Thermal history resulting in the failure of lightweight fully-wrapped composite pressure vessel for hydrogen in a fire experimental facility

We must improve our understanding of the thermal behaviour of composite gas storage in the event of fire in order to reduce the risk of bursting. In this research, results of pool fire tests were used to improve understanding of the failure mechanisms of epoxy carbon fibre composite pressure vessels with a polymeric liner (type IV vessel) designed for a working pressure of 70 MPa. The failure mode in a pool fire test depends on the storage design and on the initial pressure of the storage. For instance, for a 100 L type IV storage without any safety system, initial pressures of 70 MPa down to 52.5 MPa result in pressure vessels bursting, and initial pressures of 35 MPa down to 17.5 MPa lead pressure vessels to loss of liner tightness. The occurrence of one mechanism or the other is due to the predominance of either heat transfer through the wall, leading to a loss of tightness; or of the degradation of the materials, leading to bursting. Thermogravimetric analyses were carried out on the pressure vessel materials to determine the onset of degradation take during pool fire tests. The temperature measurements allowed for proper characterisation of the conditions leading to the loss of liner tightness. Temperature profiles were used to link the position of the composite degradation front to the loss of tensile strength leading to bursting

Sample scale testing method to prevent collapse of plastic liners in composite pressure vessels

International audienceType IV pressure vessels are commonly used for hydrogen on-board, stationary or bulk storages. When pressurised, hydrogen permeates through the materials and solves into them. Emptying then leads to a difference of pressure at the interface between composite and liner, possibly leading to a permanent deformation of the plastic liner called "collapse" or "buckling". This phenomenon has been studied through French funded project Colline, allowing to better understand its initiation and long-term effects. This paper presents the methodology followed, using permeation tests, hydrogen decompression tests on samples, and gas diffusion calculation in order to determine safe operating conditions, such as maximum flow rate or residual pressure level

Fire tests carried out in FCH JU FIRECOMP project, recommendations and application to safety of gas storage systems

In the event of a fire, composite pressure vessels behave very differently from metallic ones: the material is degraded, potentially leading to a burst without significant pressure increase. Hence, such objects are, when necessary, protected from fire by using thermally-activated devices (TPRD), and standards require testing cylinder and TPRD together. The pre-normative research project FireComp aimed at understanding better the conditions which may lead to burst, through testing and simulation, and proposed an alternative way of assessing the fire performance of composite cylinders. This approach is currently used by Air Liquide for the safety of composite bundles carrying large amounts of hydrogen gas