blowdown calculation final rev b1.pdf
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8/10/2019 Blowdown Calculation final Rev B1.pdf
1/23
PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 1 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
PT. Perusahaan Gas Negara (Persero) Tbk.
EPC OTSUKA -PURWOSARI GAS DISTRIBUTION PIPELINE PROJECT CP-19
BLOWDOWN ANALISYS REPORT
Contract No.
079800.PK/HK.02/PROYEK/2014
B Issued for review 14-10-14 ARD ILM DVD
A Issued for review 12-09-14 ARD ILM DVD
REV DESCRIPTION DATEPRPD CHKD APVD
PMC PGNPT. BRE
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PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 2 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
REVISION CONTROL SHEET
Rev No Date Page Description
A 12-09-14 All Issued for review
B 14-10-14 All Issued for review
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PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 3 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
TABLE OF CONTENT
REVISION CONTROL SHEET ______________________________________________________ 2
1. INTRODUCTION _____________________________________________________________ 41.1. General ______________________________________________________________ 4
1.2. Objection _____________________________________________________________ 4
2. REFERENCES ______________________________________________________________ 4
3. DATA SOURCE ______________________________________________________________ 53.1. Process Data __________________________________________________________ 53.2. Blowdown Design_______________________________________________________ 6
4. CALCULATION METHODS _____________________________________________________ 74.1. Upstream Restriction Orifice Calculation _____________________________________ 74.2. Downstream Restriction Orifice Calculation ___________________________________ 9
5. RESULT __________________________________________________________________ 10
6. CONCLUSION______________________________________________________________ 11
Figure 1. Blowdown scheme _________________________________________________________ 6Figure 2. Hysys Depressuring Utilities _________________________________________________ 7
ATTACHEMENT 1 : HYSYS SIMULATION REPORT ____________________________________ 12
ATTACHEMENT 2 : LINE SIZING CALCULATION ______________________________________ 13
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PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 4 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
1. INTRODUCTION
1.1. General
Perusahaan Gas Negara (persero) Tbk. (PGN) is the largest natural gas transmission and
distribution company intens to distribute gas from Otsuka to Purwosari with distance about 15
km. Sectional Valve will be installed at KP 8. The Sectional Valve is composed of a manually
operated 10 Block Valve for Otsuka Purwosari Pipeline and a vent nozzle with connections
for temporary blowdown facility. The blowdown facilities optimized for 3 5 hours of blowdown
duration. For normal condition, 5 MMSCFD of gas will deliver to consummer and it will be
increase to 17 MMSCFD as future. 48 km gas pipeline distribution to Malang shall install as a
future plan
1.2. Objection
This document is provided for size calculation from upstream and downstream of restriction
orifice on the OTSUKA PURWOSARI GAS DISTRIBUTION PIPELINE, East Java. Optimum
Restriction orifice will be determined too for 8 km lenght of pipe.
2. REFERENCES
API RP 521 Guide for Pressure Relieving Depressuring System
API 14E Recommended Practice for Design and Installation of Offshore
Production Platform Piping Systems
API RP 520 Sizing, Selection, and Installation of Pressure-Relieving Devices in
Refineries
GPSA Section 17 Fluid Flow and Piping
Kepmen LH No.48/1996 Baku Tingkat Kebisingan
Permen Naker
No. PER.13/MEN/X/2011 Nilai Ambang Batas Faktor Fisika dan Faktor Kimia di Tempat Kerja
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8/10/2019 Blowdown Calculation final Rev B1.pdf
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PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 5 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
3. DATA SOURCE
3.1. Process Data
The parameters will be use for calculating hydraulic are showed below:
Table 1. Standard Parameters
Gas composition is refer to Heat & Material Balances Table (CP19-BRE -3514-PS-BD-004)COMPOSITION Mole
CH4(Methane) 0.9844
CcH6(Ethane) 0.0050
C3H8(Propane) 0.0020
i-C4H10(i-Butane) 0.0006
n-C4H10(n-Butane) 0.0004
i-C5H12 (i-Pentane) 0.0002
n-C5H12(n-Pentane) 0.0001
n-C6H14 (n-Hexane) 0.0001
H2S 0.0000
No Parameters Unit Value
1 Flow Rate (Q) MMSCFD 5
2 Future Flowrate (Qfuture) MMSCFD 17
3 Operating Pressure (P) barg 16
4 Max Allowable Operating Pressure (MAOP) barg 25
5 Design Pressure barg 35.9
6 Operating Temperature (T)oF 80
7 Design TemperatureoF 130
8 Inside Pipe Diameter (D) inch 10
9 Pipe Lenght (L) km 15
10 Spesific Gravity (Sg) 0.565
11 Compresibilty Factor (Z) 0.9634
12 Density () lb/ft3
1.128
13 Molecular Weight (Mw) 16.36
14 Viscosity () cP 0.01182
15 Roughness in 0.001
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PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 6 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
COMPOSITION Mole
CO2 0.0027
N2 0.0046
TOTAL 1.0000
Table 2. Gas Composition
3.2. Blowdown Design
Blowdown designed for one section ( Section 1 or section 2 ) with assumed lenght 8 km /
section. The calculation performed to 3, 4 and 5 hours duration at maximum operating
pressure (25 barg) for future connection (17 MMSCFD). Final pressure target is 100 psig.
