Chapter 9 Factors Influencing the Design of Vessels - FET

Department of Chemical EngineeringStrength of Materials for Chemical Engineers (0935381)Chapter 9Factors Influencing the Design of VesselsA- Most Common Types of Vessels:• Open tanks.• Flat-bottomed, vertical cylindrical tanks.• Vertical cylindrical and horizontal vessels with formed ends.• Spherical or modified spherical vesselsB- Factors Influencing the Choice of Vessel:• The function and location of the vessel• The nature of the fluid• Operating temperature and pressure• Necessary volume for storage or capacity for processing.C- Usage:• Large volume of no hazardous liquids, such as brine and other aqueous solutions,may be stored in pounds or in open tanks.• If the fluid is toxic, combustible, or gaseous in the storage condition or if thepressure is greater than atmospheric, closed system is required.• For storage of fluids at atmospheric pressure, cylindrical tanks with flat bottomand conical or domed roofs are commonly used.• For small volumes under pressure, cylindrical tanks with formed heads are used.• For large volumes under pressure, spheres are used.D- Welding:1- T welds:

2- Butt welds:3- Plug welds:4- Lap welds:5- Edge welds:♣ The plates of the shell may be butt or lap-welded depending upon the design andeconomic consideration.♣ 5/8 in is the maximum plate thickness for lap-welded horizontal joints.♣ 3/8 in is the maximum plate thickness for lap-welded vertical joints.♣ Butt-welded joints may be used for shell plates for all thicknesses up to and including1 ½ in.♣ The plates for butt-welded joints must be squared.

♣ Squaring of the plates for lap-welded joints is not necessary♣ Plates for lap-welded joints are less expensive.