Design of Cone Roof Type Storage Tanks For

Guided bySubmitted by

ABSTRACTy Storage tanks are used for intermediate and final y y y y

product storage Petroleum products and chemicals are stored Used for mixing, blending, precipitation and setting process For storing Furnace Oil we use Cone Roof type Storage Tanks Efficient storage and better safety are to be concentrated while designing storage tanks

BPCL ,Ambalamugaly Formerly known as Kochi Refinery is now owned by Bharat Petroleum Corporation Limited y Location : Ambalamugal in Kochi y Refining Capacity : 9.5 million metric tons per annum y Products : LPG, Petrol, diesel, kerosene, ATF, FO(Furnace Oil), Naphtha, Benzene, Rubberized bitumen, MTO(mineral turpentine oil), SPBS(Specialized Boiling point Solvent) & Bitumen emulsion

INTRODUCTION TO STORAGE TANKSy Storage tanks are used for the intermediate and final

product storage in process plant or for storing petroleum products and chemicals at terminals y Can be used for Mixing, blending, precipitation and setting process or as chemical reactor vessels y Tanks are classified on the basis of product which is to be stored

FURNACE OILy Class C Petroleum product y Bunker fuel, furnace oil , Fuel oil are other names for

the same product.y Flash point standard is 66 degree C y Specific Gravity as per BPCL is 0.95 kg/mm3

TYPES OF STORAGE TANKSy Cone roof type y Floating roof type y Floating cum cone roof tanks y Spherical Vessels

CONE ROOF TANKSy Cone roof tanks have fixed and are in a sense close

vessels

y They have a conical top and are used for storing less

volatile products

y Asphalt, vaccum gas oil, fuel oil, seal oil etc can be

stored

y 32 cone roof tanks are there in BPCL Kochi

CONE ROOF TYPE

FLOATING ROOF TYPE

FOAM SYSTEMy Foam for firefighting purposes is an aggregate of air filled bubbles formed from aqueous solutions and is higher in density than the lightest flammable liquid Used to form a floating blanket on flammable and combustible liquids lighter than water and prevents or extinguishes fire by excluding air and cooling the fuel

Floating cum Cone Roof Tanksy They have fixed cone roof in addition to floating roof y Are intended to store toxic product having high vapour

pressure y Products like benzene and toluene are stored y Prevent the product from contamination and are used to store class A and class B products y There are 13 floating cum cone roof tanks in BPCL Kochi

PARTS OF STORAGE TANK Bottom plates and Annular plates Draw off Sump Shell Shell openings y Shell Manhole y Yield and Suction Nozzles y Water Drain and Roof Drain Wind Girder Cone Roof Foam System Cooling System

Why use Cone Roof type ??y Furnace oil has a flash point of 23 degree C and above

but below 65 degree C

y As we have to store furnace oil we shall use cone roof

type since it is a class C petroleum product

y They are less expensive compared to floating roof type

and they don t get vaporized fast. So we can use cone roof type since its more economical

Material Specification for Storage Tanksy Low Carbon steels are used as they are soft and ductile y After comparing the values for ASTM A36, A537 and

A537 For Shell plates ,The most cost effective material has been decided as ASTM A537 CLASS 1y Minimum Tensile Strength : 385 Mpa y Minimum Yield Strength : 485 Mpa

y For bottom plates, annular plates : IS2062 grade A y Minimum Tensile Strength : 247.6 Mpa y Minimum Yield Strength : 410.6 Mpa

Design of Storage Tank for Furnace OilTank Selection : Fixed Cone Roof type Height and Diameter : 14m and 36m Capacity : 14,230 m3 Design Code : API 650 Product Stored : Furnace Oil Design Specific Gravity of Product : 0.95 kg/mm3 Design Pressure : atmospheric pressure Corrosion allowance : 2 mm for annular, shell, roof and bottom plates y Wind Speed : 150.93km/hr y Maximum Rainfall intensity : 57mm in one hour or 254 mm in 24 hrsy y y y y y y y

Design of bottom platesy According to API 650 all bottom plates must have

thickness of 6mm exclusive of corrosive allowance y Bottom plates : 6 + CA = 6 + 2 = 8 mm y As the available size of plates in markets are 6m ,8mm, 10mm etc we have to consider 8 mm thickness for bottom plates y Available sizes of plates are of width 1.5m, 2m, 2.5, etc.

