Japan
Effect of High-pressure H2 Gas on Tensile and Fatigue Properties of Stainless Steel SUS316L by Means of the Internal High-pressure H2 Gas Method
Dec 2019
Publication
For prohibiting a global warming fuel-cell systems without carbon dioxide emissions are a one of the promising technique. In case of a fuel-cell vehicle (FCV) high-pressure H2 gas is indispensable for a long running range. Although there are lot of paper for studying a hydrogen embrittlement (HE) there are few paper referred to the effect of high-pressure H2on the HE phenomenon.
In this study an effect of high-pressure H2 gas on tensile & fatigue properties of stainless steel SUS316L were investigated by means of the internal high-pressure H2 gas technique. Main findings of this study are as follows;
In this study an effect of high-pressure H2 gas on tensile & fatigue properties of stainless steel SUS316L were investigated by means of the internal high-pressure H2 gas technique. Main findings of this study are as follows;
- Although there are almost no hydrogen embrittlement effect on the 0.2 % proof stress and tensile strength elongation and reduction of area decrease in H2 gas environment
- For case of low Nieq material fatigue life and fatigue limit decrease in H2 gas environment
- For case of low Nieq material not a few α’ martensitic phase generated on the fatigue fractured specimen.
Magnesium Based Materials for Hydrogen Based Energy Storage: Past, Present and Future
Jan 2019
Publication
Volodymyr A. Yartys,
Mykhaylo V. Lototskyy,
Etsuo Akiba,
Rene Albert,
V. E. Antonov,
Jose-Ramón Ares,
Marcello Baricco,
Natacha Bourgeois,
Craig Buckley,
José Bellosta von Colbe,
Jean-Claude Crivello,
Fermin Cuevas,
Roman V. Denys,
Martin Dornheim,
Michael Felderhoff,
David M. Grant,
Bjørn Christian Hauback,
Terry D. Humphries,
Isaac Jacob,
Petra E. de Jongh,
Jean-Marc Joubert,
Mikhail A. Kuzovnikov,
Michel Latroche,
Mark Paskevicius,
Luca Pasquini,
L. Popilevsky,
Vladimir M. Skripnyuk,
Eugene I. Rabkin,
M. Veronica Sofianos,
Alastair D. Stuart,
Gavin Walker,
Hui Wang,
Colin Webb,
Min Zhu and
Torben R. Jensen
Magnesium hydride owns the largest share of publications on solid materials for hydrogen storage. The “Magnesium group” of international experts contributing to IEA Task 32 “Hydrogen Based Energy Storage” recently published two review papers presenting the activities of the group focused on magnesium hydride based materials and on Mg based compounds for hydrogen and energy storage. This review article not only overviews the latest activities on both fundamental aspects of Mg-based hydrides and their applications but also presents a historic overview on the topic and outlines projected future developments. Particular attention is paid to the theoretical and experimental studies of Mg-H system at extreme pressures kinetics and thermodynamics of the systems based on MgH2 nanostructuring new Mg-based compounds and novel composites and catalysis in the Mg based H storage systems. Finally thermal energy storage and upscaled H storage systems accommodating MgH2 are presented.
Model of Local Hydrogen Permeability in Stainless Steel with Two Coexisting Structures
Apr 2021
Publication
The dynamics of hydrogen in metals with mixed grain structure is not well understood at a microscopic scale. One of the biggest issues facing the hydrogen economy is “hydrogen embrittlement” of metal induced by hydrogen entering and diffusing into the material. Hydrogen diffusion in metallic materials is difficult to grasp owing to the non-uniform compositions and structures of metal. Here a time-resolved “operando hydrogen microscope” was used to interpret local diffusion behaviour of hydrogen in the microstructure of a stainless steel with austenite and martensite structures. The martensite/austenite ratios differed in each local region of the sample. The path of hydrogen permeation was inferred from the time evolution of hydrogen permeation in several regions. We proposed a model of hydrogen diffusion in a dual-structure material and verified the validity of the model by simulations that took into account the transfer of hydrogen at the interfaces.
