Hydrogen Vessels Research Articles

高圧水素ガス圧力容器用ゴム製シール材の損傷解析

高圧水素ガス圧力容器用ゴム製シール材の損傷解析

Numerical simulation on the diffusion of hydrogen due to high pressured storage tanks failure

With widely utilizing of hydrogen energy, the high pressured hydrogen vessels are rapidly developed. At the same time, inevitable accidents from leakage of the vessel may occur. Thus, understanding and predicting the diffusion of high pressured hydrogen are crucial for safe operation of such devices. In this study, an analytical model for the diffusion of high pressured hydrogen due to storage tank failure was established and corresponding numerical method was presented. Several important factors which affect the diffusion of hydrogen such as the wind velocities, ambient temperature, leaking positions, diameters of the leaking hole and obstacles were taken into account. And their influences on the diffusion of hydrogen were discussed. The simulated results are in good agreement with available experimental data, which indicates that the presented model can be applied for predicting the diffusion of high pressured hydrogen due to storage tanks failure.

Technical Basis and Application of New Rules on Fracture Control of High Pressure Hydrogen Vessel in ASME Section VIII, Division 3 Code

As a part of an ongoing activity to develop ASME Code rules for the hydrogen infrastructure, the ASME Boiler and Pressure Vessel Code Committee approved new fracture control rules for Sec. VIII, Division 3 vessels in 2006. These rules have been incorporated into new Article KD-10 in Division 3. The new rules require determining fatigue-crack-growth rate and fracture resistance properties of materials in high pressure hydrogen gas. Test methods have been specified to measure these fracture properties, which are required to be used in establishing the vessel fatigue life. An example has been given to demonstrate the application of these new rules.

Thermal design study of a liquid hydrogen-cooled cold-neutron source

The use of both liquid hydrogen as a moderator and polycrystalline beryllium as a filter to enhance cold neutron flux at the UC Davis McClellan Nuclear Radiation Center has been studied. Although, more work is needed before an actual cold neutron source can be designed and built, the purpose of this preliminary study is to investigate the effects of liquid hydrogen and the thickness of a beryllium filter on the cold neutron flux generated. Liquid hydrogen is kept at 20 K, while the temperature of beryllium is assumed to be 77 K in this study. Results from Monte Carlo simulations show that adding a liquid hydrogen vessel around the beam tube can increase cold neutron flux by more than an order of magnitude. As the thickness of the liquid hydrogen layer increases up to about half an inch, the flux of cold neutrons also increases. Increasing the layer thickness to more than half an inch gives no significant enhancement of cold neutron flux. Although, the simulations show that the cold neutron flux is almost independent of the thickness of beryllium at 77 K, the fraction of cold neutrons does drop along the beam tube. This may be due to the fact that the beam tube is not shielded for neutrons coming directly from the reactor core. Further design studies are necessary for to achieve complete filtering of undesired neutrons. A simple comparison analysis based on heat transfer due to neutron scattering and gamma-ray heating shows that the beryllium filter has a larger rate of change of temperature and its temperature is higher. As a result heat will be transferred from beryllium to liquid hydrogen, so that keeping liquid hydrogen at the desired temperature will be the most important step in the cooling process.

Vehicular storage of hydrogen in insulated pressure vessels

This paper describes an alternative technology for storing hydrogen fuel onboard vehicles. Insulated pressure vessels are cryogenic capable vessels that can accept cryogenic liquid hydrogen, cryogenic compressed gas or compressed hydrogen gas at ambient temperature. Insulated pressure vessels offer advantages over conventional storage approaches. Insulated pressure vessels are more compact and require less carbon fiber than compressed hydrogen vessels. They have lower evaporative losses than liquid hydrogen tanks, and are lighter than metal hydrides. The paper outlines the advantages of insulated pressure vessels and describes the experimental and analytical work conducted to verify that insulated pressure vessels can be safely used for vehicular hydrogen storage. Insulated pressure vessels have successfully completed a series of certification tests. A series of tests have been selected as a starting point toward developing a certification procedure. An insulated pressure vessel has been installed in a hydrogen fueled truck and tested over a six month period.

