Sulfuric Acid Storage Tank: Technological Institute of The Philippines [PDF]

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Technological Institute of the Philippines

18. SULFURIC ACID STORAGE TANK EQUIPMENT SPECIFICATION SHEET CODE

T-103

NAME

Sulfuric Acid Storage Tank

TANK VOLUME

11.3611 m3

TANK CAPACITY

17.0417 m3

TANK DIAMETER

2.1425 m

TANK HEIGHT

4.5 m

DESIGN PRESSURE

200.1321kPa

WORKING PRESSURE

181.9381kPa

SHELL THICKNESS

4.4139 mm

HEAD AND BOTTOM THICKNESS

2.0025mm

NUMBER OF EQUIPMENT

1

MATERIAL OF CONSTRUCTION

Carbon Steel

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Technological Institute of the Philippines

SULFURIC ACID STORAGE TANK

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Technological Institute of the Philippines

17. SULFURIC ACID STORAGE TANK Design Description: Sulfuric Acid Storage tank is a container used to hold and store water in its operating parameters and to withstand the pressure to maintain at its phase.

Design Description: The storage tank is a cylindrical tank and with a torispherical head and bottom to eliminate sharp corners or regions into which fluid currents would not penetrate.

Data and Assumptions: 1.) The capacity of the tank is for 7 day operation 2.) The mass of sulfuric acid needed in the mixer is 2963.88 kg/day. (refer to the material balance) 3.) The density of sulfuric acid at 98% is 1826.1 kg/m3(Perry’s Chemical Engineering Handbook 8th edition, sec 2-91)

DESIGN CONSIDERATION 1. The filing capacity is 80% 2. Safety factor of 2 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 4 in (Process Equipment Design, Hesse, pg 73) 5. The height to diameter ratio of the tank is 2 (Perry’s Chemical Engineering, 7th ed. By Perry and Green, pg. 10-139) 6. A 316 Stainless Steel material of construction is used to avoid negative effect of materials handled. (Coulson and Richardson, 4th ed. p296). 7. The maximum allowable tensile stress for a 316 Stainless Steel of temperature is 579 MPa (Stainless Steel Handbook, D Gandy p5-6)

Design Calculation:

Feed Flow rate = 2963.8

kg day

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ρH2SO4 = 1826.1

kg m3 kg

Feed Volumetric Flow Rate =

2963.8 day kg

1826.1 m3

m3 Feed Volumetric Flow Rate = 1.623 day For 7 days storage operation: Total Feed Volume = (1.623

m3 ) (7 days) day

Total Feed Volume = 11.3611 m3 Tank should be 80 % full, 11.3611m3 V= 0.80 V = 14.2014m3 Tank Volume Volume allowance of 20% [Pressure Vessel.Couper,J.R., Penney,W.R.,, Fair, J.R., Walas, S. M. (2004). Chemical Process Equipment: Selection and Design] Vtank = 1.2V Vtank = 1.2(14.2014 m3 ) Vtank = 17.0417m3 Solving for the diameter using torispherical head (Silla, 2003): 𝑉𝑡𝑜𝑟𝑖𝑠𝑝ℎ𝑒𝑟𝑖𝑐𝑎𝑙 = 0.0809𝐷3

Vtank =

𝜋 2 𝐷 𝐻 + 2(0.0809𝐷3 ) 4

Where: D=diameter

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H=2D (Perry’s Chemical Engineering Handbook. 7th Edition. Perry,R., Green, J.. Page 10139)

𝜋 3 𝐷 + 2(0.0809𝐷3 ) 2 𝜋 17.0417 m3 = 𝐷3 + 2(0.0809𝐷3 ) 2 Vtank =

𝐷 = 2.1425 𝑚 Tank Height 𝐻 = 2𝐷 𝐻 = 2(2.1425 𝑚) 𝐻 = 4.2851 𝑚 Use 4.5 m as tank height.

