“ Composite Cylinders: From Birth to Grave”

“Composite Cylinders: From Birth to Grave”


Dr Roy (Rohintan) S. Irani,

Gas Package Solutions (GPS) Ltd.

London, U.K.

Gasworld Conference Wednesday, 4th December, 2013

Dubai, UAE

Gas Package Solutions (GPS) Ltd 1


Composite Cylinders

A. Brief History of Composites

B. Role of Regulations and Standards

C. Specifics for Composite Cylinders

D. Future Developments



Gas Package Solutions (GPS) Ltd

Napoleon Bonaparte3


Following on from Napoleon….almost a century later:

In 1919 a 6.9 MPa, 150 mm diameter cylinder was developed:-

• This was spirally-wound with two layers of high tensile strength steel wire to prevent sidewall rupture,

&

• The end caps were longitudinally reinforced with high-tensile rods.

A. Brief History of Composites (2)



•There next followed a spate of wire-wound designs regrettably yet again for military applications.

• During World War II, they were used by airmen as part of their breathing apparatus.

• Such is their success that they are still used for this military application in what is considered to be a conservative field.

Steel wire windings

Thin steel plate cylinder




• Following a number of years of research and development within NASA, finally commercial applications with hoop-wound composite cylinders came into being in 1972.

• Originally these were with an aluminium alloy liner and glass fibre.

• There then flowed a multitude of developments, which included a variety of liners and fibre combinations. Here we have an example of a

seamless steel liner with an Aramid fibre reinforced composite, known as a Type 2 cylinder.



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Seamless steel or aluminium alloy liner

Carbon fibre composite

Glass fibre overwrap for

protecting the carbon composite


A. A Brief History of Composites (5)

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Computer controlled wrapping of a Type 3 cylinder with a carbon fibre composite.

Note protective layer of paint, on metallic liner under the composite.



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Newsflash!!!

Technological breakthrough!!

Year 2000!!!


A. A Brief History of Composites (7)

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Metallic boss

Glass fibre composite overlay, over a polymer

liner



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Critical triple point junction


Summary of Types of Composites


• Type 1: Monolithic cylinders…no composite• Type 2: Hoop wrapped composite gas

cylinders• Type 3: Fully wrapped composite gas

cylinders with load-sharing metal liners• Type 4: Fully wrapped composite gas

cylinders with non-load-sharing metallic or non-metallic liners

• Type 5: Linerless cylinders…only composite



Some applications for composites

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Stay awake….watch this space!


B. Role of Regulations and Standards

• Regulations are Mandatory and must be followed• Regulations are essential ‘Safety Requirements’

against which the law will be applied

BUT

• Regulations are very concise and so often they rely on the application of good Standards which provide the DETAILS.




•ADR - Transport of Dangerous Goods by Road

• RID - Transport of Dangerous Goods by Rail

• ADN - Transport of Dangerous Goods by Inland Waterways

• TPED - Transportable Pressure Equipment Directive

• PED - Pressure Equipment Directive

Principal Regulations covering Pressurised Containers e.g.in Europe

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Monolithic (seamless) cylinders are manufactured using a Design Formula e.g. Lamé von-Mises.

BUT

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Safety First!Stored Energy:

There is a huge amount of energy stored in a compressed gas cylinder. E.g. In a 200 bar 50 litre cylinder i.e. 10,000 bar litres:-

• We have energy equivalent to 0.4 kgs of TNTOr

• The pressure wave alone can kill a person 15 metres awayOr

• Enough energy to raise a small car about 30 metres into the air

THEREFORE:In a ISO(CD) 17519 receptacle i.e. the Titan, whose scope is for a10,000 litre x 1000 bar WP vessel the stored energy is 10 million bar litres i.e. equivalent to 4 tons of TNT….much safety needs to built into the design.




