Basic parameters of Standardization
i. Nominal Diameter —— DN (Dg)
is a typical dimension.
(1)Rolled cylinder and head
DN = Di (inside diameter)
DN Standard of pressure vessels:
300 350 400 450 500 …… 6000
48 grades in total.
![Page 18: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/18.jpg)
(2)Seamless pipes
—— DN≠Di & DN ≠ Do,
but DN is a certain value that is smaller than
Do. When the DN is a certainty, Do is to be a
certainty, while Di depends on the thickness.
Denotation of seamless pipes:
such as 252.5 (outside × thickness)
![Page 19: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/19.jpg)
Check the standards according to DN.
Comparison of DN and Do
of seamless pipes/mm
DN 10 15 20 25 32 40 50 65
Do 14 18 25 32 38 45 57 76
δ 3 3 3 3.5 3.5 3.5 3.5 4
![Page 20: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/20.jpg)
(3)Cylinder made by seamless pipes
—— DN = Do (outside diameter)
Six grades: 159 219 273 325 377 426
(4)DN of flanges
—— consistent to their suitable cylinders,
heads and tubes.
i.e. DN of flange = DN of cylinder
DN of head
DN of tube
![Page 21: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/21.jpg)
ii. Nominal Pressure —— PN (Pg)
Prescriptive standard pressure grades
For example ——
PN (MPa) of pressure vessel flange:
0.25 、 0.6 、 1.0 、 1.6 、 2.5 、 4.0 、 6.4
![Page 22: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/22.jpg)
iii. Application
In standard designing:
(1)Diameters of cylinders, heads and tubes
must be close to the standard grades.
e.p. Diameter of cylinder
should be 500 、 600 、 700 …
shouldn’t be 520 、 645 、 750 …
![Page 23: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/23.jpg)
(2)When selecting the standard vessel parts,
the design pressure at the working
temperature should be regulated to a
certain grade of PN.
Then choose the parts according to PN
and DN.
![Page 24: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/24.jpg)
4.Classification of standards: i. Chinese Standard
Symbol: GB (Guo biao)
ii. Standard issued by Ministry
JB —— Ministry of Mechanical Industry
YB —— Ministry of Metallurgical Industry
HB —— Ministry of Chemical Industry
SY —— Ministry of Petroleum Industry
![Page 25: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/25.jpg)
iii. Specialty Standard
iv. Trade Standard
v. Plant Standard
![Page 26: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/26.jpg)
2.4 Basic Requirements
& Contents of Vessel Design
1.Basic requirements: i. Enough strength —— no breakage
ii. Enough rigidity ,Enough stability —— limit deformation
![Page 27: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/27.jpg)
iv. Durability —— assuring certain usage life
v. Tightness —— no leakage
vi. Saving materials and easy to manufacture
vii. Convenient to be installed, transported,
operated and maintained
viii. Rational technical economy
![Page 28: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/28.jpg)
2.Basic Contents: i. Selection of materials
Selecting the materials of
equipment according to the technical
indexes t, p, media and the principles of
material selection.
ii. Structure design
![Page 29: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/29.jpg)
iii. Calculation of strength and thickness
(including the cylinders and heads)
iv. Strength verification in hydraulic
pressure test
v. Seal design; selecting or designing flanges
![Page 30: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/30.jpg)
vi. Selection of support & the verification of
strength and stability
vii. Design and calculation of reinforcement
for opening
viii. Selection of other parts and accessories
ix. Other special design
x. Plotting the equipment drawings
xi. Compiling the equipment specifications
![Page 31: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/31.jpg)
Chapter 3 Stress Analysis of Chapter 3 Stress Analysis of Thin-walled Internal-P VesselThin-walled Internal-P Vessel
3.1 Stress Analysis 3.1 Stress Analysis
of thin-walled Cylinders of thin-walled Cylinders Subjected to Internal PressureSubjected to Internal Pressure
![Page 32: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/32.jpg)
1.1.Thin-walled vesselsThin-walled vessels (1)Thin-walled vessels:
S / Di < 0.1 (Do / Di = K < 1.2)
(2)Thick-walled vessels:
S / Di ≥ 0.1
2.stress characteristics:2.stress characteristics: There are always two kinds of
stress in pressure vessels.
![Page 33: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/33.jpg)
i. membrane stress
—— membrane (shell)
theory
ii. boundary stress
—— shell theory with
moments and conditions
of deformational
compatibility
P
![Page 34: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/34.jpg)
3.2 3.2 Membrane Theory ——Membrane Theory ——
Rotary Shells’ Stress AnalysisRotary Shells’ Stress Analysis
(1)rotary curved-surface & shell
1.Basic conceptions and 1.Basic conceptions and hypothesis:hypothesis: i. Basic conceptions
Cylinder , conical shell, spherical shellCylinder , conical shell, spherical shell
![Page 35: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/35.jpg)
(2)Axial Symmetry Geometry figure, endured load and restrictions of shell are all symmetry to the revolving axis (OA). Several basic conceptions generatrix (generator), meridian,
normal, parallel circle (latitude), 母线,经线,法线,纬线
longitudinal radius, tangential radius.第一曲率半径,第二曲率半径
![Page 36: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/36.jpg)
A
O
B
B’
(3)Generator (AB)
The plane curve which forms the curved surface.
(4)Longitude (AB’)
Section passing OA and intersecting with shell, the cross-line is AB’.
![Page 37: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/37.jpg)
(5)Normal (n) The line passing point M in meridian and is vertical with midwall surface. The extension of normal must intersect with OA.(6)Latitude (CND) The cross-line formed by the
conical surface passing point K2’ intersects with the rotary curved surface.
A
O
M
n
K2K1
··
·K2’
·C
ND
![Page 38: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/38.jpg)
(7)Longitudinal radius (R1) The radius of curvature of meridian which passes point M in midwall surface is called the longitudinal radius of point
M in meridian.The center K1
of curvature of the round
with diameter R1 must be in the extension of normal passing point M.For example:Longitudinal radius of point M:
R1 = M K1
A
O
MK2
K1
··
·K2’
·C
ND
![Page 39: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/39.jpg)
(8)Tangential radius (R2)
*The plane which is vertical to the normal
passing the point M in meridian
intersects with the mid-wall surface, the
resulted cross line (EMF) is a curve, the
radius of curvature of this curve in point
M is called tangential radius.
![Page 40: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/40.jpg)
*The center K2 of curvature of the
round with diameter R2 must be in the
extension of normal passing point M
and in the revolving shaft.
For example:
Tangential radius of point M:
R2 = M K2
![Page 41: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/41.jpg)
exerciseexercise AA
BB
CC
DD
dd
Calculations of R1,R2 at different
points
Calculations of R1,R2 at different
points
![Page 42: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/42.jpg)
Calculation of RCalculation of R11 and R and R22
1.Cylindrate shell R1 = ∞ R2 = D / 2
δ
D
p
![Page 43: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/43.jpg)
Spherical shell subjected to uniform gas internal
pressure:R1 = R2 = D / 2
D
δ
![Page 44: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/44.jpg)
3.Elliptical shell Known: Major semiaxis – a Short semiaxis - b
1
''
2
32'
y
y
(1)Find R1 and R2 of point A:
R1:
radius of curvature of Ay
xa
b
A(x,y).
..
k2
k1
12
2
2
2
b
y
a
x
232224
41 1
baxaba
R
![Page 45: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/45.jpg)
R2: R2 = K2 A = x / sin (b)
here:
2 1
sintg
tg
ya
xbytg
2
2'
22
222 x
a
bby
22242
1baxa
bR
putting them into (b), getting:
y
xa
b
A(x,y).
..
