LP Flare Network Calculation Rev- E0

FIRST COMMERCIAL PRODUCTION FACILITY – GARRAF FIELD DEVELOPMENT PROJECT WEATHERFORD OIL TOOL MIDDLE EAST LTD. FOR PETRONAS CARIGALI IRAQ HOLDING BV

Document Title:

LP FLARE NETWORK CALCULATION

Document No.:

P10-1033-P-CA-0191 This document supersedes the LP Flare Calculation cited in P10-1033-P-RE-0006

Approved /Reviewed

Approved with Comment Resubmit for Approval E0

21-06-2013

Issued for Construction

PKM

SY

AM

REV

DATE

STATUS

PREPARED BY

CHECKED BY

APPROVED BY

CONTRACTOR

Resubmit for Review Name

Signature

Title

Date

CLIENT

PROJECT DOCUMENTS ARE CONTROLLED DOCUMENTS. REVISIONS ARE DENOTED  IN RIGHT HAND MARGIN CLIENT:

PETRONAS CARIGALI IRAQ HOLDING BV CONTRACTOR:

WEATHERFORD OIL TOOL MIDDLE EAST LTD

CLIENT REF:

CHO/2010/DPP/067 CONTRACTOR REF:

P10-1033

FIRST COMMERCIAL PRODUCTION FACILITY GARRAF FIELD DEVELOPMENT PROJECT Document No.: Revision: Page:

P10-1033-P-CA-0191 E0 2 of 18

TABLE OF CONTENTS 1 2

Introduction ....................................................................................................... 3 Summary............................................................................................................ 3 2.1 Purpose ......................................................................................................... 3 2.2 Definition of Standard and Normal Conditions .............................................. 3 2.3 References .................................................................................................... 3 2.4 Assumptions.................................................................................................. 4 2.5 Calculation Basis........................................................................................... 4 2.6 Results and Conclusions ............................................................................... 5 2.6.1 2.6.2 2.6.3

3

LP Flare .............................................................................................................. 6 3.1 LP Flare Sources .......................................................................................... 6 3.2 LP Flare Network .......................................................................................... 7 3.3 LP Flare Relief Loads & Relief Gas Composition .......................................... 8 3.3.1 3.3.2 3.3.3 3.3.4 3.3.5 3.3.6

4

5 6 7

8

Backpressure .................................................................................................................. 5 Mach No. & Rho V2 ........................................................................................................ 6 NOISE ............................................................................................................................... 6

st

1 Stage Separator (V-1010 / 1020) ............................................................................... 8 ND 2 Stage Separator (V-1110 / 1120) .............................................................................. 8 Dehydrator (V-1510 / 1520) & Desalter (V-1610 / 1620) ................................................ 9 Produced Water Treatment Package (AQ-4210) ............................................................ 9 Fuel Gas Treatment Package (AQ-6020) ..................................................................... 10 Power Plant Fuel Gas Conditioning Package (AQ-7501) ............................................. 10

3.4 LP Flare Purge ............................................................................................ 10 3.5 LP Flare Knock Out Drum, V-6205.............................................................. 11 3.6 LP Flare Stack (Smokeless Flaring) ............................................................ 11 3.7 LP Flare Tip................................................................................................. 11 LP Flare Scenarios .......................................................................................... 11 4.1 Scenario 1 ................................................................................................... 12 4.2 Scenario 2 ................................................................................................... 12 4.3 Scenario 3 ................................................................................................... 13 4.4 Scenario 4 ................................................................................................... 13 4.5 Scenario 5 ................................................................................................... 14 4.6 Scenario 6 ................................................................................................... 14 4.7 Scenario 7 ................................................................................................... 15 4.8 Scenario 8 ................................................................................................... 15 4.9 Scenario 9 ................................................................................................... 16 4.10 Scenario 10 .............................................................................................. 16 4.11 Scenario 11 .............................................................................................. 17 Relief Load In Various Scenarios .................................................................. 17 Basis For Aspen Flare System Analyzer Study ............................................ 18 LP Flare Design Criteria ................................................................................. 18 7.1 Header and Tailpipe .................................................................................... 18 7.2 Noise Limitations ......................................................................................... 18 Recommendations .......................................................................................... 18

