EP Seminar for Irish Grain

7/28/2019 EP Seminar for Irish Grain

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EXPLOSION PROTECTION

SOLUTIONS

by

Explosion Protection Solutions

Practical Guide on:

Explosion

Fundamentals Explosion Venting

Explosion Isolation

Explosion Suppression

Open air cornstarch deflagration


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2

Explosions by Industry

Factory Mutual Data Sheet 7-76

Industry Definitions

Explosionrupture of an enclosure due to the internal pressure from

a deflagration.

Deflagrationpropagation of a combustion zone at a velocity that isless than the speed of sound.

Detonationpropagation of a combustion zone at a velocity that is

greater than the speed of sound.


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Explosion Ingredients

Fuel

Enclosure

Ignition

Oxidant

PRESSURE

(BARA)

TIME

Explosion

KSt[dp/dt]max

Explosion Pressure Curve

10

0Normal pressure

Pmax


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Explosibility Index

KSt = (dp/dt)maxV1/3KSt = (dp/dt)maxV1/3

Kst

200201-300

>>>> 300

Kst

200201-300

>>>> 300

Hazard Class

St-1St-2

St-3

Hazard Class

St-1St-2

St-3

Pmax

10

10

12

Pmax

10

10

12

MATERIALParticle Size

MicronsPMAX

barg

KSt

bar-m/sec

Hazard

Class

COAL

(Bituminous)24 9.2 129 1

SUGAR 30 8.5 138 1

POLYETHYLENE


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Explosion Ingredients

FUEL:

OXIDANT:

IGNITION:

MEC minimum explosible concentration

LOC limiting oxidant concentration

MIE minimum ignition energy

MAIT minimum auto-ignition temperature

MEC minimum explosible concentration

LOC limiting oxidant concentration

MIE minimum ignition energy

MAIT minimum auto-ignition temperature

Knowing the Kst & Pmax ofyour product will define themagnitude and speed of anexplosion in your plant.

Knowing the MEC, LOC,MIE or MAIT can identify

process areas that aresubject to explosion.

If these values are notknown, Fike Corporationcan test your product inaccordance withrecognized procedures.


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Explosion Protection

3 Step Process

Define The Hazard

Define The Protection Objective

Choose The Protection Technique

Define The Hazard


Choose The Protection Technique

Define The Hazard

Process

Characteristics

Hazard

Characteristics

Physical

Characteristics


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T. Lombardo

9/30/97

T. Lombardo

9/30/97

Process Characteristics


Bag Filter

0 to - 17mbarg

Downstream

48C

Bag Filter

0 to - 17mbarg

Downstream

48C

Enclosure

Pressure

Blower

Location

Temperature

Enclosure

Pressure

Blower

Location

Temperature


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Hazard CharacteristicsHazard Characteristics

Pmax

KSt

MEC

MIE

MAIT

LOC

Pmax

KSt

MEC

MIE

MAIT

LOC

8.3 barg

120 psig

182 bar.m/sec

2,640 psi

90 g/m3

115 mJ

410C

12%

8.3 barg

120 psig

182 bar.m/sec

2,640 psi

90 g/m3

115 mJ

410C

12%

Physical Characteristics

Location

H/D

Volume

Clean

Dirty

Design

Strength

Location

H/D

Volume

Clean

Dirty

Design

Strength

Outdoors

1.8

10 m3

1.25 m3

8.75 m3

310 mbarg

Outdoors

1.8

10 m3

1.25 m3

8.75 m3

310 mbarg


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Control the

Explosion Pressure

Control the

Explosion Propagation

Control the

Explosion Pressure

and Flame

Control the

Explosion Pressure

Control the


Control the

Explosion Pressure

and Flame

Choose The Protection TechniqueChoose The Protection Technique

Explosion Venting

Explosion Isolation


Explosion Venting

Explosion Isolation



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Venting Concept

A predetermined area Avreleases pressure at a given

level Pstat resulting in a

reduced pressure Pred.

