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