PVRV Sizing Calculation - 10% Overpressure PVRV sizing is based on API 2000 (6th Edition-Nov 2009), API 520 Part1(8thedition-Dec 2008) & Crosby Engineering Handbook (Valve Sizing and Selection)
D = Tank diameter H = Tank height C = Tank Total capacity Rf = Maximum filling rate
= = =
30.00 22.00 15551
m m 3 m
=
1200
m / hr
97659.5 bbl
3
7536 bbl/hr
3
Re = Maximum emptying rate Flash point of oil Specific Weight of Air
= = =
1000 <-40 1.251
m / hr °C
Vapour Density of Fluid (V-Power)
=
4
Design Ambient Temperature
=
41
kg/m3 °C
V1 = For oil movement
=
0.94 × Re
=
5.6 × Re
SCFH of Air
Refer Table A.1(Normal venting reguirements, pg 38, API 2000 )
=
940.00
Nm /hr
3
=
35168
SCFH of Air
=
1584.60
Nm3/hr
=
59063.8
SCFH of Air
6280 bbl/hr
3
kg/m
Inbreathing of Air - Vacuum Relief
V2 = For thermal effect Refer Table A.3 (Requirements for thermal venting, pg 39, API 2000)
Total normal venting capacity = Liquid movement (V1) + Thermal effect (V2) Vin = Total required inbreathing capacity
Actual Volume of Air m³/hr V1 = P0V0 / T0 × T1 / P1
V 1 + V2
=
V 1 + V2
=
2524.60
Nm3/hr
=
2742.52
m3/hr
=
[ W * √(TZ)] / ( C * K * P1 * Kb * √M )
=
94231.8
SCFH of Air
Sizing of PVRV - Inbreathing Area - A (mm2) where, W - required capacity (kg/hr)
=
3430.8915 kg/hr
K - Effective coefficient of discharge K = 0.975
=
0.975
C - Coefficient (Table 7/8,pg 55 to 57, API 520 Part-1)
=
0.0270
Kb - Capacity correction factor
=
M - Molecular weight of AIr (Table 7-7,pg 7-26, Crosby Engineering Handbook)
=
T - Absolute temperature of the fluid (K)
= = =
P1 - Relieveing Pressure (kPa) = set pressure + overpressure + atmospheric pressure Set pressure
=
1
28.97 41 0C 314 K 102.425 kPa
10.00 mbar
=
1 kPa
Over pressure (10%)
=
0.1 kPa
Atm pressure
=
101.325 kPa
= =
Z - Compressibility factor A - minimum required effective discharge area (m2)
Area - A (mm2) D Say
d
= =
2 4189.12 mm 73 mm
= =
100 mm 4 inch
1
Outbreathing of Air - Pressure Relief V3 = For oil movement
=
2.02 x Rf
=
12 × Rf
SCFH of Air
Refer Table A.1(Normal venting reguirements, pg 38, API 2000 )
=
2424.00
Nm3/hr
=
90432
SCFH of Air
=
1584.60
Nm /hr
3
=
59063.8
SCFH of Air
V4 = For thermal effect Refer Table A.3 (Requirements for thermal venting, pg 39, API 2000)
Total normal venting capacity = Liquid movement (V1) + Thermal effect (V2) Vout = Total required outbreathing capacity
= =
Actual Volume of Air M³/hr V1 = P0V0 / T0 × T1 / P1
=
V 3 + V4
=
4008.60 4354.62
3
Nm /hr
V 3 + V4 149496
SCFH of Air
3
m /hr
Conversion of Air Volumetric Flow @Std to Vapor volumetric Flow @ Actual
Qactual,vap = Actual vapor flow (SCF) Qstd,vap = Vapor volumetric flow @ STD (SCFH) Qstd,air = Air Volumetric flow @ STD (SCFH) Tstd,vap = Vapour temperature @ STD Tactual.vap = Actual vapor temperature Pstd,vap = Vapor pressure @ STD Pactual,vap = Actual vapor pressure MWvap = Vapor molecular weight MWair = Air molecular weight
= = = = = =
˚F ˚F Psia Psia
60 77 14.7 14.84 106 28.96
Qstd,Vap = Qstd,air × SQRT[(Tstd,vap + 460) / (Tactual,vap+460)] / SQRT[MWvap / MWair]
=
76893.5
SCFH of Gasoline Vapour
Qactual,vap = Qstd,vap × [(Tactual,vap + 460) / (Tstd,vap + 460)] ×[Pstd,vap / Pactual,vap]
=
78658.2
SCFH of Gasoline Vapour
= =
76893.542 78658.243
SCFH of Gasoline Vapour CFH of Gasoline Vapour
= =
1 2227.4
m3/hr of Gasoline vapours
PVRV Maximum Capacity(m3/hr)
=
2227.4
m3/hr of Gasoline vapours
PVRV Minimum Capacity(m3/hr)
=
222.7
Outbreathing of Gasoline Vapour - Pressure Relief Qstd,vap Qactual,vap Number of PVRV provided per tank Actual Vent Capacity for outbreathing of gasoline vapour(M3/hr)
Sizing of PVRV - Out breathing Area - A (mm2)
=
[ W * √(TZ)] / ( C * K * P1 * Kb * √M )
where, W - required capacity (kg/hr)
=
K - Effective coefficient of discharge K = 0.975
=
0.975
C - Coefficient (Table 7/8,pg 55 to 57, API 520 Part-1)
=
0.0239
Kb - Capacity correction factor
=
1
M - Molecular weight of Gasoline (Table 7-7,pg 7-26, Crosby Engineering Handbook)
=
106
T - Absolute temperature of the fluid (K)
= =
41 0C 314 K
=
P1 - Relieveing Pressure (kPa) = set pressure + overpressure + atmospheric pressure Set pressure
= =
Over pressure (10%) Atm pressure
= =
8909.41 kg/hr
104.075 kPa
25.00 mbar 2.5 kPa 0.25 kPa 101.325 kPa
= =
Z - Compressibility factor A - minimum required effective discharge area (m2)
Area - A (mm2)
=
2 6322.83 mm 90 mm
= =
100 mm 4 inch
D Say
d
1