k2
k1
![Page 46: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/46.jpg)
232224
41 1
baxaba
R
22242
1baxa
bR
Special Points:
x=0: R1=R2=a2/b
x=a : R1=b2/a , R2=a
Special Points:
x=0: R1=R2=a2/b
x=a : R1=b2/a , R2=a
![Page 47: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/47.jpg)
Conical shellConical shell
Find R1 and R2 of point A:
R1 = ∞
R2 = A K2 = r / cos
Small end:
R1 = ∞
R2 = 0
D
r
.A
k2
![Page 48: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/48.jpg)
For spherical
segment:
R1=R2=RFor knuckle segment
of transition section: R1= r1, R2=
For cylindrical shell: R1=∞, R2= r
Dished shellDished shell
rr
r1r1
11
sinr
rr
![Page 49: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/49.jpg)
ii. Basic hypothesis:ii. Basic hypothesis:
Small displacement hypothesisSmall displacement hypothesis
Straight linear law hypothesisStraight linear law hypothesis
Non-extrusion hypothesisNon-extrusion hypothesis
![Page 50: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/50.jpg)
2.2.Free body balance equation(Free body balance equation( 区域平区域平衡方程式衡方程式 ))
—— —— calculation formula of calculation formula of meridional stressmeridional stress (经向应力)(经向应力) ::
i. i. Intercepting shell Intercepting shell —— —— uncovering the longitudinal uncovering the longitudinal
stress stress m
ii. Choosing separation bodyii. Choosing separation body iii. Analysis of stressiii. Analysis of stress
![Page 51: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/51.jpg)
iv. Constitute balance equationiv. Constitute balance equation
0 0 zzz NPF
0sin 4
2 DSpD m
getting equation, above theinto
it putting 2/
sin2R
D
3)-(3 2
2
S
pRm
z
D
m
p
C C’
.k2R2
![Page 52: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/52.jpg)
3.3.Infinitesimal balance equationInfinitesimal balance equation —— —— calculation formula of hoop calculation formula of hoop stressstress (微元体平衡方程式)(微元体平衡方程式) i. Intercepting shell i. Intercepting shell
—— —— uncovering the meridional stress uncovering the meridional stress m and circumferential stress σθ
ii. Choosing separation bodyii. Choosing separation body iii. Analysis of stressiii. Analysis of stress
![Page 53: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/53.jpg)
iv. Constitute balance equation iv. Constitute balance equation
0P 0 ..n nnmn NNF
2
sin2 1221
dSdldlpdl m
02
sin2 21
d
Sdl
4)-(3 21 S
p
RRm
:整理得
k2k1
d2
d1
p
mSdl2
Sdl1
![Page 54: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/54.jpg)
Basic calculation equation of membrane stress:
2
2
S
pRm
21 S
p
RRm
Illustration of symbols:
m —— meridional stress of a random point in rotary thin shell, MPa
—— circumferential (hoop) stress of a random point in rotary thin shell, MPa
![Page 55: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/55.jpg)
P —— internal pressure, MPaS —— thickness of wall, mm
R1 —— longitudinal radius of required stress point in the mid-wall surface of the rotary shell, mm
R2 —— tangential radius of required stress point in the mid-wall surface of the rotary shell, mm
![Page 56: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/56.jpg)
v. Application range of membrane theory
☆Applicable to axial symmetric thin-walled shell without bending stress ☆No bending stress —— only normal stress (tensile stress & compression stress) ☆Thin-walled shell
—— S / Di < 0.1 ( Do / Di = K < 1.2 ) ☆Axial symmetry and continuous —— Geometry, loads, physical properties ☆Free supporting boundary
![Page 57: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/57.jpg)
3.3 Application of Membrane Theory
S
pRm 2
2
S
p
RRm
21
Calculation equations:
![Page 58: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/58.jpg)
1.Cylindrical shell subjected to uniform gas internal pressure: ∵ R1 = ∞ R2 = D / 2
Putting them into the
previous equations:
S
pD
S
pDm 2
4
s
D
p
![Page 59: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/59.jpg)
2.Spherical shell subjected to uniform gas internal pressure: ∵ R1 = R2 = D / 2
Putting them into
equations (3-3) and (3-4): D
S
S
pD
S
pDm 4
4
![Page 60: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/60.jpg)
3.Elliptical shell subjected to uniform gas internal pressure: Example: Known: Major semiaxis - a Short semiaxis - b Thickness - S Internal Pressure - P
Find the m and of a random point on the
elliptical shell.
![Page 61: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/61.jpg)
Solution:
(1)Find R1 and R2 of point A:
R1:
y
xa
b
A(x,y).
..
k2
k1
1
''
2
32'
y
y
12
2
2
2
b
y
a
x
(a)
232224
41 1
baxaba
R
radius of curvature of A
By the elliptical equation: getting y’ and y’’, then put them into (a).result is:
![Page 62: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/62.jpg)
R2: R2 = K2 A = x / sin (b)
here:
2 1
sintg
tg
ya
xbytg
2
2'
22
222 x
a
bby
22242
1baxa
bR
putting them into (b), getting:
![Page 63: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/63.jpg)
(2)Find m and of point A:
Putting R1 and R2 into (3-3) and (3-4), getting:
2224
42224
2224
22
2
baxa
abaxa
Sb
p
baxaSb
pm
![Page 64: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/64.jpg)
Stress of special points on elliptical shell:(1)x=0 (Top of elliptical shell)
b
a
S
pam 2
2
2
22
2 b
a
S
pa
S
pam
(2)x=a (Boundary or equator of elliptical shell)
![Page 65: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/65.jpg)
Standard elliptical heads: The elliptical heads whose ratio of major and
short semiaxis a / b = 2 are called standard elliptical heads.
a / b = 2 ——
x=0 (Top):
x=a (Boundary):S
pD
S
pam 2
2
42
S
pD
S
paS
pD
S
pam
m
a / b = 2
![Page 66: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/66.jpg)
4.Conical shell subjected to uniform gas internal pressure: Example: Known: Diameter of tapered bottom - D Half tapered angle - Thickness - S Internal Pressure - P
Find the m and of a random point on the conical shell.
![Page 67: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/67.jpg)
Solution:
(1)Find R1 and R2 of point A:
R1 = ∞
R2 = A K2 = r / cos (2)Find m and of point A:
Putting R1 and R2 into (3-3) and (3-4)
respectively, getting:
D
r
.Ak2
cos
1
cos
1
2
S
pr
S
prm
![Page 68: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/68.jpg)
Characteristics of stress distribution
of conical shell:
m
![Page 69: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/69.jpg)
5.Cylindrical shell subjected to liquid static pressure: i. Supporting along the boundary of bottom Example: Known: Gauge pressure – Po (Pa) Liquid level – H (m) Density of liquid - (N/m3)
Find the m and of a random
point on the wall of cylindrical shell.
D
H
.A
x
Po
![Page 70: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/70.jpg)
Solution:
(1)Meridional stress:
Cutting along section B-B, taking the
lower part as the separation body.
(H-x)
(Po+x)m m
N
D
H
.A
x
Po
B B
B-B
![Page 71: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/71.jpg)
Establishing the balance equation of axial stress:
0 xF
222
4
4)(
4)( DHSDDxHDxp mo
S
Dpo
4 m
(H-x)
(Po+x)m m
N
![Page 72: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/72.jpg)
(2) Circumferential (Hoop) stress:
Infinitesimal balance equation (3-4):
S
P
RRm
21
S
Dxpo
2
S
DHpo
2
max
For point A:
R1 = ∞ R2 = D/2 P = Po + x
Putting them into (3-4),
getting: when x=H:
![Page 73: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/73.jpg)
ii. Supporting along the boundary of top Example: Known: Gauge pressure – Po (Pa) Liquid level – H (m) Density of liquid - (N/m3)
Find the m and of a random
point on the wall of cylindrical shell.
D
H
.A
x
Po
![Page 74: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/74.jpg)
Solution:
(1)Meridional stress:
Cutting along section B-B, taking the
lower part as the separation body.
H-x
(H-x)
mm(Po+ x)
Po
D
H
.A
x
B B
B-B
![Page 75: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/75.jpg)
Establishing the balance equation of axial stress:
0 xF
0 4
4
22 SDDxpDxH mo
S
DHpo
4
m
H-x
(H-x)
mm(Po+ x)
![Page 76: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/76.jpg)
(2)Hoop stress:
Infinitesimal balance equation (3-4):
S
P
RRm
21
S
Dxpo
2
S
DHpo
2
max
For point A:
R1 = ∞ R2 = D/2 P = Po + x
Putting them into (3-4),
getting: when x=H:
![Page 77: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/77.jpg)
6.Examples: A cylindrical vessel is with a spherical upper head and a semi-elliptical lower head a / b = 2. The average diameter D is 420mm. Thickness of all cylindrical shell and heads are 8mm. The working pressure P is 4MPa. Calculating: (1)Find m and of the shell body. (2)Find the maximum stresses on the both the heads and their positions respectively.
![Page 78: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/78.jpg)
Solution:
(1)For cylinder m and :
D S
P
)MPa( 5.5284
4204
4
S
pDm
(MPa) 10522
mS
pD
(MPa) 5.524
S
pDm
(2)Upper head —— spherical
![Page 79: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/79.jpg)
(3)Lower head —— elliptical
When a / b = 2:
a = D/2 = 210 mm b = a/2 = 105 mm
x=0 (Top):
(MPa) 10522
S
pD
S
pa
b
a
S
pam
(MPa) 5.5242
S
pD
S
pam
(MPa) 105 2
22 2
2
S
pD
S
pa
b
a
S
pa
x=a (Bottom):
![Page 80: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/80.jpg)
3.4 Conception
of Boundary Stress 1.Forming of boundary stress: Boundary
—— The joint and its vicinity of
two parts with different geometry
shape, load, material and physical
conditions, i.e. discontinuous point.
![Page 81: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/81.jpg)
![Page 82: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/82.jpg)
Boundary stress forming not for
balancing the loads but for receiving
restrictions from self or exterior. It’s a
group of internal force with same value
but contrary direction occurring
between two parts which are forced to
realize transfiguration harmonization.
