Modeling of hydrogen explosion on a pressure swing adsorption facility
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Transcript of Modeling of hydrogen explosion on a pressure swing adsorption facility
Modeling of hydrogen explosion on a pressure swing adsorption facility*B. Angers1, A. Hourri1, P. Benard1
E. Demaël2, S. Ruban2, S. Jallais2
1 Institut de recherche sur l’hydrogène, Université du Québec à Trois-Rivières, Québec, Canada2 Air Liquide, Centre de Recherche Claude-Delorme, 78350 Jouy en Josas, France
Project scopeNumerical study of the consequences of
an hydrogen release from a Pressure Swing Adsorption installation operating at 30 barg
Tool: FLACS-Hydrogen from GexConWe investigated :
◦The impact of different leak orientation and wind profile on the explosive cloud formation (size and explosive mass) and on explosion consequences
◦Overpressures resulting from ignition as a function of the time to ignition
Pressure Swing Adsorption installation
Three of the 43.3 m3 reservoirs contain hydrogen◦ P = 30.4 barg ◦ T = 45°C
ScenariosDispersion
◦The jet was directed either horizontally or 45 ° toward the ground
◦Some scenarios were done with wind 3 m/s Pasquill class F 5 m/s Pasquill class D
Combustion◦The ignition point was positioned on the ground
inside the 30% concentration envelop along the centreline of the jet
◦ Ignition occurred at 2 seconds and 20 seconds after the leak onset
◦ In one case (35NW45°), the time to ignition was varied between 0.5 second and 60 seconds
Leak (1) The leak was assumed to originate from a
broken branch connection at one end of the system 0.5 m above the ground
Two leak diameters were considered: ◦ 20 mm (3/4")◦ 35 mm (1"1/2)
Leak (2)Initial mass flow rates :
◦0.50 kg/s for d = 20 mm◦1.54 kg/s for d = 35 mm
Grid
Dispersion Combustion Dispersion and combustion simulations are done on two
different grids The size of the cells encompassing the PSA was set at 0.5 m
on both grids Grid sensitivity studies were also conducted
Hydrogen 4% molar concentration envelop profile d = 35 mm, no wind
2 seconds after the onset of the leak
20 seconds after the onset of the leak
45° horizontal
45° horizontal
2 seconds after the onset of the leak
20 seconds after the onset of the leak
45° horizontal
45° horizontal
Hydrogen 4% molar concentration envelop profile d = 35 mm, Wind 5 m/s Pasquill D
2 seconds after the onset of the leak
20 seconds after the onset of the leak
45° horizontal
45° horizontal
Hydrogen 4% molar concentration envelop profile d = 20 mm, no wind
Maximum Overpressure, d = 35 mm(ignition time = 2 sec and 20 sec)
0 5 10 15 20 250
0.5
1
1.5
2
2.5
Monitor points
Ignition delay (sec)
Ove
rPre
ssur
e (b
arg)
0 5 10 15 20 250
0.5
1
1.5
2
2.5
Domain
45 degree, no windhor, no wind45 degree, Wind 3Fhor, Wind 3F45 degree, Wind 5Dhor, Wind 5D
Ignition delay (sec)
Ove
rPre
ssur
e (b
arg)
Maximum Overpressure, d = 20 mm(ignition time = 2 sec and 20 sec)
0 5 10 15 20 250
0.05
0.1
0.15
0.2
0.25
Monitor points
Ignition delay (sec)
Ove
rPre
ssur
e (b
arg)
0 5 10 15 20 250
0.05
0.1
0.15
0.2
0.25
Domain
45 degree, no windhor, no wind45 degree, Wind 3Fhor, Wind 3F45 degree, Wind 5Dhor, Wind 5D
Ignition delay (sec)
Ove
rPre
ssur
e (b
arg)
Maximum travel distance of 50 mbar, 140 mbar and 200 mbar overpressure fronts measured from the origin of the leak
0 50 100 150 2000
5
10
15
20
25
30
35
40
45
Time to ignition = 2 sec
Overpressure (mbar)
Max
imum
Dis
tanc
e fr
om R
elea
se P
oint
(m
)
0 50 100 150 2000
2
4
6
8
10
12
Time to ignition = 20 sec
