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A vertical vessel with an internal diameter of 84” has a hemispherical head at the top and an ellipsoidal head of 2:1 at the bottom. The construction material has a maximum allowable stress of 8700 psi at its design temperature. The operating pressure is stated as 48 psig. The overall height of the vessel is 38‟ and a joint efficiency of 1.0 is used.
) Determine the wall thickness of each part of the vessel.
b) If a corrosion allowance of 2 mm is being fixed by the user, determine the wall thicknesses and part MAWPs for each part of the vessel and what is the vessel MAWP?
Data provided in the problem statement
Internal diameter of the vessel = 84 inch
Radius of vessel ( R ) = 84 / 2 = 42 inch
Maximum allowable stress ( S ) = 8700 psi
Operating pressure ( P ) = 48 psi
Height of vessel = 38 inch
Joint efficiency ( E ) = 1
1) Wall thickness of vessel and heads
2)
Corrosion allowance is fixed to 2 mm = 0.07874 inch
New wall thickness of vessel = 0.2324 inch + 0.07874 inch = 0.31114 inch
Thickness of hemispherical head = 0.116 inch + 0.07874 inch = 0.19474 inch
Thickness of ellipsoidal head = 0.232 inch + 0.07874 inch = 0.31074 inch