Table 3. Blowdown Case
Figure 1. Blowdown Scheme
Upstream Pipe of Restriction Orifice Design Criteria
a. Maximum Velocity = 60 ft/s refer to API RP 521
b. P (psi/100ft) = 0.486 psi/100ft
Case Blowdown Duration Flowrate Pressure
1 3 hours 17 MMSCFD 25 barg
2 4 hours 17 MMSCFD 25 barg
3 5 hours 17 MMSCFD 25 barg
SECTION 1SECTION 2
Blowdown Area
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PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 7 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
Downstream Restriction Orifice Design Criteria
a. Beta ratio = 0.2 0.75
b. Maximum Velocity = 500 fps refer to API 14E
c. Noise = 55 dB refer to Kepmen LH No.48/1996
85 dB refer to Permen Naker No. PER.13/MEN/X/2011
4. CALCULATION METHODS
This calculation is performed using HYSYS simulation and MS Excel by input data. Methodology
being used for calculation below :
4.1. Upstream Restriction Orifice Calculation
a. Depressurization simulation using HYSYS
Depressurization simulation performed using HYSYS 7.3 with Peng-Robbinson as fluid
package. The stage are belowed:
1. Gas composition and parameters condition input to stream data.
2. Assumed the vessel orientation is horizontal. Pipe lenght and diameter input to vessel
parameters as a diameter and height. The f igure showed below.
Figure 2. Hysys Depresssuring Utilities
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8/10/2019 Blowdown Calculation final Rev B1.pdf
8/23
PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 8 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
3. Input the ambient data into heat flux and chose adiabatic for operating mode.
4. For valve parameters chose a supersonic in vapour flow equation and assumed discharge
co-efficient is 0.975.
5. Set depressuring time and final pressure at Operating Condition.
6. run the simulation.
b. Determine friction factor (MS. EXCEL) refer to API 14E
- Trial diameter (D) using gas velocity Equation (API 14E )
- Calculate Reynold number (Re)
c. Determine the value of (/D) and Re from the picture below to get (fm)
d. Determine Pressure Drop using Darcy formula
Where:
vg : Gas Velocity (fps)
Z : Gas Compresibility
Q : Molar flowrate (MMSCFD)
v
R
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PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 9 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
T : Temperature inlet (oR)
P : Pressure inlet ( psia )
D : Diameter blowdown pipe (in)
: Density (lb/ft3)
: Viscosity (cP)
W : Mass Flowrate (lb/hr)
fm : Frition factor
4.2. Downstream Restriction Orifice Calculation
a. Orifice Diameter Calculation refer to GPSA section 17
- FTPinitial value set = 1
- Determining critical flow ( YCR) by :
- Determining orifice diameter (d) :
b. Estimation noise by Lighthill's Theory :
Where:
OASPL : Overall sound pressure level of regenerated noise (dB)
d : Inside diameter of vent stack (m)
C0 : Sonic Velocity (Velocity of sound in atmosphere) (m/s)
vg : Exit velocity of vented gas (m/s)
0 : Density of atmosphere (kg/m
3
)g : Density of vented gas (kg/m
3)
R : Distance from vent (m)
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8/10/2019 Blowdown Calculation final Rev B1.pdf
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PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 10 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
5. RESULT
The result of calculations are below :
a. Case 1: 3 Hours Blowdown Duration
Table 4. Blowdown Case 1 Result
b. Case 2 : 4 Hours Blowdown Duration
Table 5. Blowdown Case 2 Result
c. Case 3 : 5 Hours Blowdown Duration
DOWNSTREAM UPSTREAM
Option ID (in) Velocity (fps) Mach Number P (psi/100ft) Noise 1 Noise 2 Status
Option 1 2 43.557 0.767 2.285 92.895 71.556 NOT OK
Option 2 3 19.359 0.341 0.277 68.242 46.904 OK
Option 3 4 10.889 0.192 0.066 50.751 29.412 OK
Option 4 6 4.840 0.085 0.008 26.098 4.759 OK
Table 6. Blowdown Case 3 Result
DOWNSTREAM UPSTREAM
Option ID (in) Velocity (fps) Mach Number P (psi/100ft) Noise 1 Noise 2 Status
Option 1 2 71.818 1.265 6.213 110.272 88.933 NOT OK
Option 2 3 31.919 0.562 0.769 85.619 64.280 NOT OK
Option 3 4 17.954 0.316 0.176 68.128 46.789 OK
Option 4 6 7.980 0.141 0.022 43.475 22.136 OK
DOWNSTREAM UPSTREAM
Option ID (in) Velocity (fps) Mach Number P (psi/100ft) Noise 1 Noise 2 Status
Option 1 2 54.391 0.958 3.565 100.625 79.286 NOT OK
Option 2 3 24.174 0.426 0.441 75.972 54.633 OK
Option 3 4 13.598 0.240 0.101 58.480 37.141 OK
Option 4 6 6.043 0.106 0.013 33.828 12.489 OK
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PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 11 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
d. Restriction Orifice Calculation Result
Table 7. RO calculation result
6. CONCLUSION
a. Based on calculation, the selected downstream diameters thats suitable of criteria is 4 inch
with 0.176 psi/100ft as maximum pressure drop , 0.316 as mach number and maximum gas
velocity calculated is 17.954 fps.