Optimal design of a Type 3 hydrogen vessel: Part I—Analytic modelling of the cylindrical section

The present paper aims to study the cylindrical section of a Type 3 high-pressure hydrogen storage vessel, combining an aluminium liner which prevents gas diffusion and an overwrapped composite devoted to reinforce the structure. Today, this technique is widely used but still requires consistent time investments whenever a competitive solution, involving to definitely increase weight efficiency, is needed. The laminate composite is assumed to be an elasto-damage material whereas the liner behaves as an elasto-plastic material. Based on the classical laminate theory and on Hill's criterion to take into account the anisotropic plastic flow of the liner, the model provides an exact solution for stresses and strains on the cylindrical section of the vessel under thermomechanical static loading. Part I focuses on the theoretical background. The effect of the stacking sequence on the gap occurrence, on the residual stress magnitude and on the structure stiffness may then be investigated. This will be done and be compared with results of experiments which are carried out on prototypes in the second part of this paper before an optimization is performed.

液体水素輸送・貯蔵用極低温材料の開発

The major activities of the Cryogenic Materials Working Group (Task 10) in the WE-NET Program are introduced, placing an emphasis on the mechanical properties of the structural materials to be used for liquid hydrogen vessels. Mechanical tests were conducted mainly using newly designed and installed liquid hydrogen facilities. In stainless steels, the fracture toughness of the weld at cryogenic temperatures is greatly increased by employing high-energy-density welding such as laser or electron-beam welding. In aluminum alloys, the properties of the welds at low temperatures are drastically improved by applying friction-stir welding. In addition, some properties of titanium and its alloy, which are considered as candidate materials for liquid hydrogen pumps, were also examined. Other activities related to the materials for liquid hydrogen vessels, including mechanical tests in gaseous hydrogen, assessment of local fracture toughness in welds and formulation of the database, are also briefly introduced.

A large experimental apparatus for measuring thermal conductance of LH2 storage tank insulations

In the Japanese hydrogen project, WE-NET (World Energy Net Work), the conceptual design of the large mass liquid hydrogen storage systems for ground tanks and transportation, whose scales would reach to that of commercialized LNG (liquid national gas), has been studied. This study has concluded that the thermal insulation for a mass storage tank, providing the excellent thermal performance with the optimized strength, should be developed. In order to evaluate thermal conductance of various devised insulations, we have manufactured a large-scale experimental apparatus. This apparatus, which adopts a double guarded flat plate boil-off calorimeter method, can provide the thermal data needed for designing a full-scale tank. It would be possible to test various kinds of specimens with allowable dimensions: diameter 120 cm, thickness up to 30 cm. In the case of a rigid specimen contacting bottom surfaces of liquid hydrogen vessels, the good flatness of their bottom plates is desirable to reduce the thermal resistance between vessels and a specimen surface. This paper describes the abstract of the developed apparatus, its structural design and also the experimental results for verifying its structural design.

Thermal design analysis of a liquid hydrogen vessel

Thermal analysis has been performed to design a high-performance liquid hydrogen (LH 2) vessel. Analysis includes the combined insulation of multi-layer insulation (MLI) and vapor-cooled radiation shield (VCS) under high vacuum. Three types of combined insulation schemes are considered in this study; fully-filled MLI and serial-type double vapor-cooled radiation shield (DVCS); fully-filled MLI and parallel-type DVCS; partially-filled MLI and single vapor-cooled radiation shield (SVCS). Thermal analysis for a vapor-cooled heat station to reduce solid conduction heat in-leak through a filling tube is also made. The results indicate that the serial-type DVCS vessel shows better performance than parallel-type DVCS vessel. The combined insulation of SVCS and partially-filled MLI shows a similar performance compared to that of DVCS and fully-filled MLI. The vapor-cooled heat stations can enhance substantially the performance of the vessel for cryogenic fluids with high C p/ h fg, where C p the specific heat and h fg the latent heat of vaporization, such as LH 2 and liquid helium (LHe).

Technical design by the ‘method of inequalities’ applied to hydrogen

The development of effective artefacts in support of hydrogen is largely concerned with weight, thermal insulation and economics. Contradictions arise, e.g. low evaporation loss of liquid hydrogen may require expensive insulation, which means high cost. The good designer knows how to compromise on such factors, and the Method of Inequalities puts such compromise on a mathematical basis. An example is given relating to a liquid hydrogen vessel, and the Paper goes on to consider application of the Method to hydrogen production. If this production is in discrete ‘Packets’, clearcut equations can be developed to relate production and effort, and the Method can then be applied to guide research for maximum production per unit of effort.