Assessing Uncertainties of Well-To-Tank Greenhouse Gas Emissions from Hydrogen Supply Chains
Jun 2017
Publication
Hydrogen is a promising energy carrier in the clean energy systems currently being developed. However its effectiveness in mitigating greenhouse gas (GHG) emissions requires conducting a lifecycle analysis of the process by which hydrogen is produced and supplied. This study focuses on the hydrogen for the transport sector in particular renewable hydrogen that is produced from wind- or solar PV-powered electrolysis. A life cycle inventory analysis is conducted to evaluate the Well-to-Tank (WtT) GHG emissions from various renewable hydrogen supply chains. The stages of the supply chains include hydrogen being produced overseas converted into a transportable hydrogen carrier (liquid hydrogen or methylcyclohexane) imported to Japan by sea distributed to hydrogen filling stations restored from the hydrogen carrier to hydrogen and filled into fuel cell vehicles. For comparison an analysis is also carried out with hydrogen produced by steam reforming of natural gas. Foreground data related to the hydrogen supply chains are collected by literature surveys and the Japanese life cycle inventory database is used as the background data. The analysis results indicate that some of renewable hydrogen supply chains using liquid hydrogen exhibited significantly lower WtT GHG emissions than those of a supply chain of hydrogen produced by reforming of natural gas. A significant piece of the work is to consider the impacts of variations in the energy and material inputs by performing a probabilistic uncertainty analysis. This suggests that the production of renewable hydrogen its liquefaction the dehydrogenation of methylcyclohexane and the compression of hydrogen at the filling station are the GHG-intensive stages in the target supply chains.
Development of Technical Regulations for Fuel Cell Motorcycles in Japan—Hydrogen Safety
Jul 2019
Publication
Hydrogen fuel cell vehicles are expected to play an important role in the future and thus have improved significantly over the past years. Hydrogen fuel cell motorcycles with a small container for compressed hydrogen gas have been developed in Japan along with related regulations. As a result national regulations have been established in Japan after discussions with Japanese motorcycle companies stakeholders and experts. The concept of Japanese regulations was proposed internationally and a new international regulation on hydrogen-fueled motorcycles incorporating compressed hydrogen storage systems based on this concept are also established as United Nations Regulation No. 146. In this paper several technical regulations on hydrogen safety specific to fuel cell motorcycles incorporating compressed hydrogen storage systems are summarized. The unique characteristics of these motorcycles e.g. small body light weight and tendency to overturn easily are considered in these regulations.
Influence of hydraulic sequential tests on the burst strength of Type-4 compressed hydrogen containers
Sep 2019
Publication
One of the topics for the revision deliberation of GTR13 on hydrogen and fuel cell vehicles is the study of an appropriate initial burst pressure of the containers. The purpose of this study is to investigate the influence of the hydraulic sequential tests on the residual burst pressure in order to examine the appropriate initial burst pressure correlated with the provisions for the residual burst pressure at the Endof-Life (EOL). Specifically we evaluated any deterioration and variations of burst pressure due to hydraulic sequential tests on 70MPa compressed-hydrogen containers. When the burst pressure after the hydraulic sequential testing (EOL) was compared with the initial burst pressure at the beginning of life (BOL) the pressure proved to have decreased by a few percent while the variation increased. In the burst test it was observed that the rupture originated in the cylindrical part in all the BOL containers while in some of the EOL containers the rupture originated in the dome part. Since the dome part is a section that suffers an impact of vertical drop test it is conceivable that some sort of damage occurred in the CFRP. Therefore it was assumed that this damage was the main causal factor for the decrease in the burst pressure and the increase of the burst pressure variation at the dome part.
Catalytic Hydrogen Production, Storage and Application
Jul 2021
Publication
Hydrogen is a clean fuel for transportation and energy storage. It has several attractive features including a higher energy content by weight use in fuel cells that produces only water as a by-product storage in small and large quantities by various methods and established transportation and infrastructures. A hydrogen economy consists of three steps i.e. hydrogen production storage and applications. All three steps involved in a hydrogen economy can be divided into catalytic and non-catalytic approaches. For catalytic processes the efficiency highly depends on the type and physico-chemical characteristics of the catalysts. Therefore for the improvement of these catalytic processes the development of highly efficient and stable catalysts is highly required.
