progress on gas and dust explosion protection in europe...

Progress on Gas & Dust Explosion Protection in Europe

PROGRESS ON GAS & DUSTPROGRESS ON GAS & DUSTPROGRESS ON GAS & DUSTEXPLOSION PROTECTION

PROGRESS ON GAS & DUSTEXPLOSION PROTECTIONEXPLOSION PROTECTION

IN EUROPEEXPLOSION PROTECTION

IN EUROPEIN EUROPEIN EUROPE

INTERNATIONAL SEMINAR IN SHENYANG OCTOBER 27INTERNATIONAL SEMINAR IN SHENYANG OCTOBER 27 29 200829 2008INTERNATIONAL SEMINAR IN SHENYANG; OCTOBER 27 INTERNATIONAL SEMINAR IN SHENYANG; OCTOBER 27 -- 29, 200829, 2008

Richard Siwek, FireEx Consultant Ltd.CH - Giebenach Switzerland; fireex.rs @ fireex.ch

Richard Siwek, FireEx Consultant Ltd.CH - Giebenach Switzerland; fireex.rs @ fireex.chCH Giebenach Switzerland; fireex.rs @ fireex.chCH Giebenach Switzerland; fireex.rs @ fireex.ch


VDI (Verein Deutscher Ingeneure/ Association of German Engineers)Association of German Engineers)

Guideline(GL)-2263, Part 9:

Dust fires and dust explosions Hazards-Dust fires and dust explosions Hazardsassessment-protective measuresDetermination of DUSTINESS of Bulk Materials (Mai 2008)Materials (Mai 2008)

New Dust Characteristic: DUSTISNESS


This VDI-Guidelines describes a procedure for thedetermination of the dustiness of combustible dustformation processes (e.g., conveying, discharging,filling, loading/ unloading, etc.).

The procedure described yields a characteristic forthe dustiness of dusts, which can be used in,particular for assessment of dust explosion hazards.

VDI 2263, Part 9: New Characteristics: Dustiness


10-l-Sample Container10 l Sample Container

Ring-Ionizer

Sensor

VDI-GL, Part 9: Equipment


The Dustiness Coefficient S is the arithmetic f 3 i di id l lmean of 3 individual values

Dustiness GroupDustiness Group Dustiness Coefficient Dustiness Coefficient SS11 0 – 111 0 – 1

22 > 1 – 5

33 > 5 – 10

44 > 10 – 20

55 > 20 5055 > 20 – 50

66 > 50

VDI-GL: 2263, Part 9: Dustiness Group and Dustiness Coefficient


ProductDustinessgroup

ProductDustinessgroupgroup group

Wheat flour 11 Aluminum dust 33

PET filter dust 11 Silicon dust 33

Crystal sugar 11 Skim milk powder 33

Methylcellulose 11 Corn starch 44

Oat filter dust 22 Optical brightener 44Oat filter dust 22 Optical brightener 44

Soya bean extraction grist filter dust 22 Brown-coal filter dust 55grist filter dust

Wood fibre dust 22 Raw-coffee filter dust 55

Molding starch 22 Brown-coal dust 66

Wheat starch 33 Potato starch 66

VDI-2263, Part 9: Example for Dustiness Groups

Wheat starch 33 Potato starch 66


Aid in the determination of zones as it supplies i f ti b t th l i d lifinformation about the volume expansion and life of potentially explosive dust clouds.

The knowledge dustiness allows to make statements about the spatial distribution of the dust clouds in plant components, which may dust clouds in plant components, which mayhave a considerable influence on safety measures in the design

Design of safety measures for e g mixers and

measures in the design.

Design of safety measures for e.g., mixers and for transfer and filling plants.