![Page 83: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/83.jpg)
2.Characteristics of boundary stress:
i. Distributing along the wall non-evenly
ii. Different joint boundary forming different
boundary stress
iii. It’s local stress, i.e. only forming large stress
locally and decaying apparently
iv. Value of boundary stress can be 3~5 times
of that of membrane stress
v. Self-constrained
![Page 84: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/84.jpg)
3.Treatments to boundary stress: i. Treatments locally in structure
(1)Improving the structure of joint boundary
![Page 85: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/85.jpg)
(2)Strengthening the boundary locally
![Page 86: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/86.jpg)
(3)Assuring the quality of welding line at
boundary
(4)Decreasing the remnant stress at local and
processing the heat treatment to eliminate
the stress
(5)Avoiding the local stress added to the
boundary region overlap with connatural
stress
ii. Materials are of high plasticity
![Page 87: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/87.jpg)
Chapter 4 Strength Chapter 4 Strength Design Design
of Cylinders and Heads of Cylinders and Heads
subjected to Internal-subjected to Internal-PressurePressure
4.1 Basic Knowledge 4.1 Basic Knowledge
of Strength Designof Strength Design
![Page 88: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/88.jpg)
1.1.Criterions of elasticity failure:Criterions of elasticity failure:ts eq
n
o
eq
eq —— equivalent stresso —— limiting (ultimate) stress, can be
s 、 b 、 n 、 D, etc.[] —— allowance stressn —— safety coefficient
Safety Allowance kept for the
requirements of safety:
![Page 89: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/89.jpg)
2.2.Strength Theory:Strength Theory: i. The first strength theory —— the maximum tensile stress theory
231
max
][1 Ieq
ii. The second strength theory —— The maximum major strain theory iii. The third strength theory —— The maximum shear stress theory
Applying to brittle materials
![Page 90: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/90.jpg)
Shear limit:
Failure condition:
Strength condition:
Applying to the plastic materials
2 :limitShear 0 s
0max
ss 3131 or
2 )-(
2
1 i.e.
][31 IIIeq
![Page 91: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/91.jpg)
iv. The fourth strength theory
—— the maximum deformation energy theory
Applying to the plastic materials
])()()[(2
1 213
232
221 IV
eq
][ IVeq
Strength condition:
![Page 92: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/92.jpg)
4.2 4.2 Strength Calculation ofStrength Calculation ofThin-walled Cylinder Subject Thin-walled Cylinder Subject to Internal Pressureto Internal Pressure
S
pD
21 S
pDm 42
03 r
1.Strength calculating equation: i. Determining the major stress
![Page 93: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/93.jpg)
ii. Determining the equivalent stress
),,( 321 feq
S
pD
S
pDIIIeq 2
0231
3)-(4 ][2
tIIIeq S
pD
iii. Strength condition
According to the third strength theory:
![Page 94: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/94.jpg)
iv. Strength calculation equation
4)-(4 ][ 2
t
pDS
Calculating pc from p.Putting them into equation (4-4), getting:
ct
ic
p
Dp
][2S
Solving equation (4-4) as following:
(1)Replacing medium diameter with internal
diameter: D + Di = S
![Page 95: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/95.jpg)
(2)Introducing the welded joint efficiency :
5)-(4 ][2 c
tic
p
DpS
6)-(4 ][ 2 2C
p
DpS
c
tic
d
This is the design thickness.
(3)Eliciting the corrosion allowable thickness C2:
This is the calculated thickness.
![Page 96: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/96.jpg)
(4)Adding negative deviation C1:
Getting the nominal thickness which indicated on the drawing.
(5)Calculating the effective thickness:
7)-(4 valueofround][2
S 12n
CCp
Dp
ct
ic
8)-(4 valueofround][2
)( 21
ct
ic
ne
p
Dp
CCSS
![Page 97: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/97.jpg)
v. Equation of strength verification
9)-(4 ][2
)( t
e
eict
S
SDp
10)-(4 ][2
][ei
et
w SD
Sp
vi. Calculating equation of pw
![Page 98: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/98.jpg)
2.Strength calculating equation of thin-walled spherical vessels:
ct
ic
p
Dp
][4S
2d ][4S C
p
Dp
ct
ic
valueofround][4
S 12
CCp
Dp
ct
icn
![Page 99: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/99.jpg)
*Equation of strength verification:
*Equation of [pw] —— the maximum allowable working pressure:
*Scope of application of previous equation:
cylinder: P≤0.4 []t (Do / Di ≤1.5)
spherical shell: P≤0.6 []t (Do / Di ≤1.35)
t
e
eict
S
SDp][
4
)(
ei
et
w SD
Sp
][4][
![Page 100: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/100.jpg)
Illumination of symbols:Pc —— Calculated pressure MPa
Di 、 Do —— Internal & external diameters of cylinder mmS —— Calculated thickness mm
Sd —— Design thickness mm
Sn —— Nominal thickness mm
Se —— Efficient thickness mm
![Page 101: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/101.jpg)
C1 —— Negative deviation mmC2 —— Corrosion allowable thickness mmC —— Additional value of wall thickness mm —— Welded joint efficiency[]t —— Allowable stress at design temperature MPat —— Calculated stress at design temperature MPa[Pw] —— The maximum allowable pressure at design T MPa
![Page 102: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/102.jpg)
3.Determination of design parameters: i. Pressure P
(1)Working pressure Pw
—— the maximum pressure at the top of vessel and under normal operating condition
![Page 103: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/103.jpg)
(2)Design pressure P
—— the maximum pressure at the
specified top of vessel
The design pressure P and the
corresponding design temperature T are
conditions of designing load, and its value
is not less than working pressure.
![Page 104: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/104.jpg)
(3)Calculated pressure Pc
—— the pressure which is used to determine
the thickness at corresponding
design temperature
Including the liquid (column) static
pressure, when the liquid (column) static
pressure < 5% design pressure, it can be
neglected.
![Page 105: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/105.jpg)
Choosing the value of design pressure
Illustrating in the following chart
![Page 106: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/106.jpg)
Conditions Evaluation of Design P
With safety valves P≤(1.05~1.1)Pw
Single vessel
(no safety devices)
P≥Pw
With explosive media
and rupture disk
P≤(1.15~1.3)Pw
With liquefied gas Determined by the charging proportion and Tmax
External Pressure Vessel Under normal working condition, P≥△P=P2-P1
Vacuum Pressure Vessel With safety valve: P=1.25△P
Without SV: P=0.1MPa
Jacketed Vessel As external P vessel
![Page 107: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/107.jpg)
ii. Design Temperature T —— the enacted temperature of metallic components under normal operating condition
Design P and design T both are the design load condition.
![Page 108: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/108.jpg)
iii. Allowable stress
min
s , ][
sb
b
nn
min
s , ][
s
t
b
tbt
nn
min
D , , ][
n
tn
D
t
s
tst
nnn
nt Coefficien Safe
Stresslimit ][
0 t
High T Vessel
Medium T Vessel
Normal T Vessel
![Page 109: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/109.jpg)
iv. Safe (Safety) coefficient n
Material
Strength
Performanceσb σt
s σtD σt
n
Safety
Coefficient
nb ns nD nn
Carbon Steel
Low Alloy Steel
≥3.0 ≥1.6 ≥1.5 ≥1.0
High Alloy Steel ≥3.0 ≥1.5 ≥1.5 ≥1.0
![Page 110: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/110.jpg)
v. Welded joint efficiency ( )
(1)Double welded butt or completely welded
butt which is the same as double one.
NDE 100% = 1.0
NDE Local = 0.85 Double welded butt
Single welded butt
(2)Single welded butt
NDE 100% = 0.9
NDE Local = 0.8
![Page 111: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/111.jpg)
vi. Additional value of wall thickness C
(1)Negative deviation of plate and tube C1
Referring to the teaching material page , figure 4-7 & 4-8, selecting according to
the nominal thickness Sn.
(2)Corrosion allowable thickness C2
C2 = Ka B
Ka —— corrosion rate, mm/year
B —— design life of utility, year
![Page 112: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/112.jpg)
Generally speaking:
Ka < 0.05 mm/year
Single corrosion C2 = 1 mm
Double corrosion C2 = 2 mm
Ka = 0.05~0.1 mm/year
Single corrosion C2 = 1 ~ 2 mm
Double corrosion C2 = 2 ~ 4 mm
For stainless steel,
when the media is little corrosive C2 = 0
![Page 113: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/113.jpg)
4.Pressure Test and Strength Verification of vessels: i. Purpose
(1)Verifying the macro-strength and
deformation of vessels
(2)Verifying the tightness of vessels
![Page 114: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/114.jpg)
ii. Time(1)For new vessels, the Pressure Test and Strength Verification should be proceeded after completely welded and heat treatment.(2)For used vessels, the Pressure Test and Strength Verification should be proceeded after examination and repair, and before putting into production.
![Page 115: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/115.jpg)
iii. Media in Test
(1)Water —— the most commonly used
Stipulation to T of water:
Carbon steels 、 16MnR 、 normalizing15MnVR —— T<\ 5 ℃ Other low alloy steels —— T<\ 15 ℃ Stainless steels ——
content of [Cl-] in water ≤ 25ppm
![Page 116: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/116.jpg)
(2)For the vessels which cannot be filled
with liquid, something like dry and
clean air, nitrogen gas or other inert
gases can be used to fill these vessels.
![Page 117: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/117.jpg)
iv. Determination of Pressure for Testing
(1)Internal Pressure Vessel
Hydrostatic Test tT PP
][
][25.1
tT PP][
][15.1
PPT 25.1
PPT 15.1
(2)External Pressure Vessel
Pneumatic Test
Pneumatic Test
Hydrostatic Test
![Page 118: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/118.jpg)
Interpretation of symbols:
P —— Design pressure, MPa
PT —— Test pressure, MPa
[] —— Allowable stress at test
temperature, MPa
[]t —— Allowable stress at design
temperature, MPa
![Page 119: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/119.jpg)
v. Pressure Testing Methods
(1)Hydrostatic Test
*Filling the vessel in test with liquid.