Explosion flame, pressureand unburned mixture are

vented to a safe area.(the most widely used method)

PRESSURE

TIME

Explosion

KSt[dp/dt]max


Normal pressure

Pmax


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PRESSURE

TIME

Vented Explosion

Normal pressure

PREDPREDPstatPstat

PmaxPmax

PesPes

Venting

Efficiency

Venting

Efficiency

Physical Characteristics

Location

H/D

Volume

Clean

Dirty

Design

Strength

Pred

Location

H/D

Volume

Clean

Dirty

Design

Strength

Pred

Outdoors

1.8

10 m3

1.25 m3

8.75 m3

310 mbarg

310 mbarg

Outdoors

1.8

10 m3

1.25 m3

8.75 m3

310 mbarg

310 mbarg


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Bag Filter

0 to - 17 mbarg

100 mbarg

Downstream

48C

Bag Filter

0 to - 17 mbarg

100 mbarg

Downstream

48C

Enclosure

Pressure

Pstat

Blower

Location

Temperature

Enclosure

Pressure

Pstat

Blower

Location

Temperature

Explosion Vent SizingExplosion Vent Sizing

AV = 0.5 m2

VDI 3673,6.1.1 HomogeneousDust Distribution

AV = 0.5 m2

VDI 3673,6.1.1 HomogeneousDust Distribution


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YesYes

Location Location IndoorsIndoors

Discharge

Duct

Discharge

Duct


Discharge Relief Pred

Duct L Area

0 m 0.5 m 0.3 barg

2m 0.5m 0.86barg

1 m 0.4 barg

4m 0.5m 1.7 barg

1 m 1 barg

Discharge Relief Pred

Duct L Area

0 m 0.5 m 0.3 barg

2m 0.5m 0.86barg

1 m 0.4 barg

4m 0.5m 1.7 barg

1 m 1 barg


L


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Available in many sizes and

shapes Diversity of materials &

designs process (compatibility)

Low cost, long life expectancy

Must vent to a safe location(outdoors)

Available in many sizes and

shapes Diversity of materials &

designs process (compatibility)

Low cost, long life expectancy

Must vent to a safe location(outdoors)

Explosion Vents

Highest efficiency

Low unit mass < 12.2 kg/m

Certified burst pressures

Full predictable opening

Non-Fragmenting

Low maintenancerequirements

Flameless Explosion Venting

An alternative to the use of

explosion discharge ducts is

the use of Vent Flame Filters

in combination with explosion

venting.

While the explosion is allowed

to run full course inside the

protected equipment, only

pressure will be vented into

the surrounding atmosphere

and a secondary explosion

risk is prevented.

An alternative to the use of

explosion discharge ducts is

the use of Vent Flame Filters

in combination with explosion

venting.

While the explosion is allowed

to run full course inside the

protected equipment, only

pressure will be vented into

the surrounding atmosphere

and a secondary explosion

risk is prevented.Flameless Venting

Conventional Explosion Venting


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Bucket Elevator Vents

The EleGuard vent is specifically designed for

Bucket Elevator Explosion protection

The number of vents is required is determined by

the Kst, design Strength of the leg and height of the

legs

Indoor Venting of Bucket Elevators

The EleQuench device is designed for Bucket

Elevator Explosion protection where the Elevators

are located Indoor

An Indicator called an RI is recommended as this

indicates that the Vent has opened


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VENTING SUMMARY

ADVANTAGES

Relatively inexpensive

Easy to install or replace

Low maintenance

Passive system

CONSIDERATIONS

Releasing pressure does not put out the flame. Flame,

pressure and unburned products will exit through thevent and may cause further damage or injury.

Toxic products may be dispersed into the atmosphere.

More Vent area than can practically be installed may

be needed.

