ATEX STANDARDS FOR EXPLOSION PREVENTION
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Transcript of ATEX STANDARDS FOR EXPLOSION PREVENTION
EXPLOSION PROTECTION IN DEDUSTING PLANTS
© BETH® Filtration GmbH 2008 . Seite 2
BETHPULS Bag Filter prototype explosions pressure test
Explosion pressure shock resistant design in combination with explosion pressure venting
© BETH® Filtration GmbH 2008 . Seite 3
BETHPULS Bag Filter prototype explosions pressure test
Explosion pressure shock resistant design in combination with explosion pressure venting Photo page 2
Place of testing: Bergbau – Versuchsstrecke / Dortmund – Derne
Kind of dust : Lignite ( 500 g / m3 ) Dust explosion class : St 1 Vessel volume : 22 m3 Vent area : 2 m2 Reduced explosion pressure : 1.18 bar ( 0.18 bar overpressure ) Number of tests : 36 Max. explosion overpressure : 0.44 bar
© BETH® Filtration GmbH 2008 . Seite 4
Explosion Protection in Dedusting Plants
Dedusting plants are in operation for the
collection and separation of dust.
Consideration different kind of dust in dedusting plants concerning the applications and industrys
For example:
Wood, wood products Food, grain, cereal Coal, coal products
Secondary fuelPlastic, rubber
Chemical products, Metal etc.
© BETH® Filtration GmbH 2008 . Seite 5
Vattenfall Europe Mining AG dedusting of the actual largest lignite mill of world
Source of dust : Vertical roller milType of dust : LigniteCapacity of the mill : 88 t/hBulk density dust : 0.35 – 0.5 t/m3Dust capacity : max. 293.3 m3/h Raw gas volume : max. 150,000 Am3/hOperating temperature : 55 – 80°C (short peaks 100°C) Dew point : 30.9°C Raw gas dust content : max. 587 g/m3Operating pressure : - 45 mbar (rawgas inlet filter)
Explosion Protection in Dedusting Plants
© BETH® Filtration GmbH 2008 . Seite 6
Vattenfall Europe Mining AG dedusting of the actual largest lignite mill of world BETHPULS Bag Filter 6.90x10.7.20 (double line)
Explosion Protection in Dedusting Plants
© BETH® Filtration GmbH 2008 . Seite 7
Explosion Protection in Dedusting PlantsVattenfall Europe Mining AG dedusting of the actual largest lignite mill of world
BETHPULS Bag Filter 6.90x10.7.20 (double line)
Filter type : BETHPULS 6.90x10.7.20Operation method : On-lineNumber of filter bags : 900Dimensions filter bags : ø160 x 5,200 mm Filter cloth : PEAC 600 Si Filtering surface area : 2,400 m2 Air to cloth ratio : max. 1.044 m3/m2 x min Admissible operating pressure: - 140 mbar Main dimensions filter : 7.28 m x 10.2 m x 12.4 m
© BETH® Filtration GmbH 2008 . Seite 8
Dust characteristics
Kind of dust LigniteDust explosion class St 1KSt- value 150 bar x m x s-1
Explosion overpressure pmax 9.0 bar
Protective measures
Prevention of effective ignition sourcesExplosion pressure shock resistant up to1.4 bar Explosion venting according VDI 3673 Venting device BETH Explosion doorsNumber / size 16 / 0.53m2per each Disengagement Diverter/rotary valves
Explosion Protection in Dedusting PlantsVattenfall Europe Mining AG dedusting of the actual largest lignite mill of world
BETHPULS Bag Filter 6.90x10.7.20 (double line)
© BETH® Filtration GmbH 2008 . Seite 9
Explosion Protection in Dedusting Plants
Defination of dust according VDI 3677 part 1 = Particle < 500 μm
This definition of dust are also valid in the explosion protection
VDI 2263 „ Dust Fires and Dust Explosions Hazards – Assessment – Protective Measures“
Exception: Flock = Short staples which are generated by cutting
endless fibers, grinding etc.