*Slowly increasing P to the test pressure PT .
*Keeping this pressure more than 30
minutes.
*Decreasing P to 80% of PT .
![Page 120: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/120.jpg)
*Checking the welded seam and connection,
reducing P to repair them if existing
leakage.
*Repeating the previous test until upping to
grade.
*After testing, discharging the liquid and
drying the vessel with compressed air.
![Page 121: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/121.jpg)
(2)Pneumatic Test
*Slowly increasing P to 10% of PT as well as
≤0.05MPa.
*Keeping this P for 5 minutes and have an
primary inspection.
*If up to grade, continue to slowly increase P
to 50% PT, then by the P=10% P△ T
degree difference increasing slowly P to PT.
![Page 122: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/122.jpg)
*Keeping this P for 10 minutes.
*Decreasing P to 87% PT, then keeping it and examining and repairing.
*Repeating the previous test until upping to grade.
![Page 123: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/123.jpg)
(3)Air (gas) Tight Test
*Slowly increasing P to PT.
*Keeping this P for 10 minutes.
*Decreasing P to the design pressure.
*Examining the sealing condition.
![Page 124: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/124.jpg)
vi. Stress verification before pressure test
(1)Hydrostatic test
s0.9 2
)(
e
eiTT S
SDP
s0.8 2
)(
e
eiTT S
SDP
T —— Calculating stress at testing pressure,
MPa
s —— Yielding point at testing temperature,
MPa
(2)Pneumatic test
![Page 125: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/125.jpg)
5.Examples: i. There is a boiler barrel which Di=1300mm,
working pressure Pw=15.6MPa and it has a safety valve. Also know that the design T=350ºC, the material is 18MnMoNbR, it is double welded butt with 100% NDE. Try to design the thickness of this boiler barrel.
![Page 126: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/126.jpg)
Solution:(1)Determining the parameters
Pc = 1.1PW = 1.1×15.6 = 17.16 MPa
(with the safety valve)
Di = 1300mm
[]t = 190MPa (Design T = 350ºC)
[] = 190 Mpa (At normal T, S > 60-100)
= 1.0 (Double welded butt, 100% NDE)
C2 = 1 mm (Single corrosion, Low alloy steel)
![Page 127: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/127.jpg)
(2)Calculating the thickness
][2 c
tic
p
DpS
mm 5.6116.1711902
130016.17
Design thickness
Sd = S + C2 = 61.5 + 1 = 62.5 mm
![Page 128: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/128.jpg)
Choosing C1 = 1.8 mm (P95 Figure 4-7)
Additional value of wall thickness
C = C1 + C2 = 1.8 + 1 = 2.8 mm
Nominal thickness
Sn = S + C + round-of value
= 61.5 + 2.8 + round-of value
= 65 mm
![Page 129: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/129.jpg)
(3)Hydrostatic test for strength verification
*Parameters:
tT PP][
][25.1
aMP45.21190
1906.1725.1
*Efficient thickness:
Se = Sn - C = 65 - 2.8 = 62.2 mm
s = 410 MPa
![Page 130: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/130.jpg)
2
)(
e
eiTT S
SDP
MPa 9.2342.622
2.62130045.21
MPa 36914109.0 9.0 s
ST 9.0
*Stress verification:
That is to say the strength in hydrostatic test is enough.
*Stress:
![Page 131: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/131.jpg)
ii. There is a oxygen cylinder which has been
kept in storage for a long time, with
Do=219mm using 40Mn2A and made by
seamless steel pipe. The actual Sn= 6.5mm and
b = 784.8MPa, s = 510.12MPa, 5 = 18%,
the design T is normal T.
If the working pressure Pw=15MPa, is the working stress less than the allowable stress? try to
find whether the thickness is enough or not. If
not, what is the maximum allowable working pressure in this cylinder?
![Page 132: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/132.jpg)
Solution:
it is the problem about strength verification
—— Whethert ≤ []t or not
(1)Determining the parameters
Pc = 15MPa Do = 219 mm Sn = 6.5 mm
MPanb
b 6.2613
8.784][
MPans
s 8.3186.1
12.510][
Choosing the little one: i.e. []t = 261.6MPa
![Page 133: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/133.jpg)
= 1.0 (for seamless steel)
C2 = 1 mm
C1 = 0 (for the minimum thickness,
negative deviation is neglected.)
Se = Sn - C = 6.5 - 1 = 5.5 mm
![Page 134: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/134.jpg)
(2)Strength verification
2
)(
e
eoct
S
SDp
MPa 1.291
5.52
5.521915
Obviously, t > []t = 261.6 MPa
So, 15MPa is too large, should be reduced.
![Page 135: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/135.jpg)
(3)Determining the maximum allowable working P
][ 2
][eo
et
SD
Sp
MPa 48.135.5219
5.516.2612
So, the maximum safety P for this
cylinder is 13.48 MPa
![Page 136: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/136.jpg)
4.3 4.3 Designing Heads subject Designing Heads subject
to Internal Pressureto Internal Pressure
![Page 137: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/137.jpg)
Classification according to the shape: i. Convex heads
Semi-spherical head
Elliptical head
Dished head (spherical head with hem)
Spherical head without hem
![Page 138: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/138.jpg)
ii. Conical heads
Conical head without hem
Conical head with hem
iii. Flat heads
![Page 139: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/139.jpg)
1.Semi-spherical head
Di
S
![Page 140: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/140.jpg)
Calculating equation for thickness
][ 4 c
tic
p
DpS
][ 4 2C
p
DpS
ct
icd
valueofround][4
S 12
CCp
Dp
ct
icn
![Page 141: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/141.jpg)
2.Thickness calculating equation of elliptical head
b
a
S
pam 2max
hi (
b)
ho
Di S
Ri (a)
i. Calculating equation
for thickness:
For the elliptical head
whose m = a / b ≤ 2
![Page 142: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/142.jpg)
2. The maximum stress should be at the top point:
Putting m = a / b, a = D / 2 into the equation,
getting:
S
mpD
4max
t
S
mpD][
4max
t
mpDS
][ 4
Then:
Under the condition about strength:
![Page 143: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/143.jpg)
(1)Replacing P with Pc
(2)Multiplying []t with welded joint efficiency (3)Substituting D with Di, D = Di + S
(4) m = a / b = Di / 2 hi
Putting these conditions into the equation:
getting:
i
i
ct
ic
ct
ic
h
D
p
Dpmmp
DpS
45.0 ][2
22
][2
m = a / b = Di / 2 hi
![Page 144: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/144.jpg)
For the standard elliptical head whose m=2:
ct
ic
p
DpS
5.0 ][2
For the elliptical head whose m>2:
at boundary » and m at the top pointThen introducing the stress strengthening
coefficient K to replace (Di / 4hi)
![Page 145: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/145.jpg)
In this equation:
2
22
6
1
i
i
h
DK
ct
ic
p
DpKS
5.0 ][ 2
For standard elliptical head: K=1
This is the common equation for calculating
the wall thickness of elliptical heads.
![Page 146: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/146.jpg)
Beside these conditions:
for standard elliptical heads Se <\ 0.15% Di
for common elliptical heads Se <\ 0.30% Di
The straight side length of standard elliptical heads should be determined according to P103, Figure 4-11
![Page 147: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/147.jpg)
iii. Working stress and the maximum
allowable working pressure
e
eict
S
SKDp
2
5.0
ei
et
SKD
Sp
5.0
][2][
![Page 148: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/148.jpg)
3.Dished head i. Structure Containing three parts:
Sphere: Ri
Transition arc (hem): r
Straightedge: ho (height)
Di
r
s
ho
R i
ct
ic
p
RpMS
5.0 ][2
r
RM i3
4
1
M —— Shape factor of dished head
and
ii. Calculating equation for thickness
![Page 149: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/149.jpg)
iii. Working stress and the maximum allowable working pressure
e
eict
S
SMRp
2
5.0
ei
et
SMR
Sp
5.0
][2][
![Page 150: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/150.jpg)
iv. Dished head
When Ri = 0.9 Di & r = 0.17 Di
the dished head is standard dished head
and M = 1.325
So the equation is:
ct
ic
p
DpS
5.0 ][2
2.1
![Page 151: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/151.jpg)
4.Conical head i. Structure
*without hem (suitable for ≤ 30 o )
without local strengthwith local strength
*with hem (suitable for > 30 o )
—— Adding a transition arc and a
straightedge between the joint
of head and cylinder
![Page 152: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/152.jpg)
ii. Calculating equation for thickness
The maximum stress is in the main aspect of conical head.
cos
1
2 maxmax S
pD
m
tmaxmax ][
cos
1
2
S
pD
According to the strength condition:
![Page 153: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/153.jpg)
Then cos
1
][2
t
pDS
cos
1
][2
ct
cc
p
DpS
Replacing P with Pc, considering , and
changing D into Dc , D=Dc+S
![Page 154: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/154.jpg)
This equation only contains the membrane stress but neglects the boundary stress at the joint of cylinder and head. Therefore the complementary design equation should be established: (1)Discriminating whether the joint of cylinder and head should be reinforced or not. (2)Calculation for the local reinforcement.