b. For upstream, diameter selected is 4 inch with maximum noise is 68.128 dB.
c. For diameter 4 inch, RO diameter caclulated is 27.17 mm at 3 hours with beta ratio value is
0.267.
No Calculation steps 3 Hours 4 Hours 5 Hours
1 Relief Load (W) (kg/h) 2885 2185 1749
2 Set Initial Value of FTP 1 1 1
3 Critical Flow Function, YCR 0.701 0.701 0.701
4 Orifice Diameter, d (mm)27.17 23.65 21.16
5 Beta Ratio, 0.267 0.233 0.208
6 FTPCalculated 1.0012 1.0007 1.0004
7 Critical Pressure, (kPa)420.81 420.60 420.50
8 Reynold Number 63442.49 48047.83 38477.69
9 Flow Region Turbulent - OK Turbulent - OK Turbulent - OK
10 Flow Behaviour Critical Flow Critical Flow Critical Flow
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PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 12 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
ATTACHEMENT 1 : HYSYS SIMULATION REPORT
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LEGENDS
Burlington, MA
USA
Case Name: BLOWDOWN 3 HOURS 8KM .HSC
Unit Set: NewUser4a113
Date/Time: Sun Sep 14 09:44:31 2014
Depressuring - Dynamics: BD 1
DESIGN
Connections
Inlet
Vessel Volume (ft3)
Liquid Volume (ft3)
FEED-2
1.431e+004
7156
Vessel Orientation
Flat End Vessel Volume (ft3)
Height (m)
Diameter (m)
Metal Mass in Contact with Vapour (lb)
Horizontal
1.431e+004
8000 *
0.2540 *
---
Initial Liquid Volume (ft3)
Cylindrical Area (ft2)
Top Head Area (ft2)
Bottom Head Area (ft2)
Metal Mass in Contact with Liquid (lb)
0.0000
6.870e+004
0.5453
0.5453
---
Heat Flux
Operating Mode : Adiabatic
Heat Loss Model : Simple
Overall U (Btu/hr-ft2-F)
Ambient Temperature (F)
2.642
82.00 *
Overall Heat Transfer Area (ft2) 6.870e+004
Valve Parameters
Vapour Flow Equation
Cd
Area (in2)
Vapour Back Pressure (bar_g)
Valve Equation Units
Supersonic
0.9750 *
0.1933 *
0.0000
lb/hr
Liquid Flow Equation
Liquid Back Pressure (bar_g)
(No Flow)
0.0000
Options
PV Work Term Contribution (%) 80.00 *
Operating Conditions
Operating Pressure (bar_g)
Time Step Size
25.00
---
Depressuring Time (seconds) 1.080e+004 *
Vapour Outlet Solving Option
Initial Cv Estimate
Calculate Cv
0.9750 *
Final Pressure (bar_g)
Solved Pressure (bar_g)
6.895 *
---
WORKSHEET
Properties
Name
Vapour Fraction
Temperature (F)
Pressure (bar_g)
Actual Vol. Flow (barrel/day)
Mass Enthalpy (Btu/lb)
Mass Entropy (Btu/lb-F)
Molecular Weight
Molar Density (lbmole/ft3)
Mass Density (lb/ft3)
Std Ideal Liq Mass Density (lb/ft3)
Liq Mass Density @Std Cond ( lb/ ft3)
Molar Heat Capac ity (Btu/lbmole-F)
Mass Heat Capacity (Btu/lb-F)
Thermal Conductivity (Btu/hr-ft-F)
Viscosity (cP)
Surface Tension (dyne/cm)
Specific Heat (Btu/lbmole-F)
Z Factor
Vap. Frac. (molar basis)
FEED-2
1.0000
80.00 *
25.00 *
1.157e+005
-1997
2.281
16.36
6.894e-002
1.128
18.99
4.332e-002
9.324
0.5698
2.073e-002
1.182e-002
---
9.324
0.9450
1.0000
Aspen Technology Inc. Aspen HYSYS Version 7.3 (25.0.0.7336) Page 1 of 2
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8/10/2019 Blowdown Calculation final Rev B1.pdf
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LEGENDS
Burlington, MA
USA
Case Name: BLOWDOWN 3 HOURS 8KM .HSC
Unit Set: NewUser4a113
Date/Time: Sun Sep 14 09:44:31 2014
Depressuring - Dynamics: BD 1 (continued)
Properties
Vap. Frac. (mass basis)
Vap. Frac. (Volume Basis)