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1

P10-1033-P-CA-0191 E0 3 of 18

INTRODUCTION The LP Flare Network is an important part of FCP as it ensures the safe disposal of st nd hydrocarbon releases from various pressurized sources. The 1 Stage and 2 Stage separators of both trains are continuously relieving to LP flare header to maintain separator pressure. The following equipment / packages are also connected to the LP flare system for relief gas disposal: desalters, dehydrators, crude heater packages, fuel gas package, power plant fuel gas conditioning and produced water treatment packages. The LP Flare source releases are estimated considering that each FCP Train is operating at the design production rate of 55000 bpd. Calculations produced in this document have been determined using Aspen Flare System Analyzer Version 7.3. Once the various operating and relief scenarios that could occur are defined and the relief rates, venting rates and fluid properties are input into the flare system model, Aspen Flare System Analyzer performs numerous iterative calculations to size the LP flare network. Piping information i.e. layout, pipe lengths and fittings data are taken from piping isometrics in order to build the model.

2

SUMMARY 2.1

Purpose

The purpose of this calculation is to identify relief scenarios and determine the relief loads directed to the LP flare system and to select the line sizes in the flare system.

2.2

Definition of Standard and Normal Conditions

The standard and normal conditions for volumetric measurement of gases and liquids are defined at pressure and temperature of: Standard = 1.013 Bara and 15.6°C. Normal = 1.013 Bara and 0°C.

2.3

References Sr No 1 2 3 4 5 6

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Documents

Attachment

No of Pages

Extract of PSV Datasheet sizing Doc No. : P101033-P-DS-0003 Rev D2 (For Process Trains) st 1 Stage Separator – Total Flaring HYSYS stream summary st 1 Stage Separator – Blocked outlet HYSYS stream summary st 1 Stage Separator – Fire Case HYSYS stream summary st nd 1 Stage & 2 Stage Separator - Blowdown Results nd 2 Stage Separator – Total Flaring HYSYS stream summary

Attachment-A

4

Attachment-B

2

Attachment-C

2

Attachment-D

2

Attachment-E

4

Attachment-F

2

FIRST COMMERCIAL PRODUCTION FACILITY GARRAF FIELD DEVELOPMENT PROJECT Document No.: Revision: Page: Sr No 7

E0 4 of 18

Attachment

nd

st

No of Pages

2 Stage Separator gas flow during 1 Stage separator blocked outlet - HYSYS stream summary nd st 2 Stage Separator- Gas blowby from 1 Stage separator - HYSYS stream summary nd 2 Stage Separator – Fire Case HYSYS stream summary Dehydrator – Fire Case HYSYS stream summary Desalter – Fire Case HYSYS stream summary PW Treatment Package- PSV Data Fuel Gas Package- PSV & BDV Data Power Plant Fuel Gas Conditioning PackagePSV & BDV Data Extract of Calculation for LP Flare KO Drum, Doc No.: P10-1033-P-CA-0146

Attachment-G

2

Attachment-H

2

Attachment-I

2

Attachment-J

2

Attachment-K

2

Attachment-L

2

Attachment-M

3

Attachment-N

3

Attachment-O

1

16

Flare package data from Flare Industries

Attachment-P

2

17

Purge gas calculation Fuel Gas Package H&M Balance

Attachment-Q

1

18

Attachment-R

2

19

P&ID’s

Attachment-S

17

20 21

Piping Isometrics

Attachment-T Attachment-U

81 11

8 9 10 11 12 13 14 15

2.4

Documents

P10-1033-P-CA-0191

Pressure/flow summary (Results for scenarios 1-11)

Assumptions

1. Any operational contingency on one train will not affect the operation of other train. 2. Pipe lengths and fittings for the Fuel Gas Conditioning Package AQ-7501 and the Produced Water Treatment Package AQ-4210 are assumed. 3. Thermal relief from piping and pig receivers are not considered in this calculation as flow rates are insignificant for this relief contingency. 4. The relief case for the Produced Water Package AQ-4210 is control valve failure based on nitrogen flow. This flow data is currently not available. However, as this flow is limited by an RO and insignificant relative to the governing case for the LP flare, the available data for the thermal relief case given in attachment L is used in the calculations.