Explosion inside a cellar



Explosion of an Oxygen Cylinder Inside a Cabin19





A large suite of tests developed …..COSTLY!!• Cyclic testing (fatigue) Complete composite cylinder

• Burst testing Liner only

• Mechanical testing (tensile, impact, hardness, bend)• Flaw tolerance (to simulate damage in service)• Drop tests• Environmental test (up to 2000 hours in some cases!)• Bonfire (subjective!!)• Penetration (Gunfire) (really needed in 21st Century?)• Permeation (Type 4) • High temp creep• Accelerated stress rupture• Extreme temp pressure cycling• Resin shear strength• Natural gas cycling• Etc.?

C. Specifics for Composite Cylinders (1)

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Despite such an exhaustive and expensive TEST PROGRAMME,

There is still little confidence that a SAFE cylinder is being produced in the minds of COMPETENT AUTHORITIES who are “committed” to achieving a safe design.

Are these sufficient and appropriate tests for SAFETY???

Specifics for Composite Cylinders (2)



NET RESULT:

The total life of a composite cylinder is limitede.g. in most cases to just 15 YEARS. But watch this space!This then results in a double blow for the user!!

Specifics for Composite Cylinders (3)

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New cylinder costs e.g. Type 3, 300 bar WP and 100 litre

€2000 € 130/annum

c.f. Type 1, 300 bar WP and 100 litre

€240 €6/annum

BUTType 1: Technical efficiency# 0.9kg/LType 3: Technical efficiency# 0.3kg/L

# Unit weight of cylinder/volume24



Lack of confidence in performance is also reflected in the use aspects of composites e.g.

P. I. & T. ……… EN ISO 11623 (2002)

Lacks any real test for degradation of composites

Despite a revision in progress after nearly a decade, very little innovative progress for vast majority of composites

Some expensive testing e.g. AE testing being developed for ‘Prestige’ Projects.

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The Grave!


The cylinder shall be made unserviceable by: Removing all labels and identification marks,

Removal of the valve and other accessories for reuse or recovery,

Either crushing the cylinder as flat as possible, or cutting irregular holes in the neck and base.

In addition see the guidance in EN ISO 11623 – “Transportable gas cylinders - Periodic inspection and testing of composite gas cylinders”.


The Grave! (2)


Where technically and economically feasible, separate materials for recycling/recovery e.g. cut up/separate different materials by shredding or crushing.

Depending on the metal content and the acceptance

criteria for the metallic waste on the waste site licence it may be possible to directly recycle the cylinder with metal wastes (without separation of materials).

If neither of above methods is technically or

economically feasible then the cylinders should be segregated and sent to a suitable landfill.



D. Future developments

1) Develop pragmatic, realistic manufacturing tests and not those which ‘might be useful’ e.g. delete the ‘Gunfire’/‘Penetration’ test.

2) Provide hard data to Competent Authorities and not ‘hearsay’e.g. stress rupture characteristics of various types of fibres.

3) More objectivity e.g. a more reproducible bonfire test than the current one.

4) Minimise permeation of gas (especially flammable ones) from Type 4 cylinders.

5) Develop an affordable test for evaluating degradation of the composite.

6) Undertake a risk analysis with due regard to the local population.

7) All of the above factors 1) -> 6) will help composites to achieve a non-limited life.Thus ensuring that composites compete COMMERCIALLY on a more equal footing with Type 1 cylinders, than they do today.

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Something to think about….Enter the “Titan”


4 x composite tubes in a 40’ ISO container= 1 module



A “Titan” on the move

Around 300 modules are now in-use worldwide



Exacting “Bonfire” Tests

Critical “Rollover”. Tubes tested after accident using AE and found to be perfectly safe for further service.




Typical leakage rate from a plastic lined Type 4 due to permeation



Permeation rates permitted by various specificationsGas Package Solutions (GPS) Ltd


Standardisation Standardisation IsIsAA

LivingLivingProcess.Process.




Documents

“ Composite Cylinders: From Birth to Grave”