Length: 0,5 – 2,5 mm Weight:0,5 bis 22 dtex = gram / 10 km fiber lenght
Source: BMFT Band 64 „Humanisierung des Arbeitslebens“
© BETH® Filtration GmbH 2008 . Seite 10
Explosion Protection in Dedusting Plants
For the Recognition of Hazards according
DIN EN 1127-1 „Explosive atmospheres – Explosion prevention and protection – Part 1: Basic concepts and methodology
German version EN 1127-1 : 1997“
in dedusting plants and the required
Analysis of Hazards
is it very important to know
Safety Characteristics of Dust ( Burning and Explosion Behaviour )
© BETH® Filtration GmbH 2008 . Seite 11
Explosion Protection in Dedusting Plants
Burning and Explosion Characteristics of Dust
according BIA – report 12/97and / or BIA data bank GESTIS-STAUB-EX
or tests according
VDI 2263 Part 1 „Test Methods for die Determination of the Safety Characteristic of Dust“
through authorize test / proof institute
© BETH® Filtration GmbH 2008 . Seite 12
Explosion Protection in Dedusting Plants
A dust explosion is possible when the hazard triangle is closed
Dust content in air higher the explosive limits ( lower dust concentration ) Oxygen concentration in the dust/air mixture higher limiting concentration Effective ignition source
Ignition source Oxygen
Explosive dust
© BETH® Filtration GmbH 2008 . Seite 13
Explosion Protection in Dedusting Plants
Safety Characteristics of Dust and the Explosion Hazards
are content of the Explosion Protection Document
according article 8 Directive 1999/92/EG ( ATEX 137 )
Responsible for the safety : Operating management of the plant Consideration : National law
Example : Germany
Betriebssicherheitsverordnung BetrSichV § 6 BGR 104 ( alt ZH 1 / 10 ) „Explosionsschutz-Regeln Regeln für das Vermeiden der Gefahren durch explosionsfähige Atmosphäre mit Beispielsammlung“ E 6
© BETH® Filtration GmbH 2008 . Seite 14
Explosion Protection in Dedusting Plants
Inertial separators VDI 3676 Filtering separators VDI 3677 Electrostatic precipitators VDI 3678 Wet separator VDI 3679
if required in combination including
Ducts with all partsFans, silencerDischarge devices ( rotary valves etc. )Screw conveyors Silos etc
All parts of the dedusting must be consider for the recognition of Explosion Hazards
Possible parts of a dedusting plant can be
© BETH® Filtration GmbH 2008 . Seite 15
Explosion Protection in Dedusting Plants
Consideration and assessment of the different separator types
Example: Filtering separators acc. VDI 3677 Part 1
Bag filters, Envelope filters ( pocket ), Cartridge filters, Candle filters, Laef filters
Arrangement filter elements: Vertical or horizontal
Operation: Suction or pressure Regeneration divices
© BETH® Filtration GmbH 2008 . Seite 16
Explosion Protection in Dedusting Plants
Typical examples of dedusting plants
1.) Bag filter for mill dedusting
Rawgas : Ducts, cyclone, bag filter, screw conveyor, rotary valvesCleangas : Bag filter, ducts, fan, silencer, stack
© BETH® Filtration GmbH 2008 . Seite 17
Explosion Protection in Dedusting Plants
Typical examples of dedusting plants
1.) Object dedusting combination cylone – bag filter
Rawgas : Ducts, cyclone, bag filter, rotary valvesCleangas : Bag filter, ducts, fan, silencer, stack
© BETH® Filtration GmbH 2008 . Seite 18
Explosion Protection in Dedusting Plants
All parts of the dedusting plant must be consider and a assessment in zones is required:
0, 1 and 2 for gas 20, 21 and 22 for dust
Consideration of the location and installation of the dedusting plant. A influence of zones through apparatus etc. they are no part of the dedusting plant, but they are installed in the near of the dedusting plant, is possible and to consider by the selection and installation of the required protective measures.
