modeling of underwater liquid releases, slick transport & evaporation
DESCRIPTION
Modeling of Underwater Liquid Releases, Slick Transport & Evaporation. V.M. Fthenakis and U.S. Rohatgi Department of Advanced Technology Brookhaven National Laboratory. Discharge Model. APG Spill from a Barge in Mississipi River -Baton Rouge, Louisiana. Overview. - PowerPoint PPT PresentationTRANSCRIPT
Modeling of Underwater Liquid Releases, Slick Transport & Evaporation
V.M. Fthenakis and U.S. Rohatgi
Department of Advanced Technology
Brookhaven National Laboratory
International Conference and Workshop on Modeling the Consequences ofAccidental Releases of Hazardous Materials, San Francisco, CA, Sept. 27-30, 1999
Discharge Model
VAPOR
FLUID
WATER
River Current
APG Spill from a Barge in Mississipi River -Baton Rouge, Louisiana
APG Spill from a Barge in Mississipi River -Baton Rouge, Louisiana
OverviewOverview
Consequence analysis requires modeling of 1) discharge, 2) transport in water, 3) evaporation and 4) atmospheric dispersion
Previous discharge models limited to initial hydrostatic pressure difference (Dodge, 1980; Fannelop, 1994) . A new discharge model was developed
Oil slick transport in rivers (Shen & Yapa, 1988) Multicomponent evaporation ( PAVE) Atmospheric Dispersion (ALOHA, ISC)
Modeling Modeling
Discharge Model • Phase 1- Initial hydrostatic pressure difference• Phase 2- Periodic vessel movements
Verification & Sensitivity Analysis Spreading & Evaporation Model Application to Real Incident Atmospheric Dispersion Modeling Verification of Predicted Concentrations
Discharge Model .
VAPOR
FLUID
Inflow WATERof WATER
River Current
Outflow
Discharge Due to OscillationsDischarge Due to Oscillations
VAPOR
FLUID WATER
WATERWaterInflow
River Current
Discharge Due to OscillationsDischarge Due to Oscillations
VAPOR
FLUID WATER
Outflow
WATER
River Current
Discharge Due to OscillationsDischarge Due to Oscillations
VAPOR
FLUID WATER
WATERWaterInflow
River Current
Discharge ModelDischarge Model Assumptions: Isothermal Outflow and/or Inflow Incompressible, Immiscible fluids; Ideal gas expansion in the vessel’s void space Based on analytical solutions for non-vented and vented
vessels; discharges due to hydrostatic pressure and periodic oscillations from waves and bouncing
The model predicts Water inflows / fluid-and-water outflows with time Change of void space and fluid inventory with time Change of water level in the barge with time Critical water layer thickness and inventory in steady-state
Discharge Model -Phase 1 VerificationDischarge Model -Phase 1 Verification
Experimental data (Dodge et al., 1980)
Liquid Density(kg/m3)
Psat(atm)
Discharge (%)Experiment Model
Iso-propylAlcohol
783 0. 2.0 2.5
MethylChloride
1280 0.92 97.6 97.7
Iso-pentane 599 0.92 97.6 100.