Molar Volume (ft3/lbmole)
Act.Gas Flow (ACFM)
Act.Liq.Flow (USGPM)
Std.Liq.Vol.Flow (barrel/day)
Std.Gas Flow (MMSCFD)
Watson K
Kinematic Viscosity (cSt)
Cp/Cv
Lower Heating Value (Btu/lbmole)
Mass Lower Heating Value (Btu/lb)
Liquid Fraction
Partial Pressure of CO2 (bar_g)
Avg.Liq.Density (lbmole/ft3)
Heat Of Vap. (Btu/lbmole)
Mass Heat Of Vap. (Btu/lb)
1.0000
1.0000
14.51
451.3
---
3.014e+006
16.97
19.27
0.6543
1.381
3.463e+005
2.116e+004
0.0000
-0.9439
1.161
3033
185.3
COMPOSITIONS
Methane
Ethane
Propane
i-Butane
n-Butane
i-Pentane
n-Pentanen-Hexane
H2S
CO2
Nitrogen
FEED-2
0.9844 *
0.0050 *
0.0020 *
0.0006 *
0.0004 *
0.0002 *
0.0001 *0.0001 *
0.0000 *
0.0027 *
0.0046 *
Results
Initial Pressure (bar_g)
Final Pressure (bar_g)
Depressuring Time (seconds)
Vapour Cv
Liquid Cv
Vessel Fluid Initial Temperature - Vapour Phase (F)
Vesssel Fluid Final Temperature - Vapour Phase (F)
Vessel Fluid Minimum Temperature - Vapour Phase (F)
Valve Outlet Initial Temperature - Vapour Phase (F)
Valve Outlet Final Temperature - Vapour Phase (F)
Valve Outlet Minimum Temperature - Vapour Phase (F)
Inner Wal l Ini tial Temperature - Vapour Phase (F)
Inner Wal l Final Temperature - Vapour Phase (F)
Inner Wall Minimum Temperature - Vapour Phase (F)
Vessel Fluid Init ial Temperature - Liquid Phase (F)
25.00
6.896
1.080e+004 *
0.9750 *
---
80.42
79.19
79.19
57.19
78.87
57.19
---
---
---
80.42
Vessel Fluid Final Temperature - Liquid Phase (F)
Vessel Fluid Minimum Temperature - Liquid Phase (F)
Valve Outlet Init ial Temperature - Liquid Phase (F)
Valve Outlet Final Temperature - Liquid Phase (F)
Valve Outlet Minimum Temperature - Liquid Phase (F)
Inner Wal l Ini tial Temperature - Liquid Phase (F)
Inner Wal l Final Temperature - Liquid Phase (F)
Inner Wall Minimum Temperature - Liquid Phase (F)
Initial Mass of Vapour (lb)
Final Mass of Vapour (lb)
Peak Vapour Flow Through Valve (lb/hr)
Initial Mass of Liquid (lb)
Final Mass of Liquid (lb)
Peak Liquid Flow Through Valve (lb/hr)
79.19
79.19
57.19
57.65
57.19
---
---
---
1.615e+004
4593
6360
0.0000
0.0000
0.0000
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8/10/2019 Blowdown Calculation final Rev B1.pdf
15/23
LEGENDS
Burlington, MA
USA
Case Name: BLOWDOWN 4 HOURS 8KM.HSC
Unit Set: NewUser4a113
Date/Time: Sun Sep 14 09:49:37 2014
Depressuring - Dynamics: BD 1
DESIGN
Connections
Inlet
Vessel Volume (ft3)
Liquid Volume (ft3)
FEED-2
1.431e+004
7156
Vessel Orientation
Flat End Vessel Volume (ft3)
Height (m)
Diameter (m)
Metal Mass in Contact with Vapour (lb)
Horizontal
1.431e+004
8000 *
0.2540 *
---
Initial Liquid Volume (ft3)
Cylindrical Area (ft2)
Top Head Area (ft2)
Bottom Head Area (ft2)
Metal Mass in Contact with Liquid (lb)
0.0000
6.870e+004
0.5453
0.5453
---
Heat Flux
Operating Mode : Adiabatic
Heat Loss Model : Simple
Overall U (Btu/hr-ft2-F)
Ambient Temperature (F)
2.642
82.00 *
Overall Heat Transfer Area (ft2) 6.870e+004
Valve Parameters
Vapour Flow Equation
Cd
Area (in2)
Vapour Back Pressure (bar_g)
Valve Equation Units
Supersonic
0.9750 *
0.1446 *
0.0000
lb/hr
Liquid Flow Equation
Liquid Back Pressure (bar_g)
(No Flow)
0.0000
Options
PV Work Term Contribution (%) 80.00 *
Operating Conditions
Operating Pressure (bar_g)
Time Step Size
25.00
---
