Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C1/00—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge
  • F17C1/02—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge involving reinforcing arrangements
  • F17C1/04—Protecting sheathings
  • F17C1/06—Protecting sheathings built-up from wound-on bands or filamentary material, e.g. wires
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C1/00—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge
  • F17C1/12—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge with provision for thermal insulation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C1/00—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge
  • F17C1/16—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge constructed of plastics materials
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C13/00—Details of vessels or of the filling or discharging of vessels
  • F17C13/002—Details of vessels or of the filling or discharging of vessels for vessels under pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C13/00—Details of vessels or of the filling or discharging of vessels
  • F17C13/12—Arrangements or mounting of devices for preventing or minimising the effect of explosion ; Other safety measures
  • F17C13/123—Arrangements or mounting of devices for preventing or minimising the effect of explosion ; Other safety measures for gas bottles, cylinders or reservoirs for tank vehicles or for railway tank wagons
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
  • F17C2201/01—Shape
  • F17C2201/0104—Shape cylindrical
  • F17C2201/0109—Shape cylindrical with exteriorly curved end-piece
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
  • F17C2201/05—Size
  • F17C2201/054—Size medium (>1 m3)
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/03—Thermal insulations
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/03—Thermal insulations
  • F17C2203/0304—Thermal insulations by solid means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
  • F17C2203/0602—Wall structures; Special features thereof
  • F17C2203/0604—Liners
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
  • F17C2203/0602—Wall structures; Special features thereof
  • F17C2203/0607—Coatings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
  • F17C2203/0602—Wall structures; Special features thereof
  • F17C2203/0612—Wall structures
  • F17C2203/0614—Single wall
  • F17C2203/0621—Single wall with three layers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
  • F17C2203/0634—Materials for walls or layers thereof
  • F17C2203/0658—Synthetics
  • F17C2203/066—Plastics
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
  • F17C2203/0634—Materials for walls or layers thereof
  • F17C2203/0658—Synthetics
  • F17C2203/0663—Synthetics in form of fibers or filaments
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
  • F17C2203/0634—Materials for walls or layers thereof
  • F17C2203/0658—Synthetics
  • F17C2203/0663—Synthetics in form of fibers or filaments
  • F17C2203/0673—Polymers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2205/00—Vessel construction, in particular mounting arrangements, attachments or identifications means
  • F17C2205/03—Fluid connections, filters, valves, closure means or other attachments
  • F17C2205/0302—Fittings, valves, filters, or components in connection with the gas storage device
  • F17C2205/0305—Bosses, e.g. boss collars
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2209/00—Vessel construction, in particular methods of manufacturing
  • F17C2209/23—Manufacturing of particular parts or at special locations
  • F17C2209/232—Manufacturing of particular parts or at special locations of walls
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2221/00—Handled fluid, in particular type of fluid
  • F17C2221/01—Pure fluids
  • F17C2221/012—Hydrogen
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
  • F17C2223/03—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the pressure level
  • F17C2223/036—Very high pressure (>80 bar)
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2260/00—Purposes of gas storage and gas handling
  • F17C2260/04—Reducing risks and environmental impact
  • F17C2260/042—Reducing risk of explosion
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2270/00—Applications
  • F17C2270/01—Applications for fluid transport or storage
  • F17C2270/0165—Applications for fluid transport or storage on the road
  • F17C2270/0168—Applications for fluid transport or storage on the road by vehicles
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/32—Hydrogen storage