Strain Rate Sensitivity of Microstructural Damage Evolution in a Dual-Phase Steel Pre-Charged with Hydrogen
Dec 2018
Publication
We evaluated the strain rate sensitivity of the micro-damage evolution behavior in a ferrite/martensite dual-phase steel. The micro-damage evolution behavior can be divided into three regimes: damage incubation damage arrest and damage growth. All regimes are associated with local deformability. Thus the total elongation of DP steels is determined by a combination of plastic damage initiation resistance and damage growth arrestability. This fact implies that hydrogen must have a critical effect on the damage evolution because hydrogen enhances strain localization and lowers crack resistance. In this context the strain rate must be an important factor because it affects the time for microstructural hydrogen diffusion/segregation at a specific microstructural location or at the damage tip. In this study tensile tests were carried out on a DP steel with different strain rates of 10− 2 and 10− 4 s−1. We performed the damage quantification microstructure characterization and fractography. Specifically the quantitative data of the damage evolution was analyzed using the classification of the damage evolution regimes in order to separately elucidate the effects of the hydrogen on damage initiation resistance and damage arrestability. In this study we obtained the following conclusions with respect to the strain rate. Lowering the strain rate increased the damage nucleation rate at martensite and reduced the critical strain for fracture through shortening the damage arrest regime. However the failure occurred via ductile modes regardless of strain rate.
Hydrogen: A Reviewable Energy Perspective
Sep 2019
Publication
Hydrogen has emerged as an important part of the clean energy mix needed to ensure a sustainable future. Falling costs for hydrogen produced with renewable energy combined with the urgency of cutting greenhouse-gas emissions has given clean hydrogen unprecedented political and business momentum.
This paper from the International Renewable Energy Agency (IRENA) examines the potential of hydrogen fuel for hard-to-decarbonise energy uses including energy-intensive industries trucks aviation shipping and heating applications. But the decarbonisation impact depends on how hydrogen is produced. Current and future sourcing options can be divided into grey (fossil fuel-based) blue (fossil fuel-based production with carbon capture utilisation and storage) and green (renewables-based) hydrogen. Green hydrogen produced through renewable-powered electrolysis is projected to grow rapidly in the coming years.
Among other findings:
Important synergies exist between hydrogen and renewable energy. Hydrogen can boost renewable electricity market growth and broaden the reach of renewable solutions.
Trade of energy-intensive commodities produced with hydrogen including “e-fuels” could spur faster uptake or renewables and bring wider economic benefits.
This paper from the International Renewable Energy Agency (IRENA) examines the potential of hydrogen fuel for hard-to-decarbonise energy uses including energy-intensive industries trucks aviation shipping and heating applications. But the decarbonisation impact depends on how hydrogen is produced. Current and future sourcing options can be divided into grey (fossil fuel-based) blue (fossil fuel-based production with carbon capture utilisation and storage) and green (renewables-based) hydrogen. Green hydrogen produced through renewable-powered electrolysis is projected to grow rapidly in the coming years.
Among other findings:
Important synergies exist between hydrogen and renewable energy. Hydrogen can boost renewable electricity market growth and broaden the reach of renewable solutions.
- Electrolysers can add demand-side flexibility. In advanced European energy markets electrolysers are growing from megawatt to gigawatt scale.
- Blue hydrogen is not inherently carbon free. This type of production requires carbon-dioxide (CO2) monitoring verification and certification.
- Synergies may exist between green and blue hydrogen deployment given the chance for economies of scale in hydrogen use or logistics.
- A hydrogen-based energy transition will not happen overnight. Hydrogen use is likely to catch on for specific target applications. The need for new supply infrastructure could limit hydrogen use to countries adopting this strategy.
- Dedicated hydrogen pipelines have existed for decades and could be refurbished along with existing gas pipelines. The implications of replacing gas abruptly or changing mixtures gradually should be further explored.
Trade of energy-intensive commodities produced with hydrogen including “e-fuels” could spur faster uptake or renewables and bring wider economic benefits.
