Transmission, Distribution & Storage
Molecular Dynamics Studies of Hydrogen Effect on Intergranular Fracture in α-Iron
Nov 2020
Publication
In the current study the effect of hydrogen atoms on the intergranular failure of α-iron is examined by a molecular dynamics (MD) simulation. The effect of hydrogen embrittlement on the grain boundary (GB) is investigated by diffusing hydrogen atoms into the grain boundaries using a bicrystal body-centered cubic (BCC) model and then deforming the model with a uniaxial tension. The Debye Waller factors are applied to illustrate the volume change of Read More
Effect of Hydrogen on Very High Cycle Fatigue Behavior of a Low-strength Cr-Ni-Mo-V Steel Containing Micro-defects
Dec 2017
Publication
The role of hydrogen in fatigue failure of low strength steels is not as well understood as of high strength steels in very high cycle fatigue regime. In this work axially cyclic tests on a low strength Cr-Ni-Mo-V steel with charged hydrogen were carried out up to the very high cycle fatigue regime under ultrasonic frequency to examine the degradation of fatigue strength and associated failure mechanisms. Results show that the S-N curves show a continuou Read More
Irreproducibility in Hydrogen Storage Material Research
Sep 2016
Publication
The storage of hydrogen in materials has received a significant amount of attention in recent years because this approach is widely thought to be one of the most promising solutions to the problem of storing hydrogen for use as an alternative energy carrier in a safe compact and affordable form. However there have been a number of high profile cases in which erroneous or irreproducible data have been published. Meanwhile the irreproducibility of resea Read More
Influence of Microstructural Anisotropy on the Hydrogen-assisted Fracture of Notched Samples of Progressively Drawn Pearlitic Steel
Dec 2020
Publication
In this study fracture surfaces of notched specimens of pearlitic steels subjected to constant extension rate tests (CERTs) are analyzed in an environment causing hydrogen assisted fracture. In order to obtain general results both different notched geometries (to generate quite distinct stress triaxiality distributions in the vicinity of the notch tip) and diverse loading rates were used. The fracture surfaces were classified in relation to four micromec Read More
Detection, Characterization and Sizing of Hydrogen Induced Cracking in Pressure Vessels Using Phased Array Ultrasonic Data Processing
Jul 2016
Publication
Pressure vessels operating in sour service conditions in refinery environments can be subject to the risk of H₂S cracking resulting from the hydrogen entering into the material. This risk which is related to the specific working conditions and to the quality of the steel used shall be properly managed in order to maintain the highest safety at a cost-effective level.Nowadays the typical management strategy is based on a risk based inspection (RBI) evaluatio Read More
Understanding Composition–property Relationships in Ti–Cr–V–Mo Alloys for Optimisation of Hydrogen Storage in Pressurised Tanks
Jun 2014
Publication
The location of hydrogen within Ti–Cr–V–Mo alloys has been investigated during hydrogen absorption and desorption using in situ neutron powder diffraction and inelastic neutron scattering. Neutron powder diffraction identifies a low hydrogen equilibration pressure body-centred tetragonal phase that undergoes a martensitic phase transition to a face-centred cubic phase at high hydrogen equilibration pressures. The average location of the hydrogen in each Read More
Modelling of Fatigue Crack Initiation in Hydrogen Charged Polycrystalline Nickel
Jun 2019
Publication
Hydrogen Embrittlement (HE) leads to deterioration of the fracto-mechanical properties of metals. In spite of vast literature it is still not clearly understood and demands significant research on this topic. For better understanding of the hydrogen effect on fatigue behaviour of metals present work focuses on developing a computational framework for fatigue crack initiation studies in metals in the presence of hydrogen. The developed framework consis Read More
Effect of Hydrogen on Short Crack Propagation in SA508 Grade 3 Class I Low Alloy Steel Under Cyclic Loading
Aug 2019
Publication
The effect of hydrogen on short crack propagation under cyclic loading in SA508 Grade 3 Class I low alloy steel is investigated. This low alloy steel is used in manufacturing of pressure vessel installed in Indian nuclear power plants. During operation these pressure vessels are subjected to continuous supply of pressurized hot water at 600 K and hence are susceptible to hydrogen embrittlement. In past research has been conducted on the effect of hydro Read More
Structural Model of Power Grid Stabilization in the Green Hydrogen Supply Chain System—Conceptual Assumptions
Jan 2022
Publication
The paper presents the conceptual assumptions of research concerning the design of a theoretical multi-criteria model of a system architecture to stabilize the operation of power distribution networks based on a hydrogen energy buffer taking into account the utility application of hydrogen. The basis of the research process was a systematic literature review using the technique of in-depth analysis of full-text articles and expert consultations. The stru Read More
Improved Overall Hydrogen Storage Properties of a CsH and KH Co-doped Mg(NH2)2/2LiH System by Forming Mixed Amides of Li–K and Cs–Mg
Jun 2017
Publication