SHELL PLATES

SHELL DESIGNy If the diameter is in the range 36 to 60m the nominal

plate thickness to be considered is 8mm y Minimum allowable design stress ,(Sd)Sd = 2/3 * yield strength = 2/3 * 345 = 230 Sd= 2/5 * tensile strength = 2/5 * 485 = 194 Taking minimum Sd = 194 Mpa

y Minimum allowable hydrostatic stress ,(St)St = 3/4 * yield strength = 3/4 * 247.6 = 258.75Mpa St= 3/7 * tensile strength = 3/7 * 410 = 207.86 Mpa Taking minimum St = 208 Mpa

SHELL DESIGN (API 650)5.3.1 5.3.1.1 General The required shell thickness shall be the greater of the design shell thickness, including any corrosion allowance, or the hydrostatic test shell thickness, but the shell thickness shall not be less than the following:

5.3.1.3

The design shell thickness shall be computed on the basis that the tank is filled to a level H (design liquid level) with a liquid that has a specific gravity specified by the purchaser. The hydrostatic test shell thickness shall be computed on the basis that the tank is filled to a level H (design liquid level) with water. The calculated stress for each shell course shall not be greater than the stress permitted for the particular material used for the course. No shell course shall be thinner than the course above it.

5.3.1.4

5.3.1.5

5.3

SHELL DESIGN : (Cont.)

5.3.3

Calculation of Thickness by the 1-Foot Method

5.3.3.1 5.3.3.2

The I-foot method calculates the thickness required at design points 03 m (I ft) above the bottom of each shell course. The required minimum thickness of shell plates shall be the greater of the values computed by the following formulas:

In SI units:

td = 4.9D(H Sd t t = 4.9D(H St

0.3)G

+ CA

03)

5.3 where

SHELL DESIGN : (Cont.)

td = design shell thickness, in mm, tt = hydrostatic test shell thickness, in mm, D = nominal tank diameter, in m r of the top joined (that is, the shell plate or the bottom H = design liquid level, in .mm, = height from the bottom of the course under consideration to the top angle, if any; to the bottom of any overflow that of the shell including the top limits the tank filling height; or to any other level specified by the purchaser, restricted by an inter-nal floating roof, or controlled to allow for seismic wave action, G = design specific gravity of the liquid to be stored, as specified purchaser, CA = corrosion allowance, in mm, as specified by the purchaser Sd = allowable stress for the design condition, in MPa St=allowable stress for the hydrostatic test condition, in MPa

by the

In page 3.6.1.1

CASE 1 I Can be divided into 6 courses as 2 II 2 III 2.50 IV 2.5 V 2.5 VI 2.5

Course 1 Nominal Tank Diameter in meters D = Height from bottom of the course = under consideration to the top of shell H Design stress to be considered Sd = Corrosion Allowance = Specific Gravity G = Max hyd stress to be considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St Max thickness Thickness selected t Width of shell course W = = = = = = = 36.00m 14.00m

194Mpa 2.00mm 0.95 208Mpa 13.80m 11.60m 13.80mm 14mm 0.014m 2.00m 3.17

Volume of Shell course V1 = 3.14 * D * W * t =

Course omi l i meter i meters Hei t from ottom of t e course under consider tion to t e top of s ell H Desi n stress to e considered d Corrosion llowance Specific ravit ax d stress to e considered . m = = = = = = = 1 . m 1 pa