Definitions

• This invention relates to a composite pressure vessel and in particular to a composite pressure vessel for storing hydrogen, more especially for the storage of high pressure hydrogen in a hydrogen fuelled vehicle.
• Hydrogen is typically stored at very high pressure in a suitable storage vessel. Rupture of a hydrogen storage vessel in a vehicle, due to damage in a collision and/or external fire, can lead to a catastrophic explosion or fire within the vehicle, resulting in a devastating blast wave and fireball that can pose severe threat to life and destroy property, particularly if the fire occurs when the vehicle is stored in a garage.
• Compressed hydrogen can be stored in composite pressure vessels, wherein a gas impermeable liner is supported by an outer layer comprising fibre windings (typically carbon fibre) embedded in a polymer material.
• the benefits of such composite pressure vessels for storing compressed gases in vehicles are generally known: they are light weight, have a high impact strength, and display corrosion-free attributes.
• a thermally activated pressure relief device to release the gas and reduce the pressure within the vessel prior to structural failure of the vessel.
• TPRD thermally activated pressure relief device
• such a TPRD typically releases the gas through a nozzle which can generate long flames of up to 15 m and can destroy garage-like enclosures in fractions of a second.
• a TPRD can become blocked or fail to operate during an accident, as increasingly reported in media in different countries. Fire could affect parts of a compressed gas storage vessel at a location remote from the TPRD, potentially leading to structural failure of the vessel prior to operation of the TPRD.
• An object of the present invention is to provide an improved composite pressure vessel for storing a high pressure flammable gas that can alleviate such risks.
• a composite pressure vessel comprising an inner normally gas impermeable liner that becomes gas permeable at a predetermined temperature, a load bearing intermediate layer configured to withstand the internal pressure exerted by the compressed gas to be stored in the vessel, and a thermally protective outer layer formed from a material having a lower thermal conductivity than the intermediate layer, whereby the thermally protective outer layer has a greater temperature gradient across its thickness than the intermediate layer when the vessel is exposed to fire.
• the liner may be adapted to become gas permeable at said predetermined temperature by melting, tearing, cracking, plastically flowing, creeping or otherwise becoming thermally instable at said predetermined temperature.
• the intermediate layer comprises a carbon fibre reinforced polymer.
• the thermally protective outer layer may comprise a glass fibre reinforced polymer.
• the thermally protective outer layer may comprise a layer of intumescent paint.
• thermally protective outer layer and the intermediate layer are substantially porous to the gas to be stored.
• the composite vessel may be adapted to store hydrogen, the liner being impervious to hydrogen and the load bearing intermediate layer being adapted to withstand an internal gas pressure within the vessel of at least 350 bar.
• the intermediate layer is preferably adapted to withstand an internal gas pressure of at least 700 bar.
• the load bearing intermediate layer is preferably adapted to withstand an internal gas pressure of at least 1000 bar.
• the liner may be adapted to become gas permeable at approximately 120°C.
• the vessel includes at least one metallic boss for transferring gas into or out of the vessel having a greater thermal conductivity than the remainder of the vessel whereby the boss acts, in use, to transfer heat to the liner.
• a method of making a composite pressure vessel having a load bearing vessel wall and a normally has impermeable liner comprising the steps of determining a temperature profile within the vessel wall and selecting material properties of the vessel wall such that the liner becomes gas permeable due to heat degradation before the wall loses its load-bearing ability.
• the liners may become has permeable by melting, tearing, cracking, plastically flowing, creeping or otherwise becoming thermally instable at a predetermined temperature.
• the vessel wall comprises a load bearing intermediate layer configured to withstand the internal pressure exerted by the compressed gas to be stored in the vessel, and a thermally protective outer layer formed from a material having a lower thermal conductivity than the intermediate layer, whereby the thermally protective outer layer has a greater temperature gradient across its thickness than the intermediate layer when the vessel is exposed to fire, said method comprising selecting the thickness and properties of the thermally protective outer layer such that heat transferred to the intermediate layer when the vessel is exposed to fire is sufficient to melt the liner before thermal degradation of the intermediate layer comprises the load bearing properties of the intermediate liner.
• Figure 1 is a sectional view through a composite pressure vessel in accordance with an embodiment of the present invention
• Figures 2a to 2d are detailed sectional views of different embodiments of the boss and liner of the vessel of Figure 1 ;
• Figure 3 is a graph showing the temperature gradient across the wall of the vessel of Figure 1 when exposed to a fire.
• a composite pressure vessel in accordance with an embodiment of the present invention comprises an inner hydrogen impermeable liner 1 formed from a suitable polymeric material having a melting point of approximately 120°C.
• Metallic bosses 2 are affixed to each end of the liner 1 to allow gas to be added to and removed from the vessel, etc.
• the liner 1 is supported by a load bearing intermediate layer formed from a carbon fibre reinforced polymer.
• the structure and thickness of the intermediate layer 3 is configured to withstand the maximum expected internal pressure within the vessel (typically at least 700 bar for hydrogen and more preferably at least 1000 bar).
• the intermediate layer 3 is not impermeable to hydrogen gas, allowing hydrogen to vent through the intermediate layer 3 when the liner disintegrates, tears, cracks, flows plastically, creeps, melts or otherwise becomes leaky due to exposure to high temperatures, gradually venting the gas over the entire surface of the vessel.