Influence of Hydrogen for Crack Formation during Mechanical Clinching
Jan 2018
Publication
Hydrogen intrudes into the steel during pickling process which is a pre-processing before a joining process promoting crack formation. In a mechanical clinching which is one of joining method in the automotive industry cracks due to large strain sometimes forms. In order to guarantee reliability it is important to clarify the influence of hydrogen on crack formation of the joint. In this study we clarified the influence of hydrogen for the crack formation on the mechanical clinching. Hydrogen charge was carried out using an electrolytic cathode charge. After the charging mechanical clinching was performed. Mechanical clinching was carried out with steel plate and aluminium alloy plate. To clarify the influence of hydrogen mechanical clinching was conducted without hydrogen charring. To investigate the crack formation the test piece was cut and the cut surface was observed. When the joint was broken during the clinching the fracture surface was observed using an optical microscope and an electron microscope. The load-displacement diagram showed that without hydrogen charging the compressive load increased as the displacement increased. On the other hand the compressive load temporarily decreased with high hydrogen charging suggesting that cracks formed at the time. The cut surface observation showed that interlock was formed in both cases with low hydrogen charging and without hydrogen charging. With low hydrogen charging no cracks were formed in the joint. When high hydrogen charging was performed cracks were formed at the joining point. Fracture analysis showed brittle-like fracture surface. These results indicate that hydrogen induces crack formation in the mechanical clinching.
3D Real Time Monitoring of H2 in FCV Applications
Sep 2019
Publication
In order to monitor a trace amount of Hydrogen in millisecond portable H2 sensor (Sx) was made by using mass spectrometer. The method of monitoring the hydrogen pulse of millisecond in exhaust gas is the increasing needed. Determining H2 concentration both inside and outside of the Fuel Cell Vehicle (FCV) for the optimized operations is becoming a critical issue. The exhaust gas of Fuel Cell Vehicle H2 consumption flushing and disposal around Fuel cell the real time monitoring of H2 in highly humid conditions is the problematic. To solve this issue the system volume of the sampling route was minimized with the heater and the dehumidifier to avoid condensation of water droplets. And also for an automatic calibration of H2 concentration the small cylinder of specific H2 concentration was mounted into the system.<br/>Our basic experiment started from a flow pattern analysis by monitoring H2 concentration in narrow tube. The flow patter analysis was carried out. When H2 gas was introduced in the N2 flow or air in the tube the highly concentrated H2 front phases were observed. This H2 sensor can provide the real time information of the hydrogen molecules and the clouds. The basic characterization of this sensor showed 0-100% H2 concentrations within milliseconds. Our observations showed the size of the high concentration phase of H2 and the low concentration phase after mixing process. The mixed and unmixed H2 unintended concentration of H2 cloud the high speed small cluster of H2 molecules in purged gas were explored by this system.
Exploring the Capability of Mayenite (12CaO·7Al2O3) as Hydrogen Storage Material
Mar 2021
Publication
We utilized nanoporous mayenite (12CaO·7Al2O3) a cost-effective material in the hydride state (H−) to explore the possibility of its use for hydrogen storage and transportation. Hydrogen desorption occurs by a simple reaction of mayenite with water and the nanocage structure transforms into a calcium aluminate hydrate. This reaction enables easy desorption of H− ions trapped in the structure which could allow the use of this material in future portable applications. Additionally this material is 100% recyclable because the cage structure can be recovered by heat treatment after hydrogen desorption. The presence of hydrogen molecules as H− ions was confirmed by 1H-NMR gas chromatography and neutron diffraction analyses. We confirmed the hydrogen state stability inside the mayenite cage by the first-principles calculations to understand the adsorption mechanism and storage capacity and to provide a key for the use of mayenite as a portable hydrogen storage material. Further we succeeded in introducing H− directly from OH− by a simple process compared with previous studies that used long treatment durations and required careful control of humidity and oxygen gas to form O2 species before the introduction of H−.
A Review for Consistent Analysis of Hydrogen Permeability through Dense Metallic Membranes
Jun 2020
Publication
The hydrogen permeation coefficient (ϕ) is generally used as a measure to show hydrogen permeation ability through dense metallic membranes which is the product of the Fick’s diffusion coefficient (D) and the Sieverts’ solubility constant (K). However the hydrogen permeability of metal membranes cannot be analyzed consistently with this conventional description. In this paper various methods for consistent analysis of hydrogen permeability are reviewed. The derivations of the descriptions are explained in detail and four applications of the consistent descriptions of hydrogen permeability are introduced: (1) prediction of hydrogen flux under given conditions (2) comparability of hydrogen permeability (3) understanding of the anomalous temperature dependence of hydrogen permeability of Pd-Ag alloy membrane and (4) design of alloy composition of non-Pd-based alloy membranes to satisfy both high hydrogen permeability together with strong resistance to hydrogen embrittlement.
