EXPLOSION PROTECTION EXPLOSION PROTECTION ––

USING THE DATABASEUSING THE DATABASE

formerly at BAM Federal Institute formerly at BAM Federal Institute for Materials Research and for Materials Research and Testing, Berlin, GermanyTesting, Berlin, Germany

Maria MolnarneMaria Molnarne

Department Department -- Chemical Safety Chemical Safety EngineeringEngineering

Database CHEMSAFE

Safety characteristics

Explosion protection

primary, secondary, tertiary (constructive) explosion protection

Examples

Summary

OutlineOutline

database for evaluated safety

characteristics of app. 3000

flammable substances: liquids,

gases, dusts and their mixtures

project partners: BAM,

DECHEMA, PTB

updated yearly ,

languages: German / English

CHEMSAFECHEMSAFE

CHEMSAFE containsCHEMSAFE contains1. Safety characteristics for fire & explosion protection,Safety characteristics for fire & explosion protection,

its definitions and information about test methodsits definitions and information about test methods

2. Occupation safety data2. Occupation safety data

3. Classification and labelling3. Classification and labelling

4. Substance identification and specifications: Synonyms,4. Substance identification and specifications: Synonyms, CASCAS--, EC, EC--, Index, Index-- and UNand UN--No., particle size distributionsNo., particle size distributions

5. References, Recommendation of experts5. References, Recommendation of experts

6. 6. Estimation methods (e.g. ISO 10156 flammability and Estimation methods (e.g. ISO 10156 flammability and oxizingoxizing potential), graphical tools, data exchangepotential), graphical tools, data exchange

Example Example -- BenzeneBenzene

Explosion region of a ternary systemExplosion region of a ternary system

Primary explosion protectionPrimary explosion protection

Explosion limits Explosion limits

Limiting values of explosion region Limiting values of explosion region (MOC, LOC, MXC, Tci), inerting(MOC, LOC, MXC, Tci), inerting

Limiting values for chemically unstableLimiting values for chemically unstable substances (maximum stability ratio)substances (maximum stability ratio)

Explosion point, Flash point Explosion point, Flash point

Safety characteristicsSafety characteristics for assessing for assessing the explosiveness (flammability) of gases & the explosiveness (flammability) of gases & liquids: liquids:

for determination of for determination of explosion limits of explosion limits of gasesgases

EN 1839EN 1839--T (tube)T (tube)

min. 100 mmmin. 100 mm

Test apparatusTest apparatus

EN 1839 EN 1839 ––B Bomb methodB Bomb method--closed vesselclosed vessel--spherical or cylindrical spherical or cylindrical --internal volume of at least 5 Liters internal volume of at least 5 Liters --spark or fusing wire igniterspark or fusing wire igniter

EN 1839 EN 1839 --T Tube methodT Tube method--open vesselopen vessel--tube (tube (

80 mm, 80 mm, minimum lengthminimum length 300 mm)300 mm)--spark igniterspark igniter

Apparatus Apparatus in EN 1839in EN 1839

Temperature influence on explosion limitsTemperature influence on explosion limits

SourceSource: : BAM, BAM, CHEMSAFECHEMSAFE

0 50 100 150 200 250 300 350 400Temperatur in oC

0

5

10

15

20

25Br

enng

asan

teil

in M

ol-%

UEG MethanOEG MethanUEG EthanOEG EthanUEG PropanOEG PropanUEG BenzenOEG Benzen

TemperatureTemperature

in in °°CC

LELLEL

UELUEL

Pressure influence on explosion limitsPressure influence on explosion limits

0,0 0,2 0,4 0,6 0,8 1,00

10

20

30

40

50

60

70

Methanol Cyclohe xan Aceton Ethanol

UEG

, O

EG

in v

ol%

p in barSourceSource: PTB, : PTB, CHEMSAFECHEMSAFE

ExplosionExplosion diagramdiagram measured data + expl. curveMOC-lineICR-lineIAR-lineSCO-line

100

100

1000

0

0

[mol %] [mol %]

[mol %]

MOC

IAR

ICR

SCOMXCA

MAI

UEL

LEL

flammable gas

inert gas

oxygen

explosion-range

withwith limiting limiting valuesvalues

MXC MXC (Tc(Tcii ))

MOC MOC (LOC)(LOC)

ExplosionExplosion

10

10

10

20

20

20

30

30

30

40

40

40

5050

50

60

60

60

70

70

70

80

80

80

90

90

90

100

100

1000

0

0

in Mol-% in Mol-%

in Mol-%

Brenngas Inertgas

Oxidator

ExplosionsbereichMXC

MOC

MAI

IAR

ICRC

Total inerting Total inerting area (areaarea (area under under LEL and ICRLEL and ICR-- line) line)

Other areas Other areas outside outside explosion explosion region are region are partially partially inertedinerted..