Analysis of Hazards Explosion Protection Document
Plant operating management – supplier of the plant
© BETH® Filtration GmbH 2008 . Seite 19
Explosion Protection in Dedusting Plants
Protective Measures
Possibilities of Explosion Protection Measures:
Preventive and through Design Measures
Preventive:
Prevention of Explosible Dust/Air Mixtures
Prevention of Dust Explosions through Inerting
Prevention of Effective Ignition Sources
© BETH® Filtration GmbH 2008 . Seite 20
Explosion Protection in Dedusting Plants
Protective Measures
Design Measures:
Explosion pressure resistant design for the max. explosion pressure
Explosion pressure resistant design in combination with explosion venting (pressure relief)
Explosion pressure resistant design in combination with explosion suppression
Explosion Disengagement, Explosion Interruption
Explosion resistant:Pressure resistant = Safety factor 1.5
Pressure shock resistant = Safety factor 1.0
© BETH® Filtration GmbH 2008 . Seite 21
Explosion Protection in Dedusting Plants
BETHPULS Bag Filter prototype explosions pressure test
Clean gas housing
Raw gas housing
Hopper
Screw conveyor
Venting openings for rupture disks orExplosion doors
Stage of erection
© BETH® Filtration GmbH 2008 . Seite 22
Explosion Protection in Dedusting Plants
BETHPULS Bag Filter prototype explosions pressure test
Hazards during the venting process in surrounding areas outside p red 0.53 bar g p red 0.64 bar g
Flames pressure
© BETH® Filtration GmbH 2008 . Seite 23
Explosion Protection in Dedusting Plants
BETHPULS Bag Filter prototype explosions pressure test
Result of exceeding the existing explosion pressure shock resistance damaged filter housing by p red 0.75 bar g
Raw gas housing:
Side panels
End panels
Hopper:
End panels
Side panels
Note: The result of incorrect sizing and design in particular concerning pressure shock resistance, flame tightness, calculation of venting area,venting devices (explosion doors, rupture disks), venting efficiency, explosion values of dust etc is the same
© BETH® Filtration GmbH 2008 . Seite 24
Explosion Protection in Dedusting Plants
EC suitability test of BETH explosion door according directive 94/9/EC (ATEX 95)
Beginning of the venting process
End of the venting explosion door closed
During venting process explosion door open pressure und flame propagation outside
© BETH® Filtration GmbH 2008 . Seite 25
Explosion Protection in Dedusting Plants
Certificate EC suitability test BETH explosion door according directive 94/9/EC
© BETH® Filtration GmbH 2008 . Seite 26
Explosion Protection in Dedusting Plants
Required QS certificates to supply EC suitability tested BETH explosion door acc 94/9/EC
© BETH® Filtration GmbH 2008 . Seite 27
Explosion Protection in Dedusting PlantsScheme of execution examples of explosion protected filters proofed by notified body
© BETH® Filtration GmbH 2008 . Seite 28
Explosion Protection in Dedusting Plants
BETH diverter based of the VDI report 701 (real execution) test of disengagement by a notified body
Test field stage of erection
© BETH® Filtration GmbH 2008 . Seite 29
Explosion Protection in Dedusting Plants
Pressure and flame
Diverter DN 1000
Ductwork DN 1000
BETH diverter based of the VDI report 701 (real execution) test of disengagement by a notified body
Cover fixed in the cage
Disengagement process during the test
© BETH® Filtration GmbH 2008 . Seite 30
Explosion Protection in Dedusting Plants
Possible Design Measures by Example Plant Item 1.)
