Basics Of Pressure Vessels 4p151y

A short Presentation on Basics of Pressure Vessels October 5, 2015

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A pressure vessel (Fig. 1) is a closed container designed to hold gases or liquids at a pressure substantially different from the ambient pressure. Basic type of vessel: 

Vertical pressure vessel



Horizontal Pressure Vessel

There are various method used to vessels,



Lug



Ring



Skirt



Leg



Saddle

Types of end attached to the vessels are 

Dish ends



Conical ends



Flat Ends

Fig. 2 shows general configuration of a pressure vessel.

ﾧ

Fig. 1: A typical pressure vessel for a process plant

Design Input:

While deg pressure vessel following inputs are required 

Internal Pressure / External Pressure



Design temperature



Material of constructions



Type of



Type of loading (wind load/seismic loading/snow loading)

Design Formula: Basic formula for deg the cylindrical shell is σ = PD/2t Therefore

t = PD/2σ

Where, 

t = thickness of shell



P = internal pressure



D = diameter of shell



σ = tensile stress

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Fig. General

2:

Configuration of a typical pressure Vessel This basic formula is modified in international design codes. For ASME Sec VIII, thickness of the cylinder is calculated by following formula (Fig. 3) ﾧ

Fig. 3: Formula for calculation of pressure vessel shell thickness Where , 

t = thickness of shell



P = internal pressure



R = radius of cylinder



S = tensile stress



E = t efficiency

Refer ASME Sec VIII Div 1 for design formulas for all sections of the vessel/cylinder. Type of Pressure Vessels: 

Vessel ed on Lug (Fig. 4)



Vessel ed on Skirt(Fig. 4)



Vessel ed on Leg(Fig. 4)



Vessel ed on Saddle(Fig. 5)

ﾧ

Fig. 4:

Various types of s for pressure vessel

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Fig. 5: Pressure Vessel ed on Saddle Vessel Parts: 

Shell, head



Nozzles



Flanges



Gaskets



Internals



Platforms & ladders

Design codes used for Pressure Vessel: 

EN 13445: The current European Standard, harmonized with the

Pressure Europe. 

Equipment

Directive

(97/23/EC).

Extensively

used

in

ASME Code Section VIII, in addition ed by Sections II

(materials), V (NDT/NDE) and IX (welding). Published by the American Society of Mechanical Engineers. 

ASME Code Section VIII Division 1: US standard, design by

formula. Almost exclusively used in North America, widely used worldwide. 

ASME Code Section VIII Division 2: Alternative Rules, design by

analysis. 

ASME Code Section VIII Division 3: Alternative Rules for

Construction of High Pressure Vessel 

BS 5500: Former British Standard, replaced in the UK by EN

13445 but retained under the name PD 5500 for the design and construction of export equipment. 

AD Merkblätter: German standard, harmonized with the Pressure

Equipment Directive. 

EN 286 (Parts 1 to 4): European standard for simple pressure

vessels (air tanks), harmonized with Council Directive 87/404/EEC. 

BS 4994: Specification for design and construction of vessels

and tanks in reinforced plastics. 

IS 2825-1969 (RE1977) : code unfired Pressure vessels

Internal used in Pressure Vessel: Internals are used to separate liquid from mixture of liquid & vapour. Refer Fig. 6

ﾧ

Fig. 6: Pressure Vessel Internals. Example of Pressure Vessel (Fig. 7): 

Separator



Scrubber



Distillation Column



Shell & Tube Heat Exchanger



Reactors

ﾧ

Fig. 7: Figure showing various types of pressure vessels. Material of Construction most widely used: 

Carbon steel and Cladding Plates



Stainless Steel



Duplex Stainless steel



Fibre Glass Reinforced Plastic

Applications: 

Refinery and Petro-chemical



Fertilizer



Oil and Gas



Chemical

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