2.5

Calculation Basis

1. Various relief loads to LP flare network is considering that both crude processing trains are operating at 55,000 bpd (Design Flow). 2. PSV rated flow is used as the relief load for all cases except fire. 3. For fire case, the required flow of relief valve is used as the relief load even if the governing case is the fire case as there are other mitigating devices in place to reduce the relief load e.g. blowdown and active fire protection. The fire case relief loads also do not govern the flare header sizing in this plant. 2

4. API Fire circle (of 232 m ) is considered to identify the number of equipment in fire zone.

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P10-1033-P-CA-0191 E0 5 of 18 nd

5. LP flare relief load for fire case scenario of any of these three equipments (2 stage separator, desalter & dehydrator) is the same. As fire circle will cover all three nd equipments 2 stage separator, desalter & dehydrator of the particular train. 6. During operational contingency on one train, it is considered that the feed to the fuel gas package AQ-6020, will be at normal user flow rate demand (i.e., 2 Crude heaters + LP & ATM purge flows + Power Plant Fuel Gas Conditioning Package=2x1591+3x80+3x55+7964=11551 kg/h) from the other normal operating train. st Otherwise, the fuel gas package will be withdrawing equally from the 1 stage separators of trains 1 and 2 and the remaining gas is flared off. 7. During a fire scenario, the relief loads considered are for equipment located in the fire zone and the blowdown rates are from equipment outside the fire zone. 8. In the case of multiple working PSVs, the total relief load is distributed equally to the operating PSVs. 9. In normal operation, fuel gas is continuously purged at 3 locations into the flare header ends to prevent burn back in the flare tip. 10. For the determination of maximum backpressures for multiple PSVs, the farthest working PSVs from the flare stack are assumed to be relieving.

2.6

Results and Conclusions

Aspen Flare System Analyzer simulations are carried out for all scenarios & results are evaluated against the design criteria.

2.6.1

BACKPRESSURE

Maximum back pressure for all scenarios (See attachment-U) is tabulated below. PCV / Relief Scenarios Maximum Back Location Valve Pressure, barg Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5 Scenario 6 Scenario 7 Scenario 8 Scenario 9 Scenario 10

0.24 Note 2 1.37 1.40 1.14 1.16 0.40 0.39 1.79 0.34

Scenario 11

0.15

nd

Train 1- 2 Stage Separator, V-1110 Note 2 nd Train 1- 2 Stage Separator, V-1110 nd Train 2- 2 Stage Separator, V-1110 Train 1- Dehydrator, V-1510 Train 2- Dehydrator, V-1520 st Train 1- 1 Stage Separator, V-1010 st Train 2- 1 Stage Separator, V-1020 Fuel Gas Package, AQ-6020 Power Plant Fuel Gas Conditioning Package, AQ-7501 AQ-4210, IGF

PCV-1110 Note-2 PSV-1110C PSV-1120C PSV-1510 PSV-1520 PSV-1010 C PSV-1020 C PSV-6000 A/B PSV-6027/28 PSV-4220/4221

Notes: 1- Maximum back pressure is observed at downstream of PSV-6000 A/B. 2- In scenario 2 (Total Blowdown), all BDV’s will be operating and BDV’s operation is independent of back pressure. 3- In scenarios 3 and 4, the maximum back pressures slightly exceed the allowable 30% nd back pressure, set in the simulation. However, as balanced bellows PSVs are used on 2 stage separators and the rated flow is 30% higher than the required flow, there is no concern.

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FIRST COMMERCIAL PRODUCTION FACILITY GARRAF FIELD DEVELOPMENT PROJECT Document No.:

P10-1033-P-CA-0191

Revision:

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2.6.2

6 of 18

MACH NO. & RHO V2

In all scenarios, Mach No is significantly lower than 0.6 in all flare headers and sub-headers as well as Mach No. is lower than 0.5 downstream of all control valves (See Attachment U). 2

2

In all scenarios, Rho V is significantly lower than 200000 kg/m/s , therefore is no concern (See Attachment-U).