![Page 155: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/155.jpg)
Conical head without hem ( ≤ 30 o )
(1)Not require reinforcing
(consistent thickness for the whole head)
main aspect:
cos
1
][2
ct
cc
p
DpS
cos
1
][2
ct
sic
p
DpS
small aspect:
![Page 156: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/156.jpg)
(2)Require reinforcing
(for the thickness of joint,
the reinforcement region)
Main aspect:
ct
icr p
DpQS
][2
ct
sicr p
DpQS
][2
Small aspect:
![Page 157: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/157.jpg)
Interpretation:Dc —— inside diameter of large end
Di.s —— inside diameter of small end
Di —— inside diameter of cylinder
Q —— coefficient (Consulting the Figure
4-16 or 4-18 in book)
![Page 158: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/158.jpg)
Conical head with hem ( > 30 o )
(1)Thickness of hem at the transition section
ct
sic
p
DpKS
5.0 ][2
ct
sic
p
DpfS
5.0 ][
K —— coefficient (Consulting Figure4-13)
f —— coefficient (Consulting Figure4-14)
(2)Thickness of conical shell at the joint with
transition section
![Page 159: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/159.jpg)
4.Flat head i. Structure
The geometric form of flat heads:
rotundity, ellipse, long roundness,
rectangle, square, etc.
ii. Characteristics of load
Round flat with shaft symmetry which is
subjected to uniform gas pressure
![Page 160: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/160.jpg)
(1)There are two kinds of bending stress states,
distributing linearly along the wall.
(2)Radial bending stress r and hoop bending
stress t distributing along the radius.
![Page 161: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/161.jpg)
▲ For fixed egde
max = r.max
The maximum stress is
at the edge of disk.
S
R
p
0
t
r.m
ax
r
2
max. 188.0
S
DPr
S
PD
S
R
275.0
![Page 162: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/162.jpg)
▲ For simply supported ends
max = r.max = t.max
The maximum stress is
in the center of disk.
S
R
P
t
r.m
ax
0r
2
max. 31.0
S
DPr
S
PD
S
R
2 24.1
![Page 163: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/163.jpg)
iii. Calculation equation for thickness
From the condition of strength max ≤ []t ,
getting:
fixed edge:
t
PDS
][
188.0
t
PDS
][
31.0
simply supported ends:
![Page 164: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/164.jpg)
In fact, the supporting condition at boundary
of flat head is between the previous two.
After introducing the coefficient K which is
called structure characteristics coefficient and
considering the welded joint efficient , getting
the calculating equation for thickness of round disk:
tc
cp
PKDS
][
valueofroundS 12 CCS pn
![Page 165: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/165.jpg)
5.Examples Design the thicknesses of cylinder and heads of a storage tank. Calculating respectively the thickness of each heads if it’s semi-spherical, elliptical, dished and flat head as well as comparing and discussing the results.
Known: Di = 1200 mm Pc = 1.6Mpa
material: 20R []t = 133Mpa C2 = 1 mm The heads can be punch formed by a complete steel plate.
![Page 166: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/166.jpg)
Solution:(1)Determining the thickness of cylinder
][ 2 c
tic
p
DpS
mm 26.76.10.11332
12006.1
mmCSSd 26.80.126.72
C1 = 0.8 mm (Checking Figure 4-7)
Sd + C1 = 8.26 + 0.8 = 9.06 mm
Round it of, getting: Sn = 10 mm
Verify the strength under pressure test
= 1.0 (Double welded butt, 100% NDE)
![Page 167: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/167.jpg)
(2)Semi-spherical head
][ 4 c
tic
p
DpS
mm 62.36.10.11334
12006.1
mmCSSd 62.40.162.32
C1 = 0.5 mm (Checking Figure 4-7)
Sd + C1 = 4.62 + 0.5 = 5.12 mm
Round it of, getting: Sn = 6 mm
= 1.0 (wholly punch forming)
![Page 168: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/168.jpg)
(3)Standard elliptical head
ct
ic
p
DpS
5.0 ][2
mm 24.7165.00.11332
12006.1
mmCSSd 24.80.124.72
C1 = 0.8 mm (Checking Figure 4-7)
Sd + C1 = 8.24 + 0.8 = 9.04 mm
Round it of, getting: Sn = 10 mm
= 1.0 (wholly punch forming)
![Page 169: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/169.jpg)
(4)Standard dished head
ct
ic
p
DpS
5.0 ][2
2.1
mm 69.86.15.00.11332
12006.12.1
mmCSSd 69.90.169.82
C1 = 0.8 mm (Checking Figure 4-7)
Sd + C1 = 9.69 + 0.8 = 10.49 mm
Round it of, getting: Sn = 12 mm
= 1.0 (wholly punch forming)
![Page 170: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/170.jpg)
(5)Flat headK = 0.25; Dc = Di = 1200 mm; []t = 110 Mpa
tc
cp
PKDS
][
mm 36.72
0.1110
6.125.01200
mmCSSd 36.730.136.722
C1 = 1.8 mm (Checking Figure 4-7) Sd + C1 =73.36 + 1.8 = 75.16 mm
Round it of, getting: Sn = 80 mm
= 1.0 (wholly punch forming)
![Page 171: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/171.jpg)
Comparison:
Head-form
Sn mm
kg
Semi-sphe. Elliptical Dished Flat
6
106
10 12 80
137 163 662
Selection:
It’s better to use the standard elliptical head whose thickness is the same to that of cylinder.
![Page 172: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/172.jpg)
Chapter 5 Design of Chapter 5 Design of Cylinders Cylinders
and Formed Heads and Formed Heads subjected to External-subjected to External-PressurePressure
5.1 Summarization5.1 Summarization
![Page 173: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/173.jpg)
1.Failure of External Pressure Vessel
Under the effect of external pressure, the vessels may deform when the pressure is larger than a certain value. This kind of damage is called the failure of external pressure vessels.
2.Classification of Failure Side bucking —— the main form of failure Axial bucking Local bucking
![Page 174: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/174.jpg)
1.Critical pressure and critical compressive stress The pressure that makes the external pressure vessels fail is called the critical
pressure, indicating by Pcr.
At the moment that exists Pcr, the stress inside the vessels is called the critical
compressive stress, indicating by cr .
5.2 Critical Pressure
![Page 175: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/175.jpg)
2.Factors affect the critical pressure i. Geometric dimension of cylinder
Degree of
vacuu
m in
failu
re
90175
0.51
(1)
90175
0.3
(2)
90
350
0.3
(3)
90350
0.3
(4) Pcr
mm HO2500 300 120~150 300
![Page 176: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/176.jpg)
Comparison and analysis
for the experimental results
Figure (1) and Figure (2):
*When the value of L / D is equal, the larger the value of S / D, the higher the Pcr.
Figure (2) and Figure (3):
*When the value of S / D is equal, the smaller the value of L / D, the higher the Pcr.
Figure (3) and Figure (4):
*When the value of S / D and L / D are equal, having the stiffening ring as well, high Pcr.
![Page 177: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/177.jpg)
ii. Materials’ Performance of the cylinders
(1)The critical pressure (Pcr) hasn’t direct
relation with the strength ( s) of the materials.
(2)The critical pressure (Pcr) depends of the
flexural rigidity of the cylinders in some
aspects.
The stronger the flexural rigidity, the more
difficult for the failure.
![Page 178: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/178.jpg)
iii. The differential in the dimension at the
process of vessels’ manufacturing
Mainly reflecting on the “ellipticity” ( 椭圆度 ),
which is the processing differential in the
dimension of the cylindrical section.
![Page 179: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/179.jpg)
*Large ellipticity e can make the critical pressure Pcr decrease and failure happen in ahead.*Regulated as in the engineering, ellipticity e ≤ 0.5% when vessels subjected to the external pressure are made.
DmaxD
min %100minmax
DN
DDe
Ellipticity:
![Page 180: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/180.jpg)
3.Long cylinder, short cylinder and rigid cylinder, the calculating equations of their critical pressure
![Page 181: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/181.jpg)
i. Long cylinder
—— cylinders with large L / Do
Calculating equation of the critical P:
2
1.122
o
et
e
ocr
e
crcr D
SE
S
DP
S
DP
3
21
2
o
et
cr D
SEP
3
2.2
o
et
D
SE
For steel cylinders: = 0.3
Calculating equation of the critical stress:
![Page 182: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/182.jpg)
ii. Short cylinder
—— cylinders with small L / Do
Calculating equation of the critical P:
o
oetcr DL
DSEP
/
/ 59.2
5.2'
o
oet
e
ocrcr DL
DSE
S
DP
/
/ 3.1
2
5.1''
Calculating equation of the critical stress:
![Page 183: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/183.jpg)
iii. Rigid cylinder
—— cylinders with small L / Do, large Se / Do Designing criterion: Only need to satisfy the strength condition:
compression ≤ [ ]tcompression
i.e. ][ 2
t
e
eict
S
SDP压压
![Page 184: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/184.jpg)
4.Critical Length
Critical length —— which is used to classify the long cylinder and short cylinder; and it is the critical dimension of the short cylinder and rigid cylinder.
L > Lcr Long cylinder
L’cr < L < Lcr Short cylinder
L < L’cr Rigid cylinder
![Page 185: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/185.jpg)
i. Critical length Lcr of long and short cylinder:
e
oocr S
DDL 17.1
ii. Critical length L’cr of short and rigid cylinder:
e
otcomp
et
cr
S
D
SEL
3.1
.