VDI-2263, Part 9: Application


Control of the Ignition Sours:gConical pipe dischargesp p g

Ignition Sources


1 Hot Surfaces

2 Flames and hot Gases, hot particles

3 Mechanically generated sparks

Hot pipelines, housings of apparatus

Match, exhaust gas, drying air

Grinding mechanical failure3 Mechanically generated sparks

4 Electrical apparatus

5 Stay electric currents, cathodic corrosion protection

Grinding, mechanical failure

Electrical separation and closing sparks

Current reversals when electr. welding

6 Static Electricity

6a Corona discharge

6b Brush discharge

Special case of brush discharges

Emptying of solids out of a plastic bag6b Brush discharge

6c Propagating brush discharge

6d Conical pile discharge

Emptying of solids out of a plastic bag

In a separator with isolating coating

Pneumatic filling of silos with polymers

6e Spark discharge

7 Lightning

8 Radio frequency (RF) electromagnetic waves from

Earthing is no longer effective

Ignition in the lightning channel

High frequency plantsq y ( ) g104 – 3 x 1012 Hz (high frequency)

9 Electromagnetic waves from 3 x 1011 – 3 x 1015 Hz

10 Ionizing radiation

g q y p

Photo lightning

UV emitter, laser10 Ionizing radiation

11 Ultrasonics

12 Adiabatic compression and shock waves

h i i i l di lf i i i f d

UV emitter, laser

Ultrasonic cleaning

Compressor

O h t d d t

Ignition Sources According to EN 1127-1

13 Exothermic reactions, including self-ignition of dust Overheated product


① Conductive silo, grounded or insulated

② Highly insulating bulk material

③ Cone discharges on the surface or inside gthe deposited bulk material

E < 1 JE < 1 JIncendive for gasIncendive for gas--airairIncendive for gasIncendive for gas--air,air,vaporvapor--air andair anddustdust--air mixturesair mixtures

Common Type of Discharges: Conical Pile Discharges

dustdust--air mixtures.air mixtures.


- Keep silo diameter small- Keep silo diameter small.

- Keep powder resistivity below 1010 Ω·m (low andmedium resistivity).

- Keep filling level below 50%.

- Installation of grounding- Installation of groundingrods.

Mechanical dividing of silo- Mechanical dividing of silo.

- Phlegmatising with N2 orCO2.

Conical Pile Discharge: Avoidance


Pure dusts with MIE >10mJPure dusts with MIE >10mJPure dusts with MIE >10mJ Pure dusts with MIE >10mJ (with inductance):(with inductance):

Thoroughly groundingdand

installation of grounding l bl (

Radius 1m

steel cable (8 mm in diameter) with a max. clearance to earth of 1m.

Conical Pipe Discharges: Avoidance by Installing Grounding Steel Cables


Pure dusts with MIEPure dusts with MIE ≤≤10mJ10mJPure dusts with MIE Pure dusts with MIE ≤≤10mJ 10mJ (with inductance):(with inductance):

Thoroughly groundingandandinstallation of internal walls to reduce the silo diameterto reduce the silo diameter.

Conical Pile Discharge: Avoidance by Mechanically Dividing the Silo


Pure dusts MIEPure dusts MIE ≤≤10mJ (with inductance) or dust with10mJ (with inductance) or dust withPure dusts MIE Pure dusts MIE ≤≤10mJ (with inductance) or dust with 10mJ (with inductance) or dust with flammable solvent:flammable solvent:

Thoroughly groundingdand

Phlegmatising with inert gas such as CO2 or N2.

Phlegmatising:Adding only a certain amount of inert gas so that theMIE of the product is higher than the energy releasedfrom the conical pile.

Conical Pile Discharge: Avoidance by Phlegmatising with an inert gas


25

LOC

700 mJ20

ntra

tion

17.516.0

10

15

en C

once

n V

ol.%

16.0

5

10

ng O

xyge in

CO2N2

00.0001 0.001 0.01 0.1 1 10 100 1000 10000

Lim

itin

0.0001 0.001 0.01 0.1 1 10 100 1000 10000

Minimum Ignition Energy MIE in J

Example for LEAD STEARATE: Silo Diameter 4m; MIE = 1mJ, M = 1mm; Powder resistivity 1013 Ohm.m

Energy cone discharge E = 550 mJ

Conical Pile Discharge: Avoidance by Phlegmatising with an Inert Gas

Energy cone discharge ECD= 550 mJ.


Large silo diameter.EECDCD = 5.22 = 5.22 ·· DD3.363.36 ·· MM1.461.46

Large silo diameter.