1.) Object dedusting combination cylone – bag filter
Protective Measure Item 3 Vessel: Explosion pressure restistant design in combination with explosion venting (pressure relief) or explosion suppression. Explosion pressure resistant design for the maximum explosion pressure
© BETH® Filtration GmbH 2008 . Seite 31
Explosion Protection in Dedusting Plants
Example BETHPULS Bag Filter for “Dedusting secondary fuel ” bunker
Diverter for explosion disengagement in the raw gas ductwork
BETHPULS Bag Filter “Explosion pressure shock resistant 1.4 bar with explosion venting”
Clean gas channel and duct
Fan
Vent duct behind the explosion flaps
© BETH® Filtration GmbH 2008 . Seite 32
Example BETHPULS Bag Filter for “Dedusting secondary fuel bunker”
Dust characteristics
Kind of dust Wood etc. Dust explosion class St 1KSt- value 200 bar x m x s-1
Explosion overpressure pmax 10 bar
Protective measures
Prevention of effective ignition sourcesExplosion pressure shock resistant up to1.4 bar Explosion venting according VDI 3673 Venting device BETH Explosion flapsDisengagement BETH diverter/rotary valve
Explosion Protection in Dedusting Plants
© BETH® Filtration GmbH 2008 . Seite 33
Explosion Protection in Dedusting Plants
Duct cyclone to bag filter
Example BETHPULS Bag Filter for “Dedusting plant for aluminium powder”
Cylindrical BETPULS – bag filter in combination with cyclone
Cyclone outlet
Cyclone inlet
Clean gas duct
Bag filter
Raw gas duct
Cyclone
© BETH® Filtration GmbH 2008 . Seite 34
Example BETHPULS Bag Filter for “Dedusting plant for aluminium powder”
Dust characteristics
Kind of dust Overspraypowder Dust explosion class St 2KSt- value 259 bar x m x s-1
Explosion overpressure pmax 9.9 barLower explosible limit 60 g/m3
Protective measures Prevention of effective ignition sources
Explosion pressure shock resistant up to11.0 bar Disengagement raw gas side Rapid action valve
clean gas side Rapid protection valve
Explosion Protection in Dedusting Plants
© BETH® Filtration GmbH 2008 . Seite 35
Explosion Protection in Dedusting Plants
Water-spray system
Example BETHPULS Bag Filter for “Dedusting a fuel-mixture preparation”
BETHPULS Single-line bag filter protected by preventive and design measures
Explosion flaps
Bag filter
Fan, silencer, and stack
Clean gas ductDiverter with raw gas duct
Maintenance platforms
Bag filter
© BETH® Filtration GmbH 2008 . Seite 36
Example BETHPULS Bag Filter for “Dedusting a fuel-mixture preparation”
Dust characteristics
Kind of dust Secondary fuel (house waste, wood)Dust explosion class St 1KSt- value 77 bar x m x s-1
Explosion overpressure pmax 7.0 bar
Protective measures
Prevention of effective ignition sourcesExplosion pressure shock resistant up to1.4 bar Explosion venting according VDI 3673 Venting device BETH Explosion flapsDisengagement BETH diverter/rotary valve
Explosion Protection in Dedusting Plants
© BETH® Filtration GmbH 2008 . Seite 37
Explosion Protection in Dedusting Plants
Conclusion
Correct operation according the range of use
The operation of explosion protected dedusting plants is only permissible with material and safety characteristics according
the documentation of the plant ( operating instructions, data sheet etc. )
Analysis of HazardsExplosion Protection Document
Maintenance acc. the service manual of the supplier Observance of the maintenance cylce time acc. service manual
By no consideration is the dedusting plant in operation not safe Dust explosion and the damaging of the plant is possible.
Danger for employees with all consequences for health and life
© BETH® Filtration GmbH 2008 . Seite 38
Explosion Protection in Dedusting Plants
Example of damaged bag filter through a dust explosion of lignite
Reason: Operating mistake, no maintenance acc. instructions Material change ( dust with higher safety characteristics )
© BETH® Filtration GmbH 2008 . Seite 39
Explosion Protection in Dedusting Plants
Example of damaged bag filter through a dust explosion of lignite
Reason: Operating mistake, no maintenance acc. instructions Material change ( dust with higher safety characteristics )
© BETH® Filtration GmbH 2008 . Seite 40
THANKS FOR YOUR ATTENTION Peter Stender Senior Engineer BETH®Filtration GmbH
BETH® Filtration GmbHBorsigstraße 823560 LübeckDEUTSCHLANDFon +49 451 5307-500 Fax +49 7151 [email protected]
BETH ®Filtration (Schweiz) AGBalz-Zimmermannstraße 7CH-8302 KlotenSCHWEIZFon +41 438133-380 Fax +41 [email protected]
WEIS ENVIRONMENTAL® LLCNiederlassung USA4445 Malone RoadP.O. Box 181070Memphis, TN 38118USAFon +1 901 531 6081Fax +1 901 531 6085 [email protected]