A CsH and KH co-doped Mg(NH2)2/2LiH composite was prepared with a composition of Mg(NH2)2/2LiH–(0.08 − x)CsH–xKH and the hydrogen storage characteristics was systematically investigated. The results showed that the presence of KH further improved the reaction thermodynamics and kinetics of hydrogen storage in a CsH-containing Mg(NH2)2/2LiH system. A sample with 0.04 mol CsH and 0.04 mol KH had optimal hydrogen storage perfor Read More
Kinetics of Brittle Fracture in Metals Under the Influence of Hydrogen
Jan 2020
Publication
Some aspects of damage accumulation modelling and brittle fracture processes mechanisms under the combined effect of mechanical loading and hydrogen has been discussed in the article. New mechanism of brittle fracture for metallic materials based on dislocation and phonon structure fingerprints and lattice hydrogen content under the static and dynamic loading at low temperature condition has been proposed. The mechanism based on theoretical re Read More
Vacuum vs Argon Technology for Hydrogen Measurement
Dec 2018
Publication
Within the framework of this paper we review the development of the problem of hydrogen diagnostic for metals. Metal sample enrichment techniques based on hydrogen vacuum extraction method used for a long time. Development of the industrial control technologies has led to the almost complete replacement of vacuum techniques with “atmospheric” ones. As a result systematic errors have occurred. These errors lead to multiple difference Read More
A Review at the Role of Storage in Energy Systems with a Focus on Power to Gas and Long-term Storage
Aug 2017
Publication
A review of more than 60 studies (plus m4ore than 65 studies on P2G) on power and energy models based on simulation and optimization was done. Based on these for power systems with up to 95% renewables the electricity storage size is found to be below 1.5% of the annual demand (in energy terms). While for 100% renewables energy systems (power heat mobility) it can remain below 6% of the annual energy demand. Combination of sectors and div Read More
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 Read More
Dissecting the Exergy Balance of a Hydrogen Liquefier: Analysis of a Scaled-up Claude Hydrogen Liquefier with Mixed Refrigerant Pre-cooling
Oct 2020
Publication
For liquid hydrogen (LH2) to become an energy carrier in energy commodity markets at scales comparable to for instance LNG liquefier capacities must be scaled up several orders of magnitude. While state-of-the-art liquefiers can provide specific power requirements down to 10 kWh/kg a long-term target for scaled-up liquefier trains is 6 kWh/kg. High capacity will shift the cost weighting more towards operational expenditures which motivates for meas Read More
Blue Hydrogen as an Enabler of Green Hydrogen: The Case of Germany
Jun 2020
Publication
In Germany decarbonization of the electricity sector by fostering renewables and now phasing out coal-fired power is on track to reach the 2050 de-carbonisation targets while decarbonising non-electric energy consumption is proving to be more difficult. The present discussion of a national hydrogen strategy has run into strong political opposition against carbon sequestration as a necessary element in the use of decarbonized natural gas (blue Read More
Micro-grid Design and Life-cycle Assessment of a Mountain Hut's Stand-alone Energy System with Hydrogen Used for Seasonal Storage
Dec 2020
Publication
Mountain huts as special stand-alone micro-grid systems are not connected to a power grid and represent a burden on the environment. The micro-grid has to be flexible to cover daily and seasonal fluctuations. Heat and electricity are usually generated with fossil fuels due to the simple on-off operation. By introducing renewable energy sources (RESs) the generation of energy could be more sustainable but the generation and consumption must be b Read More
Hydrogen Storage Performance of the Multi-principal-component CoFeMnTiVZr Alloy in Electrochemical and Gas–solid Reactions
Jun 2020
Publication
The single-phase multi-principal-component CoFeMnTiVZr alloy was obtained by rapid solidification and examined by a combination of electrochemical methods and gas–solid reactions. X-ray diffraction and high-resolution transmission electron microscopy analyses reveal a hexagonal Laves-phase structure (type C14). Cyclic voltammetry and electrochemical impedance spectroscopy investigations in the hydrogen absorption/desorption region give insi Read More
The Effect of Hydrogen on the Nanoindentation Behavior of Heat Treated 718 Alloy
Oct 2020
Publication
In this study the effect of precipitates on the surface mechanical properties in the presence of hydrogen (H) is investigated by in situ electrochemical nanoindentation. The nickel superalloy 718 is subjected to three different heat treatments leading to different sizes of the precipitates: (i) solution annealing (SA) to eliminate all precipitates (ii) the as-received (AR) sample with fine dispersed precipitates and (iii) the over-aged (OA) specimen with coarser Read More
Marked Degradation of Tensile Properties Induced by Plastic Deformation after Interactions between Strain-Induced Martensite Transformation and Hydrogen for Type 316L Stainless Steel
Jul 2020
Publication
Marked degradation of tensile properties induced by plastic deformation after dynamic interactions between strain-induced martensite transformation and hydrogen has been investigated for type 316L stainless steel by hydrogen thermal desorption analysis. Upon modified hydrogen charging reported previously the amount of hydrogen desorbed in the low temperature range increases; the degradation of tensile properties induced by interactions between Read More
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