High resistivity powders.ECD is the upper energy limit of the conedi h i J

g y p

Large particle size

discharge in mJD is the diameter of the silo in mM is the median of the particle size

di t ib ti f th d t ig p

(granules).distribution of the product in mm

II 0 2980 298 0 4350 435 High flow velocity.D = 0.612 D = 0.612 ·· MIEMIE0.298 0.298 ·· MM--0.4350.435

MIE is the minimum ignition energy of thefine product in mJ (without inductance)

Estimation of Conical Pile Discharge


VDI-2263, Part 6: Dust Fires and Dust Explosions H d A t P t ti M- Hazard-Assessment-Protective Measures –

Dust fires andDust fires and explosion protection in dust explosion protection in dust extracting installations, 2007 extracting installations, 2007 ; Beuth Verlag GmbH, Berlin.

VDI-2263, Part 6.1-Draft: Dust Fires and Dust

Beuth Verlag GmbH, Berlin.

VDI 2263, Part 6.1 Draft: Dust Fires and Dust Explosions- Hazard-Assessment-Protective Measures - Dust fires and explosion protection inMeasures - Dust fires and explosion protection in dust extracting installations, Examples, Examples, April 2008 B th V l G bH B li2008; Beuth Verlag GmbH, Berlin.

Association of German Engineers (VDI) Guidelines


Protection of Dust Extraction means:

Protection Against EXPLOSIONS and/or FIRES.

Explosion Protection Fire Protection

VDI-2263, Part 6: Safety Concept


VDI-2263,Part 6: After Fire


Determination of the Combustion Characteristic of Dust

no

yes

Are there dusts with CCT >1 ?

no

yes

yes

y

Are there dusts with CCT > 3 ?

Are the filter media combustible?

yes yes

yesAre the filter media combustible?

no

Increased availability ofyes

Increased availability ofplant or eor environmental requirements

or hazard of neighbor plants?

neinDust extractor of standard design

Dust extractor with„fire prevention measures“

Dust extractor with „fire prevention measures“and „damage control in the event of fire”

VDI-2263, Part 6: Flow Chart of Fire Hazard Assessment

Design A Design B Design C


FCU Internal alarm

T T T

SCU

Clean-gas

tiSCU

Di t

Soperatingfire water supply

Dirty-gas

1 Rotary Lock,2 Spark Detector3 Extinguishing valve4 Extinguishing tank for water

SCU: Spark Control UnitFCU: Fire Control Unit

4 Extinguishing tank for water5 Extinguishing nozzle6 Temperature detector in clean air side

VDI-2263, Part 6: Example for Aspiration of Wood Dust: Design C


Extraction Duct 20 2122 or not

zoned

Crude-gas section of separator 20 21 22

Clean-gas section of separator

unknown dust concentration 21 21 22- unknown dust concentration 21 21 22

- LEVEL monitoring / shutdown of FAN 22 22 not zoned

- SAFETY FILTER / shutdown of FAN not zoned not zoned not zoned

- calculated dust concentration > 1% LEL 21 21 22

- calculated dust concentration < 1% LELwithout checks or cleaning measures

22 22 22

l l t d d t t ti 1% LEL- calculated dust concentration < 1% LELwith checks or cleaning measures not zoned not zoned not zoned

VDI-2263, Part 6: Hazard Area Classification: Example for Inertial Separators


Under operating condition to be specified, avoidingeffective ignition sources can be sufficient as the soleeffective ignition sources can be sufficient as the soleprecaution where only explosive dust/air mixtures with atemperature related minimum ignition energy MIE ≥10mJtemperature-related minimum ignition energy MIE ≥10mJ(measured without inductance) occur in dust separators.

Handling of explosive dust/air mixtures or hybridHandling of explosive dust/air mixtures or hybridmixtures with a temperature-related minimum ignitionenergy MIE < 10 mJ (measured without inductance)energy MIE < 10 mJ (measured without inductance)usually required additional safety measures (inerting orconstructional explosion protection) for potentiallyconstructional explosion protection) for potentiallyexplosive atmospheres allocated to Zone 0 and 20 and toZones 1 and 21, respectively.