2. mm 0. 208 pa 12.08m 9.91m

Td=(( . *D*(H-0. )* )/Sd))+CA Tt =( . D(H 0. ))/St

Max t ic ness

=

12.08mm

Thic ness selected t Width of shell course W Volume of Shell course V2 = .1 * D * W * t

= = = =

1 mm 0.01 m 2.00m 3.17

Course 3 Nominal Tank Diameter in meters D Height from bottom of the course under consideration to the top of shell H Design stress to be considered Sd Corrosion Allowance Specific Gravity G Ma hyd stress to be considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St Ma thickness Thickness selected t = = 36.00m 10.00m

= = = = = = = = =

194Mpa 2.00mm 0.95 20 Mpa 10.36m .21m 10.36mm 12mm 0.012m 2.50m 3.39

Width of shell course W Volume of Shell course V3 = 3.14 * D * W * t

= =

Course 4

Nominal Tank Diameter in meters D Hei ht from ottom of the course under consideration to the top of shell H Desi n stress to e considered Sd

= =

36.00m . 0m

=

194Mpa

Corrosion Allowance

=

2.00mm

Specific Gravity G Max hyd stress to e considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St Max thickness Thickness selected t

= = = = = = =

0.9 208Mpa 8.20m 6.10m 8.20mm 10mm 0.010m 2. 0m 2.83

Width of shell course W Volume of Shell course V4 = 3.14 * D * W * t

= =

Course 5 Nominal Tank Diameter in meters D = 36.00m 5.00m

Height from bottom of the course under consideration to = the top of shell H

Design stress to be considered Sd

=

194Mpa

Corrosion Allowance

=

2.00mm

Specific Gravity G Max hyd stress to be considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St Max thickness Thickness selected t

= = = = = = =

0.95 208Mpa 6.05m 3.98m 6.05mm 8mm 0.008m 2.50m 2.26

idth of shell course Volume of Shell course V5 = 3.14 * D * *t

= =

Course 6 Nominal Tank Diameter in meters D = 36.00m 2.50m

Height from bottom of the course under consideration to = the top of shell H

Design stress to be considered Sd

=

194Mpa

Corrosion Allowance

=

2.00mm

Specific Gravity G Max hyd stress to be considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St

= = = =

0.95 208Mpa 3.90m 1.86m

Max thickness

=

3.90mm

Thickness selected t

= =

8mm 0.008m 2.50m 2.26 = 17.07

Width of shell course W = Volume of Shell course V6 = 3.14 * D * W * t Total Volume V = V1+ V2 + V3+V4+V5+V6 =

CASE 2 Can be divided into 6 courses as

I 1.5

II 1.5

III 2.50

IV 2.5

V 2.5

VI 3.5

Course 1 Nominal Tank Diameter in meters D = 36.00m 14.00m

Height from bottom of the course under = consideration to the top of shell H Design stress to be considered Sd Corrosion Allowance Specific Gravity G Max hyd stress to be considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St = = = = = =

194Mpa 2.00mm 0.95 208Mpa 13.80m 11.60m

Max thickness Thickness selected t

= = =

13.80mm 14mm 0.014m 1.50m 2.37m3

Width of shell course W Volume of Shell course V1 = 3.14 * D * W * t

= =

Course 2 Nominal Tank Diameter in meters D Height from bottom of the course under consideration to the top of shell H Design stress to be considered Sd = = 36.00m 12.50m

=

194Mpa

Corrosion Allowance Specific Gravity G Max hyd stress to be considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St Max thickness Thickness selected t

= = = = = = = =

2.00mm 0.95 208Mpa 12.51m 10.33m 12.51mm 14mm 0.014m 1.50m 2.37m3

Width of shell course W Volume of Shell course V2 = 3.14 * D * W * t

= =

Course 3 Nominal Tank Diameter in meters D = = Height from bottom of the course under consideration to the top of shell H 36.00m 11.00m

Design stress to be considered Sd

=

194Mpa

Corrosion Allowance

=

2.00mm

Specific Gravity G Max hyd stress to be considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St Max thickness Thickness selected t

