jerry locatelli - ecka granules australia - case study: converting an old plant to a dust free...

A Case Study of Redeveloping the Ecka Granules plant in Tasmania

by

Jerry Locatelli

1 18th June 2014 © Ecka Granules Australia 5th Informa Dust Explosions Conference 2014

JERRY LOCATELLI

Engineering Manager

Involved in redevelopment and expansion the Tasmanian plant since 1992

Responsible for all engineering design and construction

THE PLANT

Produces aluminium granules and aluminium powder products

Aluminium Granules are mostly sold locally

Aluminium Powder sales are mainly exported

ECKA GRANULES

Largest producer of metal powders in the world

Other plants located in Europe, Middle East, China and USA


Built in 1968 and progressively redeveloped and expanded from 1991 to date

Located in Northern Tasmania next door to the Pacific Aluminium Smelter

Output has increased from 2,000 tpa in 1991 to about 18,000 tpa in 2014

Currently employs 43 people


4

Molten metal supplied direct from the adjacent aluminium smelter

Atomisation using High Pressure/Temp. compressed air from two atomising lines

Collection of powder in High Efficiency Cyclones

Screening and Packaging of powders from 4µ to 400µ in an inert atmosphere.

Shipping in FIBCs, Steel Drums and Paper Sacks

18th June 2014 © Ecka Granules Australia 5th Informa Dust Explosions Conference 2014

COARSE POWDER

MEDIUM POWDER

~SCREENING~

~GRANULE CASTING~

SCREEN

SUPER FINE

GRANULES

~POWDER COLLECTION~

MOLTEN

METAL

ATOMISED

POWDER

SUPERFINE

FINE POWDER

FINE SCREENED SUPER FINE

SECONDARY CYCLONES PRIMARY CYCLONES

~ATOMISING~

CLASSIFIER


Open powder transfers

Dust traps in buildings

Drains blocked with powder

Electrical equipment was not all ignition proof

Mechanical equipment had unacceptable ignition risks

It was decided to Redevelop the plant to target the emerging fine aluminium powder market

Commission an External Safety Audit by a recognised Safety Engineering group:

Improve housekeeping and address dust leakage

Implement urgent Safety Audit measures , such as upgrading equipment earthing and removal of some hazardous process equipment

Development of Engineering Process to be adopted for the Plant Redevelopment Plan


Sound design and engineering was recognised as fundamental to the operation of a Safe Plant

Understanding the Hazards and consistent, quantified Risk Assessment was also considered important

A set of Engineering Safety Principles was developed to address the particular issues relating to processing Aluminium Powder

Process control and Safety Systems


Dusty products require a multifaceted design approach to facilitate good house-keeping to minimise the risk of fugitive dust causing secondary explosions, such as:

Dust free design (minimising dust traps)

Externally run services (cables and piping)

Inside-out buildings (with no internal framing)

Smooth floors with minimal obstructions

Total Product Containment to minimise fugitive dust


9

DUST FREE DESIGN RULES

© Ecka Granules Australia 5th Informa Dust Explosions Conference 2014 18th June 2014

10

ELIMINATING DUST TRAPS & LEDGES


11

SERVICES RUN EXTERNALLY


12

INSIDE OUT BUILDING


13

ELIMINATING FLOOR OBSTRUCTIONS


14 © Ecka Granules Australia 5th Informa Dust Explosions Conference 2014 18th June 2014

An example of a “de-cluttered” screen setup installed in a building designed without dust collecting ledges

15 © Ecka Granules Australia 5th Informa Dust Explosions Conference 2014 18th June 2014

Open powder transfers have became a thing of the past

16 10th June 2009 © Ecka Granules Australia Dust Explosions 2009

1. Measuring the properties of Aluminium Powder

2. Performing a Risk Analysis on each process utilising a

Fault Tree Analysis method to achieve a design Fatal

Accident Rate (FAR) target of less than 2.0 for the

entire plant

3. Perform a HAZOP analysis on each process

17 18th June 2014

Explosibility of Common Dusts

Type of Dust Ignition

Sensitivity Explosion Severity Explosibility Index

Dust Explosion

Class

Aluminium superfines 7.3 >10.2 >70.0

St 3

Polyethylene 24 2.2 52.8

Sulfur 20.2 1.9 38.4

Magnesium 3.0 7.4 22.2

Polystyrene 6.0 2.0 12.0

Aluminium fines 1.4 >7.7 >10.0

Aspirin 2.4 >4.3 >10.0

Sugar 4.0 2.4 9.6

St 2

Grain dust 2.8 3.3 9.24

Rubber 4.6 1.6 7.36

Flour 2.1 1.8 3.78

Vitamin C 1.0 2.2 2.2

Milk, powdered 1.6 0.9 1.44

Coal (Pittsburgh) 1.0 1.0 1.0

Egg white <0.1 0.2 0.02

St 1 Coffee bean 0.1 0.1 0.01

Cotton <0.1 <0.1 <0.01

© Ecka Granules Australia 5th Informa Dust Explosions Conference 2014

18th June 2014 18

0

50

100

150

200

250

300

0 50 100 150 200 250

Min

imum

Explo

siv

e C

oncentr

ation

- M

EC

- g/m

3

Average Particle Size, microns

Variation of Explosive Concentration with particle size - Aluminium Powder

0.0

0.2

2.0

20.0

10 100

Variation in Explosibility with Particle Size - Aluminium Powder

Average Particle Size - Microns

Explo

sib

ility

Index

SUPERFINE

FINE POWDER

MEDIUM POWDER

COARSE POWDER

© Ecka Granules Australia 5th Informa Dust Explosions Conference 2014

Dust properties assumed to apply plant-wide

19

Aluminium fines < 10 microns

MIE ~10 milliJoules

Kst ~ 800 bar.m/sec

Pmax ~ 13 bar

Minimum Explosive Concentration = 35 g/m3

Estimated explosive energy is approx. 3 x TNT


20

Line of Tolerable Risk: 1 x Medical

Treatment

Injury (MTI)