Discharge Model- Sensitivity AnalysisDischarge Model- Sensitivity Analysis
Gas-phase pressure Temperature & Saturation Pressure Depth of the break Area of the break Discharge coefficient Fluid density Amplitude of vessel movement Period of vessel movement
River Spreading Modeling River Spreading Modeling
Advection of the slick due to river currents and the wind
Spreading of the slick due to gravitational, inertia, viscous and surface tension forces
Multi-component evaporation
Spreading & Evaporation ModelSpreading & Evaporation Model
Change of spill thickness, width, leading edge andtrailing edge as a function of time
Spill volume decreasing due to evaporation
)48(
0 0
hXdydxdt
Xhd LEX h
LELE
Evaporation ModelingEvaporation Modeling
Experimental studies -(crude oil, Payne et al. 1984; chlorobenzene and toluene, Waden and Triemer, 1989)
PAVE multi-component evaporation model Diffusion through the liquid phase and mass transfer
from surface. Heat conduction to water, convection to the
atmosphere, solar radiation, atmospheric radiation and evaporative cooling
Verified with chlorobenzene and toluene evaporation data
Break Flow & Evaporation RatesBreak Flow & Evaporation Rates
0 20 40 60 80 100 120 140 160 180 200
TIME (min)
0
2
4
6
8
10
12
14
16
18
Ev
ap
/Bre
ak
Flo
w r
ate
(k
g/s
)
Evaporation Rate, Ka=2.e-7
Break Flow Rate
Evaporation Rate, Ka=1.e-7
Spill Area as function of TimeSpill Area as function of Time
0 20 40 60 80 100 120 140 160 180 200
TIME (min)
0100002000030000400005000060000700008000090000
Sp
ill A
rea
(m
2) Ka=2.e-7
Ka=1.e-7
Spill Area after 10 MinutesSpill Area after 10 Minutes
0 1000 2000 3000 4000 5000 6000
Location From Barge (m)
-40
-30
-20
-10
0
10
20
30
40
Plu
me
wid
th (
m)
10 min
Spill Area after 20 MinutesSpill Area after 20 Minutes
0 1000 2000 3000 4000 5000 6000
Location From Barge (m)
-40
-30
-20
-10
0
10
20
30
40
Plu
me
wid
th (
m)
10 min
20 min
Spill Area after 30 MinutesSpill Area after 30 Minutes
0 1000 2000 3000 4000 5000 6000
Location From Barge (m)
-40
-30
-20
-10
0
10
20
30
40
Plu
me
wid
th (
m)
10 min
20 min
30 min
Spill Area after 45 Minutes(Leak lasted 30 minutes)
Spill Area after 45 Minutes(Leak lasted 30 minutes)
1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
Location from Barge, m
40
30
20
10
0
-10
-20
-30
-40
Plu
me
wid
th, m
45 min
Spill Area after 75 MinutesSpill Area after 75 Minutes
1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
Location from Barge, m
40
30
20
10
0
-10
-20
-30
-40
Plu
me
wid
th, m
75 min
Spill Area after 100 MinutesSpill Area after 100 Minutes
1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
Location from Barge, m
40
30
20
10
0
-10
-20
-30
-40
Plu
me
wid
th, m
100 min
A Barge Discharge IncidentA Barge Discharge Incident
A barge-tank containing APG overturned in the Mississippi River in March 1997
For days the barge was bounced by tugboats & moved by river currents leaking APG from valves under the water
Buoyant APG fluid floated to the surface Barge was loaded with ~400,000 gal of APG and
lost at least 15% of it during the incident The incident lasted 11 days till barge was upheld
and remaining APG recovered
Barge Incident: Predictions of Release Rates during 11 Days
Barge Incident: Predictions of Release Rates during 11 Days
1
10
100
1,000
10,000
100,000
0 24 48 72 96 120 144 168 192 216 240 264Time (hours from start of incident)
AP
G D
isch
arge
(kg/
hr)
Fluid Left in the Barge (%)Fluid Left in the Barge (%)
84
86
88
90
92
94
96
98
100
0 24 48 72 96 120 144 168 192 216 240 264
Time (hr)
% A
PG
le
ft i
n b
arg
e
Baton Rouge -APG Spill in MississipiALOHA predictions on MARPLOT map
Baton Rouge -APG Spill in MississipiALOHA predictions on MARPLOT map
Cumulative APG Dose (ppm-hr) 11 days -ISC3 predictions
Cumulative APG Dose (ppm-hr) 11 days -ISC3 predictions
P er io d av erag e c oncentra tions ppm -h r
665200 670200 675200 6802003356700.00
3361700.00
3366700.00
3371700.00
3376700.00
3381700.00
3386700.00
3391700.00
5
10
30
50
100
750
1000
1500
2000
3000
ConclusionConclusion
New model of underwater liquid leaks from vessel in periodic motion.
New model of spreading of a river spill. Limited verification and sensitivity analysis
showed that predictions are reasonable. The models were applied to a known incident
and the predictions were in agreement with observations and measurements.
These models may be used in real time to minimize consequences of accidental releases.