'
![Page 186: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/186.jpg)
5.3 Engineering Design of
External-P Vessels
][ m
PPP cr
c
1.Designing criterions
![Page 187: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/187.jpg)
Pc —— Calculating Pressure, MPa
Pcr —— Critical Pressure, MPa
[p] —— Allowable External Pressure, MPa
m —— Stable safety coefficient
For cylinders, m = 3
at the same time, 椭圆度 e ≤ 0.5%
![Page 188: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/188.jpg)
2.Nomograph for the thickness designing of the external-P cylinders
i. Calculating Steps
Step 1: L 、 Do 、 Se →
Drawing the curve
oeo DLSDf ,
2
1.122
o
et
e
ocr
e
crcr D
SE
S
DP
S
DP
o
oet
e
ocrcr DL
DSE
S
DP
/
/ 3.1
2
5.1''
2
B :Making tEm
o
e
D
SBPSo ][:
O
et
cr
t
cr
e
Ocrcr
Ds
mE
mP
P
E
SDP
2][
2
![Page 189: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/189.jpg)
Step 2: Find the relationship between and [P]
2
B :Making tEm
3
2 tEB For cylinder m=3 and
o
e
D
SBPSo ][:
Then getting the relationship curve B = f ()
![Page 190: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/190.jpg)
ii. Steps of nomograph for the thickness designing of the external-P cylinders (Tubes)
For the cylinders and tubes whose Do/Se ≥20: (1)Supposing Sn, Se = Sn - C, calculating the values of L / Do and Do / Se.
(2)Calculating the value of (value of A), checking the Figure (5-5).
If L / Do > 50, checking the figure using L / Do = 50. If L / Do < 0.05, checking the figure using L / Do = 0.05.
![Page 191: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/191.jpg)
(3)Calculating the value of B
According to the used material, choosing
the relevant graphs from Figure (5-7) and
Figure (5-14) and then finding the point A
from abscissa.
![Page 192: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/192.jpg)
Two situations maybe encountered:
*Point A with that certain value lies at the right
of the curve and intersects with the curve,
then the value of B can be found directly in the
figure.
*Point A with that certain value lies at the left
of the curve and has no joint with the curve,
then the value of B is calculated by the
following equation:A
3
2 tEB
![Page 193: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/193.jpg)
(4)Calculating [P]
Putting the value of B into Equation (9) →[P]
)(9 ][eoo
e
SD
B
D
SBP
![Page 194: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/194.jpg)
(5)Comparing
cPPIf ~~ ][
cPPIf ][
cPPIf ][ i.e. the supposed Sn is too small and
should be increased appropriately,
repeating the previous calculating steps until
satisfying the first condition.
i.e. the supposed Sn is too large and
should be decreased
appropriately, repeating the previous calculating
steps until satisfying the first condition.
i.e. the supposed Sn is usable, safe
![Page 195: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/195.jpg)
3.Pressure test of external-P vessels
i. Pressure test of external-P vessels and vacuum vessels is processing as the hydrostatic pressure test.
Testing pressure:
PT = 1.25 P
P —— design pressure
![Page 196: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/196.jpg)
4.Example and discussion Design the thickness of an external-P cylinder.
Known:
Calculating pressure: Pc = 0.2 MPa
Design temperature: t = 250℃ Inside diameter: Di = 1800 mm
Calculating length: L = 10350 mm
Additional value of wall thickness: C = 2 mm
Material: 16MnR; Et = 186.4 103 MPa
![Page 197: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/197.jpg)
Solution:(1)Assuming Sn = 14 mm
Then Do = Di + 2 Sn = 1828 mm
Se = Sn - C = 12 mm
Finding out:
L / Do = 10350 1828 = 5.7
Do / Se = 1828 12 = 152
(2)Calculating the value of (A)
Checking the Figure 5-5, getting:
A = 0.000102
![Page 198: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/198.jpg)
(3)Calculating the value of B
From Figure 5-9, we can see that point A is at the left of the curve, then the calculating equation is like following:
A 3
2 tEB MPa 78.12000102.0104.186
3
2 3
![Page 199: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/199.jpg)
(4)Calculating [P]
][ eo SD
BP MPa 0834.0
152
78.12
(5)Comparing [P] and Pc
[P] < Pc = 0.2 MPa unsatisfied
Reassuming Sn, or setting the stiffening ring.
![Page 200: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/200.jpg)
Calculation under the condition that supposes there have two stiffening rings:
(1)Thickness is the same: Sn = 14 mm
After setting two stiffening rings,
the calculating length is like following:
mmL
L origin 34503
10350
3
)152SD( 9.11828
3450DL eoo Then
![Page 201: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/201.jpg)
(2)Calculating the value of (A)
Checking the Figure 5-5, getting:
A = 0.00035
(3)Calculating the value of B
From Figure 5-9, we can see that point A is at the right of the curve, getting B = 42.5 MPa
![Page 202: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/202.jpg)
(4)Calculating [P]
][ eo SD
BP MPa 28.0
152
5.42
(5)Comparing [P] and Pc
[P] > Pc = 0.2 MPa satisfied
![Page 203: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/203.jpg)
Calculation under the condition that supposes to increase the thickness:
(1)Assuming: Sn = 20 mm
Then Do = Di + 2 Sn = 1840 mm
Se = Sn - C = 18 mm
Finding out:
L / Do = 10350 1840 = 5.6
Do / Se = 1828 18 = 102
![Page 204: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/204.jpg)
(2)Calculating the value of (A)
Checking the Figure 5-5, getting:
A = 0.00022
(3)Calculating the value of B
From Figure 5-9, we can see that point A is at the right of the curve, getting B = 27.5 MPa
![Page 205: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/205.jpg)
(4)Calculating [P]
][ eo SD
BP MPa 27.0
102
5.27
(5)Comparing [P] and Pc
[P] > Pc = 0.2 MPa and closing
So, we can use the steel plate with
Sn = 20 mm, whose material is 16MnR.
![Page 206: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/206.jpg)
5.4 Design of External-P
Spherical Shell and Convex Head
1.Design of external-P spherical shell and semi-spherical head
i. Assuming Sn, and Se = Sn - C.
Calculating the value of Ro / Se.
![Page 207: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/207.jpg)
ii. Calculating the value of (A)
eo SRA
125.0
iii. Calculating the value of B and [P] According the used material, choosing the relevant graph from Figure 5-7 and Figure 5-14 and finding out the point A at the abscissa.
![Page 208: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/208.jpg)
Two situations maybe encountered:(1)If point A is at the right of the curve, the
value of B can be found from the figure directly.
(2)If point A is at the left of the curve, directly calculating:
eo SR
BThen [P]
2)(
0833.0][
eo
t
SR
EP
![Page 209: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/209.jpg)
iv. Comparison
cPPIf ~~ ][
cPPIf ][
i.e. the original assuming Sn is usable, and safety.
i.e. the original assuming Sn istoo small, Sn should be increased appropriately, repeating the previouscalculating steps until satisfyingthe first condition.
![Page 210: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/210.jpg)
2.Design of external-P convex head
The method of designing the external-P
convex head is the same to that of designing
external-P spherical head. But the Ro in the
designing of spherical head should be adjusted
like following:
![Page 211: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/211.jpg)
i. For elliptical head
Ro —— the equivalent spherical diameter of
elliptical head; Ro = K1Do
K1 —— coefficient; depending on a / b,
checking P141, Figure 5-3
![Page 212: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/212.jpg)
ii. For dished head
Ro —— the equivalent spherical diameter
of the dished head; it’s the outside
diameter of the spherical part at
the dished head.
![Page 213: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/213.jpg)
5.5 Design of the Stiffening Ring
in External-P Vessels 1.Function of stiffening ring
3
2.2
o
etcr D
SEP
o
o
e
tcr
DL
DS
EP
5.2
'
59.2
m
PP crAnd ][
![Page 214: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/214.jpg)
From the previous equations, we can know the methods to increase [P]:
i. Increasing S
ii. Decreasing the calculating length L
∴ Function of stiffening ring
—— decreasing calculating length to
increase [P]
![Page 215: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/215.jpg)
2.Space length and number of stiffening ringAssuming the space length of stiffening ring is Ls
From the design criterions of external-P:
Pc ≤ [P] and [P] = Pcr / m
Making Pc = [P] then Pcr = m Pc (a)
From the equation for the critical pressure of short cylinder:
o
oetcr DL
DSEP
5.2'
59.2
![Page 216: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/216.jpg)
Putting equation (a) in, getting:
Then putting m=3 in, getting:
c
os
oetcr pm
DL
DSEP
59.2
5.2'
5.2
max 86.0)(
o
e
c
ots D
S
P
DEL
![Page 217: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/217.jpg)
(Ls)max —— Under the condition that Do and
Se of the cylinder is determined,
the maximum space length
between the needed stiffening
rings working safely under the
calculating external pressure Pc,
mm.
![Page 218: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/218.jpg)
The actual space length between stiffening rings Ls ≤ (Ls)max is indicating safety.
