TANK CACULATION
API 650 11th June 2007
TPHCM 15 Nov 2022
1 DATA DESIGN
Design Code
API 650 11th June 2007
Type Of Tank
Type Of Bottom
Type Of Roof
Vertical tank
Flat
Cone roof
Stored Liquid
Specific gravity of the Liquid
Water
G=
1
Tank Internal Diameter
Height Of Tank Shell
Design Liquid Level
Normal Fill Level
Hydrostatic Fluid Level
Minimum Fill Level
Tank Design Capacity
Tank Operation Capacity
Internal Design Pressure
Design External Pressure
Design Temprature
PWHT
D=
Ht =
Ht =
H=
H=
3990 mm
10000 mm
10000 mm
9650 mm
9650 mm
235 mm
125.04 m3
120.66 m3
0 bar (gauge)
0 bar (gauge)
40 °C
None
Corrosion Allowance
Mateial
CA =
Pi =
Pe =
0 mm
SS304
2 CALCULATION
2.1 Shell Thickness Calculation
=
=
Where
td =
tt =
D=
H=
G=
E=
CA =
Sd =
St =
Ls =
n=
tstd =
tsc =
4.9
− 0.3
4.9
− 0.3
+
design shell thickness (mm)
Hydrostatic test shell thickness (mm)
4 Nominal diameter of tank (m)
design liquid level (m)
1 specific gravity of the liquid to be stored
0.7 joint efficiency (table S-4)
corrosion allowable (mm)
155 allowable stress for the design condition (Mpa) (Table S-2a, S-2b)
186 allowable stress for the hydrostatic test condition (Mpa) (Table S-2a, S-2b)
1.5 Height of each course / wide of plate (m)
Number of course
Nominal thinkness listed in 5.6.1.1 except note 4
Thickness selected and used (refer S.3.2.1.1)
1st Course
2nd Course
3rd Course
4th Course
5th Course
6th Course
Last Course
n
1
2
3
4
5
6
7
H
10.0
8.5
7.0
5.5
4.0
2.5
1.0
td
tt
1.7
1.5
1.2
0.9
0.7
0.4
0.1
1.5
1.2
1.0
0.8
0.6
0.3
0.1
tstd
5.0
5.0
5.0
5.0
5.0
5.0
5.0
tcs
5.0
5.0
5.0
5.0
5.0
5.0
5.0
2.2 Bottom Thickness Calculation
Minimum thickness as per S.3.1.1 (tb1)
tb1 =
5 mm
Minimum thickness required tb = tb1 + CA
tb =
5 mm
Connection between the bottom plate and loweset course shell plate to be used Fillet Weld
Minimum size of Fillet Weld is 5mm
Result
OK
OK
OK
OK
OK
OK
OK
2.3 Roof thickness design
Using self-support roof
=
17.72 Degree (slope = 9:20)
Minimum thickness t = greates of
=
4.8
2.2
(2.3.1)
5.5
2.2
(2.3.2)
(5.10.5.1)
or
=
and 5 mm
(2.3.3)
Where
D=
3.99 nominal diameter if the tank (m)
Dl =
0.40 Dead load of roof (kPa)
Pe =
0
Lr =
0.16 kPa
T = Dl+Pe+0.4.Lr =
0.46 kPa
U = Dl+Pe+0.4.Lr =
0.46 kPa
=> Minimum thickness t = greates of (2.3.1) =
1.25 or (2.3.2) =
1.09 or(2.3.3)=
Selected
t=
5.00 mm
5
2.4 Intermediate Wind Girders
Calculation for and installation of intermediate wind girders are not required for small tank
mm
2.5 Roof manhole
Table 5.13a, Figure 5.16
Diameter of Diameter of
Size of
neck
cover plate
manhole
ID
Dc
500
500
660
Diameter
of bole Number of
circle
Boles
Db
597
16
Dia. Of Dia. Of
hole in reinfocci
roof plate ng plate
Outside
Dp
Dr
Diameter of gasket
Inside
500
660
524
1050
2.6 Roof venting
5.8.5.2 API 650 Normal venting shall meet the requirments specified in API Std 2000
Normal diameter, Di
3990 mm
Tank height, H
10000 mm
Design Capacity
125.04 m3
Design pressure, Pi
0 bar (gauge)
Boiling point (NBP)
<149 °C
Design temprature
40 °C
Filling rate ( Pumping in/Flow rate to tank ), Vi
40 m3/h
20m3/h for RFC system
and 20 m3/h for city water supply
Emptying rate ( Pumping out/Flow rate from tank ), Vo
140 m3/h
40 m3/h for transfer pump / 2 pumps
60 m3/h for 5" outlet
40 m3/h for 4" outlet
Inbreathing (Vacuum Relief)
See table 1B, select 0.94 Nm3/h of air for each cubic meter per hour
Flow rate of free air Vfi = (T+273.15)/273.15*0.94*Vo =
150.87 m3/h
Thermal venting capacity requirment
From table 2B column 2a
Flow rate of free air Vti = (T+273.15)/273.15*33.7 =
(select tank capacity is 200 cubic meters)
Total vacuum flow required, Vvi ( = Vfi + Vti ) =
38.64 m3/h
189.51 m3/h
Outbreathing (pressure relieft)
See section 4.3.2.3.1, the requirment for venting capacity for maximum liquide movement
into tank with a normal boiling below 148.9 °C should be equivlant 2.02 Nm3/h per cubic
metrer per hour
Flow rate of free air Vfo = (T+273.15)/273.15*2.02*Vi =
43.11 m3/h
Thermal venting capacity requirment
From table 2B column 4c
Flow rate of free air Vto = (T+273.15)/273.15*33.7 =
(select tank capacity is 200 cubic meters)
Total vacuum flow required, Vvo ( = Vfo + Vto ) =
33.70 m3/h
76.81 m3/h
Open venting sizing
Maximum flow Q is greater Vvi ad Vvo =
=
= . . 2
=
=
. 2
189.51 m3/h
0.05 m3/s
2
Where
k=
A=
g=
H=
p=
= p.g =
=> A =
=
0.7 Discharge coefficient (Figure 1)
cross sectional area of vent (m2)
9.81 acceleration due to gravity (m/s2)
10 Head as measure pressure differential (m)
1 Air density (kg/m3)
9.81 Specific weight of Air (kg/m2s2)
0.02 m2
16,815.45 mm2
Selected bleeder vent size
Number of vent, N
Outside diameter of the vent, do
Inside Dia. of one vent , di
Total cross sectional area of vents, Av_actual
Safety ratio k = Av/A
5" SCH40 6" SCH40 8" SCH40
1
1
1
141
168
219 mm
134.5
161.5
211.6 mm
14,208
20,485
35,166 mm2
0.84
1.22
2.09
Selected
2.7 Opening hole
a. Shell manhole 20"( D500)
OD =
508 mm
Bolts size M20x
Bolts hole
23 mm
tn =
5 mm
t=
5 mm
T=
5 mm
Db =
667 mm
Dc =
730 mm
tc =
14 mm
tf =
14 mm
b.
Outside diameter of shell manhole (Selected)
Figure 5-7A
Bolts hole diameter
neck of manhole thickness (Table 5-4a)
Compted above
Figure 5-8
Figure 5-8
Thickness of shell manhole cover Plate (Table 5-3a)
Thickness of shell manhole Bolting flange (Table 5-3a)
Other opening holes
As per section S.3.3.1 the minimum thickness of connections and openings shall be as table
Size of nozzle
Minimum Nominal Neck Thickness
NPS 2 and less
Schedule 80
NPS 3 and NPS 4
Schedule 40
Over NPS4
6 mm