atmospheric pressure water storage tank in a chemical process plant is planned t

Question

atmospheric pressure water storage tank in a chemical process plant is planned to be drained out for internal maintenance purpose. The tank has a cylindrical geometry with internal diameter of 50 ft and height of 30 ft. The draining pump unfortunately is not working, andTit is therefore decided to empty out the tank (80% filled) by opening a drain valve mounted on a 4" outlet (nominal pipe size (NPS), Sch 405, stainless steel, see attached pipe size chart) located at 6" above the ground level at the bottom of the tank. Determine a) Time required to empty out the tank to the extent possible b) Average flow rate of water at the valve discharge 10

Explanation / Answer

Time required to empty tank=(D^2)/(C*d^2) ((2h)/g)

C = Orifice discharge coefficient, 1.0

d = diameter of drain pipe diameter, m = 0.1016

D = Tank diameter, m = 15.24

g = Acceleration due to gravity, 9.8066 m/s2.

h = Vertical distance from center line of drain pipe to liquid surface, m = 30*12 – 6 + 0.1016/2

                                                                                = 360 – 6 + 0.0508
                                                                                = 354.0508 inches

Time required to empty tank, t = (15.24)^2/(1.0*0.1016^2)*(2*8.99/9.8066)^(1/2)

t = 30466 sec
t = 507.76

Flow rate will chnage with water height in tank

you can calculate flow rate at outlet nozzle using:

Q = A*V

V = velocity = (2gh)^1/2

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.