Depressuring Time (seconds) 1.440e+004 *
Vapour Outlet Solving Option
Initial Cv Estimate
Calculate Cv
0.9750 *
Final Pressure (bar_g)
Solved Pressure (bar_g)
6.895 *
---
WORKSHEET
Properties
Name
Vapour Fraction
Temperature (F)
Pressure (bar_g)
Actual Vol. Flow (barrel/day)
Mass Enthalpy (Btu/lb)
Mass Entropy (Btu/lb-F)
Molecular Weight
Molar Density (lbmole/ft3)
Mass Density (lb/ft3)
Std Ideal Liq Mass Density (lb/ft3)
Liq Mass Density @Std Cond ( lb/ ft3)
Molar Heat Capac ity (Btu/lbmole-F)
Mass Heat Capacity (Btu/lb-F)
Thermal Conductivity (Btu/hr-ft-F)
Viscosity (cP)
Surface Tension (dyne/cm)
Specific Heat (Btu/lbmole-F)
Z Factor
Vap. Frac. (molar basis)
FEED-2
1.0000
80.00 *
25.00 *
1.157e+005
-1997
2.281
16.36
6.894e-002
1.128
18.99
4.332e-002
9.324
0.5698
2.073e-002
1.182e-002
---
9.324
0.9450
1.0000
Aspen Technology Inc. Aspen HYSYS Version 7.3 (25.0.0.7336) Page 1 of 2
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8/10/2019 Blowdown Calculation final Rev B1.pdf
16/23
LEGENDS
Burlington, MA
USA
Case Name: BLOWDOWN 4 HOURS 8KM.HSC
Unit Set: NewUser4a113
Date/Time: Sun Sep 14 09:49:37 2014
Depressuring - Dynamics: BD 1 (continued)
Properties
Vap. Frac. (mass basis)
Vap. Frac. (Volume Basis)
Molar Volume (ft3/lbmole)
Act.Gas Flow (ACFM)
Act.Liq.Flow (USGPM)
Std.Liq.Vol.Flow (barrel/day)
Std.Gas Flow (MMSCFD)
Watson K
Kinematic Viscosity (cSt)
Cp/Cv
Lower Heating Value (Btu/lbmole)
Mass Lower Heating Value (Btu/lb)
Liquid Fraction
Partial Pressure of CO2 (bar_g)
Avg.Liq.Density (lbmole/ft3)
Heat Of Vap. (Btu/lbmole)
Mass Heat Of Vap. (Btu/lb)
1.0000
1.0000
14.51
451.3
---
3.014e+006
16.97
19.27
0.6543
1.381
3.463e+005
2.116e+004
0.0000
-0.9439
1.161
3033
185.3
COMPOSITIONS
Methane
Ethane
Propane
i-Butane
n-Butane
i-Pentane
n-Pentanen-Hexane
H2S
CO2
Nitrogen
FEED-2
0.9844 *
0.0050 *
0.0020 *
0.0006 *
0.0004 *
0.0002 *
0.0001 *0.0001 *
0.0000 *
0.0027 *
0.0046 *
Results
Initial Pressure (bar_g)
Final Pressure (bar_g)
Depressuring Time (seconds)
Vapour Cv
Liquid Cv
Vessel Fluid Initial Temperature - Vapour Phase (F)
Vesssel Fluid Final Temperature - Vapour Phase (F)
Vessel Fluid Minimum Temperature - Vapour Phase (F)
Valve Outlet Initial Temperature - Vapour Phase (F)
Valve Outlet Final Temperature - Vapour Phase (F)
Valve Outlet Minimum Temperature - Vapour Phase (F)
Inner Wal l Ini tial Temperature - Vapour Phase (F)
Inner Wal l Final Temperature - Vapour Phase (F)
Inner Wall Minimum Temperature - Vapour Phase (F)
Vessel Fluid Init ial Temperature - Liquid Phase (F)
25.00
6.898
1.440e+004 *
0.9750 *
---
80.42
79.08
79.08
57.19
78.80
57.19
---
---
---
80.42
Vessel Fluid Final Temperature - Liquid Phase (F)
Vessel Fluid Minimum Temperature - Liquid Phase (F)
Valve Outlet Init ial Temperature - Liquid Phase (F)
Valve Outlet Final Temperature - Liquid Phase (F)
Valve Outlet Minimum Temperature - Liquid Phase (F)
Inner Wal l Ini tial Temperature - Liquid Phase (F)
Inner Wal l Final Temperature - Liquid Phase (F)
Inner Wall Minimum Temperature - Liquid Phase (F)
Initial Mass of Vapour (lb)
Final Mass of Vapour (lb)
Peak Vapour Flow Through Valve (lb/hr)
Initial Mass of Liquid (lb)
Final Mass of Liquid (lb)
Peak Liquid Flow Through Valve (lb/hr)
79.08
79.08
57.19
57.65
57.19
---
---
---
1.615e+004
4606
4818