2.6.3

NOISE

In all scenarios noise is significantly lower than 85 dB (A) thus there are no noise issues (See Attachment-U).

3

LP FLARE 3.1

LP Flare Sources

LP Flare sources are tabulated below Source

Name

PCV / BDV / Relief Valve st

V-1010

Train 1, 1 Stage Separator

V-1110

Train 1, 2

V-1510

Train 1, Dehydrator

PSV-1510

V-1610

Train 1, Desalter

PSV-1610

AQ-1111

Train 1, Crude Heater (Note 1)

TSV-11101

V-1020

Train 2, 1 Stage Separator

nd

Stage Separator

st

nd

PCV-1110, BDV-1110, PSV-1110 A/B/C

PCV-1020, BDV-1020, PSV-1020 A/B

V-1120

Train 2, 2

V-1520

Train 2, Dehydrator

PSV-1520

V-1620

Train 2, Desalter

PSV-1620

AQ-1112

Train 2, Crude Heater (Note 1)

TSV-11201

AQ-6020

Fuel Gas Package (Note 2)

PSV-6000 A/B, BDV-6001, BDV-6010

AQ-7501

Power Plant Fuel Gas Conditioning Package (Note 2) Produced Water Treatment Package

AQ-4210

Stage Separator

PCV-1011, BDV-1010, PSV-1010 A/B/C

PCV-1120, BDV-1120, PSV-1120 A/B

PSV-6027/28, BDV-6001, BDV-6002 PSV-4210/4211, PSV-4220/4221

Note 1: Source modeled in Flare-Net but as this is a thermal relief case it is ignored in the simulations. Note 2: Only the governing and blowdown sources that are modeled in Flare-Net are given here.

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3.2

LP Flare Network

The LP flare network model schematic is shown below.

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P10-1033-P-CA-0191 E0 7 of 18


3.3

P10-1033-P-CA-0191 E0 8 of 18

LP Flare Relief Loads & Relief Gas Composition

The LP flare sources have different relief loads in accordance with the overall relief scenario. The relief gas composition is dependent on the relieving scenario.

3.3.1

1ST STAGE SEPARATOR (V-1010 / 1020)

PCV / BDV / Relief Valve

Scenario

Total Flaring

PSV-1010 A/B/C / 1020 A/B/C Blocked outlet

Reference

Attachment-B

Attachment-A

Attachment-A

Adiabatic Blowdown Attachment-E

36668.7

30713*

10637

4559

9.9

19.8

21.8

10.3

Temperature, C

65.8

66.0

174.3

66

M.W.

24.2

22.8

34.8

24.2

Attachment-B

Attachment-C

Attachment-D

Attachment-B

Relief load, kg/h Pressure, barg o

Composition

PCV-1011 /1021

PSV-1010 A/B/C / 1020 A / B /C Fire

BDV-1010 / 1020

For adiabatic blowdown, composition is considered similar to total flaring case. *Required flow given, the rated flow of 33654 kg/h for two operating PSVs is used in calculations.

3.3.2

2ND STAGE SEPARATOR (V-1110 / 1120)


PCV-1011 /1021

PCV-1011 /1021

Scenario

Total Flaring

During 1 Stage Blocked outlet

Gas Blowby

PSV-1010 A/B/C / 1020 A / B /C Fire

Reference

Attachment-F

Attachment-G

Attachment-A

Attachment-A

10545.9

12921

55556

8813

Relief load, kg/h Pressure, barg

st

PSV-1110 A/B/C / 1120 A/B/C

2.4

2.4

4.9

5.6

Temperature, C

104.1

104.6

105.0

141.7

M.W.

38.3

42.6

25.6

37.8

Attachment-F

Attachment-G

Attachment-H

Attachment-I

o

Composition

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P10-1033-P-CA-0191 E0 9 of 18

Stage Separator (V-1110 / 1120) During Blowdown


Scenario Reference

BDV-1110 / 1120 Adiabatic Blowdown Attachment-E

Relief load, kg/h

BDV-1110 / 1120 Fire Case Blowdown Attachment-E

4354

6207

2.8

4.5

Temperature, C

105

105

M.W.