VDI-2263, Part 6: Avoidance of Effective Ignition Sources

Zones 1 and 21, respectively.


Insulating filter materials can be used in Zones 20, 21and 22 (for dusts with a temperature related MIE ≥ 3mJand 22 (for dusts with a temperature-related MIE ≥ 3mJmeasured without inductance) and in zone 2 unless theyinterrupt the grounding of such parts of the dustinterrupt the grounding of such parts of the dustseparator as consist of conductive or electrostatic-dissipative materials especially of stiffening basketsdissipative materials, especially of stiffening baskets.

Conductive or electrostatic-dissipative materials must beused in Zones 0 and 1 and Zones 20 and 21 for dustsused in Zones 0 and 1 and Zones 20 and 21 for dustswith a temperature-related MIE < 3mJ (measured withoutinductance)inductance).

Filter Materials: Conductive or NOT Conductive ?


Design straightforward sophisticated complex

ContainmentContainmentPressure-resistanceIsolation

SuppressionSuppressionPressure-resistanceIsolation

VentingVentingPressure-resistanceIsolation

Criterion

Isolation IsolationInternal InstallationsInternal Installations

IsolationInternal InstallationsInternal InstallationsLocationLocationSafe DirectionSafe DirectionSafety DistanceSafety DistanceEnvironmentalEnvironmentalEnvironmentalEnvironmental

Constructional Explosion Protection of Separators (Cyclones)


ThTh tt h th t tt hh ththTheThe toptop--sheetsheet mustmust havehave thethesamesame pressurepressure--resistanceresistance asasthethe filterfilter housinghousingthethe filterfilter housinghousing..TheThe filterfilter elementselements mustmust bebesupportedsupported byby ee..gg..,, basketsbaskets..

Constructional Explosion Protection: Conditions


The internali t ll tiinstallations

must not obstructth tthe vent area

neither partiallynor completely!!nor completely!!

Application of Explosion Venting


Due to the hindrance of the relief process, the reduced l i i i l i d dexplosion pressure Pred is seriously increased and may

cause destruction of the filter housing!

Application of Explosion Venting


X DIS

IS

Distance X ≥ Diameter D

Isolation SystemISIS IS

Isolation SystemIS

Retention installation must prevent that filter elements cannot block the Retention installation must prevent that filter elements cannot block the t i f l it i f l i

Consideration of the Filter Elements: Normal Situation

vent area in case of an explosion vent area in case of an explosion


Pocket FilterHose Filter

a a ≤ r : The volume enveloped by the filter media can be deducted from the filter housing≤ r : The volume enveloped by the filter media can be deducted from the filter housing

a >a > r : ONLY the volume of the filter media can be deducted from the filter housingr : ONLY the volume of the filter media can be deducted from the filter housinggg

a a ≤ b : The volume enveloped by the filter media can be deducted from the filter housing≤ b : The volume enveloped by the filter media can be deducted from the filter housing

a >a > b : ONLY the volume of the filter media can be deducted from the filter housingb : ONLY the volume of the filter media can be deducted from the filter housing

Consideration of the Filter Elements: Normal Situation

a >a > b : ONLY the volume of the filter media can be deducted from the filter housingb : ONLY the volume of the filter media can be deducted from the filter housing


AA AAIS

V1V1LPLP

IS

V1V1LPLPIS IS

AA AA

V2V2 V2V2

IS Isolation SystemISIS

V3V3

Volume Cyclone = V1 + V2 Volume Cyclone = V1 + V2 +V3yVent area = ALength vent pipe = LP

yVent area = ALength vent pipe = LP

Venting of Cyclone: Consideration of Internal Pipe


Because of the FILTER ELEMENTSh di ib i fa homogeneous distribution of

Suppressant between the filter medias is not possible !medias is not possible !