Working Pressure 𝑃𝑡𝑜𝑡𝑎𝑙 = 𝑃𝑜𝑝𝑡𝑖𝑚𝑢𝑚 + 𝜌𝑔𝐻 Since the tank is vented,𝑃𝑜𝑝𝑡𝑖𝑚𝑢𝑚 = 101.325 𝑘𝑃𝑎 𝑃𝑡𝑜𝑡𝑎𝑙 = 101.325 𝑘𝑃𝑎 + [(1826.1

kg m kPa ) (9.81 2 ) (4.5 𝑚)] ( ) 3 1000 𝑃𝑎 m s

𝑃𝑡𝑜𝑡𝑎𝑙 = 181.9381 𝑃𝑎 = 𝑃𝑤𝑜𝑟𝑘𝑖𝑛𝑔

Design Pressure

Maximum Operating Pressure=10% Working Pressure [Pressure Vessel.Couper,J.R., Penney,W.R.,, Fair, J.R., Walas, S. M. (2004). Chemical Process Equipment: Selection and Design] 𝑃𝑑𝑒𝑠𝑖𝑔𝑛 = 1.1𝑃𝑤𝑜𝑟𝑘𝑖𝑛𝑔 𝑃𝑑𝑒𝑠𝑖𝑔𝑛 = 1.1(181.9381 𝑘𝑃𝑎) 𝑃𝑑𝑒𝑠𝑖𝑔𝑛 = 200.132 𝑘𝑃𝑎 ≈ 0.2001𝑀𝑃𝑎

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Shell Thickness From Table 13.2 Typical Maximum Allowable Stresses for Plates Under ASME BPV Code Sec. VIII D.1 (The Appropriate Material Standards Should be Consulted for Particular Grades and Plate Thicknesses),

𝑆 = 88.9

𝑁 ≈ 88.9 𝑀𝑃𝑎 𝑚𝑚2

Computing for the shell thickness, ts =

P𝐷𝑖 +C 2𝑆𝑒 − P

Corrosion Allowance=2 mm t=

(0.2001 MPa)(2142.5 mm) + 2 𝑚𝑚 2(88.9 𝑀𝑃𝑎)(1) − (0.2001 MPa ) t = 2.4139 mm + 2 mm 𝒕𝒔 = 𝟒. 𝟒𝟏𝟑𝟗 𝐦𝐦 ≈ 𝟎. 𝟎𝟎𝟒𝟒 𝐦

Shell Outside Diameter t s = D𝑜 − Di D𝑜 = 0.0044 m + 2.1425 m D𝑜 = 2.1469 𝑚 Use 2.5 m as Outside Diameter

Head and Bottom Thickness For Torispherical head thickness: th =

Pi R c Cs 2Jf + Pi (Cs − 0.2)

Where: Rc = crown radius Rk = Knuckle radius Cs = Stress Concentration f = design stress J = joint factor Pi= internal pressure

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Crown Radius, Rc

R c = Do R c = 2.1469 𝑚 Knuckle Radius, Rk R k = 0.06R c R k = 0.1288 𝑚 Stress Cocnentration, Cs 1 2.1469 𝑚 𝐶𝑠 = [3 + √ ] 4 0.1288 𝑚 𝐶𝑠 = 1.7706 𝑚 For Allowable Working Stress in Carbon Steel 𝑆 = 𝑆𝑢 𝐹𝑚 𝐹𝑎 𝐹𝑟 𝐹𝑠 Su = 110000 psi (Process Equipment Design, Hesse, Table 3-3. Pg 62) Fs = 0.25 (Fig 2.6, Process Equipment Design by Brownell and Young, p25) Fm = 1 for Carbon Steel Fa = Fr = 1 since radiographing and stress relieving is not required 0.00689476 𝑀𝑝𝑎 𝑆𝑒 = (110000 𝑝𝑠𝑖) ( ) (1)(1)(1)(0.25) 1 𝑝𝑠𝑖 𝑆𝑒 = 189.6059 𝑀𝑃𝑎

Head Thickness th = th =

Pi R c Cs +𝐶 2Jf + Pi (Cs − 0.2)

(0.2001 MPa)(2.1469 𝑚)(1.7706 m) + 2 𝑚𝑚 2(0.8)(189.6059 MPa) + [(0.2001 MPa)(1.7706 𝑚 − 0.2)] t h = 0.002 m ≈ 2.0025 mm

Bottom Thickness t b = t h = 0.002 m ≈ 2.0025 mm

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