InertingInerting

ExplosionExplosion

Explosion region: Ethylene oxide/NExplosion region: Ethylene oxide/N22 /air/air

OHCOOOHC 22242 2225

Initial conditions:Initial conditions:100 100 °°C,C, 40 kPa40 kPa

Test method:Test method:EN 1839EN 1839--BB

ExplosionExplosion

explosive explosive without airwithout air

CombustionCombustion

DecompositionDecomposition

CombustionCombustion442 CHCOOHC

DecompositionDecomposition

Explosion region of the system Explosion region of the system Ethene/HEthene/H22 O/air at different temperaturesO/air at different temperatures

Explosion region of the ternary system Explosion region of the ternary system CHCH44 /N/N22 /air at 10 bar and 100 bar /air at 10 bar and 100 bar

chlorinenitrous oxidenitric oxideairnitrogen trifluoride

10

10

10

20

20

20

30

30

30

40

40

40

5050

50

60

60

60

70

70

70

80

80

80

90

90

90

100

100

1000

0

0

ethane nitrogen

oxidiser

oxidiser

in mol% in mol%

in mol%

Explosion region of ethane/NExplosion region of ethane/N22 with with different oxidizing gasesdifferent oxidizing gases

NN22oxidizing gasoxidizing gas

ethaneethane

CalculationCalculation methodmethod forfor flammabilityflammability (ISO 10156)(ISO 10156)

n

1i

m

1jjj

ii KB1

Tc100A

If this condition fulfilled – the mixture is classified as nonnon--flammableflammable

Flammable component

Inert component

0 10 20 30 40 50 60 70 80 90 100nitrogen in mol %

0

2

4

6

8

10

12

14

16

18

20

met

hane

in m

ol %

Explosion range methane/nitrogen/airmeasurement by Schulz BAM Lab. II.22 (1996)

LEL : 4.2 mol %LEL : 4.2 mol %UEL : 16.3 mol %UEL : 16.3 mol %TCi : 8.49 mol %TCi : 8.49 mol %

Tci-valueTci-value

0 % air0 % air

explosion rangeexplosion range

Determination of TcDetermination of Tc i i from from xx--yy diagramdiagram

Tci Tci (ISO)(ISO)

Tci Tci (BAM)(BAM)

= 8.4 = 8.4 mol%mol%

ISO 10156 (1996) Tci value for methane was 14.3 mol in %ISO 10156 (1996) Tci value for methane was 14.3 mol in %

Acetylene Acetylene –– Chemically unstable gasChemically unstable gas

Stability pressure limits for acetylene Stability pressure limits for acetylene with other gaseswith other gases

0 10 20 30 40 50 60 70 80 90 100Stoffmengenanteil Acetylen in %

0

5

10

15

20

Stab

ilität

sgre

nzdr

uck

in b

ar

WasserstoffStickstoffMethanPropan

H2N2 CH4

C3H8

Ignition energy: 70 WsIgnition energy: 70 Ws

Acetylene in mol%Acetylene in mol%

Stability

Stability pressure

pressure limit in bar

limit in bar

DustDust explosionexplosion accidentaccidentFebruaryFebruary 8, 20088, 2008 SugarSugar factoryfactorySavannahSavannah, , Georgia, USAGeorgia, USA

11-- cubic meter vessel cubic meter vessel

2020--literliter spheresphere

Dust explosion test in BAMDust explosion test in BAM

Search for sugar in CHEMSAFESearch for sugar in CHEMSAFE

Secondary explosion protectionSecondary explosion protection

Autoignition temperature of gases &Autoignition temperature of gases & vapors vapors

Minimum ignition temperatures ofMinimum ignition temperatures of dusts (clouds, layer, heaps)dusts (clouds, layer, heaps)

Minimum ignition energyMinimum ignition energy

Safety characteristicsSafety characteristics to assess to assess the ignitability of substances the ignitability of substances

Autoignition temperatureAutoignition temperature

0 2 4 6 8 10 12 14 16200

250

300

350

400

450

500

T2T3

T1T2

Methylacetat Ethylacetate Propylacetate Butylacetate Pentylacetate

Tz

in

°C

p in bar

of of flammable flammable liquids in liquids in function offunction of pressurepressure

(autoclave)(autoclave)

Quelle: PTB, Quelle: PTB, CHEMSAFECHEMSAFE

Constructive explosion protectionConstructive explosion protection

Maximum explosion pressureMaximum explosion pressure Maximum rate of pressure rise Maximum rate of pressure rise ((dp/dt)dp/dt)maxmax

KKGG value for gases and vapors: value for gases and vapors: KG -value = (dp/dt)max * V 1/3 (cubic law)

KKstst value for dust, Dust explosion classvalue for dust, Dust explosion class Maximum experimental safe gapMaximum experimental safe gap

Safety characteristicsSafety characteristics to assess to assess the severity of an explosion the severity of an explosion

5050--liter spherical liter spherical autoclave designed for autoclave designed for pressures up to 1.100 pressures up to 1.100 barbar in BAMin BAM