0.0000
0.0000
0.0000
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LEGENDS
Burlington, MA
USA
Case Name: BLOWDOWN 5 HOURS 8KM.HSC
Unit Set: NewUser4a113
Date/Time: Sun Sep 14 09:53:08 2014
Depressuring - Dynamics: BD 1
DESIGN
Connections
Inlet
Vessel Volume (ft3)
Liquid Volume (ft3)
FEED-2
1.431e+004
7156
Vessel Orientation
Flat End Vessel Volume (ft3)
Height (m)
Diameter (m)
Metal Mass in Contact with Vapour (lb)
Horizontal
1.431e+004
8000 *
0.2540 *
---
Initial Liquid Volume (ft3)
Cylindrical Area (ft2)
Top Head Area (ft2)
Bottom Head Area (ft2)
Metal Mass in Contact with Liquid (lb)
0.0000
6.870e+004
0.5453
0.5453
---
Heat Flux
Operating Mode : Adiabatic
Heat Loss Model : Simple
Overall U (Btu/hr-ft2-F)
Ambient Temperature (F)
2.642
82.00 *
Overall Heat Transfer Area (ft2) 6.870e+004
Valve Parameters
Vapour Flow Equation
Cd
Area (in2)
Vapour Back Pressure (bar_g)
Valve Equation Units
Supersonic
0.9750 *
0.1155 *
0.0000
lb/hr
Liquid Flow Equation
Liquid Back Pressure (bar_g)
(No Flow)
0.0000
Options
PV Work Term Contribution (%) 80.00 *
Operating Conditions
Operating Pressure (bar_g)
Time Step Size
25.00
---
Depressuring Time (seconds) 1.800e+004 *
Vapour Outlet Solving Option
Initial Cv Estimate
Calculate Cv
0.9750 *
Final Pressure (bar_g)
Solved Pressure (bar_g)
6.895 *
---
WORKSHEET
Properties
Name
Vapour Fraction
Temperature (F)
Pressure (bar_g)
Actual Vol. Flow (barrel/day)
Mass Enthalpy (Btu/lb)
Mass Entropy (Btu/lb-F)
Molecular Weight
Molar Density (lbmole/ft3)
Mass Density (lb/ft3)
Std Ideal Liq Mass Density (lb/ft3)
Liq Mass Density @Std Cond ( lb/ ft3)
Molar Heat Capac ity (Btu/lbmole-F)
Mass Heat Capacity (Btu/lb-F)
Thermal Conductivity (Btu/hr-ft-F)
Viscosity (cP)
Surface Tension (dyne/cm)
Specific Heat (Btu/lbmole-F)
Z Factor
Vap. Frac. (molar basis)
FEED-2
1.0000
80.00 *
25.00 *
1.157e+005
-1997
2.281
16.36
6.894e-002
1.128
18.99
4.332e-002
9.324
0.5698
2.073e-002
1.182e-002
---
9.324
0.9450
1.0000
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LEGENDS
Burlington, MA
USA
Case Name: BLOWDOWN 5 HOURS 8KM.HSC
Unit Set: NewUser4a113
Date/Time: Sun Sep 14 09:53:08 2014
Depressuring - Dynamics: BD 1 (continued)
Properties
Vap. Frac. (mass basis)
Vap. Frac. (Volume Basis)
Molar Volume (ft3/lbmole)
Act.Gas Flow (ACFM)
Act.Liq.Flow (USGPM)
Std.Liq.Vol.Flow (barrel/day)
Std.Gas Flow (MMSCFD)
Watson K
Kinematic Viscosity (cSt)
Cp/Cv
Lower Heating Value (Btu/lbmole)
Mass Lower Heating Value (Btu/lb)
Liquid Fraction
Partial Pressure of CO2 (bar_g)
Avg.Liq.Density (lbmole/ft3)
Heat Of Vap. (Btu/lbmole)
Mass Heat Of Vap. (Btu/lb)
1.0000
1.0000
14.51
451.3
---
3.014e+006
16.97
19.27
0.6543
1.381
3.463e+005
2.116e+004
0.0000
-0.9439
1.161
3033
185.3
COMPOSITIONS
Methane
Ethane
Propane
i-Butane
n-Butane
i-Pentane
n-Pentanen-Hexane
H2S
CO2
Nitrogen
FEED-2
0.9844 *
0.0050 *
0.0020 *
0.0006 *
0.0004 *
0.0002 *
0.0001 *0.0001 *
0.0000 *
0.0027 *
0.0046 *
Results
Initial Pressure (bar_g)
Final Pressure (bar_g)
Depressuring Time (seconds)
Vapour Cv
Liquid Cv
Vessel Fluid Initial Temperature - Vapour Phase (F)
Vesssel Fluid Final Temperature - Vapour Phase (F)
Vessel Fluid Minimum Temperature - Vapour Phase (F)
Valve Outlet Initial Temperature - Vapour Phase (F)
Valve Outlet Final Temperature - Vapour Phase (F)