38.3

38.3

Pressure, barg o

Composition

Attachment-F Attachment-F For adiabatic & fire blowdown, composition is considered similar to total flaring case.

3.3.3

DEHYDRATOR (V-1510 / 1520) & DESALTER (V-1610 / 1620)


Scenario Reference Relief load, kg/h Pressure, barg o Temperature, C M.W. Composition

3.3.4

PSV-1510 / 1520 Fire Attachment-A

PSV-1610 / 1620 Fire Attachment-A

15993 20.5 199.3 34.7

15991 20.5 199.3 34.7

Attachment-J

Attachment-K

PRODUCED WATER TREATMENT PACKAGE (AQ-4210)


Scenario

PSV-4210 / 4211 Thermal Relief*

PSV-4220 / 4221 Thermal Relief*

Reference Attachment-L Attachment-L Relief load, kg/h 650* 650* Pressure, barg 9.6 9.6 o Temperature, C 70 70 M.W. 24.2 24.2 Composition Attachment-R Attachment-R *Thermal relief load used in calculations in the absence of actual data for control valve failure case. See section 2.4.

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FIRST COMMERCIAL PRODUCTION FACILITY GARRAF FIELD DEVELOPMENT PROJECT Document No.:

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3.3.5

10 of 18

FUEL GAS TREATMENT PACKAGE (AQ-6020)

Fuel Gas Treatment Package (AQ-6020) relief load is 63000 Kg/hr for the governing case. The PSV rated flow is limited to this required flow by the upstream train 1 and 2 control valve Cvs and system hydraulics. Equipment

V-6000

V-6000

S-6000 A/B

PSV-6000A/B

BDV-6000

BDV-6010

Scenario

Control Valve Failure

Adiabatic Blowdown

Adiabatic Blowdown

Reference

Attachment-M

Attachment-M

Attachment-M

63000

331.5

932.6

15.1

8.6

8.0

60 24.2

60 24.2

75 24.2

Attachment-M&R

Attachment-M&R



Temperature, C M.W. Composition

3.3.6

Attachment-M&R

POWER PLANT FUEL GAS CONDITIONING PACKAGE (AQ-7501)

Power Plant Fuel Gas Conditioning Package (AQ-7501) relief load is 8381 kg/hr for the governing case. Equipment E-6006 V-6005 E-6001 PCV / BDV / Relief Valve

Scenario

PSV-6027 / 6028 Tube Rupture

Reference

Attachment-N

Attachment-N

Attachment-N

8381*

705

1596

8.3

21.6

20.5

32.2

10.0

10.0


Temperature, C M.W. Composition

BDV-6002

BDV-6001

Adiabatic Blowdown

Adiabatic Blowdown

24.0

24.0

24.0

Attachment-N

Attachment-N

Attachment-N

*Required flow is used as the relief rate is limited by the supply of gas to this package.

3.4

LP Flare Purge

LP flare network is purged continuously with fuel gas through three locations (Train1 flare header, Train 2 flare header and fuel gas package, AQ-6020). Fuel gas purging requirement (for burnback prevention) is based on Flare Industries values and velocity criteria are adjusted to match the flow requirement. Purge gas flow rates are estimated based on a velocity of 0.092 m/s at flare tip.

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P10-1033-P-CA-0191 E0 11 of 18

During loss of fuel gas supply or during startup/shutdown, LP flare network is continuously purged with nitrogen through two locations (Train 1 Flare header, Train 2 Flare header). N2 purging requirement (for air-ingress prevention) is based on API velocity criteria (0.006-0.012 m/sec). Velocity of 0.012 m/sec is used for calculation and this is in close agreement with Flare Industries values. Refer to Attachment-Q for purge gas calculation.

3.5

LP Flare Knock Out Drum, V-6205

Calculated pressure drop across the LP flare KOD is approximately 10 mbar at the rated flow of 94400 kg/h. However, the actual pressure drop across the drum is likely to be higher because of the inlet device and sump pump obstruction to flow path. (Refer to Attachment-O, Calculation for LP Flare KO Drum P10-1033-P-CA-0146).

