Transmission, Distribution & Storage
Feasibility of Renewable Hydrogen Based Energy Supply for a District
Sep 2017
Publication
Renewable generation technologies (e.g. photovoltaic panels (PV)) are often installed in buildings and districts with an aim to decrease their carbon emissions and consumption of non-renewable energy. However due to a mismatch between supply and demand at an hourly but also on a seasonal timescale; a large amount of electricity is exported to the grid rather than used to offset local demand. A solution to this is local storage of electricity for subsequent self-consumption. This could additionally provide districts with new business opportunities financial stability flexibility and reliability.<br/>In this paper the feasibility of hydrogen based electricity storage for a district is evaluated. The district energy system (DES) includes PV and hybrid photovoltaic panels (PVT). The proposed storage system consists of production of hydrogen using the renewable electricity generated within the district hydrogen storage and subsequent use in a fuel cell. Combination of battery storage along with hydrogen conversion and storage is also evaluated. A multi-energy optimization approach is used to model the DES. Results of the model are optimal battery capacity electrolyzer capacity hydrogen storage capacity fuel cell capacity and energy flows through the system. The model is also used to compare different system design configurations. The results of this analysis show that both battery capacity and conversion of electricity to hydrogen enable the district to decrease its carbon emissions by approximately 22% when compared to the reference case with no energy storage.
Metal Hydride Hydrogen Compressors
Feb 2014
Publication
Metal hydride (MH) thermal sorption compression is an efficient and reliable method allowing a conversion of energy from heat into a compressed hydrogen gas. The most important component of such a thermal engine – the metal hydride material itself – should possess several material features in order to achieve an efficient performance in the hydrogen compression. Apart from the hydrogen storage characteristics important for every solid H storage material (e.g. gravimetric and volumetric efficiency of H storage hydrogen sorption kinetics and effective thermal conductivity) the thermodynamics of the metal–hydrogen systems is of primary importance resulting in a temperature dependence of the absorption/desorption pressures). Several specific features should be optimised to govern the performance of the MH-compressors including synchronisation of the pressure plateaus for multi-stage compressors reduction of slope of the isotherms and hysteresis increase of cycling stability and life time together with challenges in system design associated with volume expansion of the metal matrix during the hydrogenation.<br/>The present review summarises numerous papers and patent literature dealing with MH hydrogen compression technology. The review considers (a) fundamental aspects of materials development with a focus on structure and phase equilibria in the metal–hydrogen systems suitable for the hydrogen compression; and (b) applied aspects including their consideration from the applied thermodynamic viewpoint system design features and performances of the metal hydride compressors and major applications.
Influence of Hydrogen-Based Storage Systems on Self-Consumption and Self-Sufficiency of Residential Photovoltaic Systems
Aug 2015
Publication
This paper analyzes the behavior of residential solar-powered electrical energy storage systems. For this purpose a simulation model based on MATLAB/Simulink is developed. Investigating both short-time and seasonal hydrogen-based storage systems simulations on the basis of real weather data are processed on a timescale of 15 min for a consideration period of 3 years. A sensitivity analysis is conducted in order to identify the most important system parameters concerning the proportion of consumption and the degree of self-sufficiency. Therefore the influences of storage capacity and of storage efficiencies are discussed. A short-time storage system can increase the proportion of consumption by up to 35 percentage points compared to a self-consumption system without storage. However the seasonal storing system uses almost the entire energy produced by the photovoltaic (PV) system (nearly 100% self-consumption). Thereby the energy drawn from the grid can be reduced and a degree of self-sufficiency of about 90% is achieved. Based on these findings some scenarios to reach self-sufficiency are analyzed. The results show that full self-sufficiency will be possible with a seasonal hydrogen-based storage system if PV area and initial storage level are appropriate.
Effect of Ternary Transition Metal Sulfide FeNi2S4 on Hydrogen Storage Performance of MgH2
Jan 2022
Publication
Hydrogen storage is a key link in hydrogen economy where solid-state hydrogen storage is considered as the most promising approach because it can meet the requirement of high density and safety. Thereinto magnesium-based materials (MgH2) are currently deemed as an attractive candidate due to the potentially high hydrogen storage density (7.6 wt%) however the stable thermodynamics and slow kinetics limit the practical application. In this study we design a ternary transition metal sulfide FeNi2S4 with a hollow balloon structure as a catalyst of MgH2 to address the above issues by constructing a MgH2/Mg2NiH4−MgS/Fe system. Notably the dehydrogenation/hydrogenation of MgH2 has been significantly improved due to the synergistic catalysis of active species of Mg2Ni/Mg2NiH4 MgS and Fe originated from the MgH2-FeNi2S4 composite. The hydrogen absorption capacity of the MgH2-FeNi2S4 composite reaches to 4.02 wt% at 373 K for 1 h a sharp contrast to the milled-MgH2 (0.67 wt%). In terms of dehydrogenation process the initial dehydrogenation temperature of the composite is 80 K lower than that of the milled-MgH2 and the dehydrogenation activation energy decreases by 95.7 kJ mol–1 compared with the milled-MgH2 (161.2 kJ mol–1). This method provides a new strategy for improving the dehydrogenation/hydrogenation performance of the MgH2 material.
Hydrogen Assisted Fracture of 30MnB5 High Strength Steel: A Case Study
Nov 2020
Publication
When steel components fail in service due to the intervention of hydrogen assisted cracking discussion of the root cause arises. The failure is frequently blamed on component design working conditions the manufacturing process or the raw material. This work studies the influence of quench and tempering and hot-dip galvanizing on the hydrogen embrittlement behavior of a high strength steel. Slow strain rate tensile testing has been employed to assess this influence. Two sets of specimens have been tested both in air and immersed in synthetic seawater at three process steps: in the delivery condition of the raw material after heat treatment and after heat treatment plus hot-dip galvanizing. One of the specimen sets has been tested without further manipulation and the other set has been tested after applying a hydrogen effusion treatment. The outcome for this case study is that fracture risk issues only arise due to hydrogen re-embrittlement in wet service.
Localized Plasticity and Associated Cracking in Stable and Metastable High-Entropy Alloys Pre-Charged with Hydrogen
Dec 2018
Publication
We investigated hydrogen embrittlement in Fe20Mn20Ni20Cr20Co and Fe30Mn10Cr10Co (at.%) alloys pre-charged with 100 MPa hydrogen gas by tensile testing at three initial strain rates of 10−4 10−3 and 10−2 s−1 at ambient temperature. The alloys are classified as stable and metastable austenite-based high-entropy alloys (HEAs) respectively. Both HEAs showed the characteristic hydrogen-induced degradation of tensile ductility. Electron backscatter diffraction analysis indicated that the reduction in ductility by hydrogen pre-charging was associated with localized plasticity-assisted intergranular crack initiation. It should be noted as an important finding that hydrogen-assisted cracking of the metastable HEA occurred not through a brittle mechanism but through localized plastic deformation in both the austenite and ε-martensite phases.
Effects of Alloying Elements Addition on Delayed Fracture Properties of Ultra High-Strength TRIP-Aided Martensitic Steels
Dec 2019
Publication
To develop ultra high-strength cold stamping steels for automobile frame parts the effects of alloying elements on hydrogen embrittlement properties of ultra high-strength low alloy transformation induced plasticity (TRIP)-aided steels with a martensite matrix (TM steels) were investigated using the four-point bending test and conventional strain rate tensile test (CSRT). Hydrogen embrittlement properties of the TM steels were improved by the alloying addition. Particularly 1.0 mass% chromium added TM steel indicated excellent hydrogen embrittlement resistance. This effect was attributed to (1) the decrease in the diffusible hydrogen concentration at the uniform and fine prior austenite grain and packet block and lath boundaries; (2) the suppression of hydrogen trapping at martensite matrix/cementite interfaces owing to the suppression of precipitation of cementite at the coarse martensite lath matrix; and (3) the suppression of the hydrogen diffusion to the crack initiation sites owing to the high stability of retained austenite because of the existence of retained austenite in a large amount of the martensite–austenite constituent (M–A) phase in the TM steels containing 1.0 mass% chromium
Hydrogen Transport to Fracture Sites in Metals and Alloys Multiphysics Modelling
Sep 2017
Publication
Generalised continuum model of hydrogen transport to fracture loci is developed for the purposes of analysis of the hydrogenous environment assisted fracture (HEAF). The model combines the notions of the theories of gas flow surface science and diffusion and trapping in stressed solids. Derived flux and balance equations describe the species migration across different states (gas adsorbed specie at the gas-metal interface interstitial solute in metal bulk) and a variety of corresponding sites of energy minimums along the potential relief for hydrogen in a system. The model accounts for the local kinetics of hydrogen interchange between the closest dissimilar neighbour sites and for the nonlocal interaction of hydrogen trapping in definite positions with the species wandering in their farer surroundings. In particular situations certain balance equations of the model may degenerate into equilibrium constraints as well as some terms in the generalised equations may be insignificant. A series of known theories of hydrogen transport in material-environment system can be recovered then as particular limit cases of the generalised model. Presented theory can help clarifying the advantages and limitations of particularised models so that appropriate one may be chosen for the analysis of a particular HEAF case.
Corrosion Cracking of Carbon Steels of Different Structure in the Hydrogen Sulfide Environment Under Static Load
Dec 2018
Publication
Hydrogen sulfide corrosion is one of the main reasons of steels destruction in the oil and gas industry. Damages appear as a result of corrosion and hydrogen embrittlement and corrosion cracking occurs when the load is applied. The influence of the steels structure on its stress corrosion cracking under the loads in hydrogen sulfide environment is insufficiently studied. The aim of the study is to determine the influence of the steels structure on its corrosion hydrogenation and corrosion cracking in the NACE hydrogen sulfide solution.<br/>It was established that the corrosion rate and hydrogenation of steel У8 in the NACE solution grows when the structure dispersion increases from perlite to sorbite troostite and martensite. The corrosion rate and hydrogenation of steel 45 are the greatest in pearlite-ferrite while the smallest - in sorbite.<br/>The corrosion of steels У8 and 45 in the NACE solution is localized: the average size of the ulcers is 50 ... 80 μm on the steel У8 and 45 ... 65 μm on steel 45. The depth of ulcers is maximal on the steel У8 with the martensite structure (~ 260 μm) and on the steel 45 with the troostite structure (~ 210 μm).<br/>Static load (σ = 300 MPa) increases the hydrogenation of steels in the hydrogen sulfide environment. The concentration of hydrogen in steel У8 with troostite structure increases by ~ 1.8 times. The concentration of hydrogen in steel 45 with troostite and martensite structures increases by ~ 1.2...1.3 and by ~ 1.4...1.6 times respectively.<br/>The steel У8 with martensite and perlite structures and steel 45 with troostite structure has the lowest resistance to corrosion cracking. Steels destruction depends on both hydrogen permeation and the corrosion localization which leads to the increase of the microelectrochemical heterogeneity of the surfaces.
