CFD OIL 2008 COMPUTATIONAL COMPUTATION AL MODELING OF JET FIRES August 19th, 2008 Norman Neumann Marcelo Mendes
Bureau Veritas –Technical Centers
Aberdeen Paris Shan hai
ou s o n Abu Dhabi Mumbai
Rio de Janeiro
Kuala Lumpur
Perth
August 2008
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BV Brazil’ Brazil’s s AIM AIM Division Division – MAIN SERVICE SERVICES S Asset Integrity Services
► Reliability Studies implementation n ► Risk Based Inspection (RBI) implementatio ► Reliability Centered Maintenance (RCM) implementation ► Pipework Systems Integrity (PSI) studies ► HAZOP, PHA, HAZID, SIL and LOPA Analyses
Risk Analysis
► QRA (Quantitative Risk Analysis) ► Consequence Analysis on Accidents in O&G Plants ► 3-D Gas Dispersion Calculations (CFD)
3-D Gas Dispersion
CFD = Computational Fluid Dynamics ► Gas Detectors Positioning Studies
► Fire Computational Simulations
3-D Fire Simulations
► Passive Protection Studies ► Thermal Analysis – Flare, Helideck
Fire-Fighting Systems Studies Acoustic Studies
► Deluge, Foam, CO2 ► Noise Mapping and Reduction
Syste ms Studies Studi es ► P.A. Systems
Vibratio Vib ration n Stu Studies dies
Dynamic amic Anal Analysis ysis ► Dyn
Structural Dynamic Analyses
measurements nts ► Thermal studies, stress and strain measureme August 2008
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Gas Acc Accide idents nts - His Histor tory y ►
The reports cover the Gulf of Mexico, Pacific, Alaska and Atlantic areas under US government control from years 1956 to 1990 (MMS 92-0058) and 1990 to 1994 (MMS 95-0052). The Figure 1 show the frequency of some kinds of important accidents, from 1964 to 1994.
Fig. 1 - Percentage of Fire and Explosions associated with gas gas realted realted to the total total number of Fire F ire and and Explosion Explosio n accidents (918) at Gulf of Mexico, from 1964 to 1994
Fire and Explosions associated with gas 36%
Others 64%
August 2008
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Gas Acc Accide idents nts - His Histor tory y ►
Using accident reports, items of equipment with higher accident frequency were identified. The results of the research are shown on Figure 2, where the individual contribution of each group of equipment is highlighted.
Fig. 2 - Frequency (%) of teh presence of equipment in in Fire and and Explosions associat assoc iated ed with gas (total (total = 110) at Gulf of Mexico Mexico from 1985 to 1994
"Production header" 2%
Deck draining System Line Heater - 3%
Start Motor Motor - 2%
Draining pipes 2%
Piping - 3%
Oil Piping Pump - 3% Gas washer3%
Compressor 33%
"Production sump" 3% Test Separator - 3% Separator - 3% Glycol System - 4% Not specified - 6% Generator 6%
August 2008
Others 22%
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Gas Acc Accide idents nts - His Histor tory y ►
The ROAs, covering a period from January/92 to December/95 and comprising platforms platforms both fixed and semi-submersible, semi-subme rsible, are a reliable and updated picture of the operational accidents in the Company Company’s ’s platforms. Fig. 3 - Gas Leakages at PETROBRAS' Offshore Platforms Wells Water Disch. Disch. -1% Low-pressure Gas Export - 1% Dehydration Tower. -1% Christmas Tree - 1% Heat-exchangers - 1%
Flare - 1%
Vessels Turbo compressor
Ball Valve - 1%
Gas Lift
Flexible Line -1%
Daniel Valve
Wells - 21%
Gas Export
Motor Compressor - 1%
Chicksan Piping Instrument
SDV - 3%
Separator
Separat. 4%
SDV Vessels 11%
Water Disch. Low-pressure Gas Export Heat-exchangers
Lines 5%
Flare Motor Compressor Valplac Valve
Instrum. 5%
Dehydration Tower Christmas Tree
Chicksan Piping 5%
Turbo-Compressor 10% Gas Export 5%
Daniel Valve - 7%
Flexible Line Ball Valve
Gas Lift 10%
August 2008
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ADVANCE ADV ANCED D COMPU COMPUT TATIO TIONAL NAL SIMU SIMULA LATION TIONS S