3.6

LP Flare Stack (Smokeless Flaring)

The LP flare stack assembly consists of a 36 inch inner flare gas riser and a 78 inch outer pipe. The dilution air is blown through the annulus between the riser and the outer pipe. The stack height is 45.7 m from ground level (see Attachment-P, LP Flare Package data from Flare Industries).

3.7

LP Flare Tip

The Flare Tip contains a dynamic seal. Its pressure drop is 25.77 mbar at the design flow (see Attachment-P, LP Flare package data from Flare Industries).

4

LP FLARE SCENARIOS The following 11 scenarios are identified for the LP flare calculations. An individual scenario is selected to have maximum relief load in different parts of LP flare system or simultaneous maximum load in different area.

Various Scenarios are listed below: Scenario 1 Total gas flaring Train 1 & 2 Scenario 2 Total Facility Blowdown nd Scenario 3 2 Stage Separator gas blowby, Train 1 nd Scenario 4 2 Stage Separator gas blowby, Train 2 Scenario 5 Fire Case Train-1 Scenario 6 Fire Case Train-2 st Scenario 7 Blocked outlet 1 Stage separator, Train-1 st Scenario 8 Blocked outlet 1 Stage separator, Train-2 Scenario 9 FG Package control valve failure Scenario 10 Power Plant Fuel Gas Conditioning Package Scenario 11 PWT Package control valve failure

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4.1

P10-1033-P-CA-0191 E0 12 of 18

Scenario 1

Scenario 1 is maximum flaring of associated gas from both trains and each train is operating at design flowrate of 55000 bopd. Relief Loads from various sources are tabulated below. Source

Name


Mass Relief Rate (Gas), kg/h

Relief Scenario

V-1010

Train-1, 1st Stage Separator

PCV-1011

36668.7

Total Flaring

V-1110

Train-1, 2nd Stage Separator

PCV-1110

10545.9

Total Flaring

V-1020


PCV-1021

36668.7

Total Flaring

V-1120


PCV-1120

10545.9

Total Flaring

Total LP Flare Load

4.2

94429.3

Scenario 2

Scenario 2 is considering the total facility Blowdown e.g. during ESD. Relief Loads from various sources are tabulated below. Source

Name



Relief Scenario

V-1010


BDV-1010

4559

Adiabatic Blowdown

V-1110


BDV-1110

4354

Adiabatic Blowdown

V-1020


BDV-1020

4559

Adiabatic Blowdown

V-1120


BDV-1120

4354

Adiabatic Blowdown

AQ-6020

Fuel Gas Package

BDV-6000

331.5

Adiabatic Blowdown

AQ-6020

Fuel Gas Package

BDV-6010

932.6

Adiabatic Blowdown

BDV-6001

1596

Adiabatic Blowdown

BDV-6002

705

Adiabatic Blowdown

AQ-7501 AQ-7501

Power Plant Fuel Gas Conditioning Package Power Plant Fuel Gas Conditioning Package

Total LP Flare Load

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21391.1


4.3

P10-1033-P-CA-0191 E0 13 of 18

Scenario 3 nd

Scenario 3 is considering the Gas blowby from train 1, 2 Stage Separator and gas from train 2 is under normal flaring. Relief Loads from various sources is tabulated below. Source

Name



Relief Scenario

V-1110


PSV-1110 B

27778.0

Gas Blowby

V-1110


PSV-1110 C

27778.0

Gas Blowby

V-1020


PCV-1021

25117.7

Total Flaring less Fuel Gas Consumption of 11551 kg/h

V-1120


PCV-1120

10545.9

Total Flaring

Purge Gas Flow

240.0 91459.6

Total LP Flare Load

4.4

Scenario 4 nd

Scenario 4 is considering the Gas blowby from train 2, 2 Stage Separator and gas from train 1 is under normal flaring. Relief Loads from various sources is tabulated below. Source