Parametric Studies on LaNi4.7Al0.3 Based Hydrogen Storage Reactor with Embedded Cooling Tubes
Mar 2019
Publication
This study reports the investigative conclusions of parametric studies conducted to understand the effect of operating parameters on absorption and desorption characteristics of LaNi4.7Al0.3 metal hydride system for thermal management applications. Reactor with improved design containing 55 embedded cooling tubes is fabricated and filled with 4 kg of metal hydride alloy. Using water as heat transfer fluid (HTF) effects of supply pressure HTF temperature and HTF flow rate on absorption and desorption characteristics of the reactor are analyzed. Increasing supply pressure leads to prominent improvement in absorption capacity while the increase in HTF temperature enhanced desorption performance. At 20 bar and 20 °C 46.2877 g of hydrogen (1.16 wt%) was absorbed resulting in total energy output of 707.3 kJ for 300 s. During desorption at 80 °C with water flow rate of 8 lpm heat input of 608.1 kJ for 300 s resulted in 28.5259 g of hydrogen desorption.
Beyond Haber-Bosch: The Renaissance of the Claude Process
Apr 2021
Publication
Ammonia may be one of the energy carriers in the hydrogen economy. Although research has mostly focused on electrochemical ammonia synthesis this however remains a scientific challenge. In the current article we discuss the feasibility of single-pass thermochemical ammonia synthesis as an alternative to the high-temperature high-pressure Haber-Bosch synthesis loop. We provide an overview of recently developed low temperature ammonia synthesis catalysts as well as an overview of solid ammonia sorbents. We show that the low temperature low pressure single-pass ammonia synthesis process can produce ammonia at a lower cost than the Haber-Bosch synthesis loop for small-scale ammonia synthesis (<40 t-NH3 d−1).
Hydrogenation and Dehydrogenation of Liquid Organic Hydrogen Carriers: A New Opportunity for Carbon-Based Catalysts
Jan 2022
Publication
The development of a hydrogen-based economy is the perfect nexus between the need of discontinuing the use of fossil fuels (trying to mitigate climate change) the development of a system based on renewable energy (with the use of hydrogen allowing us to buffer the discontinuities produced in this generation) and the achievement of a local-based robust energy supply system. However extending the use of hydrogen as an energy vector must still overcome challenging issues with the key issues being related to its storage. Cryogenic or pressurized storage is relatively expensive technically complex and presents important safety concerns. As a promising alternative the use of organic hydrogen carriers has been suggested in recent years. The ideal carrier will be an organic compound with a low melting point and low viscosity with a significant number of unsaturated carbon–carbon bonds in addition to being easy to hydrogenate and dehydrogenate. These properties allow us to store and transport hydrogen in infrastructures designed for liquid fuels thus facilitating the replacement of fossil fuels by hydrogen
A Review on Advanced Manufacturing for Hydrogen Storage Applications
Dec 2021
Publication
Hydrogen is a notoriously difficult substance to store yet has endless energy applications. Thus the study of long-term hydrogen storage and high-pressure bulk hydrogen storage have been the subject of much research in the last several years. To create a research path forward it is important to know what research has already been done and what is already known about hydrogen storage. In this review several approaches to hydrogen storage are addressed including high-pressure storage cryogenic liquid hydrogen storage and metal hydride absorption. Challenges and advantages are offered based on reported research findings. Since the project looks closely at advanced manufacturing techniques for the same are outlined as well. There are seven main categories into which most rapid prototyping styles fall. Each is briefly explained and illustrated as well as some generally accepted advantages and drawbacks to each style. An overview of hydrogen adsorption on metal hydrides carbon fibers and carbon nanotubes are presented. The hydrogen storage capacities of these materials are discussed as well as the differing conditions in which the adsorption was performed under. Concepts regarding storage shape and materials accompanied by smaller-scale advanced manufacturing options for hydrogen storage are also presented.
Estimation of Filling Time for Compressed Hydrogen Refueling
Mar 2019
Publication
In order to facilitate the application of hydrogen energy and ensure its safety the compressed hydrogen storage tank on board needs to be full of hydrogen gas within 3 minutes. Therefore to meet this requirement the effects of refueling parameters on the filling time need to be investigated urgently. For the purpose of solving this issue a novel analytical solution of filling time is obtained from a lumped parameter model in this paper. According to the equation of state for real gas and dimensionless numbers Nu and Re the function relationships between the filling time and the refueling parameters are presented. These parameters include initial temperature initial pressure inflow temperature final temperature and final pressure. These equations are used to fit the reference data the results of fitting show good agreement. Then the values of fitting parameters are further utilized so as to verify the validity of these formulas. We believe this study can contribute to control the hydrogen filling time and ensure the safety during fast filling process.
Corrosion Study of Pipeline Steel under Stress at Different Cathodic Potentials by EIS
Dec 2019
Publication
The effect of different cathodic potentials applied to the X70 pipeline steel immersed in acidified and aerated synthetic soil solution under stress using a slow strain rate test (SSRT) and electrochemical impedance spectroscopy (EIS) was studied. According to SSRT results and the fracture surface analysis by scanning electron microscopy (SEM) the steel susceptibility to stress corrosion cracking (SCC) increased as the cathodic polarization increased (Ecp). This behavior is attributed to the anodic dissolution at the tip of the crack and the increment of the cathodic reaction (hydrogen evolution) producing hydrogen embrittlement. Nevertheless when the Ecp was subjected to the maximum cathodic potential applied (−970 mV) the susceptibility decreased; this behavior is attributed to the fact that the anodic dissolution was suppressed and the process of the SCC was dominated only by hydrogen embrittlement (HE). The EIS results showed that the cathodic process was influenced by the mass transport (hydrogen diffusion) due to the steel undergoing so many changes in the metallic surface as a result of the applied strain that it generated active sites at the surface.
Clean Energy and Fuel Storage
Aug 2019
Publication
Clean energy and fuel storage is often required for both stationary and automotive applications. Some of the clean energy and fuel storage technologies currently under extensive research and development are hydrogen storage direct electric storage mechanical energy storage solar-thermal energy storage electrochemical (batteries and supercapacitors) and thermochemical storage. The gravimetric and volumetric storage capacity energy storage density power output operating temperature and pressure cycle life recyclability and cost of clean energy or fuel storage are some of the factors that govern efficient energy and fuel storage technologies for potential deployment in energy harvesting (solar and wind farms) stations and on-board vehicular transportation. This Special Issue thus serves the need to promote exploratory research and development on clean energy and fuel storage technologies while addressing their challenges to a practical and sustainable infrastructure.
Modelling a Kinetic Deviation of the Magnesium Hydrogenation Reaction at Conditions Close to Equilibrium
May 2019
Publication
A model has been derived for the magnesium hydrogenation reaction at conditions close to equilibrium. The reaction mechanism involves an adsorption element where the model is an extension of the Langmuir adsorption model. The concept of site availability (σs) is introduced whereby it has the capability to reduce the reaction rate. To improve representation of σs an adaptable semi-empirical equation has been developed. Supplement to the surface reaction a rate equation has been derived considering resistance effects. It was found that close to equilibrium surface resistance dominated the reaction.
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 measures to improve the efficiency. Detailed exergy analysis is the best means for gaining a clear understanding of all losses occurring in the liquefaction process. This work analyses in detail a hydrogen liquefier that is likely to be realisable without intermediate demonstration phases and all irreversibilities are decomposed to the component level. The overall aim is to identify the most promising routes for improving the process. The overall power requirement is found to be 7.09 kWh/kg with stand-alone exergy efficiencies of the mixed-refrigerant pre-cooling cycle and the cryogenic hydrogen Claude cycle of 42.5% and 38.4% respectively. About 90% of the irreversibilities are attributed to the Claude cycle while the remainder is caused by pre-cooling to 114 K. For a component group subdivision the main contributions to irreversibilities are hydrogen compression and intercooling (39%) cryogenic heat exchangers (21%) hydrogen turbine brakes (15%) and hydrogen turbines (13%). Efficiency improvement measures become increasingly attractive with scale in general and several options exist. An effective modification is to recover shaft power from the cryogenic turbines. 80% shaft-to-shaft power recovery will reduce the power requirement to 6.57 kWh/kg. Another potent modification is to replace the single mixed refrigerant pre-cooling cycle with a more advanced mixed-refrigerant cascade cycle. For substantial scaling-up in the long term promising solutions can be cryogenic refrigeration cycles with refrigerant mixtures of helium/neon/hydrogen enabling the use of efficient and well scalable centrifugal compressors.
TM-doped Mg12O12 Nano-cages for Hydrogen Storage Applications: Theoretical Study
Feb 2022
Publication
DFT calculations at B3LYP/6-31g(dp) with the D3 version of Grimme’s dispersion are performed to investigate the application of TM-encapsulated Mg12O12 nano-cages (TM= Mn Fe and Co) as a hydrogen storage material. The molecular dynamic (MD) calculations are utilized to examine the stability of the considered structures. TD-DFT method reveals that the TM-encapsulation converts the Mg12O12 from an ultraviolet into a visible optical active material. The adsorption energy values indicate that the Mn and Fe atoms encapsulation enhances the adsorption of H2 molecules on the Mg12O12 nano-cage. The pristine Mg12O12 and CoMg12O12 do not meet the requirements for hydrogen storage materials while the MnMg12O12 and FeMg12O12 obey the requirements. MnMg12O12 and FeMg12O12 can carry up to twelve and nine H2 molecules respectively. The hydrogen adsorption causes a redshift for the λmax value of the UV-Vis. spectra of the MnMg12O12 and FeMg12O12 nano-cages. The thermodynamic calculations show that the hydrogen storage reaction for MnMg12O12 nano-cage is a spontaneous reaction while for FeMg12O12 nano-cage is not spontaneous. The results suggested that the MnMg12O12 nano-cage may be a promising material for hydrogen storage applications.
Hydrogen Permeation in X65 Steel under Cyclic Loading
May 2020
Publication
This experimental work analyzes the hydrogen embrittlement mechanism in quenched and tempered low-alloyed steels. Experimental tests were performed to study hydrogen diffusion under applied cyclic loading. The permeation curves were fitted by considering literature models in order to evaluate the role of trapping—both reversible and irreversible—on the diffusion mechanism. Under loading conditions a marked shift to the right of the permeation curves was noticed mainly at values exceeding the tensile yield stress. In the presence of a relevant plastic strain the curve changes due to the presence of irreversible traps which efficiently subtract diffusible atomic hydrogen. A significant reduction in the apparent diffusion coefficient and a considerable increase in the number of traps were noticed as the maximum load exceeded the yield strength. Cyclic loading at a tensile stress slightly higher than the yield strength of the material increases the hydrogen entrapment phenomena. The tensile stress causes a marked and instant reduction in the concentration of mobile hydrogen within the metal lattice from 55% of the yield strength and it increases significantly in the plastic field.
