Question

A storage tank for concentrated nitric acid will be constructed from aluminum to resist corrosion. The tank is to have an inside diameter of 6 m and a height of 17 m. The maximum liquid level in the tank will be at 16 m. Estimate the plate thickness required at the base of the tank. Take the allowable design stress for aluminum as 90 /^2.

Answer 1

Answer: P = ρ x g x H

Explanation:Where

ρ = density of water = 1000kg/m³

H = Height of the tank = 10m

g = acceleration due to gravity = 9.81m/s²

Substituting these values into ----- Eqn 1 gives

P = 9.81 x 10⁴Pa

Now for cylindrical shaped vessel,

The Longitudinal stress σ1 = P x r / 2 x t

where t= tank thickness = 10mm = 0.01m

r = tank radius = 2m

substituting these values into eqn2 gives

σ1 = 9.8 x 10⁶Pa

But from the mohr's circle stress analysis, we have

The maximum normal stress σm = σ1m = 2 x 9.8 x 10⁶Pa = 19.6MPa

The maximum shear stress σ1s = 9.8 x 10⁶Pa = 9.8Mpa