= = = = = = =

0.95 208Mpa 11.22m 9.06m 11.22mm 12mm 0.012m 2.50m 3.39m3

Width of shell course W Volume of Shell course V3 = 3.14 * D * W * t

= =

Course 4 Nominal Tank Diameter in meters D = 36.00m 8.50m

Height from bottom of the course under consideration to the = top of shell H

Design stress to be considered Sd

=

194Mpa

Corrosion Allowance

=

2.00mm

Specific Gravity G Max hyd stress to be considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St Max thickness Thickness selected t

= = = = = = =

0.95 208Mpa 9.07m 6.94m 9.07mm 10mm 0.010m 2.50m 2.83m3

Width of shell course W Volume of Shell course V4 = 3.14 * D * W * t

= =

Course 5 Nominal Tank Diameter in meters D Height from bottom of the course under consideration to the top of shell H Design stress to be considered Sd Corrosion Allowance Specific Gravity G Max hyd stress to be considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St Max thickness Thickness selected t Width of shell course W Volume of Shell course V5 = 3.14 * D * W * t = = = = = = = = = = = = = 36.00m 6.00m 194Mpa 2.00mm 0.95 208Mpa 6.91m 4.83m 6.91mm 8mm 0.008m 2.50m 2.26m3

Course 6 Nominal Tank Diameter in meters D Height from bottom of the course under consideration to the top of shell H Design stress to be considered Sd Corrosion Allowance Specific Gravity G Max hyd stress to be considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St Max thickness Thickness selected t Width of shell course W olume of Shell course 6 = 3.14 * D * W * t Total olume : 1+ 2+ 3+ 4+ 5+ 6 = = = = = = = = = = = = = = 36.00m 3.50m 194Mpa 2.00mm 0.95 208Mpa 4.76m 2.71m 4.76mm 8mm 0.008m 3.50m 3.17m3 16.39m3

Case 3

Course 1 I Can be divided into 6 courses as 1 = = = = = = = = = = = = = II 1.5 III 2.50 36.00m 14.00m 194Mpa 2.00mm 0.95 208Mpa 13.80m 11.60m 13.80mm 14mm 0.014m 1.00m 1.58m3 IV 2.5 V 3 VI 3.5

Nominal Tank Diameter in meters D Height from bottom of the course under consideration to the top of shell H Design stress to be considered Sd Corrosion Allowance Specific Gravity G Max hyd stress to be considered Td=((4.9*D*(H-0.3)*G)/Sd))+CA Tt =(4.9D(H 0.3))/St Max thickness Thickness selected t Width of shell course W Volume of Shell course V1 = 3.14 * D * W * t

Course 2 Nominal Tank Diameter in meters D = Height from bottom of the course under consideration to the top of shell H = Design stress to be considered Sd = Corrosion Allowance = Specific Gravity G = Max hyd stress to be considered St = Td=((4.9*D*(H-0.3)*G)/Sd))+CA = Tt =(4.9D(H 0.3))/St = Max thickness = Thickness selected t = = idth of shell course = Volume of Shell course V1 = 3.14 * D * * t = 36.00m 13.00m 194Mpa 2.00mm 0.95 208Mpa 12.94m 10.75m 12.94mm 14mm 0.014m 1.50m 2.37m3

Course 3 Nominal Tank Diameter in meters D = Height from bottom of the course under = consideration to the top of shell H Design stress to be considered Sd = Corrosion Allowance = Specific Gravity G = Max hyd stress to be considered St = Td=((4.9*D*(H-0.3)*G)/Sd))+CA = Tt =(4.9D(H 0.3))/St = Max thickness = Thickness selected t = = Width of shell course W = Volume of Shell course V1 = 3.14 * D * W * t = 36.00m 11.50m 194Mpa 2.00mm 0.95 208Mpa 11.65m 9.48m 11.65mm 12mm 0.012m 2.50m 3.39m3