Hydrogen Storage Using a Hot Pressure Swing Reactor
Jun 2017
Publication
Our contribution demonstrates that hydrogen storage in stationary Liquid Organic Hydrogen Carrier (LOHC) systems becomes much simpler and significantly more efficient if both the LOHC hydrogenation and the LOHC dehydrogenation reaction are carried out in the same reactor using the same catalyst. The finding that the typical dehydrogenation catalyst for hydrogen release from perhydro dibenzyltoluene (H18-DBT) Pt on alumina turns into a highly active and very selective dibenzyltoluene hydrogenation catalyst at temperatures above 220 °C paves the way for our new hydrogen storage concept. Herein hydrogenation of H0-DBT and dehydrogenation of H18-DBT is carried out at the same elevated temperature between 290 and 310 °C with hydrogen pressure being the only variable for shifting the equilibrium between hydrogen loading and release. We demonstrate that the heat of hydrogenation can be provided at a temperature level suitable for effective dehydrogenation catalysis. Combined with a heat storage device of appropriate capacity or a high pressure steam system this heat could be used for dehydrogenation.
Complex Metal Hydrides for Hydrogen, Thermal and Electrochemical Energy Storage
Oct 2017
Publication
Hydrogen has a very diverse chemistry and reacts with most other elements to form compounds which have fascinating structures compositions and properties. Complex metal hydrides are a rapidly expanding class of materials approaching multi-functionality in particular within the energy storage field. This review illustrates that complex metal hydrides may store hydrogen in the solid state act as novel battery materials both as electrolytes and electrode materials or store solar heat in a more efficient manner as compared to traditional heat storage materials. Furthermore it is highlighted how complex metal hydrides may act in an integrated setup with a fuel cell. This review focuses on the unique properties of light element complex metal hydrides mainly based on boron nitrogen and aluminum e.g. metal borohydrides and metal alanates. Our hope is that this review can provide new inspiration to solve the great challenge of our time: efficient conversion and large-scale storage of renewable energy.
Review and Assessment of the Effect of Hydrogen Gas Pressure on the Embrittlement of Steels in Gaseous Hydrogen Environment
Apr 2021
Publication
Hydrogen gas pressure is an important test parameter when considering materials for high-pressure hydrogen applications. A large set of data on the effect of hydrogen gas pressure on mechanical properties in gaseous hydrogen experiments was reviewed. The data were analyzed by converting pressures into fugacities (f) and by fitting the data using an f|n| power law. For 95% of the data sets |n| was smaller than 0.37 which was discussed in the context of (i) rate-limiting steps in the hydrogen reaction chain and (ii) statistical aspects. This analysis might contribute to defining the appropriate test fugacities (pressures) to qualify materials for gaseous hydrogen applications.
Recent Advances on the Thermal Destabilization of Mg-based Hydrogen Storage Materials
Jan 2021
Publication
Magnesium hydride and its compounds have a high hydrogen storage capacity and are inexpensive and thus have been considered as one of the most promising hydrogen storage materials for on-board applications. Nevertheless Mg/MgH2 systems suffer from great drawbacks in terms of kinetics and thermodynamics for hydrogen uptake/release. Over the past decades although significant progress has been achieved with respect to hydrogen sorption kinetics in Mg/MgH2 systems their high thermal stability remains the main drawback which hinders their practical applications. Accordingly herein we present a brief summary of the synthetic routes and a comprehensive overview of the advantages and disadvantages of the promising strategies to effectively tune the thermodynamics of Mg-based materials such as alloying nanostructuring metastable phase formation changing reaction pathway and nano Mg-based composites. Among them nanostructuring and metastable phase formation which have the superiority of changing the thermodynamics without affecting the hydrogen capacity have attracted increasing interest in this field. To further optimize the hydrogen storage performance we specially emphasize novel nanostructured materials which have the advantage of combining alloy engineering nanostructuring and the synergistic effect to change the thermodynamics of Mg/MgH2 to some extent. Furthermore the remaining challenges and the directions of further research on MgH2 including the fundamental mechanism of the Mg–H bond instability advanced synthetic routes stabilizing nanostructures and predicting novel composite materials are proposed.
Seasonal Energy Storage for Zero-emissions Multi-energy Systems Via Underground Hydrogen Storage
Jan 2020
Publication
The deployment of diverse energy storage technologies with the combination of daily weekly and seasonal storage dynamics allows for the reduction of carbon dioxide (CO2) emissions per unit energy provided. In particular the production storage and re-utilization of hydrogen starting from renewable energy has proven to be one of the most promising solutions for offsetting seasonal mismatch between energy generation and consumption. A realistic possibility for large-scale hydrogen storage suitable for long-term storage dynamics is presented by salt caverns. In this contribution we provide a framework for modelling underground hydrogen storage with a focus on salt caverns and we evaluate its potential for reducing the CO2 emissions within an integrated energy systems context. To this end we develop a first-principle model which accounts for the transport phenomena within the rock and describes the dynamics of the stored energy when injecting and withdrawing hydrogen. Then we derive a linear reduced order model that can be used for mixed-integer linear program optimization while retaining an accurate description of the storage dynamics under a variety of operating conditions. Using this new framework we determine the minimum-emissions design and operation of a multi-energy system with H2 storage. Ultimately we assess the potential of hydrogen storage for reducing CO2 emissions when different capacities for renewable energy production and energy storage are available mapping emissions regions on a plane defined by storage capacity and renewable generation. We extend the analysis for solar- and wind-based energy generation and for different energy demands representing typical profiles of electrical and thermal demands and different CO2 emissions associated with the electric grid.
Innovation Insights Brief - Five Steps to Energy Storage
Jan 2020
Publication
As the global electricity systems are shaped by decentralisation digitalisation and decarbonisation the World Energy Council’s Innovation Insights Briefs explore the new frontiers in energy transitions and the challenges of keeping pace with fast moving developments. We use leadership interviews to map the state of play and case studies across the whole energy landscape and build a broader and deeper picture of new developments within and beyond the new energy technology value chain and business ecosystem.<br/><br/>With major decarbonisation efforts and the scaling up of renewable power generation the widespread adoption of energy storage continues to be described as the key game changer for electricity systems. Affordable storage systems are a critical missing link between intermittent renewable power and a 24/7 reliability net-zero carbon scenario. Beyond solving this salient challenge energy storage is being increasingly considered to meet other needs such as relieving congestion or smoothing out the variations in power that occur independently of renewable-energy generation. However whilst there is plenty of visionary thinking recent progress has focused on short-duration and battery-based energy storage for efficiency gains and ancillary services; there is limited progress in developing daily weekly and even seasonal cost-effective solutions which are indispensable for a global reliance on intermittent renewable energy sources.
Hydrogen Trapping Behavior in Vanadium Microalloyed TRIP-Assisted Annealed Martensitic Steel
Jun 2019
Publication
Transformation induced plasticity (TRIP)-assisted annealed martensitic (TAM) steel combines higher tensile strength and elogangtion and has been increasingly used but appears to bemore prone to hydrogen embrittlement (HE). In this paper the hydrogen trapping behavior and HE of TRIP-assisted annealed martensitic steels with different vanadium additions had been investigated by means of hydrogen charging and slow strain rate tensile tests (SSRT) microstructral observartion and thermal desorption mass spectroscope (TDS). Hydrogen charging test results indicates that apparent hydrogen diffusive index Da is 1.94 × 10−7/cm2·s−1 for 0.21 wt.% vanadium steel while the value is 8.05 × 10−7/cm2·s−1 for V-free steel. SSRT results show that the hydrogen induced ductility loss ID is 76.2% for 0.21 wt.%V steel compared with 86.5% for V-free steel. The trapping mechanism of the steel containing different V contents is analyzed by means of TDS and Transmission electron microscope (TEM) observations. It is found out that the steel containing 0.21 wt.%V can create much more traps for hydrogen trapping compared with lower V steel which is due to vanadium carbide (VC) precipitates acting as traps capturing hydrogen atoms.The relationship between hydrogen diffusion and hydrogentrapping mechanism is discussed in details.
Synthesis of Spherical V-Nb-Mo-Ta-W High-Entropy Alloy Powder Using Hydrogen Embrittlement and Spheroidization by Thermal Plasma
Dec 2019
Publication
V-Nb-Mo-Ta-W high-entropy alloy (HEA) one of the refractory HEAs is considered as a next-generation structural material for ultra-high temperature uses. Refractory HEAs have low castability and machinability due to their high melting temperature and low thermal conductivity. Thus powder metallurgy becomes a promising method for fabricating components with refractory HEAs. Therefore in this study we fabricated spherical V-Nb-Mo-Ta-W HEA powder using hydrogen embrittlement and spheroidization by thermal plasma. The HEA ingot was prepared by vacuum arc melting and revealed to have a single body-centered cubic phase. Hydrogen embrittlement which could be achieved by annealing in a hydrogen atmosphere was introduced to get the ingot pulverized easily to a fine powder having an angular shape. Then the powder was annealed in a vacuum atmosphere to eliminate the hydrogen from the hydrogenated HEA resulting in a decrease in the hydrogen concentration from 0.1033 wt% to 0.0003 wt%. The angular shape of the HEA powder was turned into a spherical one by inductively-coupled thermal plasma allowing to fabricate spherical V-Nb-Mo-Ta-W HEA powder with a d50 value of 28.0 μm.
Effect of Hydrogen on the Deformation Behavior and Localization of Plastic Deformation of the Ultrafine-Grained Zr–1Nb Alloy
Oct 2020
Publication
In this paper comparison studies of the hydrogen effect on the structural and phase state deformation behavior and mechanical properties of the fine- (average grain size 4 µm) and ultrafine-grained (average element size 0.3 and 0.4 µm) Zr–1wt.%Nb (hereinafter Zr–1Nb) alloy under tension at temperatures in the range of 293–873 K were conducted. The formation of an ultrafine-grained structure is established to increase the strength characteristics of the Zr–1Nb alloy by a factor of 1.5–2 with a simultaneous reduction of its resistance to the localization of plastic deformation at the macro level and the value of deformation to failure. The presence of hydrogen in the Zr–1Nb alloy in the form of a solid solution and hydride precipitates increases its resistance to the localization of plastic deformation at the macro level if the alloy has an ultrafine-grained structure and decreases if the structure of the alloy is fine-grained. In the studied temperature range the Zr–1Nb alloy in the ultrafine-grained state has a higher resistance to hydrogen embrittlement than the alloy in the fine-grained state.
