Design of pressure vessel with codes

1. The very important phase to construct a pressure vessel is
“DESIGN PHASE” Design phase is carried out with the
care with the help of “CODES ” . The values of which
ensure the safety performance of vessel .
α INTRODUCTION:-
“ PRESSURE VESSELS ARE VESSELS WORKING
UNDER INTERNAL OR EXTERNAL / VACUUM
PRESSURE WITH VARIOUS TEMPERATURES
CONDITION.”
Pressure vessel is the basic equipment for
any processing system. The liquid and gaseous
hydrocarbons are processed in this vessels.
These processes are: -
• Regeneration
• Separation
• Splitters
• Buffers
• Chemical Reaction
These processes take place only in predetermined
pressure and temperature conditions.

2. In this modern era, there is need for petrol, diesel
And various petrochemical products. It difficult to think life
without any petrochemical products. This product reaches
passing through refineries and petrochemicals plants after
various processes. It means process industries become primary
requirements.
η PROCESS OF MANUFACTURINGPROCESS OF MANUFACTURING
PRESSURE VESSELS:-PRESSURE VESSELS:-
As we know understand the criticality of pressure
vessel
This becomes mandatory to take the care in each example
every stage of. Manufacturing of pressure vessel
Any disobey of code rule may be lead to either chemical
leakage or explosion of vessel. We must remember the code of
union carbide at “BHOPAL”, where the poisonous gas leakage
took place and 1000’s of people took their lives.
The processes of manufacturing of pressure vessel can be
classifies as:
 Design Phase
 Material procurements phase
 Testing Phase
 Transportation / Handling phase

3.  Erection and commissioning Phase.
χ TYPES OF PRESSURE VESSELS:-TYPES OF PRESSURE VESSELS:-
There are various types of Pressure Vessels defined base upon
its construction and manufacturing.
 Single-wall Vessel
 Multi-wall Vessel
 Claded Vessel
 Overlayed Vessel
 High thick Vessel.
χ MATERIAL FOR PRESSURE VESSELS:-MATERIAL FOR PRESSURE VESSELS:-
• Carbon Steel
• Carbon Manganese steel
• Carbon Manganese Silicon Steel
• Chromium Steel
1. 1Cr.-0.5Mo. Steel
2. 2Cr- 1 Mo. Steel
3. 2- ¼ Cr. - ½ Mo. Steel
• Stainless steel
• Titanium
 Generally Carbon Steel is used to construct vessels. But
Sometimes where the corrosion is higher than the
Normal corrosion at that time Stainless Steel may be
Used or sometimes Titanium is also used due to process

4. Requirement and highly corrosive condition.
χ DESIGN OF PRESSURE VESSELS:-DESIGN OF PRESSURE VESSELS:-
Pressure Vessel is contain following main equipment.
 SHELL
 DISHED END [ D’END]
 NOZZLES
 MANWAYS
 LUGS
 SUPPORTS

5. But in this Report we are looking only for Design of SHELL,
DISHED END & NOZZLES.
As Shown in the figure. “The portion between Top D’end and
Bottom D’end is known as SHELL”
Shell is made from rectangle plate. The material used to
make a shell is SA516 GR 70. SA means in India we describe
the material in IS. While in America they are described their
standard which is called SA. SA516 means Carbon Steel and GR
THICKNESS OF SHELL

6. means Grade. Grade is depending upon the different material
which we used for Pressure Vessel.
 The thickness of shell is depending upon the type of shell and
stresses. Generally Shell can be classified in 2 categories.
1. Cylindrical Shell
2. Spherical Shell
 Stress can also classified in 2 categories.
1. Circumferential Stress
2. Longitudinal Stress
 Thickness for Cylindrical Shell :-
 Circumferential Stress
T = PR +C.A. OR P = SEt + C.A.
SE - 0.6P R + 0.6t
 Longitudinal Stress: -
T = PR +C.A. OR P = 2SEt + C.A.
2SE + 0.4P R - 0.4t
 Thickness for Spherical Shell :-
T = PR +C.A. OR P = 2SEt + C.A.
2SE - 0.2P R + 0.2t
Here,
P = Internal Design Pressure

7. t = Minimum Required thickness of Shell in inches.
R = Inside radius of Shell
S = Maximum Allowable Stress value in Psi
E = Joint Efficiency
Shown in the figure , the portion above and below the shell
is known as “ DISHED-END OR HEAD ”.
The portion above the shell is known as
“ Top Dished-End ” and the portion below the shell is known as
“ Bottom Dished-End ” .