Course 4 Nominal Tank Diameter in meters D = Height from bottom of the course under = consideration to the top of shell H Design stress to be considered Sd = Corrosion Allowance = Specific Gravity G = Max hyd stress to be considered St = Td=((4.9*D*(H-0.3)*G)/Sd))+CA = Tt =(4.9D(H 0.3))/St = Max thickness = Thickness selected t = = Width of shell course W = Volume of Shell course V1 = 3.14 * D * W * t = 36.00m 9.00m 194Mpa 2.00mm 0.95 208Mpa 9.50m 7.37m 9.50mm 10mm 0.010m 2.50m 2.83m3

Course 5 Nominal Tank Diameter in meters D = Height from bottom of the course under = consideration to the top of shell H Design stress to be considered Sd = Corrosion Allowance = Specific Gravity G = Max hyd stress to be considered St = Td=((4.9*D*(H-0.3)*G)/Sd))+CA = Tt =(4.9D(H 0.3))/St = Max thickness = Thickness selected t = = Width of shell course W = Volume of Shell course V1 = 3.14 * D * W * t = 36.00m 6.50m 194Mpa 2.00mm 0.95 208Mpa 7.34m 5.25m 7.34mm 8mm 0.008m 3.00m 2.71m3

Course 6 Nominal Tank Diameter in meters D = Height from bottom of the course under = consideration to the top of shell H Design stress to be considered Sd = Corrosion Allowance = Specific Gravity G = Max hyd stress to be considered St = Td=((4.9*D*(H-0.3)*G)/Sd))+CA = Tt =(4.9D(H 0.3))/St = Max thickness = Thickness selected t = = Width of shell course W = Volume of Shell course V1 = 3.14 * D * W * t = Total Volume V1+V2+V3+V4+V5+V6 = 36.00m 3.50m 194Mpa 2.00mm 0.95 208Mpa 4.76m 2.71m 4.76mm 8mm 0.008m 3.50m 3.17m3 16.05m3

CASE 1 Total volume of shell plate required in m3 = Density in kg/m3 The total weight of shell plates = V * density Material cost of shell plates Overall material cost of shell plates Weight * Cost = = = = 17.07m3 9.50 162.16tonnes 40000.00 64.86lakhs

CASE 2

Total volume of shell plate required in m3

=

16.39m3

Density in kg/m3

=

9.50

The total weight of shell plates =

density

=

155. 1tonnes

Material cost of shell plates

=

40000.00

Overall material cost of shell plates Weight Cost

=

62.29lakhs

CASE 3

Total volume of shell plate required in m3 =

16.05m3

Density in kg/m3

=

9.50

The total weight of shell plates = V * density

=

152.49tonnes

Material cost of shell plates

=

40000.00

Overall material cost of shell plates Weight * Cost

=

61.00lakhs

Most economic CASE cost =

= 61.00

lakhs

So the case we should consider should be :

= CASE 3

So the values on Shell plates are :

1st shell course thickness 2nd shell course thickness 3rd shell course thickness 4th shellcourse thickness th shell course thickness 6th shellcourse thickness

= = = = = =

14.00mm 14.00mm 12.00mm 10.00mm .00mm .00mm

Width of the plate for 1st to 6th course are :

2,

2,

2. 0,

2. ,

2. ,

2.

Conclusiony

Thus e are i t esi a c e r f st ra e ta st ra e f fur ace il as er the re uire e ts f The calculati s f shell thic ee c lete The calculatiy y y y y y y y y y y y

f r the , chi

y y

ess a e e are

tt

lates have

s f arts t

ular tt lates a ial i th f tt late esi f ri ary ec ary i ir er I ter e iate i ir er (if ecessary) a syste iser i e a hole olts ozzles ater rai ra off umps ooli ater system

Referencesy API 650 STANDARDS (11th EDITION) y BOOK OF ABOVE GROUND STORAGE TANKS y www.bpcl.co.in

Thank you .