Two-Stage Energy Management Strategies of Sustainable Wind-PV-Hydrogen-Storage Microgrid Based on Receding Horizon Optimization
Apr 2022
Publication
Hydrogen and renewable electricity-based microgrid is considered to be a promising way to reduce carbon emissions promote the consumption of renewable energies and improve the sustainability of the energy system. In view of the fact that the existing day-ahead optimal operation model ignores the uncertainties and fluctuations of renewable energies and loads a two-stage energy management model is proposed for the sustainable wind-PV-hydrogen-storage microgrid based on receding horizon optimization to eliminate the adverse effects of their uncertainties and fluctuations. In the first stage the day-ahead optimization is performed based on the predicted outpower of WT and PV the predicted demands of power and hydrogen loads. In the second stage the intra-day optimization is performed based on the actual data to trace the day-ahead operation schemes. Since the intra-day optimization can update the operation scheme based on the latest data of renewable energies and loads the proposed two-stage management model is effective in eliminating the uncertain factors and maintaining the stability of the whole system. Simulations show that the proposed two-stage energy management model is robust and effective in coordinating the operation of the wind-PV-hydrogen-storage microgrid and eliminating the uncertainties and fluctuations of WT PV and loads. In addition the battery storage can reduce the operation cost alleviate the fluctuations of the exchanged power with the power grid and improve the performance of the energy management model.
Study on Critical Technologies and Development Routes of Coal-based Hydrogen Energy
Jul 2019
Publication
Hydrogen is considered a secondary source of energy commonly referred to as an energy carrier. It has the highest energy content when compared to other common fuels by weight having great potential for further development. Hydrogen can be produced from various domestic resources but based on the fossil resource conditions in China coal-based hydrogen energy is considered to be the most valuable because it is not only an effective way to develop clean energy but also a proactive exploration of the clean usage of traditional coal resources. In this article the sorption-enhanced water–gas shift technology in the coal-to-hydrogen section and the hydrogen-storage and transport technology with liquid aromatics are introduced and basic mechanisms technical advantages latest progress and future R&D focuses of hydrogen-production and storage processes are listed and discussed. As a conclusion after considering the development frame and the business characteristics of CHN Energy Group a conceptual architecture for developing coal-based hydrogen energy and the corresponding supply chain is proposed.
Hydrogen Embrittlement of Medium Mn Steels
Feb 2021
Publication
Recent research efforts to develop advanced–/ultrahigh–strength medium-Mn steels have led to the development of a variety of alloying concepts thermo-mechanical processing routes and microstructural variants for these steel grades. However certain grades of advanced–/ultrahigh–strength steels (A/UHSS) are known to be highly susceptible to hydrogen embrittlement due to their high strength levels. Hydrogen embrittlement characteristics of medium–Mn steels are less understood compared to other classes of A/UHSS such as high Mn twinning–induced plasticity steel because of the relatively short history of the development of this steel class and the complex nature of multiphase fine-grained microstructures that are present in medium–Mn steels. The motivation of this paper is to review the current understanding of the hydrogen embrittlement characteristics of medium or intermediate Mn (4 to 15 wt pct) multiphase steels and to address various alloying and processing strategies that are available to enhance the hydrogen-resistance of these steel grades.
Heuristic Design of Advanced Martensitic Steels That Are Highly Resistant to Hydrogen Embrittlement by ε-Carbide
Feb 2021
Publication
Many advanced steels are based on tempered martensitic microstructures. Their mechanical strength is characterized by fine sub-grain structures with a high density of free dislocations and metallic carbides and/or nitrides. However the strength for practical use has been limited mostly to below 1400 MPa owing to delayed fractures that are caused by hydrogen. A literature survey suggests that ε-carbide in the tempered martensite is effective for strengthening. A preliminary experimental survey of the hydrogen absorption and hydrogen embrittlement of a tempered martensitic steel with ε-carbide precipitates suggested that the proper use of carbides in steels can promote a high resistance to hydrogen embrittlement. Based on the surveys martensitic steels that are highly resistant to hydrogen embrittlement and that have high strength and toughness are proposed. The heuristic design of the steels includes alloying elements necessary to stabilize the ε-carbide and procedures to introduce inoculants for the controlled nucleation of ε-carbide.
Analysis of the Physicochemical, Mechanical, and Electrochemical Parameters and Their Impact on the Internal and External SCC of Carbon Steel Pipelines
Dec 2020
Publication
The review presented herein is regarding the stress corrosion cracking (SCC) phenomena of carbon steel pipelines affected by the corrosive electrolytes that comes from external (E) and internal (I) environments as well as the susceptibility and tensile stress on the SCC. Some useful tools are presented including essential aspects for determining and describing the E-SCC and I-SCC in oil and gas pipelines. Therefore this study aims to present a comprehensive and critical review of a brief experimental summary and a comparison of physicochemical mechanical and electrochemical data affecting external and internal SCC in carbon steel pipelines exposed to corrosive media have been conducted. The SCC hydrogen-induced cracking (HIC) hydrogen embrittlement and sulfide stress cracking (SSC) are attributed to the pH and to hydrogen becoming more corrosive by combining external and internal sources promoting cracking such as sulfide compounds acidic soils acidic atmospheric compounds hydrochloric acid sulfuric acid sodium hydroxide organic acids (acetic acid mainly) bacteria induced corrosion cathodic polarization among others. SCC growth is a reaction between the microstructural chemical and mechanical effects and it depends on the external and internal environmental sources promoting unpredictable cracks and fractures. In some cases E-SCC could be initiated by hydrogen that comes from the over-voltage during the cathodic protection processes. I-SCC could be activated by over-operating pressure and temperature at flowing media during the production gathering storage and transportation of wet hydrocarbons through pipelines. The mechanical properties related to I-SCC were higher in comparison with those reviewed by E-SCC suggesting that pipelines suffer more susceptibility to I-SCC. When a pipeline is designed the internal fluid being transported (changes of environments) and the external environment concerning SCC should be considered. This review offers a good starting point for newcomers into the field it is written as a tutorial and covers a large number of basic standards in the area.
Quantitative Risk Analysis Of Gaseous Hydrogen Storage Unit
Sep 2005
Publication
A quantitative risk analysis to a central pressurized storage tank for gaseous hydrogen has been performed to attend requirements of licensing procedures established by the State Environment Agency of São Paulo State Brazil. Gaseous hydrogen is used to feed the reactor to promote hydrogenation at the surfactant unit. HAZOP was the hazard identification technique selected. System components failures were defined by event and fault tree analysis. Quantitative risk analysis was complied to define the acceptability concepts on societal and individual risks required by the State Environmental Agency to approve the installation operation license. Acceptable levels to public society from the analysis were reached. Safety recommendations to the gaseous hydrogen central were proposed to assure minimization of risk to the near-by community operators environment and property.
Addressing H-Material Interaction in Fast Diffusion Materials—A Feasibility Study on a Complex Phase Steel
Oct 2020
Publication
Hydrogen embrittlement (HE) is one of the main limitations in the use of advanced high-strength steels in the automotive industry. To have a better understanding of the interaction between hydrogen (H) and a complex phase steel an in-situ method with plasma charging was applied in order to provide continuous H supply during mechanical testing in order to avoid H outgassing. For such fast-H diffusion materials only direct observation during in-situ charging allows for addressing H effects on materials. Different plasma charging conditions were analysed yet there was not a pronounced effect on the mechanical properties. The H concentration was calculated while using a simple analytical model as well as a simulation approach resulting in consistent low H values below the critical concentration to produce embrittlement. However the dimple size decreased in the presence of H and with increasing charging time the crack propagation rate increased. The rate dependence of flow properties of the material was also investigated proving that the material has no strain rate sensitivity which confirmed that the crack propagation rate increased due to H effects. Even though the H concentration was low in the experiments that are presented here different technological alternatives can be implemented in order to increase the maximum solute concentration.
Implementation of hydrogen plasma activation of Mg powder in two steps hydrogenation
Oct 2017
Publication
Development of technologically and economically feasible solutions for hydrogen storage stimulates progress in hydrogen economy. High gravimetric and volumetric capacities of magnesium hydride makes it promising material capable to accelerate implementation of hydrogen-based technologies in our daily life. However widely discussed limitations of sorption kinetics and thermodynamic properties must be managed in MgH2. This work investigates two steps hydrogenation when process of hydrogen absorption is followed after hydrogen plasma activation. Such technique initiates creation of new channels for enhanced hydrogen sorption. Moreover synthesis of negligible amount of hydride acts as positive factor for further hydrogenation.
In-situ Study of the Effect of Hydrogen on Fatigue Crack Initiation in Polycrystalline Nickel
Aug 2019
Publication
Correlating hydrogen embrittlement phenomenon with the metallic microstructural features holds the key for developing metals resistant to hydrogen-based failures. In case of fatigue failure of hydrogen charged metals in addition to the hydrogen-based failure mechanisms associated with monotonic loading such as HELP HEDE etc. microstructural features such as grain size type of grain boundary (special/random) fraction of special grain boundaries; their network and triple junctions can play a complex role. The probable sites for fatigue crack initiation in such metals can be identified as the sites of highest hydrogen concentration or accumulated plastic strain. To this end we have developed an experimental framework based on in-situ fatigue crack initiation and propagation studies under scanning electron microscope (SEM) to identify the weakest link in the metallic microstructure leading to failure. In-situ fatigue experiments are performed on carefully designed polycrystalline nickel (99.95% pure) specimens (miniaturised shallow-notched & electro-polished) using a 10 kN fatigue stage inside the SEM. Electron Back Scattering Diffraction (EBSD) map of the notched region surface helps identify the distribution of special/random grain boundaries triple junctions and grain orientation. The specimen surface in the shallow notched region for both the hydrogen charged and un-charged specimens are then carefully studied to correlate the microstructural feature associated with fatigue crack initiation sites. Such correlation of the fatigue crack initiation site and microstructural feature is further corroborated with the knowledge of hydrogen trapping and grain’s elastic anisotropicity to be either the site of high hydrogen concentration accumulated plastic slip or both.
The Role of CCS in Meeting Climate Policy Targets
Oct 2017
Publication
Carbon capture and storage (CCS) refers to a set of technologies that may offer the potential for large-scale removal of CO2 emissions from a range of processes – potentially including the generation of electricity and heat industrial processes and the production of hydrogen and synthetic fuels. CCS has both proponents and opponents. Like other emerging low carbon technologies CCS is not without risks or uncertainties and there are various challenges that would need to be overcome if it were to be widely deployed. Policy makers’ decisions as to whether to pursue CCS should be based on a judgement as to whether the risks and uncertainties associated with attempting to deploy CCS outweigh the risks of not having it available as part of a portfolio of mitigation options in future years.