Name



V-1010


PCV-1011

25117.7


V-1110


PCV-1110

10545.9

Total Flaring

V-1120


PSV-1120 B

27778.0

Gas Blowby

V-1120


PSV-1120 C

27778.0

Gas Blowby

Purge Gas Flow Total LP Flare Load

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240.0 91459.6

Relief Scenario


4.5

P10-1033-P-CA-0191 E0 14 of 18

Scenario 5 nd

Scenario 5 is considering Train 1, 2 stage separator is under fire and depressurized. Fire st circle is spreading over desalter and dehydrator.1 stage separator is depressurized adiabatically. Train 2, Fuel gas Package & Power Plant Fuel Gas Conditioning Package is under adiabatic blowdown. Relief Loads from various sources is tabulated below. Source

Name

V-1010

Train-1, 1st Stage Separator Train-1, 2nd Stage Separator

V-1110

PCV / BDV / Relief Valve BDV-1010

Mass Relief Rate (Gas), kg/h 4559

Relief Scenario

BDV-1110

6207

Fire Case Blowdown

Adiabatic Blowdown

V-1510

Train-1, Dehydrator

PSV-1510

15993

Fire Case

V-1610

Train-1, Desalter

PSV-1610

15991

Fire Case

V-1020


BDV-1020

4559

Adiabatic Blowdown

V-1120


BDV-1120

4354

Adiabatic Blowdown

AQ-6020

Fuel Gas Package

BDV-6000

331.5

Adiabatic Blowdown

AQ-6020

Fuel Gas Package

BDV-6010

932.6

Adiabatic Blowdown

BDV-6001

1596

Adiabatic Blowdown

BDV-6002

705

Adiabatic Blowdown

AQ-7501 AQ-7501


Total LP Flare Load

4.6

55228.1

Scenario 6 nd

Scenario 6 is considering Train 2, 2 stage separator is under fire and depressurized. Fire st circle is spreading over desalter and dehydrator.1 stage separator is depressurized adiabatically. Train 1, Fuel gas Package & Power Plant Fuel Gas Conditioning Package is under adiabatic blowdown. Relief Loads from various sources is tabulated below. Source

Name



Relief Scenario

V-1010


BDV-1010

4559

Adiabatic Blowdown

V-1110


BDV-1110

4354

Adiabatic Blowdown

V-1020


BDV-1020

4559

Adiabatic Blowdown

V-1120


BDV-1120

6207

Fire Case Blowdown

V-1520

Train-2, Dehydrator

PSV-1510

15993

Fire Case

V-1620

Train-2, Desalter

PSV-1610

15991

Fire Case

AQ-6020

Fuel Gas Package

BDV-6000

331.5

Adiabatic Blowdown

AQ-6020

Fuel Gas Package

BDV-6010

932.6

Adiabatic Blowdown

BDV-6001

1596

Adiabatic Blowdown

BDV-6002

705

Adiabatic Blowdown

AQ-7501 AQ-7501


Total LP Flare Load

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55228.1


4.7

P10-1033-P-CA-0191 E0 15 of 18

Scenario 7 st

Scenario 7 is considering that Train 1, 1 stage separator is under relieving under blocked outlet condition and Train 2 is normal flaring. Relief Loads from various sources is tabulated below. Source

Name



Relief Scenario

V-1010


PSV-1010 C

16827

Blocked Outlet

V-1010


PSV-1010 B

16827

Blocked Outlet

V-1110


PCV-1110

12921

V-1020


PCV-1021

25118

V-1120


PCV-1120

10545.9

Purge Gas Flow

Total Flaring

240.0

Total LP Flare Load

4.8

Blocked Outlet of 1st Stage separator Total Flaring less Fuel Gas Consumption of 11551 kg/h

82478.9

Scenario 8 st

Scenario 8 is considering that Train 2, 1 stage separator is relieving under blocked outlet condition and Train 1 is total flaring. Relief Loads from various sources is tabulated below. Source

Name



V-1010


PCV-1011

25118


V-1110


PCV-1110

10545.9

Total Flaring

V-1020


PSV-1020 C

16827

Blocked Outlet

V-1020


PSV-1020 B

16827

Blocked Outlet

V-1120


PCV-1120

12921

Blocked Outlet of 1st stage separator


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240 82478.9

Relief Scenario


4.9

P10-1033-P-CA-0191 E0 16 of 18

Scenario 9 st

In this scenario, the 1 Stage Separator fuel gas PCVs of both trains are wide open and the maximum flow through each PCV, assuming a hydraulically balanced system, is 63000 kg/h st divided by 2 i.e. 31500 kg/h. Thus, the flare PCV flow from each 1 stage separator is equal nd to the total flaring load of 36668.7 kg/h less 31500 which equals 5168.7 kg/h. The 2 stage separator flare PCV is maintaining its position and relieving 10545.9 kg/h. Relief loads for this scenario are given below. Source