• the intermediate layer 3 is coated with a thermally protective outer layer 4 having a lower thermal conductivity than the intermediate layer 3 such that, when the vessel is exposed to fire, the thermally protective outer layer 4 has a greater temperature gradient across its thickness than the intermediate layer 3, thus reducing the maximum temperature to which the load bearing intermediate layer 3 is exposed and greatly reducing decomposition of the intermediate layer 3 due to heat, enabling the intermediate layer 3 to maintain its structural integrity until the liner 1 fails and the gas vents through the intermediate and outer layers 3,4, and maintaining sufficient structural integrity to withstand the internal pressure within the vessel as the gas vents and reduces the internal pressure within the vessel, thus reducing the pressure within the vessel in a controlled and relatively safe manner.
• the thermally protective outer layer 4 may comprise intumescent paint or a glass fibre reinforced polymer, both having a lower thermal conductivity than the carbon fibre reinforced polymer intermediate layer 3.
• a fire test following requirements of Global Technical Regulation 2013 was carried out on a composite vessel in accordance with an embodiment of the present invention of 36 litres pressurised to 700 bar, the vessel having a carbon fibre reinforced polymer intermediate layer 3 or shell.
• the outer thermally protective layer 4 comprised a non-load bearing layer of intumescent paint of 7 mm thickness. After 67 minutes in a fire, the liner 1 of vessel melted and gas was safely released through the vessel surface. The vessel was not equipped by TPRD.
• the heat flux from a fire passes through the outer thermally protective layer 4 with some reduction, e.g. due to losses on polymer decomposition, and then transferred further through the intermediate layer 3, which is a composite material with a higher thermal conductivity and thus a smaller gradient of temperature compared to the gradient of temperature through the outer thermally protective layer 4, and finally through the liner 1 to the compressed gas stored within the vessel.
• the liner 1 is selected to have melting temperature satisfying regulations for filling such vessels with compressed gas (compressed gas tends to heat up upon filling of a tank due to expansion), and lower than decomposition temperature of polymer matrix of the load bearing intermediate layer 3. Due to these thermal arrangements, the liner 1 melts before the intermediate layer 3 loses its load-bearing ability, and the compressed gas starts to penetrate (leak) through the vessel wall as both intermediate layer 3 and outer thermally protective layer 4 are not tight to high- pressure gas, especially hydrogen.
• the invention provides a leak-no-burst (explosion-free in a fire) performance of compressed gas storage vessel in a fire even if a TPRD does malfunction or is blocked during an accident for any envisaged storage pressure.
• Figures 2(a-c) show longitudinal cross-sectional detailed views of the vessel part with the boss 2 in contact with liner 1 , intermediate layer 3 and thermally protective layer 4, and Figure 2(d) shows a sectional end view of the boss.
• Figures 2(a) and 2(b) illustrate two different boss 2 and liner 1 arrangements.
• the boss 2 has a plurality of channels 2a projecting through its thickness in the part in between the intermediate layer 3 and the liner 1 , that can be filled with the liner 2 plastic material, e.g. during liner moulding.
• the boss 2 is exposed to a fire from outside, the heat is rapidly transferred through the relatively highly thermally conductive boss 2 to the liner 1 , speeding up the thermal degradation of the liner 1 .
• the liner material embedded into the boss channels 2a becomes substantially porous due to heat, permitting the gas to pass through, to the intermediate layer 3, and then vent through the vessel wall 3, 4.
• the boss 2 has an increased wall thickness, providing absorbance of larger amounts of heat from an outer fire and hence transferring more heat to the liner, accelerating the initiation of a leak through the liner.
• Figure 3 shows schematically the temperature gradient across the wall of a pressure vessel of Figure 1 showing from left to right the thermally protective outer layer 4 (dark grey region on the left), carbon fibre reinforced resin intermediate layer 3 (light grey region in the centre) and liner 1 used to reduce hydrogen permeation through the wall to the regulated level (white region on the right).
• the radiative and convective heat flux from the fire is applied to the outer surface of the thermally protective layer 4.
• the change of temperature profile throughout the wall is shown by solid curves for six different moments of time t1 to t6.
• the horizontal stripe in the liner area indicates the liner melting temperature. The leak is possible when the liner melts throughout its full depth. This happens in Fig. 2 at time t5 (curve t5).
• the vertical dash curve denotes the necessary load-bearing wall thickness that is increasing in time due to internal pressure growth as a result of heat transfer from a fire to a gas through the walls. If this curve intersect the polymer degradation temperature range (the horizontal stripe) before the liner melts the vessel would rupture.
• the vessel failure criterion is the equality of the location of the polymer decomposition wave (moving from left to the right in Fig. 3) to the load-bearing wall thickness, which is equal to the wall thickness multiplied by the ratio of transient pressure to the established burst pressure and is increasing in time in the absence of TPRD (dash curve).
• the vertical dash line marked “With TPRD” shows a decrease of load-bearing wall thickness due to pressure drop in the case of a gas release through TPRD, if it operates at time t2.
• the change of dash line direction at time t5 is due to the melt of the liner (indicated by dash circle) and start of a leak through the vessel wall. Indeed, the wall thickness needed to bear the internal pressure decreases with the decrease of pressure.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)

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• 2017
  • 2017-02-14 GB GBGB1702362.3A patent/GB201702362D0/en not_active Ceased
• 2018
  • 2018-02-12 WO PCT/EP2018/053384 patent/WO2018149772A1/en unknown
  • 2018-02-12 EP EP18706224.5A patent/EP3583346A1/de active Pending

Non-Patent Citations (3)

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