The full report can be found on the Global CSS Institute website at this link
The full report can be found on the Global CSS Institute website at this link
Carbon Capture, Usage and Storage: An Update on Business Models for Carbon Capture, Usage and Storage
Dec 2020
Publication
An update on the proposed commercial frameworks for transport and storage power and industrial carbon capture business models.
From Coal Ashes to Solid Sorbents for Hydrogen Storage
Jun 2020
Publication
The purpose of this work is the literature review in the field of hydrogen storage in solid sorbents. The best solid sorbents for hydrogen storage were selected with the possibility of synthesis them from coal fly ash. In addition the on-board hydrogen storage analysis was carried out. The review method consists of two parts. The first part based on research questions included types of the best sorbents for hydrogen storage the possibility to obtain them from coal fly ash and practical use in hydrogen storage system on-board. The second part was the selection of publications from The Web of Science and Elsevier Scopus databases and the analysis as well as available reports on the websites at this scope. After searching the relevant articles in the databases abstracts were analysed in terms of the questions asked. The links between references and research were checked. The search procedure was repeated several times. Finally articles with high Impact Factor index published by authors recognized on a global scale were selected for the presented review. The collected information proved that carbon materials are suited to hydrogen storage because of their high porosity large specific surface area and thermal stability. Besides solid sorbents such as zeolites metal-organic frameworks activated carbons or zeolite template carbons can be obtained from coal fly ash. Thanks to silicon aluminium and unburned carbon content fly ash is a good material for the synthesis of hydrogen sorbents. Under cryogenic conditions and high pressure it is possible to adsorb as much as 8.5 wt% of hydrogen. Although the Department of Energy (DOE) requirements for the hydrogen storage system on-board vehicles are not met the review of scientific publications shows that research in this area is developing and better parameters are being obtained.
Analysis of the Environmental Degradation Effects on the Cables of “La Arena” Bridge (Spain)
Sep 2017
Publication
After nearly 25 years of service some of the wires of the tendons of “La Arena” bridge (Spain) started to exhibit the effects of environmental degradation processes. “La Arena” is cable-stayed bridge with 6 towers and a reference span between towers of about 100 meters. After a maintenance inspection of the bridge evidences of corrosion were detected in some of the galvanized wires of the cables. A more in-deep analysis of these wires revealed that many of them exhibited loss of section due to the corrosion process. In order to clarify the causes of this degradation event and to suggest some remedial actions an experimental program was designed. This program consisted of tensile and fatigue tests on some strand samples of the bridge together with a fractographic analysis of the fracture surfaces of the wires its galvanized layer thickness and some hydrogen measurements (hydrogen embrittlement could be another effect of the environmental degradation process).Once the type and extension of the flaws in the wires was characterized a structural integrity assessment of the strands was performed with the aim of quantifying the margins until failure and establishing some maintenance recommendations.
Failure Analysis of Cooling Duct of Top Engine Cowl Panel of Fighter Aircraft
Jun 2019
Publication
Present work describes the failure analysis of cooling duct of a fighter aircraft. The analyzed chemical composition of cooling duct indicates that it is manufactured from Al-based alloy (AA 3003 or its equivalent). Microstructure of cooling duct displays the presence of two phases namely matrix and insoluble particles. The hardness values at different locations within damaged area of cooling duct reflect nearly same and consistent. The fracture surface of the cooling duct exhibits transgranular features and cracks with little branching. The analyzed hydrogen content in cooling duct is significantly higher (∼ 12 ppm) than the specified one (< 1 ppm). However the alloy used to fabricate cooling duct is not susceptible to typical hydrogen embrittlement. This shows hydrogen pick up during operation. The presence of cracks with branching does reflect features of hydrogen embrittlement. In addition striations indicative of fatigue features are also observed. It thus appears that the cooling duct has failed due to pick up of large amount of hydrogen as well as vibrational fatigue.
The Hydrogen Trapping Ability of TiC and V4C3 by Thermal Desorption Spectroscopy and Permeation Experiments
Dec 2018
Publication
Hydrogen (H) presence in metals is detrimental as unpredictable failure might occur. Recent developments in material’s design indicated that microstructural features such as precipitates play an essential role in potentially increasing the resistance against H induced failure. This work evaluates the H trapping characteristics for TiC and V4C3 by thermal desorption spectroscopy and permeation experiments. Two microstructural conditions are compared: as quenched vs. quenched and tempered in which the carbides are introduced. The tempered induced precipitates are able to deeply trap a significant amount of H which decreases the H diffusivity in the materials and removes some of the detrimental H from the microstructure. For microstructural design purposes it is important to know the position of H. Here H is demonstrated to be trapped at the carbide/matrix interface by modifying the tempering treatment.
Engineering Thoughts on Hydrogen Embrittlement
Jul 2018
Publication
Hydrogen Embrittlement (HE) is a topical issue for pipelines transporting sour products. Engineers need a simple and effective approach in materials selection at design stage. In other words they must know if a material is susceptible to cracking to be able of:
As an example material selection for sour service pipeline is the object of well-known standards e.g. by Nace International and EFC: they pose some limits in the sour service of steels with reference to surface hardness. These standards have shown some weak points namely:
- selecting the right material
- and apply correct operational measures during the service life.
As an example material selection for sour service pipeline is the object of well-known standards e.g. by Nace International and EFC: they pose some limits in the sour service of steels with reference to surface hardness. These standards have shown some weak points namely:
- In the definition of sour service;
- In defining the role of crack initiation and propagation considering that in Hydrogen embrittlement stress state and stress variations are very important.
Hydrogen-induced Failure of TiNi Based Alloy with Coarse-grained and Ultrafine-grained Structure
Jul 2016
Publication
The objective of this work is to investigate the effect of hydrogen-induced fracture of TiNi-based alloy. In this report we performed the first studies comparing inelastic properties and fracture of the specimens of the binary alloy of TiNi wire under the action of hydrogen with coarse-grained (CG) and ultrafine-grained (UFG) microstructure. It is shown that hydrogen embrittlement (HE) occurs irrespective of the grain size in the studied specimens at approximately equal strain values. However compared to the specimens with CG structure those with UFG structure accumulate two to three times more hydrogen for the same hydrogenation time. It is found that hydrogen has a much smaller effect on the inelastic properties of specimens with UFG structure as compared to those with CG structure.
Study on Temper Embrittlement and Hydrogen Embrittlement of a Hydrogenation Reactor by Small Punch Test
Jun 2017
Publication
The study on temper embrittlement and hydrogen embrittlement of a test block from a 3Cr1Mo1/4V hydrogenation reactor after ten years of service was carried out by small punch test (SPT) at different temperatures. The SPT fracture energy Esp (derived from integrating the load-displacement curve) divided by the maximum load (Fm) of SPT was used to fit the Esp/Fm versus-temperature curve to determine the energy transition temperature (Tsp) which corresponded to the ductile-brittle transition temperature of the Charpy impact test. The results indicated that the ratio of Esp/Fm could better represent the energy of transition in SPT compared with Esp. The ductile-to-brittle transition temperature of the four different types of materials was measured using the hydrogen charging test by SPT. These four types of materials included the base metal and the weld metal in the as-received state and the base metal and the weld metal in the de-embrittled state. The results showed that there was a degree of temper embrittlement in the base metal and the weld metal after ten years of service at 390 °C. The specimens became slightly more brittle but this was not obvious after hydrogen charging. Because the toughness of the material of the hydrogenation reactor was very good the flat samples of SPT could not characterize the energy transition temperature within the liquid nitrogen temperature. Additionally there was no synergetic effect of temper embrittlement and hydrogen embrittlement found in 3Cr1Mo1/4V steel.
Prospects of Enhancing the Understanding of Material-hydrogen Interaction by Novel In-situ and In-operando Methods
Jan 2022
Publication
A main scientific and technical challenge facing the implementation of new and sustainable energy sources is the development and improvement of materials and components. In order to provide commercial viability of these applications an intensive research in material-hydrogen (H) interaction is required. This work provides an overview of recently developed in-situ and in-operando H-charging methods and their applicability to investigate mechanical properties H-absorption characteristics and H embrittlement (HE) susceptibility of a wide range of materials employed in H-related technologies such as subsea oil and gas applications nuclear fusion and fuel cells.
Hydrogen Embrittlement in Advanced High Strength Steels and Ultra High Strength Steels: A New Investigation Approach
Dec 2018
Publication
In order to reduce CO2 emissions and fuel consumption and to respect current environmental norms the reduction of vehicles weight is a primary target of the automotive industry. Advanced High Strength Steels (AHSS) and Ultra High Strength Steel (UHSS) which present excellent mechanical properties are consequently increasingly used in vehicle manufacturing. The increased strength to mass ratio compensates the higher cost per kg and AHSS and UHSS are proving to be cost-effective solutions for the body-in-white of mass market products.
In particular aluminized boron steel can be formed in complex shapes with press hardening processes acquiring high strength without distortion and increasing protection from crashes. On the other hand its characteristic martensitic microstructure is sensitive to hydrogen delayed fracture phenomena and at the same time the dew point in the furnace can produce hydrogen consequently to the high temperature reaction between water and aluminum. The high temperature also promotes hydrogen diffusion through the metal lattice under the aluminum-silicon coating thus increasing the diffusible hydrogen content. However after cooling the coating acts as a strong barrier preventing the hydrogen from going out of the microstructure. This increases the probability of delayed fracture. As this failure brings to the rejection of the component during production or even worse to the failure in its operation diffusible hydrogen absorbed in the component needs to be monitored during the production process.
For fast and simple measurements of the response to diffusible hydrogen of aluminized boron steel one of the HELIOS innovative instruments was used HELIOS II. Unlike the Devanathan cell that is based on a double electrochemical cell HELIOS II is based on a single cell coupled with a solid-state sensor. The instrument is able to give an immediate measure of diffusible hydrogen content in sheet steels semi-products or products avoiding time-consuming specimen palladium coating with a guided procedure that requires virtually zero training.
Two examples of diffusible hydrogen analyses are given for Usibor®1500-AS one before hot stamping/ quenching and one after hot stamping suggesting that the increase in the number of dislocations during hot stamping could be the main responsible for the lower apparent diffusivity of hydrogen.