Name


Mass Relief Rate (Gas), Kg/Hr

V-1010


PCV-1011

5168.7

1st Stage Separator fuel gas PCVs

V-1110


PCV-1110

10545.9

Total Flaring

V-1020


PCV-1021

5168.7

1st Stage Separator fuel gas PCVs

V-1120


PCV-1120

10545.9

Total Flaring

Fuel Gas Package

PSV-6000 A/B

63000


AQ-6020

Total LP Flare Load

Relief Scenario

94429.3

4.10 Scenario 10 Scenario 10 is considering normal train operation with tube rupture occurring in the chiller exchanger in the Power Plant Fuel Gas Conditioning Package. Relief loads for this scenario are given below. Source

Name



V-1010


PCV-1011

30893

Total Flaring less half of 11551 kg/h

V-1110


PCV-1110

10545.9

Total Flaring

V-1020


PCV-1021

30893


V-1120


PCV-1120

10545.9

Total Flaring

AQ-7501

Power Plant Fuel Gas Conditioning Package

PSV-6027/28

8381

Tube Rupture


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240 91498.8

Relief Scenario


P10-1033-P-CA-0191 E0 17 of 18

4.11 Scenario 11 Scenario 11 is considering normal train operation with the PWT Package fuel gas padding valve failing open. Relief loads for this scenario are given below.

Source

Name



V-1010


PCV-1011

30893


V-1110


PCV-1110

10545.9

Total Flaring

V-1020


PSV-1010 A

30893


V-1120


BDV-1120

10545.9

Total Flaring

AQ-4210

PW Treatment Package

PSV-4210/11 or PSV4220/21

650


Purge Gas Flow

240

Total LP Flare Load

5

83768.3

RELIEF LOAD IN VARIOUS SCENARIOS LP flare relief load for various scenarios is tabulated below Scenarios Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5 Scenario 6 Scenario 7 Scenario 8 Scenario 9 Scenario 10 Scenario 11

Relief Load , kg/h

Relief Load, MMscfd

94429.3 21391.1 91459.7 91459.7 55228.1 55228.1 82478.7 82478.7 94429.3 91498.8 83768.3

71.87 15.07 70.04 70.04 34.79 34.79 62.97 62.97 71.87 69.64 63.02

Scenario 1 and 9 are the governing relief load for LP flare system.

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Relief Scenario


6

P10-1033-P-CA-0191 E0 18 of 18

BASIS FOR ASPEN FLARE SYSTEM ANALYZER STUDY 1. Calculation is carried out in the Rating Mode. 2. Pipe roughness used is 0.050 mm. 3. Calculation options assumed are as follows: VLE Method = Peng Robinson; Enthalpy Method = Lee Kessler; Pressure Drop Method = Beggs and Brill (Homogenous) Friction Factor Method = Chen

7

LP FLARE DESIGN CRITERIA 7.1

Header and Tailpipe

Pipe Work

Parameter

Criteria

Reference

Main Header / Sub header

Mach No.

<0.6

Process Design Philosophy, P10-1033-P-RE-0003

7.2

Noise Limitations

A. For emergency conditions the noise level not to exceed 115 dB(A). B. For normal operation noise levels not to exceed 85 dB(A).

8

RECOMMENDATIONS The Power Plant Fuel Gas Conditioning Package (AQ-7501) PSV`s are currently conventional types. From the Flarenet simulations it is recommended to select balance bellow PSV`s to handle higher back pressures. It is also recommended for Petronas to revise the Flarenet model with final PSV relief loads and back pressures once the Power Plant Fuel Gas Conditioning Package vendor has finalized the design.

Document1

LP Flare Network Calculation Rev- E0

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