8. There are many Types of Dished-End like :-
 Hemispherical head
 Elliptical Head
 Torispherical Head
 Conical Head
 Toriconical Head
[1] HEMISPHERICAL HEAD:-HEMISPHERICAL HEAD:-

9. As the name implies ,. The profile of this type head is half
sphere. This type of head has through out constant radius This
is also widely used especially for high thick vessel like
REACTORS.
It’s benefit is it gives half thickness but when we have very small
space at that time it is not use .
The thickness of the Hemispherical D’end is calculated by
Following formula:-
T = PL + C.A.
2SE - 0.2P
FIGURE
THICKNESS

10. [2][2] ELLIPTICAL HEAD:-ELLIPTICAL HEAD:-
This type of head consist of 2:1 ellipse profile as shown in
the figure. This type of head is widely used in pressure vessel
which is used in Tower.
The thickness of the Elliptical Head is calculated by following
formula:-
T = PD + C.A.
2SE - 0.2P
[3] TORISPHERICAL HEAD:-[3] TORISPHERICAL HEAD:-
FIGURE:-
THICKNESS

11. As shown in figure. This type of head consist of profile
generated by two different circle having crown radius and
knuckle radius. There various aspects for selection of type
head like volume inside of head are used for low thick vessel.
The thickness of Torispherical Head is calculated by following
formula
T = 0.885 PL + C.A.
SE - 0.1P
[[4] CONICAL HEAD:-4] CONICAL HEAD:-
FIGURE
THICKNESS:
-

12. As shown in the figure, this type of head consist of inside radius
of cone head at the point under consideration measured
perpendicular to the longitudinal axis. This is not generally used
as a dished end of Pressure Vessel because this is worked under
lower pressure.
The thickness of Conical head is measured by following
formula:-
T = PD + C.A.
2Cosά (SE - 0.6P)
[5] TORICONICAL HEAD:-[5] TORICONICAL HEAD:-
FIGURE
THICKNESS

13. This type of head consist of profile generated by different radius
like crown radius, knuckle radius etc. This type of head is used
when there is different diameter of shell are used and we want to
join these to shell.
The thickness of Toriconical head can calculate by following
formula:-
T = PDi + C.A.
2Cosα(SE - 0.6P)
Here, Di = L X 2Cosα
FIGURE
THICKNESS

14. Νοzzle are opening in vessel for various purpose like inlet ,
outlet , pressure indicator , level indicator ,etc.
CONSTRUCTION :-
There are various constructions available in code , which
is allowed for pressure vessel . As defined earlier , the nozzle are
opening in vessel . Hence the compensate the strength of cutout ,
the nozzle are reinforced using various constructions . To
elaborate little more , when we make cutout in shell reduces in
that local region & to compensate this reduction strength nozzle
are reinforced .
The various construction are :-
1. Nozzle with Pipe & Flange
2. Nozzle with Pipe , flange & reinforcement pad
3. Long weld neck type nozzle
4. Self Reinforced Nozzles

15. [1] FLANGE PIPE CONSTRUCTION :-
This type construction consist of a flange with pipe
intruding vessel wall. The flanges used in such
construction are generally standard flanges from
ASME B16.5. These flanges of forged grain structure.
Another important part is pipe which is either seamless
or fabricated from plate with long seam. Seamless
Pipes are manufactured using extrusion methods.
These type of nozzles are either SET-IN type (in which
pipe enters till inside of vessel ID) or SET-ON type (in
which pipe up to OD of vessel).Generally, this type of
nozzles are used for low pressure services.

16. [2]Flange Pipe Construction with Reinforcement
pad :
This type of construction is similar like Flange type
construction with difference of additional reinforcement
provided to compensate the reduction in strength due
to cutout in vessel wall, using pad. As can be nicely
understood from figure the pads are provided outside
the vessel wall & welded with shell using fillet welds.
These pads are provided with 1 or 2 No of holes which
is used for removal of hot gases between pad & vessel
wall during heat treatment. These holes are also used
for air test of pad weld with shell.

17. [3] Long Weld Neck Construction:
This is another type of construction widely used in
pressure vessel. The constructional details can be
seen in figure. Long weld neck flanges are the flanges
manufactured as per manufacturer standards like
Taylor Forge. These flanges are readily available in
market with various lengths. ASME Code allows use
these flanges in ASME jobs.

18. [4]Self Reinforced Nozzles:
This is the most widely used construction of High thick
vessel & reactors. In this type of construction, the
nozzle opening is made of forged material machined to
suit the shape required for reinforcement of nozzle
cutout. This construction allows very pressures &
temperatures.