In particular aluminized boron steel can be formed in complex shapes with press hardening processes acquiring high strength without distortion and increasing protection from crashes. On the other hand its characteristic martensitic microstructure is sensitive to hydrogen delayed fracture phenomena and at the same time the dew point in the furnace can produce hydrogen consequently to the high temperature reaction between water and aluminum. The high temperature also promotes hydrogen diffusion through the metal lattice under the aluminum-silicon coating thus increasing the diffusible hydrogen content. However after cooling the coating acts as a strong barrier preventing the hydrogen from going out of the microstructure. This increases the probability of delayed fracture. As this failure brings to the rejection of the component during production or even worse to the failure in its operation diffusible hydrogen absorbed in the component needs to be monitored during the production process.
For fast and simple measurements of the response to diffusible hydrogen of aluminized boron steel one of the HELIOS innovative instruments was used HELIOS II. Unlike the Devanathan cell that is based on a double electrochemical cell HELIOS II is based on a single cell coupled with a solid-state sensor. The instrument is able to give an immediate measure of diffusible hydrogen content in sheet steels semi-products or products avoiding time-consuming specimen palladium coating with a guided procedure that requires virtually zero training.
Two examples of diffusible hydrogen analyses are given for Usibor®1500-AS one before hot stamping/ quenching and one after hot stamping suggesting that the increase in the number of dislocations during hot stamping could be the main responsible for the lower apparent diffusivity of hydrogen.
The Effect of Cold Rolling on the Hydrogen Susceptibility of 5083 Aluminium Alloy
Oct 2017
Publication
This work focuses in investigating the effect of cold deformation on the cathodic hydrogen charging of 5083 aluminum alloy. The aluminium alloy was submitted to a cold rolling process until the average thickness of the specimens was reduced by 7% and 15% respectively. A study of the structure microhardness and tensile properties of the hydrogen charged aluminium specimens with and without cold rolling indicated that the cold deformation process led to an increase of hydrogen susceptibility of this aluminum alloy.
Hydrogen Embrittlement and Improved Resistance of Al Addition in Twinning-Induced Plasticity Steel: First-Principles Study
Apr 2019
Publication
Understanding the mechanism of hydrogen embrittlement (HE) of austenitic steels and developing an effective strategy to improve resistance to HE are of great concern but challenging. In this work first-principles studies were performed to investigate the HE mechanism and the improved resistance of Al-containing austenite to HE. Our results demonstrate that interstitial hydrogen atoms have different site preferences in Al-free and Al-containing austenites. The calculated binding energies and diffusion barriers of interstitial hydrogen atoms in Al-containing austenite are remarkably higher than those in Al-free austenite indicating that the presence of Al is more favorable for reducing hydrogen mobility. In Al-free austenite interstitial hydrogen atoms caused a remarkable increase in lattice compressive stress and a distinct decrease in bulk shear and Young’s moduli. Whereas in Al-containing austenite the lattice compressive stress and the mechanical deterioration induced by interstitial hydrogen atoms were effectively suppressed.
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 differences between certified and measured hydrogen concentration values for standard samples.<br/>In this paper we analyze reasons of systematic errors genesis observed for hydrogen measurements while applying the thermal conductivity cell technique. As a result we demonstrated that measurements resulting from samples heating and melting in the inert gas flow depend on its heat capacity and surface temperature of the melting pot. Due to this reason one can obtain multiple errors and even negative values for measurements of a low hydrogen concentration."
Rechargeable Proton Exchange Membrane Fuel Cell Containing an Intrinsic Hydrogen Storage Polymer
Oct 2020
Publication
Proton exchange membrane fuel cells (PEMFCs) are promising clean energy conversion devices in residential transportation and portable applications. Currently a high-pressure tank is the state-of-the-art mode of hydrogen storage; however the energy cost safety and portability (or volumetric hydrogen storage capacity) presents a major barrier to the widespread dissemination of PEMFCs. Here we show an ‘all-polymer type’ rechargeable PEMFC (RCFC) that contains a hydrogen-storable polymer (HSP) which is a solid-state organic hydride as the hydrogen storage media. Use of a gas impermeable SPP-QP (a polyphenylenebased PEM) enhances the operable time reaching up to ca. 10.2 s mgHSP −1 which is more than a factor of two longer than that (3.90 s mgHSP −1) for a Nafion NRE-212 membrane cell. The RCFCs are cycleable at least up to 50 cycles. The features of this RCFC system including safety ease of handling and light weight suggest applications in mobile light-weight hydrogen-based energy devices.
Environmentally Assisted Cracking Behavior of S420 and X80 Steels Containing U-notches at Two Different Cathodic Polarization Levels: An Approach from the Theory of Critical Distances
May 2019
Publication
This paper analyzes using the theory of critical distances the environmentally assisted cracking behaviour of two steels (S420 and API X80) subjected to two different aggressive environments. The propagation threshold for environmentally assisted cracking (i.e. the stress intensity factor above which crack propagation initiates) in cracked and notched specimens (KIEAC and KNIEAC) has been experimentally obtained under different environmental conditions. Cathodic polarization has been employed to generate the aggressive environments at 1 and 5 mA/cm2 causing hydrogen embrittlement on the steels. The point method and the line method both belonging to the theory of critical distances have been applied to verify their capacity to predict the initiation of crack propagation. The results demonstrate the capacity of the theory of critical distances to predict the crack propagation onset under the different combinations of material and aggressive environments.
20 Years of Carbon Capture and Storage - Accelerating Future Deployment
Nov 2016
Publication
Carbon capture and storage (CCS) technologies are expected to play a significant part in the global climate response. Following the ratification of the Paris Agreement the ability of CCS to reduce emissions from fossil fuel use in power generation and industrial processes – including from existing facilities – will be crucial to limiting future temperature increases to ""well below 2°C"" as laid out in the Agreement. CCS technology will also be needed to deliver ""negative emissions"" in the second half of the century if these ambitious goals are to be achieved.
CCS technologies are not new. This year is the 20th year of operation of the Sleipner CCS Project in Norway which has captured almost 17 million tonnes of CO2 from an offshore natural gas production facility and permanently stored them in a sandstone formation deep under the seabed. Individual applications of CCS have been used in industrial processes for decades and projects injecting CO2 for enhanced oil recovery (EOR) have been operating in the United States since the early 1970s.
This publication reviews progress with CCS technologies over the past 20 years and examines their role in achieving 2°C and well below 2°C targets. Based on the International Energy Agency’s 2°C scenario it also considers the implications for climate change if CCS was not a part of the response. And it examines opportunities to accelerate future deployment of CCS to meet the climate goals set in the Paris Agreement.
Link to Document on IEA Website
CCS technologies are not new. This year is the 20th year of operation of the Sleipner CCS Project in Norway which has captured almost 17 million tonnes of CO2 from an offshore natural gas production facility and permanently stored them in a sandstone formation deep under the seabed. Individual applications of CCS have been used in industrial processes for decades and projects injecting CO2 for enhanced oil recovery (EOR) have been operating in the United States since the early 1970s.
This publication reviews progress with CCS technologies over the past 20 years and examines their role in achieving 2°C and well below 2°C targets. Based on the International Energy Agency’s 2°C scenario it also considers the implications for climate change if CCS was not a part of the response. And it examines opportunities to accelerate future deployment of CCS to meet the climate goals set in the Paris Agreement.
Link to Document on IEA Website
Numerical Simulation of Tensile Behavior of Corroded Aluminum Alloy 2024 T3 Considering the Hydrogen Embrittlement
Jan 2018
Publication
A multi-scale modeling approach for simulating the tensile behavior of the corroded aluminum alloy 2024 T3 was developed accounting for both the geometrical features of corrosion damage and the effect of corrosion-induced hydrogen embrittlement (HE). The approach combines two Finite Element (FE) models: a model of a three-dimensional Representative Unit Cell (RUC) representing an exfoliated area and its correspondent hydrogen embrittled zone (HEZ) and a model of the tensile specimen. The models lie at the micro- and macro-scales respectively. The characteristics of the HEZ are determined from measurements of nanoindentation hardness conducted on pre-corroded specimens. Using the model of the RUC the local homogenized mechanical behavior of the corroded material is simulated. Then the behavior of the exfoliated areas is assigned into different areas (elements) of the tensile specimen and final analyses are performed to simulate the tensile behavior of the corroded material. The approach was applied to model specimens after 8 16 and 24 h exposure periods of the Exfoliation Corrosion (EXCO) test. For validation of the approach tensile tests were used. The numerical results show that this approach is suitable for accurately simulating the tensile behavior of pre-corroded experimental specimens accounting for both geometrical features of corrosion damage and corrosion-induced HE.
Mechanical Properties of Gas Main Steels after Long-Term Operation and Peculiarities of Their Fracture Surface Morphology
Feb 2019
Publication
Regularities of steel structure degradation of the “Novopskov-Aksay-Mozdok” gas main pipelines (Nevinnomysskaya CS) as well as the “Gorky-Center” pipelines (Gavrilovskaya CS) were studied. The revealed peculiarities of their degradation after long-term operation are suggested to be treated as a particular case of the damage accumulation classification (scheme) proposed by prof. H.M. Nykyforchyn. It is shown that the fracture surface consists of sections of ductile separation and localized zones of micro-spalling. The presence of the latter testifies to the hydrogen-induced embrittlement effect. However the steels under investigation possess sufficiently high levels of the mechanical properties required for their further safe exploitation both in terms of durability and cracking resistance.
Hydrogen in the Gas Distribution Networks: A Kickstart Project as an Input into the Development of a National Hydrogen Strategy for Australia
Nov 2019
Publication
The report investigates a kickstart project that allows up to 10% hydrogen into gas distribution networks. It reviews the technical impacts and standards to identify barriers and develop recommendations.
You can see the full report on the Australian Government website here
This report is developed in support of Australia's National Hydrogen Strategy
You can see the full report on the Australian Government website here
This report is developed in support of Australia's National Hydrogen Strategy
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 research and experimental and numerical studies. The experiments include the energy spectrum of internal friction determination and impact toughness testing for low-temperature brittle-ductile transition revealing. The numerical study based on damage accumulation modeling under the influence of up-hill diffusion in the elastic-plastic problem of solid state by finite element method. A new simple activation model of low temperature and hydrogen influence on damage accumulation process has been proposed. The model shows the rate of damage strong dependence of stress level and hydrogen content and test temperature. The combination of low temperature and high hydrogen content is most dangerous so the weld structures in extreme environment such as the Arctic and Subarctic regions have a high risk of breakage. So it is possible to estimate the energy and phonon spectrum of crystal lattice and predict the properties of microcrystalline and nanostructured materials with the high cold-short threshold on the base of such the approach. There are the recommendations propose to improve the cold resistance of steels and alloys by controlling the characteristics of the dislocation structure of new materials with polycrystalline and ultrafine-grained structure.
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.