The number of stiffening rings:
In the above equation:
L —— the calculating length of cylinder before
setting the stiffening rings, mm
Ls—— the space length between stiffening
rings, mm
1sL
Ln
![Page 219: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/219.jpg)
3.Connection of stiffening rings and cylinders
i. Connection Demands
Must assure all the cylinder and stiffening
ring are under the load together.
ii. Connection Methods
Welding —— Continuous Weld ( 连续焊接 )
Tack Weld ( 间断焊接 )
![Page 220: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/220.jpg)
iii. The stiffening rings should not
be randomly crippled or cut
off. If those must be done, the
length of the arc that are crippled
or cut off should not be larger
than the values shown in Figure 5-19.
![Page 221: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/221.jpg)
For example:
There is a horizontal external pressure vessel.
When the stiffening ring is set inside the
cylinder, in order not to affect the fluid flowing
or fluid discharging, we must leave a hole 豁口 at
the lowest position of the stiffening ring or set a
thoroughfare of fluid.
![Page 222: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/222.jpg)
As illustrating like the following two figures
![Page 223: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/223.jpg)
Chapter 5 Components Chapter 5 Components and and
Parts of Parts of VesselsVessels
6.1 Flange Connection6.1 Flange Connection1.The Sealing Theory ( 密封原理 )
and Connection Structure of Flanges
![Page 224: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/224.jpg)
i. Connection Structure
Three parts:
(1)Connected parts
—— a couple of flanges
(2)Connecting parts
—— several couples of
bolts and nuts
(3)Sealing parts
—— gasket
![Page 225: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/225.jpg)
ii. Sealing Theory
Taking the bolts’ forced sealing as an example to illustrate the Sealing Theory:
(1)Before butting (2)After butting (3)After chargingmedium
![Page 226: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/226.jpg)
2.The Structure and Classification of Flanges According to the connection ways of
flanges and equipment (pipelines)
(1)Integrated flange
—— S.O.flange (slip on flange)
W.N.flange (welding neck flange)
![Page 227: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/227.jpg)
S.O.flange
Pipeline Flange Vessel Flange
W.N.flange
![Page 228: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/228.jpg)
(2)Simple [loose (type), lap joint, lapped] flange
Interlink on the turn-down rims
On the welding ring
![Page 229: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/229.jpg)
(3)Screwed flange
Square flange Elliptical flange
![Page 230: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/230.jpg)
3.Factors effect the sealing of flangesi. Bolt load under pretension condition (bolt load for gasket sealing)
The bolt load is too small to seal specific pressure ( 顶紧密封比压 ).
The bolt load is too large to avoid the gasket being pressed or extruded.
![Page 231: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/231.jpg)
Increasing the bolt load
appropriately can strengthen the
sealing ability of gasket.
So under the condition of certain
bolt load, decreasing the
diameter of bolts center circle or
increasing the number of them
are both beneficial for sealing.
![Page 232: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/232.jpg)
ii. The types of sealing face
(1)plain (face) flange ( Raised Face )
(2)M&FM (male and female)
(3)T&G (tongue and groove face)
(4)Conical face
(5)Trapezoidal groove face
![Page 233: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/233.jpg)
![Page 234: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/234.jpg)
iii. Properties of gasket(1)The common-used materials of gasket *Non-metal Material —— Rubber, Asbestos, Synthetic resins. Advantages: soft and corrosion resistant Disadvantages: the properties of high-T resistance and pressure resistance is inferior to the metallic materials. Used in: Common and Medium T; Flange sealing of Medium and Low P devices and pipes.
![Page 235: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/235.jpg)
*Metal (Metallic) Material
—— soft aluminum, copper, iron (soft
steel), 18-8 stainless steel.
Advantages: high-T resistant, with high strength
Demands: Excellent soft toughness
Used in: Medium and high T; Flange sealing
subjected to medium and high P
![Page 236: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/236.jpg)
(2)Gasket Types (Classifying according to the
properties of materials)
*Non-metal Gasket
—— such as rubber gasket, asbestos-rubber
gasket.
*Compound Gasket (Metal and non-metal
compound gasket)
—— such as metal jacketed gasket ( 金属包 垫片 ) and Metal spirotallic [spiral-
wound] gasket (金属缠绕垫)
![Page 237: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/237.jpg)
Metal jacketed gasket ( 金属包垫片 ), i.e.
wrapping the metal slice around the asbestos
gasket or asbestos-rubber gasket
Metal spirotallic [spiral-wound] gasket ( 金属 缠绕垫片 ), i.e. making by alternately rolling
thin steel belt and asbestos
![Page 238: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/238.jpg)
*Metal gasket
—— such as octagon ring gasket, elliptical
gasket, lens ring (washer) [grooved
metallic gasket]
![Page 239: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/239.jpg)
(3)Selection of gasket
*Factors of working pressure and temperature
Medium and low P; common and medium T
—— Non-metal gasket
Medium P; Medium T
—— Metal and non-metal compound gasket
High P; high T —— Metal gasket
High vacuum; cryogenic —— Metal gasket
![Page 240: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/240.jpg)
*Degree of demands for sealing
*Demands for the types of sealing face
*Properties of gasket
Concrete selection should be referred to
JB4704-92, JB4705-92, JB4706-92.
At the same time, the practical experience
should be taken into account.
![Page 241: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/241.jpg)
iv. Rigidity ( 刚度 ) of flange
(1)If the rigidity of flange is not enough, there
will occur the serious buckling [ 翘曲 ]
deformation, as well the specific pressure will
decrease and the sealing face will be loose, as
a result, the sealing will fail.
(2)Measures to increase the rigidity of flangeBolt circle, Outer diameter, ThicknessBolt circle, Outer diameter, Thickness
(3)Strengthening the rigidity of flange to
increase the weight of flange as well the cost
of whole-flange’s sealing.
![Page 242: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/242.jpg)
v. Effect of working conditions
of medium
TemperatureTemperatureTemperatureTemperature
PressurePressurePressurePressure
Corrosive CharacteristicsCorrosive CharacteristicsCorrosive CharacteristicsCorrosive Characteristics
Penetrant CharacteristicsPenetrant CharacteristicsPenetrant CharacteristicsPenetrant Characteristics
Combined effectGreatly affecting the sealing
![Page 243: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/243.jpg)
4.Standard and Selection
of Flanges
i. Standard number of pressure vessel flanges
JB / T 4701-2000 JB / T 4703-2000 ∼
![Page 244: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/244.jpg)
A-S.O.FlangeJB/T 4701-2000
B-S.O.Flange
JB/T 4702-2000
W.N.Flange
JB/T 4703-2000
Plain PlainM&FM M&FMT&G
M FM T G
P
P
P
P
P
P
A
A
A
A
A
A
T
T
T
T
T
T
S
S
S
S
S
S
C
C
C
C
C
C
Type
Sealing
Code
Without lined ring With lined ring (C)face
Standard types and marks of pressure vessel flanges
T&GM FM T G
![Page 245: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/245.jpg)
For example:
PN=1.6MPa, DN = 800mm, T&G C-S.O.Flange
with lined ring
T Flange: C-S 800 — 1.6 JB4702-92
G Flange: C-C 800 — 1.6 JB4702-92
![Page 246: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/246.jpg)
C-S 800 — 1.6 JB4702-92
NominalPressure
MPa
NominalPressure
MPa
Code of Flange TypeCode of Flange Type
Code of Sealing face Type
Code of Sealing face Type
NominalDiameter
mm
NominalDiameter
mm
StandardCode
StandardCode
![Page 247: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/247.jpg)
ii. Dimension of pressure vessel flanges
Dimension of flanges is only confirmed by
two standardized parameters PN and DN of
flanges.
Confirmation of Nominal Pressure PN of
flanges: JB4700-92 (Book, P160)
![Page 248: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/248.jpg)
iii. Selection steps for pressure vessel flanges
(1)According to the design task, confirming
the types of flanges (S.O. or W.N.).
(Referring to P157 Table 6-2)
(2)According to the nominal diameter DN of
flanges , working temperature, design
pressure, material of flanges, confirming
the nominal diameter DN and nominal
pressure PN of flanges.
(Referring to P160 Table 6-4; P332 Appendix 12)
![Page 249: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/249.jpg)
(3)Confirming the sealing face types of flanges and the types of gaskets. (Referring to P155 Table 6-1)
(4)According to the types of flanges, DN and
PN of flanges, checking and finding out the dimension of flanges; number of bolts and their specification. (Referring to P336 Appendix 14)
![Page 250: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/250.jpg)
(5)Confirming the material of bolts and nuts.
(Referring to P163 Table 6-6; P333
Appendix 13)
(6)Portraying the unit drawing of flanges.
![Page 251: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/251.jpg)
Example:
There are flanges to connect the body of a fractionating (rectifying) tower and the heads.Knowns:
Inside diameter of tower: Di = 1000mm Working temperature: t = 280℃ Design Pressure: P = 0.2MPa Material of tower: Q235-AR
![Page 252: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/252.jpg)
Solution:
(1)From P157 Table 6-2, A-S.O.Flange is selected.
(2)Confirming the nominal diameter DN and
nominal pressure PN
DN = 1000 mm (Equal to the inside diameter of tower) From P160 Table 6-4, choose the material of tower as that of flanges, i.e. Q235-AR t = 280 ℃
![Page 253: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/253.jpg)
When PN = 0.25 Mpa,
Pallowable = 0.14 MPa < Pdesign = 0.2 Mpa
When PN = 0.6 Mpa,
Pallowable = 0.33 MPa > Pdesign = 0.2 Mpa
So, the nominal pressure of flanges is:
PN = 0.6 MPa
![Page 254: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/254.jpg)
(3)Confirming the sealing face types of flanges
From P155 Table 6-1, choosing plain sealing
face, spirotallic [spiral-wound] gasket
(4)According to the DN and PN of flanges, from
Appendix 14, Table 32, finding out the
dimension of every part of flanges.
