mitigation of hydrogen-air detonations - hysafe
TRANSCRIPT
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 1
Mitigation of hydrogen-airdetonations
Andrzej TeodorczykWarsaw University of Technology
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 2
Outline
• Flame quenching, MSEG
• Deflagration arresters
• Detonation arresters
• Detonation quenching – new ideas• by inert gas zone
• by foams and meshes
• by air gaps
• Testing of arresters
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 3
Flame quenching by walls
• Cooling – dominant effect• Chemical effect (destruction of
radicals)
• Quenching distance:
Lp
u
Lupq SpMc
TSc
d 11
0
λρλδ ∝∝∝ SL – laminar burning velocity
δ - flame thickness
• only about 22% of the heat generated by the flame per unit surface must be removed in order to quench the flame
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 4
Flame quenching by walls
(Yang et al., 2003)
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 5
Maximum experimental safe gap (MESG)
Forced flow conditions parameter – in explosions, fast deflagrations
Fuel in stoichiometric
mixture with air
Pressure after explosion pe
(atm)
MESG for a partition of
25 mm thick (mm)
Quenching distance at p = 1 atm
(mm)
Quenching distance at
p = pe(mm)
Hexane 7.8 0.95 3.56 0.5
Benzol 8.7 0.95 2.0 0.4
Hydrogen 9.3 0.15 0.2 0.07
Acetylene 6.9 0.02 0.76 0.05
MESG – dynamic parameter (depends on the directionof the flow relative to flame)
(Chomiak, 1990)
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 6
Deflagration arresters
• Devices to prevent the passage of flame along a pipe
• Three types: • Type 1 – with multiple small channels (planar sheet metal,
crimped ribbon, wire gauze, perforated plate,
perforated block, sintered metal, parallel plate, wire
pack, packed bed);
• Type 2 – hydraulic devices;
• Type 3 – velocity flame stoppers.
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 7
Deflagration arresters
Type1• Mechanism of operation: flame quenching and heat loss
• Diameter of the aperture of an arrester should be smaller thanthe quenching diameter by at least 50%.
• Desirable properties• high free cross-sectional area available for flow• low resistance to flow• high capacity to absorb the heat of the flame• ability to withstand mechanical shock
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 8
Deflagration arresters
Type 2
• Contain a liquid, usually water, which serves to break up the gas
stream into bubbles and so prevents passage of the flame
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 9
Deflagration arresters
Type 3 – velocity stoppers
• Used in end-of-line applications to prevent a flame passing from downstream to the upstream side
• Principle of operation: to assure that the velocity of the upstream gaspassing through the arrester is sufficiently high to prevent a flame propagating through the arrester from the downstream side.
• Velocity necessary to prevent flashback through apertures larger than those which would give quenching:
D – internal pipe diameter (m)gL – laminar velocity gradient (s-1); a function of the gas and its concentration; for
hydrogen its maximum value is equal to 10 000 s-1
uT – turbulent flashback velocity (m/s)
Dgu LT 2015.0=
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 10
Deflagration arresters
On the market:
PROTEGO - ranging in size from 10 mm to 400 mm, approved in Germany for mixtures of hydrogen and air in all ranges of concentration
ENARDO - arresters for hydrogen-air mixtures
WESTECH Ltd.
Others ……………..
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 11
Detonation arresters
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 12
Detonation arresters
1. Same as for deflagration – just longer channels and stronger
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 13
Detonation arresters
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 14
Detonation arresters
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 15
Detonation arresters
2. With a "shock absorber"
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 16
Detonation arresters
3. With a "detonation momentum attenuator"
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 17
Detonation arrestersDetonation propagating through detonationarrester with "detonation momentum attenuator„
2H2+O2+Ar
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 18
Detonation arresters
Simulation of detonation propagating through detonationarrester with "detonation momentum attenuator„ - DETO2D code
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 19
Detonation quenching
Active arresters for waste gas recovery processes(Kidde Graviner Ltd.)
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 20
Detonation quenching by inert zone
2H2+O2 mixture
P0 = 0.3MPa and 0.5MPa
3.6m x 60mm x 60mm channel
Inerts: Ar, He, N2, CO2
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 21
Detonation quenching by inert zone
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 22
Detonation quenching by inert zone
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 23
Detonation quenching by inert zone
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 24
Detonation quenching by inert zone
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 25
Detonation quenching by inert zone
1D numerical simulation – DL code
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 26
Detonation quenching by meshes
Detonation interaction withthe mesh lining the wall
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 27
Detonation quenching by meshesDetonation interaction withthe wire mesh lining the wall
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 28
Detonation quenching by meshesNo meshes
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 29
Detonation quenching by fiberglassDetonation propagation overthe fiberglass section
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 30
Detonation quenching by fiberglass
Detonation propagation overthe fiberglass section
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 31
Detonation quenching by perforated plate
CJ detonation
perforated plate reaction zoneinterface
precursor shock
reflected shock
(Courtesy of J.Chao, McGill University)
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 32
Detonation quenching by perforated plate
window section
parabolic mirror pressure transducers or ionization probes
streak camera
incident CJ detonation
knife edge
perforated plate
2.0 m 2.5 m
100 J spark
65 mm
(Courtesy of J.Chao, McGill University)
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 33
Detonation quenching by perforated plate
t
x
1200 m/s
t
x
1200 m/s
(Courtesy of J.Chao, McGill University)
Urtiew & Oppenheim (1966)
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 34
Detonation quenching by perforated plate
0
20
40
60
80
100
120
140
160
180
1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6Time (ms)
Pres
sure
(kPa
)
theoreticalCJ detonation pressure
incidentCJ detonation
transition todetonation
(Courtesy of J.Chao, McGill University)
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 35
Detonation quenching by perforated plate
t
x
0
20
40
60
80
100
120
140
1.6 2.1 2.6 3.1 3.6Time (ms)
Pre
ssur
e (k
Pa)
Theoretical CJ Pressure
incidentCJ detonation
(Courtesy of J.Chao, McGill University)
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 36
Detonation quenching by diffraction
t
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 37
Detonation quenching by air gap
Objective: controlled DDT for testing arresters
t
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 38
Detonation quenching by air gap
Experimental setup
• 50 mm tube
• 0.1MPa initial pressure
t
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 39
Detonation quenching by air gap
No quenchingt
Quenching and DDT
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 40
Detonation quenching by air gap
t
Quneching and DDT Quenching
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 41
Testing of arresters
t
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 42
Testing of arresters
8 - arrester
9 – pressure transducer
10 – photodiode
Flame transmitted
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 43
Testing of arresters
Problems: • existing protocols for testing arresters differ from country to country• unsteady detonations – DDT, overdriven• fast deflagration vs CJ detonation• tests are subject to misinterpretation
14.8 14.9 15.0 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8Time (ms)
0
15
30
45
60
75
Ove
rres
sure
(bar
g)
2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0Time (ms)
0
4
8
12
16
20
Ove
rres
sure
(bar
g)
CJ detonation Overdriven detonation
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 44
Testing of arresters
Scaling effect
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 45
Testing of arresters
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 46
Pressure histories without obstacles
50 mm tube 150 mm tube
First European Summer School on Hydrogen Safety, Belfast, 15-24 August 2006 by Andrzej Teodorczyk 47
Pressure histories with obstacles
150 mm tube