Evaluation of the Performance Degradation of a Metal Hydride Tank in a Real Fuel Cell Electric Vehicle
May 2022
Publication
In a fuel cell electric vehicle (FCEV) powered by a metal hydride tank the performance of the tank is an indicator of the overall health status which is used to predict its behaviour and make appropriate energy management decisions. The aim of this paper is to investigate how to evaluate the effects of charge/discharge cycles on the performance of a commercial automotive metal hydride hydrogen storage system applied to a real FCEV. For this purpose a mathematical model is proposed based on uncertain physical parameters that are identified using the stochastic particle swarm optimisation (PSO) algorithm combined with experimental measurements. The variation of these parameters allows an assessment of the degradation level of the tank’s performance on both the quantitative and qualitative aspects. Simulated results derived from the proposed model and experimental measurements were in good agreement with a maximum relative error of less than 2%. The validated model was used to establish the correlations between the observed degradations in a hydride tank recovered from a real FCEV. The results obtained show that it is possible to predict tank degradations by developing laws of variation of these parameters as a function of the real conditions of the use of the FCEV (number of charging/discharging cycles pressures mass flow rates temperatures).
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.
Evaluation of Strength and Fracture Toughness of Ferritic High Strength Steels Under Hydrogen Environments
Sep 2017
Publication
The susceptibility of high strength ferritic steels to hydrogen-assisted fracture in hydrogen gas is usually evaluated by mechanical testing in high-pressure hydrogen gas or testing in air after pre-charging the specimens with hydrogen. We have used this second methodology conventionally known as internal hydrogen. Samples were pre-charged in an autoclave under 195 bar of pure hydrogen at 450ºC for 21 hours.<br/>Different chromium-molybdenum steels submitted to diverse quenching and tempering heat treatments were employed. Diverse specimens were also used: small cylindrical samples to measure hydrogen contents and the kinetics of hydrogen egression at room temperature tensile specimens notched tensile specimens with a sharp notch and also compact fracture toughness specimens. Fractographic examination in SEM was finally performed in order to know the way hydrogen modify fracture micromechanisms.<br/>The presence of hydrogen barely affects the conventional tensile properties of the steels but it clearly alters their notched tensile strength and fracture toughness. This is due to the strong effect that stress triaxiality (dependent also on the steel yield strength) has on the accumulation of hydrogen on the notch/crack front region being the displacement rate used in the test another important variable to be controlled due to its influence on hydrogen diffusion to the embrittled process zone. Moreover the modification of fracture micromechanisms was finally determined being ductile (initiation growth and coalescence of microvoids) in the absence of hydrogen and brittle and intergranular under the material conditions of maximum embrittlement.
Toward a Non-destructive Diagnostic Analysis Tool of Exercises Pipelines: Models and Experiences
Dec 2018
Publication
Strategic networks of hydrocarbon pipelines in long time service are adversely affected by the action of aggressive chemicals transported with the fluids and dissolved in the environment. Material degradation phenomena are amplified in the presence of hydrogen and water elements that increase the material brittleness and reduce the safety margins. The risk of failure during operation of these infrastructures can be reduced if not prevented by the continuous monitoring of the integrity of the pipe surfaces and by the tracking of the relevant bulk properties. A fast and potentially non-destructive diagnostic tool of material degradation which may be exploited in this context is based on the instrumented indentation tests that can be performed on metals at different scales. Preliminary validation studies of the significance of this methodology for the assessment of pipeline integrity have been carried out with the aid of interpretation models of the experiments. The main results of this ongoing activity are illustrated in this contribution.
The Potential of Hydrogen Hydrate as a Future Hydrogen Storage Medium
Dec 2020
Publication
Hydrogen is recognized as the “future fuel” and the most promising alternative of fossil fuels due to its remarkable properties including exceptionally high energy content per unit mass (142 MJ/kg) low mass density and massive environmental and economical upsides. A wide spectrum of methods in H2 production especially carbon-free approaches H2purification and H2storage have been investigated to bring this energy source closer to the technological deployment. Hydrogen hydrates are among the most intriguing material paradigms for H2storage due to their appealing properties such as low energy consumption for charge and discharge safety cost-effectiveness and favorable environmental features. Here we comprehensively discuss the progress in understanding of hydrogen clathrate hydrates with an emphasis on charging/discharging rate of H2 (i.e. hydrate formation and dissociation rates) and the storage capacity. A thorough understanding on phase equilibrium of the hydrates and its variation through different materials is provided. The path toward ambient temperature and pressure hydrogen batteries with high storage capacity is elucidated. We suggest that the charging rate of H2 in this storage medium and long cyclic performance are more immediate challenges than storage capacity for technological translation of this storage medium. This review and provided outlook establish a groundwork for further innovation on hydrogen hydrate systems for promising future of hydrogen fuel.
Investigation of the Influence of Pre-Charged Hydrogen on Fracture Toughness of As-Received 2.25Cr1Mo0.25V Steel and Weld
Jun 2018
Publication
Fracture failure caused by hydrogen embrittlement (HE) is a major concern for the system reliability and safety of hydrogen storage vessels which are generally made of 2.25Cr1Mo0.25V steel. Thus study of the influence of pre-charged hydrogen on fracture toughness of as-received 2.25Cr1Mo0.25V steel and weld is of significant importance. In the current work the influence of hydrogen on fracture toughness of as-received 2.25Cr1Mo0.25V steel and weld was systematically studied. Base metal (BM) and weld metal (WM) specimens under both hydrogen-free and hydrogen-charged conditions were tested using three-point bending tests. Hydrogen was pre-charged inside specimens by the immersion charging method. The J-integral values were calculated for quantitatively evaluating the fracture toughness. In order to investigate the HE mechanisms optical microscopy (OM) and scanning electron microscopy (SEM) were used to characterize the microstructure of BM and WM specimens. The results revealed that the presence of pre-charged hydrogen caused a significant decrease of the fracture toughness for both BM and WM specimens. Moreover the pre-charged hydrogen led to a remarkable transition of fracture mode from ductile to brittle pattern in 2.25Cr1Mo0.25V steel.
Optimisation-based System Designs for Deep Offshore Wind Farms including Power to Gas Technologies
Feb 2022
Publication
A large deployment of energy storage solutions will be required by the stochastic and non-controllable nature of most renewable energy sources when planning for higher penetration of renewable electricity into the energy mix. Various solutions have been suggested for dealing with medium- and long-term energy storage. Hydrogen and ammonia are two of the most frequently discussed as they are both carbon-free fuels. In this paper the authors analyse the energy and cost efficiency of hydrogen and ammonia-based pathways for the storage transportation and final use of excess electricity from an offshore wind farm. The problem is solved as a linear programming problem simultaneously optimising the size of each problem unit and the respective time-dependent operational conditions. As a case study we consider an offshore wind farm of 1.5 GW size located in a reference location North of Scotland. The energy efficiency and cost of the whole chain are evaluated and compared with competitive alternatives namely batteries and liquid hydrogen storage. The results show that hydrogen and ammonia storage can be part of the optimal solution. Moreover their use for long-term energy storage can provide a significant cost-effective contribution to an extensive penetration of renewable energy sources in national energy systems.
Fractographic Features of Long Term Operated Gas Pipeline Steels Fracture Under Impact Loading
Jan 2020
Publication
Pipelines during their service life subjected to operational degradation i.e. their mechanical characteristics worsened with time. Pronounced texture of pipe steels associated with their manufacturing process revealed itself in an essential difference in impact toughness determined for specimens cut in mutually perpendicular directions with respect to the pipe axis. Higher KCV values for longitudinal specimens as compared with transverse ones were explained by the difference in a length of perlite grain strips separated by ferrite grains in specimens of different orientation. A role of hydrogen absorbed my metal during its operation in steel degradation was discussed.<br/>The main fractographic peculiarity for the operated steels comparing to the steels in the initial state is the appearance of delamination on the fracture surfaces which are oriented in the rolling direction. Correlation was found for the tested steels between fractographic sings of their embrittlement due to operational degradation and their loss of brittle fracture resistance. It is concluded that a decrease of impact toughness caused by long term operation of pipeline steels is definitely concerned with the amount of delamination on the fracture surfaces.
Property Optimization in As-Quenched Martensitic Steel by Molybdenum and Niobium Alloying
Apr 2018
Publication
Niobium microalloying is the backbone of modern low-carbon high strength low alloy (HSLA) steel metallurgy providing a favorable combination of strength and toughness by pronounced microstructural refinement. Molybdenum alloying is established in medium-carbon quenching and tempering of steel by delivering high hardenability and good tempering resistance. Recent developments of ultra-high strength steel grades such as fully martensitic steel can be optimized by using beneficial metallurgical effects of niobium and molybdenum. The paper details the metallurgical principles of both elements in such steel and the achievable improvement of properties. Particularly the underlying mechanisms of improving toughness and reducing the sensitivity towards hydrogen embrittlement by a suitable combination of molybdenum and niobium alloying will be discussed.
Recent Progress Using Solid-State Materials for Hydrogen Storage: A Short Review
Feb 2022
Publication
With the rapid growth in demand for effective and renewable energy the hydrogen era has begun. To meet commercial requirements efficient hydrogen storage techniques are required. So far four techniques have been suggested for hydrogen storage: compressed storage hydrogen liquefaction chemical absorption and physical adsorption. Currently high-pressure compressed tanks are used in the industry; however certain limitations such as high costs safety concerns undesirable amounts of occupied space and low storage capacities are still challenges. Physical hydrogen adsorption is one of the most promising techniques; it uses porous adsorbents which have material benefits such as low costs high storage densities and fast charging–discharging kinetics. During adsorption on material surfaces hydrogen molecules weakly adsorb at the surface of adsorbents via long-range dispersion forces. The largest challenge in the hydrogen era is the development of progressive materials for efficient hydrogen storage. In designing efficient adsorbents understanding interfacial interactions between hydrogen molecules and porous material surfaces is important. In this review we briefly summarize a hydrogen storage technique based on US DOE classifications and examine hydrogen storage targets for feasible commercialization. We also address recent trends in the development of hydrogen storage materials. Lastly we propose spillover mechanisms for efficient hydrogen storage using solid-state adsorbents.