35NW45°35NWHor35W3F45°35W3FHor35W5D45°35W5DHor20NW45°20NWHor20W3F45°20W3FHor20W5D45°20W5DHor
Overpressure (mbar)
Max
imum
Dis
tanc
e fr
om R
elea
se P
oint
(m
)
Maximum overpressure and hydrogen mass at stoichiometric concentration (28-32%) as a function of time to ignitiond = 35 mm, no wind, 45°
0 10 20 30 40 50 600.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
Maximum OP on Monitor points Maximum OP in DomainHydrogen mass
Ignition delay (sec)
Max
imum
ove
rpre
ssur
e (b
arg)
Hyd
roge
n m
ass
at s
toic
hiom
etric
con
cent
ratio
n (k
g)
0 10 20 30 40 50 600
2
4
6
8
10
12
14
16
0
20
40
60
80
100
120
140
160
Flammable mass between 4-75% (vol.) Flammable mass between 11-75% (vol.)Equivalent stoichiometric cloud (Q9)
Ignition delay (sec)
Flam
mab
le m
ass
of h
ydro
gen
(kg)
Equi
vale
nt s
toic
hiom
etric
clo
ud v
olum
e (m
3)
Flammable mass of hydrogen between mole fraction intervals of 4-75% (vol.) and 11-75% (vol.) as a function of time to ignitiond = 35 mm, no wind, 45°
Future perspectiveComparing results with
traditional non-CFD methods
Questions ?
Thank you!
Grid sensitivity
Max overpressure in domain(barg)
Max overpressure on monitor points
(barg)
Tign = 2 sec Tign = 20 sec Tign = 2 sec Tign = 20 sec
Coarser grid (0.50 m) 0.332 0.280 0.230 0.191
Refined grid (0.20 m) 0.318 0.349 0.227 0.190
difference -4% 25% -1% -1%
Grid sensitivity (overpressure)
0 10 20 30 40 50 600.000.050.100.150.200.250.300.350.400.450.50
0.000.050.100.150.200.250.300.350.400.450.50
Max OP on MP (GridSize:0.5m)Max OP in Dom (GridSize:0.5m)Hydrogen massMax OP on MP (GridSize:0.2m)Max OP in Dom (GridSize:0.2m)Max OP on MP (GridSize:0.2m, Same IgnPos as 0.5m)Max OP in Dom (GridSize:0.2 m, Same IgnPos as 0.5m)
Time to ignition (sec)
Max
imum
ove
rpre
ssur
e (b
arg)
Hyd
roge
n m
ass
at s
toic
hiom
etric
con
cent
ratio
n (k
g)
Grid sensitivity (what was done)Dispersion
◦PSA zone cell size: 0.5m compared to 0.25m
◦Without any geometry: no PSACombustion
◦Various boundaries, with and without WIND (Plane_Wave, Euler, Nozzle)
◦More precise domain (0.25, 0.2 m, 0.1 m)◦Without any geometry: no PSA◦Varied ignition position based on
concentration contours (15%, 45%, 60%)
Grid sensitivity (fuel mass)
Mass histogram prior to ignition d = 35 mm, no wind, 45°
[4; 8
[[8
; 12[
[12;
16[
[16;
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[20;
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[24;
28[
[28;
32[
[32;
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[36;
40[
[40;
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02468
101214161820
9.34
13.1
5 15.6
912
.95
17.5
415
.30
7.24
3.68
1.60
1.62
0.64
0.18
0.19
0.21
0.21
0.21
0.00 0.26
Hydrogen mole fraction interval (% (vol))
% o
f tot
al m
ass
[4; 8
[[8
; 12[
[12;
16[
[16;
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[20;
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[24;
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[28;
32[
[32;
36[
[36;
40[
[40;
44[
[44;
48[
[48;
52[
[52;
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[56;
60[
[60;
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[64;
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[68;
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[72;
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0
10
20
30
40
50
60 54.8
516
.96
11.0
07.
934.
452.
381.
040.
450.
380.
280.
030.
040.
040.
090.
000.
040.
050.
00
Hydrogen mole fraction interval (% (vol))
% o
f tot
al m
ass
Simulation time: 2 seconds
Simulation time: 20 seconds