EXAMPLES

VENTING

OF SILOS

VENTING OF

PIPELINES


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EXAMPLES

Explosion Protection Solutions

Practical Guide on:

Explosion

Fundamentals Explosion Venting

Explosion Isolation


Open air cornstarch deflagration


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Explosion Isolation

Why Isolation ?Why Isolation ? Explosion pressure and flame will propagate

through process interconnections to other plant

equipment or personnel occupied areas.

Explosions in connected vessels tend to be of

higher severity than explosions occurring in

single unconnected vessels because of pre-

compression and flame-jet ignition.

Deflagrations can accelerate to detonation

velocities while traveling through pipelines.

Explosion pressure and flame will propagate

through process interconnections to other plant

equipment or personnel occupied areas.

Explosions in connected vessels tend to be of

higher severity than explosions occurring in

single unconnected vessels because of pre-

compression and flame-jet ignition.

Deflagrations can accelerate to detonation

velocities while traveling through pipelines.

Explosion Pressureand Flame

Propagation inBucket Elevator

Explosion Pressureand Flame

Propagation inBucket Elevator


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Explosions inInterconnected Enclosures

P = 7.4 bardP/dt = 32 bar/s




V = 1.0 m3V = 1.0 m3

V = 5.0 m3V = 5.0 m3

P = 11 bardP/dt = 1.200 bar/s

P = 11 bardP/dt = 1.200 bar/s

P = 10.2 bardP/dt = 1.000 bar/s

P = 10.2 bardP/dt = 1.000 bar/s

V = 1.0 m3V = 1.0 m3

V = 5.0 m3V = 5.0 m3

Explosions in

Interconnected Enclosures


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Chemical Explosion-isolation System

No restriction, clean procesconnection

Only to be used in combination with explosion venting or

explosion suppression (Pred Pmax)

only stops the explosionflame, not the explosionpressure

different suppressant agents are available, depending on

the application requirements (food industry, CIP, metal

dust explosions, etc.)

No restriction, clean procesconnection

Only to be used in combination with explosion venting or

explosion suppression (Pred Pmax)

only stops the explosionflame, not the explosionpressure

different suppressant agents are available, depending on

the application requirements (food industry, CIP, metal

dust explosions, etc.)

0.3 m min10 dia. max

Xmax

Xmin

Explosion IsolationExplosion Isolation

Fike


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Control the

Explosion Pressure

Control the


Control the

Explosion Pressure and

Flame

Control the

Explosion Pressure

Control the


Control the

Explosion Pressure and

Flame

Choose The Protection TechniqueChoose The Protection Technique

Explosion Venting

Explosion Isolation


Explosion Venting

Explosion Isolation



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Suppression Concept

The heat of combustion develops pressure.

Upon pressure detection, sufficient

suppressant agent is dispersed into the

protected volume.

Flame is quenched which prevents any further

pressure increase.

Flame, pressure and unburned mixture arecontained inside the vessel

IgnitionSpark/Flame starts in a closed vessel

equipped with detector, control panel and suppressant

container

Fike


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DetectionDetector senses pressure wave and sends signal to controlpanel

Time : LESS THAN 1 Milliseconds

Fike

Fike

ActivationControl Panel issues command to suppressant container.

Initiator opens rupture disc. Time: less than 1 millisecond


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InjectionSuppression agent released through dispersion nozzle.

Fike

SuppressionContainer continues to release agent. Explosion is

suppressed.

Response time is measured in Milliseconds

Fike


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PRESSURE

TIME

Explosion

KSt[dp/dt]max


Normal pressure

Pmax


ADVANTAGES

Process media is contained

It can be used inside buildings - near personnel -

Provides fire protection (after initial deflagration)

Can provide automatic process shutdown

CONSIDERATIONS

Active system

Requires regular maintenance

CONSIDERATIONS

Active system

Requires regular maintenance


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Explosion risks are an industrial reality;

equipment loss, downtime, environmental

issues and hazards to personnel can be

avoided through the application of the most

suitable protection method.

Explosion protection technology offers

the process and safety engineer a

variety of reliable tools.

Fike Explosion Protection Solutions

EP Seminar for Irish Grain

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