*Pred,max = Pred,max + [VO·TU·Pmax/V·Tb]

*Pred,max = considering the internal obstructions [bar]Pred,max = without internal obstructions [bar]V0 = volume that is not effectively covered by

deployed suppressant [m³]V = total volume [m³]V = total volume [m³]Tu = initial temperature (unburned) [K]Tb = adiabatic flame temperature (burned) [K]Pmax = maximum explosion overpressure of fuel [bar]

Explosion Suppression: Consideration of the Filter Elements


VDI-2263, Part 7-Draft: Dust Fires and Dust Explosions- Hazard-Assessment-Protective Measures – Dust fires andDust fires and explosion protection inexplosion protection inMeasures Dust fires andDust fires and explosion protection in explosion protection in spray drying equipment , 2008 spray drying equipment , 2008 ; Beuth Verlag GmbH BerlinBeuth Verlag GmbH, Berlin.

7

2

7

2

7

9

5

3 6

7

9

5

3 69

1 8

9

1 8

AE

4

AE

4



1 Feeding system

2 S i t2 Spraying system

3 Inlet air system

4 Air distributor

5 Drying chamber

6 outlet air system

AE Discharge

Zone 20Z 21

device

Zone 21Zone 22

VDI-GL-2263, Part 7: Example for Zoning


VDI-2263, Part 8-Draft: Dust Fires and Dust Explosions- Hazard-Assessment-Protective Measures – Dust fires andDust fires and explosion protection inexplosion protection inMeasures Dust fires andDust fires and explosion protection in explosion protection in elevators, 2008 elevators, 2008 ; Beuth Verlag GmbH, Berlin.

SeePresentationDr A VoglDr. A. Vogl



P i ibilit fPermissibility of different types of package fordifferent types of package for

flammable liquids and combustible dusts

ESCIS: Expert Commission forSafety in the Swiss Chemical Industry:Safety in the Swiss Chemical Industry:Static Electricity – rules for plant safety

Packaging Materials


BAGSP b Pl ti bPaper bags, Plastic bags

DRUMSMetal drums, Fiber drums Cardboard drums

CONTAINERSCONTAINERSMetal container, Plastic container

FIBC (BIG BAGS)FIBC (BIG BAGS)Type A, Type B, Type C, Type D

Contents of Packaging Materials


Hazards:- In a very dry atmosphere and/or in case of high separation speed (>1m/s) brush discharges may occur.- If he bag becomes wet and is not in contact with ground, spark discharges may occur.If he bag becomes wet and is not in contact with ground, spark discharges may occur.

ProductExplosive atmosphere in the Permitted Requirements and limits

during filling and emptying Remarkspenvironment during filling and emptying

Non-combustiblepowder None Yes None

Consider hazards of electric shockelectric shock

Combustiblepowder

NoneCombustible powder Yes

- Filling and emptying by gravity

- Volume ≤ 50 ℓNon-combustiblePowder

Flammable gasor vaporor hybrid mixture

Yes

- Filling and emptying by gravity- Volume ≤ 50 ℓ- Contact to ground via theoperator or conductive surface

CombustibleP d hybrid mixture operator or conductive surface

of the grounded equipmentPowder


- Volume ≤ 50 ℓPowder with flammable solvent Any Yes

o u e 50 ℓ- Contact to ground via theoperator or conductive surfaceof the grounded equipment

Example: BAGS - Paper Bag


Hazards: - If the drum is not grounded, spark discharges may occur.

E l i

Product

Explosive atmosphere in the environment

Permitted Requirements and limits during filling and emptying Remarks

Non-combustiblepowder None Yes None

Consider hazards of electric shock

C b tibl N Filli d t i b itCombustiblepowder

None orCombustible powder

Yes


- Volume ≤ 200 ℓ- Grounding required

b ibl l blNon-combustiblePowder

Flammable gasor vaporor hybrid mixture

NoCombustiblePowder hybrid mixturePowder

Flammable liquid Any No

Powder with Any Noflammable solvent Any No

Flammable suspension Any No

Example: DRUMS - Metal Drum with Plastic Liner


Bulk Material Surroundings

MIE of dust ( itho t ind ctance)

Explosive gas and vapor atmosphere

Explosive dust

Non flammable (without inductance)

p p(group IIA or IIB) atmosphere atmosphere

MIE > 1 J C, D B, C, D A, B, C, DMIE > 1 J C, D B, C, D A, B, C, D

1 J ≤ MIE > 3 mJ C, D B, C, D B, C, D, , , , ,

MIE ≤ 3 mJ C, D

Dust with flammable solvent C, D and additionally measures, e.g., Inerting!