ADVANCED COMPUTATIONAL SIMULATIONS fluid-dynamics, structural, non-linear, plasticity ► Thermal, fluid-dynamics, Includes “specific “specific analyses”: analyses ”: - Fir Fire e Sim Simula ulatio tions ns - Ga Gas s Dispersio Dispersion n simulat simulation ions s - Simu Simulatio lation n of gas release release through through Vents Vents - Exp Explos losion ion Simul Simulati ations ons - The Therma rmall Anal Analysi ysis s for Flare Flare - Dynam Dynamics ics analysis analysis of equipme equipment nt and structure structures s
August 2008
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FIRE SIMULATIONS METHODOLOGY
Fire scenarios identification
Flame modeling (Pool and Jet Fires)
Temperature Tempera ture calculation
Stress analysis
Collapse evaluation
Passive fire protection design
References:
11 FPSO units: P-31, P-32, P-34, P-37, P-38, P-43, P-47,P-48, P-50, P-54, FPSO Cidade de São Mateus 22 Fixed and semi-submersible platforms August 2008
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GAS DISPERSION SIMULATIONS METHODOLOGY ► Identification and characterization of leakage scenarios ► Construction of 3-D model ► Wind calculation ► Gas Dispersion Analysis, for each scenario ►
uperpos on o gas c ou s => gas e ec on FPSO CFD Model
► Definition of position of Vents ► Special Studies (Cargo Tanks, smoke,
temperature, Gas accumulation, air changes, etc)
August 2008
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GAS DISPERSION SIMULATIONS platform orm - FLACS and CFX CFX models models ► Fixed platf CFX
FLACS (GexCon)
August 2008
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GAS DISPERSION SIMULATIONS Gas leakage at SDV (SE wind = 5.19 m/s, Leak direction = Horizontal, S to N)
Gas leakage at SDV (SE wind = 5.19 m/s, Leak direction = vertical to floor)
FLACS FLACS (length = 44 m)
CFX CFX (length=44,3m)
August 2008
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FIRE SIMULATIONS ► Jet Fire (ARGOS) Heat flow:
Q
=
f (V , P C , F )
V = leak flow P C = Heat of combustion F = Diffusivity parameter
Flame length:
L f (V , Pressão ,Gas properties) =
Flame tilting angle: Iterative method
α
=
f vwind ,
,V , D ,
wind
, L
gas
August 2008
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FIRE SIMULATIONS ► Thermal model
FPSO
Module P01-A
► Structural model
FPSO Skid
Module P01-A August 2008
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FIRE SIMULATIONS Table 1 - Gas Export Pipeline (9.13”)
► Jet Fire
Orifice Leakage Size/ Flow Rate Flame Characteristics
Time : 1 min.
FPSO Time: 15 min.
Large
Medium
Small
50kg/s
5kg/s
0.5kg/s
Flame Length (m)
72.97
24.87
8.40
Heat Radiation (MW)
1099
115.4
11.89
Flame Length (m)
48.32
23.81
8.36
Heat Radiation (MW)
463.7
105.4
11.78
92
800
>5000
Duration (min.)
Table 2 - Gas Lift Riser (2.5”) Orifice Leakage Size/ Flow Rate Flame Characteristics
Time : 1 min.
Time: 15 min.
Large
Medium
Small
50kg/s
5kg/s
0.5kg/s
Flame Length (m)
72.97
24.87
8.40
Heat Radiation (MW)
1099
115.4
11.89
Flame Length (m)
-
16.51
8.06
Heat Radiation (MW)
-
49.56
10.90
9
93
900
Duration (min.)
August 2008
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FIRE SIMULATIONS ► Flame calculation
FPSO
Gas Export Line
Large flow Medium flow
August 2008
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FIRE SIMULATIONS ► Flame calculation
FPSO Balcony and Skid
Gas Lift riser
August 2008
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FIRE SIMULATIONS ► Flame calculation
FPSO Skid CFD Flame length = 35,2 m
ARGOS Flame length = 36 m
August 2008
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FIRE SIMULATIONS ► Flame calculation
FPSO floor isolation
Jet fire fire - Co Comp mpres ressor sor Vess Vessel el
Without bottom beams
With bottom beams August 2008
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FIRE SIMULATIONS ► Radiation analysis
FPSO
Riser Balcony
Jet Fire at the Production Separator
Jet Fire at the 3rd Stage Compressor
Jet Fire at the Safety Gas KO Drum August 2008
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Thank you for your attention!