Valve Outlet Minimum Temperature - Vapour Phase (F)
Inner Wal l Ini tial Temperature - Vapour Phase (F)
Inner Wal l Final Temperature - Vapour Phase (F)
Inner Wall Minimum Temperature - Vapour Phase (F)
Vessel Fluid Init ial Temperature - Liquid Phase (F)
25.00
6.904
1.800e+004 *
0.9750 *
---
80.42
79.07
79.07
57.19
78.78
57.19
---
---
---
80.42
Vessel Fluid Final Temperature - Liquid Phase (F)
Vessel Fluid Minimum Temperature - Liquid Phase (F)
Valve Outlet Init ial Temperature - Liquid Phase (F)
Valve Outlet Final Temperature - Liquid Phase (F)
Valve Outlet Minimum Temperature - Liquid Phase (F)
Inner Wal l Ini tial Temperature - Liquid Phase (F)
Inner Wal l Final Temperature - Liquid Phase (F)
Inner Wall Minimum Temperature - Liquid Phase (F)
Initial Mass of Vapour (lb)
Final Mass of Vapour (lb)
Peak Vapour Flow Through Valve (lb/hr)
Initial Mass of Liquid (lb)
Final Mass of Liquid (lb)
Peak Liquid Flow Through Valve (lb/hr)
79.07
79.07
57.19
57.65
57.19
---
---
---
1.615e+004
4615
3857
0.0000
0.0000
0.0000
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PT.PERUSAHAAN GAS NEGARA
(Persero) TbkPT. CONNUSA ENERGINDO PT.BINARASANO ENGINEERING
BLOWDOWN ANALYSIS REPORTDocument No. Rev. Date
Page 13 of 13CP19-BRE-3514-PS-CA-002 B 14/10/2014
ATTACHEMENT 2 : LINE SIZING CALCULATION
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1. Upstream RO
Design Data Design Criteria
Pressure P = 377.3 psia Max. Velocity = 60 ft/s Refer to API RP 521
Temperature T = 80 F P (psi/100 ft) = 0,486 psi/100 ft
= 540 R
Density = 1.128 lb/ft3
Molecular Weight Mw = 16.36
Viscosity = 0.01182 cP
Compressibility Factor Z = 0.945
Roughness = 0.001 in
Pipe Material = Carbon Steel
Calculation Methode
1. Determine friction factor refer to API 14E
- Trial diameter (D) using gas velocity Equation (API 14E )
- Calculate Reynold number (Re)
2. Determine the value of (/D) and Re from the picture below to get (fm)
3. Determine Pressure Drop using Darcy formula
LINE SIZING
V =
R =
=
0,000336
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Calculation Result
- Depressuring time = 3 hours
- Molar Flowrate (Q) = 3.54 MMSCFD from HYSYS
- Mass Flowrate (W) = 6360 lb/hr from HYSYS
Option (/D) Gas Velocity (fps) Re fm P (psi/100ft) Status
Option 1 0.0005 71.818 1699710.084 0.0165 6.213 NOT OK
Option 2 0.000333333 31.919 1133140.056 0.0155 0.769 NOT OK
Option 3 0.00025 17.954 849855.042 0.015 0.176 OK
Option 4 0.000166667 7.980 566570.028 0.0145 0.022 OK
- Depressuring time = 4 hours
- Molar Flowrate (Q) = 2.681 MMSCFD from HYSYS
- Mass Flowrate (W) = 4818 lb/hr from HYSYS
Option (/D) Gas Velocity (fps) Re fm P (psi/100ft) Status
Option 1 0.0005 54.391 1287266.309 0.0165 3.565 NOT OK
Option 2 0.000333333 24.174 858177.540 0.0155 0.441 OK
Option 3 0.00025 13.598 643633.155 0.015 0.101 OK
Option 4 0.000166667 6.043 429088.770 0.0145 0.013 OK
- Depressuring time = 5 hours
- Molar Flowrate (Q) = 2.147 MMSCFD from HYSYS
- Mass Flowrate (W) = 3857 lb/hr from HYSYS
Option (/D) Gas Velocity (fps) Re fm P (psi/100ft) Status
Option 1 0.0005 43.557 1030869.364 0.0165 2.285 NOT OK
Option 2 0.000333333 19.359 687246.243 0.0152 0.277 OK
Option 3 0.00025 10.889 515434.682 0.0152 0.066 OK
Option 4 0.000166667 4.840 343623.121 0.0145 0.008 OK