1 x

Compensible

Injury (CI) or

10 x MTI's 10 x CI's

1 x

Permanent

Disablement

(PD) 1 x Fatality 10 x Fatalities

Frequent: ≥1 per year Medium/Low

(10) Medium (100) High (1,000)

Very High

(10,000)

Severe

(100,000)

Very Severe

(1,000,000)

Possible: < 1 per year

(but ≥ 0.1 per year) Low (1)

Medium/Low

(10) Medium (100) High (1,000)

Very High

(10,000)

Severe

(100,000)

Unlikely: < 0.1 per year

(but > 0.01 per year) Low (0.1) Low (1)

Medium/Low

(10) Medium (100) High (1,000)

Very High

(10,000)

Very Unlikely: < 0.01 per year

(but ≥ 0.001 per year) Low (0.01) Low (0.1) Low (1)

Medium/Low

(10) Medium (100) High (1,000)

Barely Credible: < 0.001 per year

(but ≥ 0.0001 per year) Low (0.01) Low (0.01) Low (0.1) Low (1)

Medium/Low

(10) Medium (100)

Low (1)

Medium/Low

(10)

Note: Risk Reduction Factors (RRF) shown in brackets Low (1)

Target is to stay below the red line in the green box area


10th June 2009 © Ecka Granules Australia Dust Explosions 2009 21

The Hazard & Operability Study (HAZOP) method is considered an essential tool to:

Validate the safe design of each process

Ensure the process can be operated and maintained safely and efficiently

Examine the effects of process deviations and failures

Involve Operators, Maintainers & technicians in the design process


Powder Plant Safety Design Principles The following is a list of ten major safety design principles employed by Ecka Granules Australia to minimise the risk of personnel injury due to a powder explosion or fire.

1. Separation of personnel from non - inert proce sses . One of the most effective means of avoiding personnel injury in hazardous plants is the use of separation. Personnel located over 15 m from an aluminium powder explosion will be unlikely to sustain serious injuries.

2. Explosion venting of non - iner t processes is used to reduce the peak pressure generated in vessels and ducts resulting from an explosion to a level which minimises the risk of injury to personnel. Explosion venting at ECKA GRANULES Is designed to comply with the NFPA 68 standard. (NFPA = National Fire Prevention Association, USA).

3. Operation of non inert processes safely below the MEC (Minimum Explosive Concentration) Powder concentration

In conveying ductwork and fan is maintained below 50 % of the MEC to ensure that there is insufficient concentration of powder for an explosion to take place, however operation below the MEC cannot be achieved in the cyclones where a

region

In the explosive range is unavoidable.

4. Inert gas blanketing of all processes where practical . The use of nitrog en with 3% oxygen eliminates the risk of explosion by the exclusion of sufficient oxygen for ignition, whilst ensuring some oxygen is present to oxidise any newly created surfaces. This is effectively used in the screening and powder handling areas.

5. Use of non - sparking conductive materials, earth bonding and Intrinsically Safe or DIP (Dust - excluding Ignition Proof) electrical systems. This eliminates the major sources of ignition resulting from electrical and electrostatic discharge and sparking due to impact.

6. Avoid use of mechanical moving parts where possible . This reduces the likelihood of ignition caused by friction, heat or sparks resulting from mechanical equipment failure. Where high energy mechanical devices cannot be isolated from explosive or flamm able materials, personnel are excluded from the danger zone by fencing.

7. Fail safe, independent, instrumented automated shutdown systems . The use of automated systems to shutdown the plant in the event of malfunction ensures a fast unambiguous response in time to avoid potentially hazardous incidents.

8. Fully sealed transfer systems to ensure total containment of powder and the minimisation of fugitive emissions.

9. Elimination of dust accumulation by dust free design of equipment and structures. By designing equ ipment and structures to minimise the accumulation of dust, areas can be easily kept clean and a potential safety hazard thus minimised.

10. Minimisation of process inventory . The minimisation of powder inventory in process ensures that the least amount of fue l is available in the event of a fire or explosion.

Hard Wired trips on critical equipment

Critical equipment monitoring

Fail safe device handling

Multiple Safety Layers


24

DUCT CONVEYING EXPLOSIVE DUST

– EXAMPLE OF MULTIPLE SAFETY LAYERS

1. Dust

Concentration

50% of M.E.C.

2. Explosion

venting in duct

3. 15 m exclusion

zone around

duct


Today, the plant at Bell Bay in Tasmania sets the standard for Safe Design and Operation within the Global Ecka Granules Group

This has been achieved through

Sound Design

Engineered Risk Control

Safe Design Principles

Fail Safe Control and Protective Systems

And through the dedication and professionalism of our Production and Maintenance teams


26

Thank You


We Researched the causes of serious dust explosions occurring in our industry since the 1960s and this revealed explosions were associated with the following equipment:

Bag houses

Vacuum cleaners

Star feeders

Screw conveyors

Bucket elevators

So we decided not to use them at the Bell Bay plant.


jerry locatelli - ecka granules australia - case study: converting an old plant to a dust free...

Engineering

grain dust

ecka granules plant

risk of fugitive dust

address dust leakage

secondary explosions

powder collection

aluminium powder sales

screen super fine granules