WATER STORAGE TANK DESIGN DESCRIPTION Water storage tanks are containers used to hold and store water
necessary to supply the required amount of water needed in the production in the washing of raw materials and as a feed in sulfuric acid dilution tank. DESIGN SELECTION The storage tank is a cylindrical tank and with a hemispherical head and bottom to eliminate sharp corners or regions into which fluid currents would not penetrate and due to less expensive to produce than spheres. DATA AND ASSUMPTIONS 1. The capacity of the tank is for 1day operation 2. The mass of water needed in the spray washer and sulfuric dilution tank is 22395.5985 kg/batch (based on material balance) and a total of 67186.7955 kg per day operation 3. The density of water at 25C is 997.042 kg/m3 (Perrys Chemical Engineering Handbook 8th edition, sec 2-91) DESIGN CONSIDERATION 1. The filing capacity is 80% 2. Safety factor of 20% 3. The efficiency of tap-welded joints is 80% (Plant Design and Economics for Chemical Engineers, 5th ed, Peters and Timmerhaus, pg. 555 Table 12-10) 4. The minimum corrosion allowance is 1/16 in (Process Equipment Design, Hesse, pg 73) 5. The height to diameter ratio of the tank is 2 (Perrys Chemical Engineering, 7th ed. By Perry and Green, pg. 10-139) 6. A stainless steel type 301 materials of construction is used to avoid negative effect of materials handled and for higher corrosion resistance (Perrys Chemical Engineering, 7th ed. 28-31) 7. The maximum allowable tensile stress for steel of temperature up to 650F is 110000 psi (Process Equipment Design, Hesse, Table 3-3. Pg 62)
DESIGN REQUIREMENTS 1. Capacity of the Tank 2. Tank Diameter 3. Tank Height 4. Thickness of the Shell 5. Head and Bottom Thickness DESIGN CALCULATION 1. Capacity of the Tank
At filing capacity
Safety factor
2. Tank Diameter
Since H = 2D
D = 3.64084 m 3. Total Tank Height Since Height for head and bottom is D/2 (Based on 10-140, Table 10-65 Perrys Chemical Engineering Handbook)
4. Shell Thickness
(Eq. 4-3, page 85, Process Equipment Design by Hesse) Where: = thickness of the plate P = internal pressure D = internal diameter S = allowable working stress e = efficiency C = corrosion allowance
Su = 11000 psi (Table 3.1 Process Equipment Design page 60) Fm = 1.00 for high tensile strength carbon steels Fa = Fr = 1.00 since radiographing and stress relieving is not required Fs = 0.25 (Table 4.2, Process Equipment Design by Hesse, page 84)
Internal Pressure:
5. Head and Bottom Thickness
(eq. 4-8 page 86, Process Equipment Design by Hesse for hemispherical head and bottom) ( )
DESIGN SPECIFICATION WATER STORAGE TANK Identification Item: Number of Required Units: Materials handled: Function: Water Storage Tank 1 Water To store water that would supply the required amount of water for washing and for dilution of sulfuric acid Stainless Steel Type 301
Materials of Construction: Design Data Parameters Capacity Height of the Tank Diameter of the Tank Shell Thickness Head and Bottom Thickness Pressure Head Accessories Cost Source
Propo sed Design 1 01.1 3 1 0.9 3 .7 1 4.5 m 8 m 1 4.4 si
m m m m m p
Existing Design 50 m3 5m 2.44 m _ _ _
P33,000.00
Preheat Engineering and Technical Services Address 406-C D.Reyes Street Pasay, Philippines Pasay 1300