Investigation of detonation phenomenaInvestigation of detonation phenomena

Constructive explosion protectionConstructive explosion protection

Explosion pressure in function of Explosion pressure in function of concentration of methane in airconcentration of methane in air

0,00

1,00

2,00

3,00

4,00

5,00

6,00

7,00

8,00

9,00

3,00 5,00 7,00 9,00 11,00 13,00 15,00 17,00 19,00

CH4 [mol-%]

pex /

pi [-

]

TUD 20 °C

TUD 100 °C

TUD 120 °C

TUD 200 °C

TUD 240 °C

Data from SAFEKINEX EUData from SAFEKINEX EU--Project, TU Delft, NLProject, TU Delft, NL-- CHEMSAFECHEMSAFE

KKG G valuesvalues in functions of the test vessel in functions of the test vessel and the hydrogen composition in airand the hydrogen composition in air

0

200

400

600

800

1000

1200

0,00 10,00 20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00

H2 [mol-%]

KG

[bar

m/s

]

BAM 2.8-dm 3̂BAM 6.0-dm 3̂BAM 14.0-dm 3̂

Data from SAFEKINEX EUData from SAFEKINEX EU--Project, CHEMSAFEProject, CHEMSAFE

Experimental setup (IEC 60079Experimental setup (IEC 60079--11--1)1)

Inner (1) and outer (2) Inner (1) and outer (2) volume is filled with the same volume is filled with the same flammable mixture. flammable mixture.

Concentration of the Concentration of the flammable flammable mmixture is varied ixture is varied

Width of the gap (3) is varied Width of the gap (3) is varied by turning the screw (6)by turning the screw (6)

Ignition occurs in the centre of Ignition occurs in the centre of the inner volume; Power of the inner volume; Power of the ignition source (5) is the ignition source (5) is about 10 J about 10 J

Criterion: flame transmission Criterion: flame transmission through the gap observed through the gap observed through window (4)through window (4)

maximum experimental safe gap (MESG)maximum experimental safe gap (MESG)

Determination and estimation of MESG Determination and estimation of MESG of mixturesof mixtures

Only a few Only a few MESG MESG of mixtures are experimentally of mixtures are experimentally determineddetermined

MESG determination is time consumingMESG determination is time consuming

Using the lowest MESG of the mixtureUsing the lowest MESG of the mixture components rises often technical problemscomponents rises often technical problems

Based on some 150 measurements of differentBased on some 150 measurements of different mixtures an estimation method was developedmixtures an estimation method was developed

0,00 0,25 0,50 0,75 1,000,0

0,2

0,4

0,6

0,8

1,0

1,2

measured at 120 °C estimated measured at 40 °C estimated

MES

G

in m

m

Relative molar amount CH4

0,0

0,2

0,4

0,6

0,8

1,0

1,2Lines mean linear interpolations at 40 Lines mean linear interpolations at 40 °°C and 120 C and 120 °°CC

Mixture of methane and dioxaneMixture of methane and dioxane

MESG MESG -- measuredmeasured and estimatedand estimated

Minimum ignition energy Minimum ignition energy

maximum maximum experimental safe gapexperimental safe gap

SubstanceSubstance MIE in mJMIE in mJ MESG in mmMESG in mm

HydrogenHydrogen 0.0170.017 0.290.29

AcetyleneAcetylene 0.0190.019 0.370.37

Diethyl etherDiethyl ether 0.190.19 0.870.87

PropanePropane 0.240.24 0.920.92

MethaneMethane 0.290.29 1.141.14

AmmoniaAmmonia 1414 3.183.18

Safety characteristics of hazardous substances Safety characteristics of hazardous substances needed under process conditions needed under process conditions

Chemically unstable gases represent furtherChemically unstable gases represent further difficulties by explosion protectiondifficulties by explosion protection

Dust explosion data are needed Dust explosion data are needed with particle size distribution with particle size distribution

CHEMSAFE contains this information and CHEMSAFE contains this information and data data evaluation is given by experts evaluation is given by experts

SummarySummary

The author would like to thank Dr. M. Sam Mannan, Director of the Mary O’Connor Process Safety Center for the financial support of this presentation and BAM for the presentation materials.

AcknowledgementAcknowledgement

Thank you for attention!Thank you for attention!

BAM Test Site Technical Safety BAM Test Site Technical Safety

Limiting values of flammable mixtureLimiting values of flammable mixture

LEL lower explosion limits (mol%)

UEL upper explosion limits (mol%)

MAI minimum required amount of inert gas in inert gas-oxidizer mixtures (mol%)

MXC maximum permissible amount of flammable gas in inert gas-flammable gas mixture in mol% (if nitrogen then Tci)

MOC maximum (permissible) oxidizing gas content in mol% (if air then LOC)

SCO stoichiometric concentration for the oxidizing reaction (mol%)

ICR minimum inert gas-combustible ratio (-)

IAR minimum inert gas/oxidizer (air) ratio (-)