A: No special requirements; B: Breakdown voltage of FIBC wall material ≤ 6 kV to prevent propagating brush discharge. C: Bag Material including the slings must be electrostatically conductive and have a grounding tap. D M d f d ti f b i t i i d ti th d fil t hi h t i t t d

Flexible Intermediate Bulk Container FIBC: Types/Application

D: Made from non conductive fabric containing conducting threads or filaments which are not interconnected.


FIBC: Type C and D


FIBCs of Type C show typical grids of interwoven conductive FIBCs of Type C show typical grids of interwoven conductive threads or tapes which are all electrically interconnected.threads or tapes which are all electrically interconnected.

Type C-FIBC have to be grounded when filling or emptyingwhen filling or emptying.

FIBC: Type C


AA TypeType--DD FIBCFIBC operatesoperates accordingaccording toto aa differentdifferent principleprinciple..

The effect of charge dissipation The effect of charge dissipation with such an FIBCwith such an FIBC is based on is based on a system of independent a system of independent conductive fibres which does conductive fibres which does not follow the concept of not follow the concept of conductivity. conductivity. O i ll th f b i iO i ll th f b i iOccasionally, the fabric is Occasionally, the fabric is additionally equipped with additionally equipped with

ti t ti t t tti t ti t t tantistatic treatment. antistatic treatment.

FIBC: Type D


The CoronaThe Corona--Principle is used which permits to disperse static chargePrinciple is used which permits to disperse static chargebut not entirely !but not entirely !

ThTh t ti ht ti h li dli d

but not entirely ! but not entirely !

The The static chargestatic charge supplied supplied with the with the charged bulk charged bulk will be dispersed intowill be dispersed intothe surroundings ofthe surroundings ofthe surroundings of the surroundings of the FIBC by means ofthe FIBC by means of»Corona»Corona Effect«Effect«»Corona»Corona--Effect«Effect«

Grounding is useless.

FIBC: Type D


The static charges released by the The static charges released by the »»CoronaCorona--EffectEffect««drift away from the FIBC Type drift away from the FIBC Type »D«»D«..y ypy yp

++++

+ + +++++ + +++FIBC: Type D


The released static charges follow the „line of least resistance“ to ground.

++ ++

+ + ++++

+ + ++FIBC: Type D


DoDo theythey meet,meet, ee..gg..,, aa groundedgrounded compositecompositecontainercontainer thenthen thesethese freefree movingmoving chargeschargescontainer,container, thenthen thesethese freefree movingmoving chargeschargesareare dissipateddissipated immediatelyimmediately..

+ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ +

+ ++ ++ +

+D+D

+ ++ ++ ++ + +++ ++D+D ++ ++

FIBC: Type D


If the container is not grounded, it will be charged by thecorona discharge of the FIBC Type »D«»D«.g yp

+ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ + +++ + ++ +

+ ++ +

+ ++ +++


If approached by a grounded part, k di h illa spark discharge will occur.

++++ ++++FIBC: Type D


When FIBC grounded, behavior as Type Cbehavior as Type C

When FIBC NOT grounded, behavior as Type D

NEW FIBC: Type CD or “Supper Bag”


International Section of Machine and System Safety of the ISSA


VDI-2263, Part 7.1- In preparation: Dust Fires and Dust Explosions Hazard Assessment ProtectiveDust Explosions- Hazard-Assessment-Protective Measures - Dust fires and explosion protection in d ll lldust extracting installations, Examples.Examples.

ExamplesExamplesRisk assessmentRisk assessmentRisk assessmentRisk assessmentApplication of preventive measuresApplication of preventive measuresA li ti /D i f t tiA li ti /D i f t tiApplication/Design of protective measuresApplication/Design of protective measures

OUTLOOK – In Preparation


EN XXXX In preparation:Flameless Explosion Venting Devices..

OUTLOOK – In Preparation


Thank You – Obligado – Gracias – Merci – Grazie – Dankeschön – 谢谢 – Вы

progress on gas and dust explosion protection in europe...

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