A New Design Concept for Prevention of Hydrogen-induced Mechanical Degradation: Viewpoints of Metastability and High Entropy
Dec 2018
Publication
‟How crack growth is prevented” is key to improve both fatigue and monotonic fracture resistances under an influence of hydrogen. Specifically the key points for the crack growth resistance are hydrogen diffusivity and local ductility. For instance type 304 austenitic steels show high hydrogen embrittlement susceptibility because of the high hydrogen diffusivity of bcc (α´) martensite. In contrast metastability in specific austenitic steels enables fcc (γ) to hcp (ε) martensitic transformation which decreases hydrogen diffusivity and increases strength simultaneously. As a result even if hydrogen-assisted cracking occurs during monotonic tensile deformation the ε-martensite acts to arrest micro-damage evolution when the amount of ε-martensite is limited. Thus the formation of ε-martensite can decrease hydrogen embrittlement susceptibility in austenitic steels. However a considerable amount of ε-martensite is required when we attempt to have drastic improvements of work hardening capability and strength level with respect to transformation-induced plasticity effect. Since the hcp structure contains a less number of slip systems than fcc and bcc the less stress accommodation capacity often causes brittle-like failure when the ε-martensite fraction is large. Therefore ductility of ε-martensite is another key when we maximize the positive effect of ε-martensitic transformation. In fact ε-martensite in a high entropy alloy was recently found to be extraordinary ductile. Consequently the metastable high entropy alloys showed low fatigue crack growth rates in a hydrogen atmosphere compared with conventional metastable austenitic steels with α´-martensitic transformation. We here present effects of metastability to ε-phase and configurational entropy on hydrogen-induced mechanical degradation including monotonic tension properties and fatigue crack growth resistance.
Role of Hydrogen-Charging on Nucleation and Growth of Ductile Damage in Austenitic Stainless Steels
May 2019
Publication
Hydrogen energy is a possible solution for storage in the future. The resistance of packaging materials such as stainless steels has to be guaranteed for a possible use of these materials as containers for highly pressurized hydrogen. The effect of hydrogen charging on the nucleation and growth of microdamage in two different austenitic stainless steels AISI316 and AISI316L was studied using in situ tensile tests in synchrotron X-ray tomography. Information about damage nucleation void growth and void shape were obtained. AISI316 was found to be more sensitive to hydrogen compared to AISI316L in terms of ductility loss. It was measured that void nucleation and growth are not affected by hydrogen charging. The effect of hydrogen was however found to change the morphology of nucleated voids from spherical cavities to micro-cracks being oriented perpendicular to the tensile axis.
Cost Optimization of a Stand-Alone Hybrid Energy System with Fuel Cell and PV
Mar 2020
Publication
Renewable energy has become very popular in recent years. The amount of renewable generation has increased in both grid-connected and stand-alone systems. This is because it can provide clean energy in a cost-effective and environmentally friendly fashion. Among all varieties photovoltaic (PV) is the ultimate rising star. Integration of other technologies with solar is enhancing the efficiency and reliability of the system. In this paper a fuel cell–solar photovoltaic (FC-PV)-based hybrid energy system has been proposed to meet the electrical load demand of a small community center in India. The system is developed with PV panels fuel cell an electrolyzer and hydrogen storage tank. Detailed mathematical modeling of this system as well as its operation algorithm have been presented. Furthermore cost optimization has been performed to determine ratings of PV and Hydrogen system components. The objective is to minimize the levelized cost of electricity (LCOE) of this standalone system. This optimization is performed in HOMER software as well as another tool using an artificial bee colony (ABC). The results obtained by both methods have been compared in terms of cost effectiveness. It is evident from the results that for a 68 MWh/yr of electricity demand is met by the 129 kW Solar PV 15 kW Fuel cell along with a 34 kW electrolyzer and a 20 kg hydrogen tank with a LPSP of 0.053%. The LCOE is found to be in 0.228 $/kWh. Results also show that use of more sophisticated algorithms such as ABC yields more optimized solutions than package programs such as HOMER. Finally operational details for FC-PV hybrid system using IEC 61850 inter-operable communication is presented. IEC 61850 information models for FC electrolyzer hydrogen tank were developed and relevent IEC 61850 message exchanges for energy management in FC-PV hybrid system are demonstrated.