Specification of bolts: M20; Number: 36
![Page 255: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/255.jpg)
(5)From P163 Table 6-6, finding out:
Material of bolts: 35 steel
Material of nuts: Q235-A
(6)Portraying the unit drawing of flanges
(Omitting)
![Page 256: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/256.jpg)
Standard of tube flanges
(New Standard issued by Chemical Ministry)
European: HG 20592 — 97 ~ HG 20600 — 97
American: HG 20615 — 97 ~ HG 20621 — 97
![Page 257: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/257.jpg)
6.2 Support for vessels6.2 Support for vessels
Support for horizontal vessels Saddle support, ring support, leg, etc.Support for vertical vessels Skirt support, hanging support, etc.
![Page 258: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/258.jpg)
1.Double-saddle support i. The structure of double-saddle support
120°
Gasket
Web-plate
Anchor bolt
Sub-plate
![Page 259: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/259.jpg)
ii. Position of support (A)
A≤Do/4 & < 0.2L. The maximum value < 0.25L
iii. Standard and selection of double-saddle
support
Type —— Stationary type: F Movable type: S
Model Type —— Light-duty: A Heavy-duty: B
Mark —— JB / T 4712-92 Support
Model TypeModel Type Nominal DiameterNominal Diameter TypeType
![Page 260: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/260.jpg)
2.Checking calculation of stress in double-saddle horizontal vessels
i. Load analysis for horizontal vessels
![Page 261: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/261.jpg)
Shearing ForceDiagram
Bending Moment Diagram
M1
M2
M3
F FA A
q
![Page 262: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/262.jpg)
ii. Reserved force to support
In this equation:q —— Mass load/unit length of vessels, N / mmL —— Distance between the T.L. (tangent lines) of two heads, mm
hi —— Height of curved surface of heads, mm
2
mgF
ihL
qmgFor
3
4
22
![Page 263: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/263.jpg)
iii. The maximum radical bending moment
The section across the middle point of moment
The section at support
mm)(N
4
3
41
21
4
2
22
1
L
A
L
hL
hRFL
Mi
im
mm)(N 4
3
41
21
4
2
22
1
L
A
L
hL
hRFL
Mi
im
mm)(N
34
1
21
1
22
2
Lh
ALhR
LA
FAMi
im
mm)(N
34
1
21
1
22
2
Lh
ALhR
LA
FAMi
im
![Page 264: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/264.jpg)
iv. Calculation for stress of cylinder
—— to the vessels subjected to internal pressure(1)Stress across the middle section
The most highest point in section (Point 1):
The most lowest point in section (Point 2):eme
mc
SR
M
S
RP
2
21
1
eme
mc
SR
M
S
RP
2
21
1
eme
mc
SR
M
S
RP
2
21
2
eme
mc
SR
M
S
RP
2
21
2
![Page 265: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/265.jpg)
(2)Stress in the section of support
The most highest point in section (Point 3):
The most lowest point in section (Point 4):eme
mc
SRK
M
S
RP
2
21
23
eme
mc
SRK
M
S
RP
2
21
23
eme
mc
SRK
M
S
RP
2
22
24
eme
mc
SRK
M
S
RP
2
22
24
![Page 266: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/266.jpg)
v. Checking calculation for stress of cylindertensile stress
compressive stress
ttensilecomb max. t
tensilecomb max.
luesmaller va the
max..
Bcr
t
compcomb
luesmaller va the
max..
Bcr
t
compcomb
![Page 267: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/267.jpg)
In these two equations:
[]t —— The allowable stress of material at the
design T, MPa
[]c r —— The allowable compressive stress of
material, MPa
B —— Calculation method is the same with that
in design of external pressure, see P172
![Page 268: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/268.jpg)
6.3 Reinforcement for
opening of vessels
1.The phenomena and reason for opening stress concentration
![Page 269: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/269.jpg)
Stress concentration factor:
max —— The maximum stress
at the boundary of opening
* —— The maximum basic
stress of shell
max
K
Small opening in plate
![Page 270: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/270.jpg)
Reasons for stress concentration:
(1)Local Material of vessel wall is decreased
(2)The continuity of structure is
damaged
![Page 271: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/271.jpg)
2.Opening reinforcement’s Designing
i. Designing Criterions
(1)Equi-area criterion of reinforcement
(2)Plastic failure criterion of reinforcement
![Page 272: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/272.jpg)
ii. Reinforcement Structure
(1)Structure of Stiffening Ring
Nozzle (Connecting Tube)
Shell
Stiffening Ring
![Page 273: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/273.jpg)
(2)Structure of 加强元件 Method —— Taking the
parts of nozzles or vicinity of
shells’ openings which need
to be reinforced as the 加强元件 , then welding these
parts with nozzles or shells.
![Page 274: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/274.jpg)
(3)Structure of Integral Reinforcement
Method —— Taking the connecting parts of nozzles and shells as the integral forgings, at the same time thickening them, then welding them with nozzles and shells.
![Page 275: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/275.jpg)
iii. Diameter Range of the openings that need
not to be reinforced
When the following requirements are all met, the reinforcement is out of need.
(1)Design Pressure P ≤ 2.5 MPa
(2)The distance between two mid-points of two nearby openings (taking length of are as the length of curved surface) should be larger than 2× (D1+D2), D1, D2 are the diameters of the two openings respectively.
![Page 276: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/276.jpg)
(3)Nominal Outside Diameter of
connecting tubes ≤ 89 mm
(4)The minimum wall thickness δmin
of connecting tubes should meet
the following requirements:(mm)
δmin
25 32 38 45 48 57 65 76 89
3.5 4.0 5.0 6.0
![Page 277: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/277.jpg)
3.Designing methods of equi-area reinforcement
Metallic areas in local reinforcementMetallic areas in local reinforcement
≥≥
the area of sections which are
the position of openings
the area of sections which are
the position of openings
![Page 278: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/278.jpg)
i. Confirmation of the effective range of opening and reinforcement areas
A1 A3 A4A2A
B
h1
h2
d
![Page 279: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/279.jpg)
Effective width:
Effective [working] height:
Outside height
Inside height
max .22
2
tnn SSdB
dB
min1
.1
nozzle ofheight overhang actual
h
Sdh tn
min2
.2
nozzle ofheight embedded actual
h
Sdh tn
![Page 280: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/280.jpg)
In these equations:
Sn —— Nominal thickness of cylinders
Sn.t —— Nominal thickness of connecting
tubes (nozzles)
d —— Diameter of openings d = di +2C
di —— Inside diameter of openings
C —— Additional value of wall thickness
![Page 281: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/281.jpg)
Computation of metallic areas for
effective reinforcement
(1)The area of the sections on shell which
are the positions of openings A: A = S×d
(2)The unnecessary metallic area A1 on shell or
heads which is larger than calculating thickness S:
A1 = (B – d) (Se – S) – 2 (Sn.t – C) (Se – S) (1 – fr)
![Page 282: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/282.jpg)
(3)The unnecessary metallic area A2 on nozzles
which is larger than the calculating thickness S:
A2 = 2 h1 ( Sn.t – St –C ) fr + 2 h2 ( Sn.t – C – C2 ) fr
(4)The metallic area of welding seam in the
reinforcement region A3:
A3 = according to the actual dimension
![Page 283: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/283.jpg)
ii. Designing Steps in Reinforcement for openings
(1)Getting the following data from the strength
calculation:
Calculating wall thickness of cylinders or heads S
Nominal wall thickness of cylinders or heads Sn
Calculating wall thickness of nozzles St
Nominal wall thickness of nozzles Sn.t
Additional value of wall thickness C = C1+ C2
![Page 284: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/284.jpg)
(2)Calculating the effective reinforcement range
B, h1, h2
(3)Calculating the necessary reinforcement area
A according to P183 Table 6-17
(4)Calculating the available reinforcement area
A1, A2, A3
![Page 285: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/285.jpg)
(5)Judging whether it is necessary to add
some reinforcement area
If A1 + A2 + A3 ≥ A
reinforcement not required
If A1 + A2 + A3 < A
reinforcement required
![Page 286: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/286.jpg)
(6)If reinforcement is required, calculating the
added reinforcement area A4
A4 = A -( A1 + A2 + A3 )
(7)Comparison
Finally getting A1 + A2 + A3 + A4 ≥ A
![Page 287: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/287.jpg)
6.4 Attachment of vessels
1.Man Hole and Hand Holei. Nominal Diameter of standard man-hole
DN : 400 450 500 600
ii. Nominal Diameter of standard hand-hole
DN : 150 250
![Page 288: Section 2 Design of Process Vessels Chapter 2 Panorama](https://reader035.vdocuments.site/reader035/viewer/2022081420/56649d595503460f94a39698/html5/thumbnails/288.jpg)
2.Connecting Tubes (Nozzles) [ 接管 ]
3.Flg (Flange, Flanch) [ 凸缘 ]
4.Sight (Level) Glass [ 视镜 ]