Transcript Vessel Design

Design of Vessels Under External
Pressure
Design of Shell:
“k” can be get from the following graph:
Design of heads:
Hemispherical head:
Dished head:
Elliptical head:
Conical bottom:
i.
If 2  45  :
L

D
ii.
h
D ish
If 45  2  120  :
L
 1
D
iii.
If 2 120  :
Get the thickness of the conical bottom from:
1.
A Vacuum crystallizer of 1.25
m inside
diameter is to be fabricated from mild steel
(σall = 1000 Kg / cm2). Conical bottom with
a height of 1.1 m is to be fabricated; the
shell is 3.25 m in length. The crystallizer is
to be designed for full vacuum service.
Calculate:
i-Thickness of the shell.
ii-Thickness of the conical bottom.
iii-Thickness of the top head (Dished head).
Operation
12 psi
8 psi
Preheating
Steam
Shut Down
0 psi
12 psi
8 psi
Vessel : Under internal Vessel : Under External
8>0
12 > 8
Jacket : Under internal Jacket : Under internal
8>0
8>0
0 psi
Vessel : Under internal
12 > 0
Jacket : Under internal
0=0
“Jacket”
under internal
“Vessel”
under internal
(any one of them)
under external
Take
tsh
&
th
Operation
Preheating
5 psi
0 psi
10 psi
10 psi
Vessel : Under External Vessel : Under External
10 > 0
10 > 5
Jacket : Under internal Jacket : Under internal
10 > 0
10 > 0
Steam
Shut Down
5 psi
0 psi
Vessel : Under internal
5>0
Jacket : Under internal
0=0
“Jacket”
under internal
“Vessel”
under external
(with Pact )
under internal
Take
tsh
&
th
2.
It is required to design a jacketed vessel which
will be placed indoor. The vessel has an internal
diameter of 1.5m, length of 3m and the jacket
has an internal diameter of 1.8 m. The maximum
operating pressure in the vessel is 22 Kg / cm2
and the working temperature is 150ºC.The
steam passes in the jacket with a pressure 11 kg
/ cm2 for heating purpose. The vessel and jacket
are fabricated from carbon steel with σall
=1000 Kg / cm2.
Calculate:
i-Thickness of the vessel and its bottom.
ii-Thickness of the jacket and its bottom.
Note: the type of bottom heads is elliptical.