The Spread of Fire from Adjoining Vehicles to a Hydrogen Fuel Cell Vehicle
Sep 2011
Publication
Two vehicle fire tests were conducted to investigate the spread of fire to adjacent vehicles from a hydrogen fuel cell vehicle (HFCV) equipped with a thermal pressure relief device (TPRD) : – 1) an HFCV fire test involving an adjacent gasoline vehicle 2) a fire test involving three adjoining HFCV assuming their transportation in a carrier ship. The test results indicated that the adjacent vehicles were ignited by flames from the interior and exterior materials of the fire origin HFCV but not by the hydrogen flames generated through the activation of TPRD.
Effect of Gasoline Pool Fire on Liquid Hydrogen Storage Tank in Hybrid Hydrogen-gasoline Fueling Station
Nov 2015
Publication
Multiple-energy-fuelling stations which can supply several types of energy such as gasoline CNG and hydrogen could guarantee the efficient use of space. To guide the safety management of hybrid hydrogen–gasoline fuelling stations which utilize liquid hydrogen as an energy carrier the scale of gasoline pool fires was estimated using the hazard assessment tool Toxic Release Analysis of Chemical Emissions (TRACE). Subsequently the temperature and the stress due to temperature distribution were estimated using ANSYS. Based on the results the safety of liquid hydrogen storage tanks was discussed. It was inferred that the emissivity of the outer material of the tank and the safety distance between liquid hydrogen storage tanks and gasoline dispensers should be less than 0.2 and more than 8.5 m respectively to protect the liquid hydrogen storage tank from the gasoline pool fire. To reduce the safety distance several measures are required e.g. additional thermal shields such as protective intumescent paint and water sprinkler systems and an increased slope to lead gasoline off to a safe domain away from the liquid hydrogen storage tank
Techno-economic Analysis on Renewable Energy Via Hydrogen, Views from Macro and Micro Scopes
Mar 2019
Publication
This paper addresses from both macro- and micro- areal coverage in introducing hydrogen system in terms of cost and performance where the produced hydrogen from surplus photovoltaic (PV) power is stored. Feed-in tariff in Japan had successful achievement for great expansion of renewable energy systems (RES) causing problematic operation due to excess power by overcapacity of RES. One of the candidate approaches to overcome this surplus energy by RES is Power to gas (P2G) system using electrolysis cells (ECs) fuel cells (FCs) or co-firing in gas turbines both for energy conversion as well as power balancing. Numerous studies had been investigated on P2G however within our knowledge no study had been addressed the system from both coverages with different capacity and scales. We investigate micro level (zero emission building in our university) and macro level (Kyushu one of big regions in Japan). We describe for macro side preliminary result on economic analysis of using surplus power of RES via production and storage of hydrogen while for micro side research design.
Proposal and Verification of Novel Fatigue Crack Propagation Simulation Method by Finite Element Method.
Dec 2018
Publication
In this paper we propose and verify a novel method to simulate crack propagation without propagating a crack by finite element method. We propose this method for elastoplastic analysis coupled with convection-diffusion. In the previous study we succeeded in performing elastoplastic analysis coupled with convection-diffusion of hydrogen for a material with a crack under tensile loading. This research extends the successful method to fatigue crack propagation. In convection-diffusion analysis in order to simulate the invasion and release of elements through the free surface the crack tip is expressed by using a notch with a sufficiently small radius. Therefore the node release method conventionally used to simulate crack propagation cannot be applied. Hence instead of crack propagation based on an analytical model we propose a novel method that can reproduce the influence of the vicinity of the crack tip on a crack. We moved the stress field near the crack tip in the direction opposite to that of crack propagation by an amount corresponding to the crack propagation length. When we extend the previous method to fatigue crack propagation simulation we must consider the difference in strain due to loading and unloading. This problem was solved by considering the strain due to loading as a displacement. Instead of moving the strain due to loading we moved the displacement. First we performed a simple tensile load analysis on the model and output the displacement of all the nodes of the model at maximum load. Then the displacement was moved in the direction opposite to that of crack propagation. Finally the stress field was reproduced by forcibly moving all the nodes by the displacement amount. The strain due to unloading was reproduced by removing the displacement. Furthermore we verified the equivalence of the crack propagation simulation and the proposed method.
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