Pressure Vessel Design and Safety
Pressure Vessel Design and Safety
Pressure Vessel Design and Safety
The codes used in our country for the UFPV ( Unfired Pressure Vessels) are:
2. OVER PRESSURE PROTECTION
Safety by Pressure Relief Devices
A) General
All pressure vessels, irrespective of size or pressure, shall be provided with over pressure
protection in accordance with the requirements as per the code and system design
In addition following shall apply:
(1) It is the user’s responsibility to identify all potential over pressure
and the method of overpressure protection used to mitigate over pressure
(2) It is the responsibility of the user to ensure that the required over pressure
protection system is properly installed prior to initial operation.
(3) It is the responsibility of the user or his/her designated agent to size and select
the pressure relief device(s) based on its intended service.
The Intended service considerations shall include the following:
(a) normal operating and upset conditions
(b) fluids
(c) fluid phases
(4) The overpressure protection system need not be supplied by the vessel Manufacturer
(c) When a pressure vessel can be exposed to fire or other unexpected sources of external
heat, the pressure relief device shall be capable of preventing the pressure rise more than
21% above Max Allowable pressure
(C) LOCATION
Pressure relief devices shall be constructed, located, Installed such that they are readily
accessible for testing, inspection, replacement & repair and so that they do not
become inoperative
d) Relief valve
It is a pressure relief valve actuated by inlet static pressure which opens in proportion to
the increase in pressure over the opening pressure.
HOLDER A rupture disk holder is the structure that encloses and clamps the
rupture disk in position.( Flange End, Screw etc.)
(a) A pin device may be used as the sole pressure relieving device on a vessel
* It can be installed between the vessel and pressure relief valve
In a manner same as rupture disc and capacity with all its limitation
We all are aware that the design, installation of the over protection system is a solely
responsibility of the pressure vessel user, they can either design the pressure vessel at
higher working capacity or adopt pressure relieving device by proper selection and
installation of instruments over pressure protection system. It ma be in combination of
both devices
I would like to recommend a High‐Pressure _Trip Systems for the pressure vessel
protection when run away reaction occurs .
The oxidation , Hydrogenation , polymerisation etc are few examples
It will be difficult to install relief valves that are large in size and to be open quickly enough
to avoid over pressuring the equipment.
2. OVER PRESSURE PROTECTION
a)Design, Select & Install A High ( rising) pressure sensor & Pressure
switch on the overhead Gas/Vapour /Vent line to operate and activate a relay
contactor
b) The relay contactor should stop the power supply line connected with the
heating device either by hot water pump or Hot oil pump
c) Select and install a solenoid valve associated with trip valve installed on the
steam/Hot water/Hot oil supply line use to heat Pressure Vessel or Reactor