Selected Pipe Size
Based on calculation result that suitable of criteria :
D = 4 in
P = 0.176 psi/100ft
Gas Velocity = 17.954 fps
Depressuring time = 3 hours
D(in)
D(in)
2
3
4
6
D(in)
2
3
4
6
2
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2. Downstream RO
Design Data Design Criteria
Pressure P = 100 psig Beta ratio 0.2 - 0.75
= 790.8 kPa Max. Velocity 500 fps Refer to API 14E
Pressure Tip = 0 psig Noise 85 dB Refer to Kepmen LH No.48/1996
= 14.7 psia 55 dB Refer to Kepmen Naker No.51/1999
Downstream Pressure Pd = 1 bar
Temperature T = 82.5 F
= 301.2 K
Density = 1.128 lb/ft3
Spesific Gravity SG = 0.565
Molecular Weight Mw = 16.36
Viscosity = 0.01182 cP
Compressibility Factor Z = 0.945
Specific Heat Ratio Cp/Cv = 1.381
Roughness = 0.001 in
Piping Data
Upstream Diameter D = 4 in
101.6 mm
Restriction Orifice Data
Discharge Coeficient Constant = 0.975
Calculation
Estimation noise by Lighthill's Theory :
OASPL = Overall sound pressure level of regenerated noise (dB)
d = Inside diameter of vent stack (m)
C0 = Sonic Velocity (Velocity of sound in atmosphere) (m/s)
Vg = Exit velocity of vented gas (m/s)
0 = Density of atmosphere (kg/m3)
g = Density of vented gas (kg/m3)
R = Distance from vent (m)
No 3 Hours 4 Hours 5 Hours
1 Relief Load (W) (kg/h) 2885 2185 1749
2 Set Initial Value of FTP 1 1 1
3 Critical Flow Function, YCR 0.701 0.701 0.701
4 Orifice Diameter, d (mm) 27.17 23.65 21.16
5 0.267 0.233 0.208
6 1.0012 1.0007 1.0004
7 Critical Pressure, (kPa) 420.81 420.60 420.50
8 63442.49 48047.83 38477.69
9 Turbulent - OK Turbulent - OK Turbulent - OK
10 Critical Flow Critical Flow Critical Flow
Calculation steps
Beta Ratio,
FTPCalculated
Reynold Number
Flow Region
Flow Behaviour
= 61,8 + 10 log
20 log
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Noise
Sonic Velocity = 459.861987 m/s
Wind Velocity = 6 knots
= 3.084 m/s
Air Density = 1.27605002 kg/m3
Vapour Density = 0.70028956 kg/m3
Note :
Noise 1 85 dB Distance 3 m Refer to Kepmen LH No.48/1996
Noise 2 55 dB Distance 35 m Refer to Kepmen Naker No.51/1999
Blowdown Time 3 Hours
Option Mach Number Noise 1 Noise 2
Option 1 1.265 110.272 88.933
Option 2 0.562 85.619 64.280
Option 3 0.316 68.128 46.789
Option 4 0.141 43.475 22.136
Blowdown Time 4 Hours
Option Mach Number Noise 1 Noise 2
Option 1 0.958 100.625 79.286
Option 2 0.426 75.972 54.633
Option 3 0.240 58.480 37.141
Option 4 0.106 33.828 12.489
Blowdown Time 5 Hours
Option Mach Number Noise 1 Noise 2
Option 1 0.767 92.895 71.556
Option 2 0.341 68.242 46.904
Option 3 0.192 50.751 29.412
Option 4 0.085 26.098 4.759
Selected RO Size
Blowdown Time = 3 Hours
ID Downstream = 4 in
Mach Number = 0.316
Beta Ratio = 0.267
Orifice Diameter = 27.17 mm
1.070 in
Reference
1. API RP 521 - "Guide for Pressure Relieving - Depressuring System"
2. API 14E - "Recommended Practice for Design and Installation of Offshore Production Platform Piping Systems"
2. API RP 520 - "Sizing, Selection, and Installation of Pressure-Relieving Devices in Refineries"
4. GPSA Section 17 - " Fluid Flow and Piping"
StatusID Downstream (in)
2 NOT OK
3 NOT OK
4 OK
6 OK
ID Downstream (in) Status
2 NOT OK
3 OK
4 OK
6 OK
4 OK
6 OK
ID Downstream (in) Status
2 NOT OK
3 OK
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