Review on the Influence of Temperature upon Hydrogen Effects in Structural Alloys
Mar 2021
Publication
It is well-documented experimentally that the influence of hydrogen on the mechanical properties of structural alloys like austenitic stainless steels nickel superalloys and carbon steels strongly depends on temperature. A typical curve plotting any hydrogen-affected mechanical property as a function of temperature gives a temperature THEmax where the degradation of this mechanical property reaches a maximum. Above and below this temperature the degradation is less. Unfortunately the underlying physico-mechanical mechanisms are not currently understood to the level of detail required to explain such temperature effects. Though this temperature effect is important to understand in the context of engineering applications studies to explain or even predict the effect of temperature upon the mechanical properties of structural alloys could not be identified. The available experimental data are scattered significantly and clear trends as a function of chemistry or microstructure are difficult to see. Reported values for THEmax are in the range of about 200–340 K which covers the typical temperature range for the design of structural components of about 230–310 K (from −40 to +40 °C). That is the value of THEmax itself as well as the slope of the gradient might affect the materials selection for a dedicated application. Given the current lack of scientific understanding a statistical approach appears to be a suitable way to account for the temperature effect in engineering applications. This study reviews the effect of temperature upon hydrogen effects in structural alloys and proposes recommendations for test temperatures for gaseous hydrogen applications
Wax: A Benign Hydrogen-storage Material that Rapidly Releases H2-rich Gases Through Microwave-assisted Catalytic Decomposition
Oct 2016
Publication
Hydrogen is often described as the fuel of the future especially for application in hydrogen powered fuel-cell vehicles (HFCV’s). However its widespread implementation in this role has been thwarted by the lack of a lightweight safe on-board hydrogen storage material. Here we show that benign readily available hydrocarbon wax is capable of rapidly releasing large amounts of hydrogen through microwave-assisted catalytic decomposition. This discovery offers a new material and system for safe and efficient hydrogen storage and could facilitate its application in a HFCV. Importantly hydrogen storage materials made of wax can be manufactured through completely sustainable processes utilizing biomass or other renewable feedstocks.
European Hydrogen Backbone
Jul 2020
Publication
This paper authored by eleven gas infrastructure companies and supported by Guidehouse describes how a dedicated hydrogen infrastructure can be created in
a significant part of the EU between 2030 and 2040 requiring work to start during the 2020s. The hydrogen infrastructure as proposed in this paper fits well with the ambitions of the EU Hydrogen Strategy and the Energy System Integration Strategy plus it aligns well with the goals of the recently announced Clean Hydrogen Alliance to scale up hydrogen enabled by hydrogen transport. Hydrogen clearly gains momentum and this paper aims to provide a contribution towards accelerating a large scale-up of hydrogen by enabling its transport from supply to demand across Europe.
This paper analyses the likely routes across Europe by 2030 2035 and 2040. The included maps show the suggested topology of hydrogen pipelines in ten European countries: Germany France Italy Spain the Netherlands Belgium Czech Republic Denmark Sweden and Switzerland.
You can download the whole report by clicking this link
a significant part of the EU between 2030 and 2040 requiring work to start during the 2020s. The hydrogen infrastructure as proposed in this paper fits well with the ambitions of the EU Hydrogen Strategy and the Energy System Integration Strategy plus it aligns well with the goals of the recently announced Clean Hydrogen Alliance to scale up hydrogen enabled by hydrogen transport. Hydrogen clearly gains momentum and this paper aims to provide a contribution towards accelerating a large scale-up of hydrogen by enabling its transport from supply to demand across Europe.
This paper analyses the likely routes across Europe by 2030 2035 and 2040. The included maps show the suggested topology of hydrogen pipelines in ten European countries: Germany France Italy Spain the Netherlands Belgium Czech Republic Denmark Sweden and Switzerland.
You can download the whole report by clicking this link
Advanced Optimal Planning for Microgrid Technologies Including Hydrogen and Mobility at a Real Microgrid Testbed
Apr 2021
Publication
This paper investigates the optimal planning of microgrids including the hydrogen energy system through mixed-integer linear programming model. A real case study is analyzed by extending the only microgrid lab facility in Austria. The case study considers the hydrogen production via electrolysis seasonal storage and fuelling station for meeting the hydrogen fuel demand of fuel cell vehicles busses and trucks. The optimization is performed relative to two different reference cases which satisfy the mobility demand by diesel fuel and utility electricity based hydrogen fuel production respectively. The key results indicate that the low emission hydrogen mobility framework is achieved by high share of renewable energy sources and seasonal hydrogen storage in the microgrid. The investment optimization scenarios provide at least 66% and at most 99% carbon emission savings at increased costs of 30% and 100% respectively relative to the costs of the diesel reference case (current situation)
Long-Term Hydrogen Storage—A Case Study Exploring Pathways and Investments
Jan 2022
Publication
Future low-carbon systems with very high shares of variable renewable generation require complex models to optimise investments and operations which must capture high degrees of sector coupling contain high levels of operational and temporal detail and when considering seasonal storage be able to optimise both investments and operations over long durations. Standard energy system models often do not adequately address all these issues which are of great importance when considering investments in emerging energy carriers such as Hydrogen. An advanced energy system model of the Irish power system is built in SpineOpt which considers a number of future scenarios and explores different pathways to the wide-scale adoption of Hydrogen as a low-carbon energy carrier. The model contains a high degree of both temporal and operational detail sector coupling via Hydrogen is captured and the optimisation of both investments in and operation of large-scale underground Hydrogen storage is demonstrated. The results highlight the importance of model detail and demonstrate how over-investment in renewables occur when the flexibility needs of the system are not adequately captured. The case study shows that in 2030 investments in Hydrogen technologies are limited to scenarios with high fuel and carbon costs high levels of Hydrogen demand (in this case driven by heating demand facilitated by large Hydrogen networks) or when a breakthrough in electrolyser capital costs and efficiencies occurs. However high levels of investments in Hydrogen technologies occur by 2040 across all considered scenarios. As with the 2030 results the highest level of investments occur when demand for Hydrogen is high albeit at a significantly higher level than 2030 with increases in investments of large-scale electrolysers of 538%. Hydrogen fuelled compressed air energy storage emerges as a strong investment candidate across all scenarios facilitating cost effective power-to-Hydrogen-to-power conversions.
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.
Integration of Wind Energy, Hydrogen and Natural Gas Pipeline Systems to Meet Community and Transportation Energy Needs: A Parametric Study
Apr 2014
Publication
The potential benefits are examined of the “Power-to-Gas” (P2G) scheme to utilize excess wind power capacity by generating hydrogen (or potentially methane) for use in the natural gas distribution grid. A parametric analysis is used to determine the feasibility and size of systems producing hydrogen that would be injected into the natural gas grid. Specifically wind farms located in southwestern Ontario Canada are considered. Infrastructure requirements wind farm size pipeline capacity geographical dispersion hydrogen production rate capital and operating costs are used as performance measures. The model takes into account the potential production rate of hydrogen and the rate that it can be injected into the local gas grid. “Straw man” systems are examined centered on a wind farm size of 100 MW integrating a 16-MW capacity electrolysis system typically producing 4700 kg of hydrogen per day.
Hydrogen/Manganese Hybrid Redox Flow Battery
Dec 2018
Publication
Electrochemical energy storage is a key enabling technology for further integration of renewables sources. Redox flow batteries(RFBs) are promising candidates for such applications as a result of their durability efficiency and fast response. However deployment of existing RFBs is hindered by the relatively high cost of the (typically vanadium-based) electrolyte. Manganese is an earth-abundant and inexpensive element that is widely used in disposable alkaline batteries. However it has hitherto been little explored for RFBs due to the instability of Mn(III) leading to precipitation of MnO2 via a disproportionation reaction. Here we show that by combining the facile hydrogen negative electrode reaction with electrolytes that suppress Mn(III) disproportionation it is possible to construct a hydrogen/manganese hybrid RFB with high round trip energy efficiency (82%) and high power and energy density (1410 mW cm−2 33 Wh l−1 ) at an estimated 70% cost reduction compared to vanadium redox flow batteries.
Strength, Hardness, and Ductility Evidence of Solid Solution Strengthening and Limited Hydrogen Embrittlement in the Alloy System Palladium-Copper (Cu wt. % 5–25)
Jul 2021
Publication
Strength hardness and ductility characteristics were determined for a series of palladium-copper alloys that compositionally vary from 5 to 25 weight percent copper. Alloy specimens subjected to vacuum annealing showed clear evidence of solid solution strengthening. These specimens showed as a function of increasing copper content increased yield strength ultimate strength and Vickers microhardness while their ductility was little affected by compositional differences. Annealed alloy specimens subsequently subjected to exposure to hydrogen at 323 K and PH2 = 1 atm showed evidence of hydrogen embrittlement up to a composition of ~15 wt. % Cu. The magnitude of the hydrogen embrittlement decreased with increasing copper content in the alloy.
The Effect of Hydrogen Content and Yield Strength on the Distribution of Hydrogen in Steel a Diffusion Coupled Micromechanical FEM Study
Mar 2021
Publication
In this study we investigate the effect of the heterogeneous micromechanical stress fields resulting from the grain-scale anisotropy on the redistribution of hydrogen using a diffusion coupled crystal plasticity model. A representative volume element with periodic boundary conditions was used to model a synthetic microstructure. The effect of tensile loading initial hydrogen content and yield strength on the redistribution of lattice (CL) and dislocation trapped (Cx) hydrogen was studied. It was found that the heterogeneous micromechanical stress fields resulted in the accumulation of both populations primarily at the grain boundaries. This shows that in addition to the well-known grain boundary trapping the interplay of the heterogeneous micromechanical hydrostatic stresses and plastic strains contribute to the accumulation of hydrogen at the grain boundaries. Higher yield strength reduced the amount of Cx due to the resulting lower plastic deformation levels. On the other side the resulting higher hydrostatic stresses increased the depletion of CL from the compressive regions and its diffusion toward the tensile ones. These regions with increased CL are expected to be potential damage initiation zones. This aligns with the observations that high-strength steels are more susceptible to hydrogen embrittlement than those with lower-strength.
Materials for End to End Hydrogen Roadmap
Jun 2021
Publication
This report is commissioned by the Henry Royce Institute for advanced materials as part of its role around convening and supporting the UK advanced materials community to help promote and develop new research activity. The overriding objective is to bring together the advanced materials community to discuss analyse and assimilate opportunities for emerging materials research for economic and societal benefit. Such research is ultimately linked to both national and global drivers namely Transition to Zero Carbon Sustainable Manufacture Digital & Communications Circular Economy as well as Health & Wellbeing.
This paper can be download from their website
This paper can be download from their website
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 consists of a nonlocal crystal plasticity model coupled with hydrogen transport model to study the fatigue behaviour of hydrogen charged metals. The nonlocal crystal plasticity model accounts for the statistically stored dislocations (SSDs) and geometrically necessary dislocations (GNDs) in polycrytalline metal. Hydrogen transport model on the other hand accounts for diffusion and trapping behavior of hydrogen due to concentration gradient pressure gradient plastic strain-rate with dislocations as the only trapping sites along the slip systems. A polycrystalline representative volume element (RVE) with periodic boundary conditions is used in this study. Fatigue crack initiation criterion is proposed for the simulated RVE with controlled microstructure by considering a critical value of the fatigue indicator parameter (FIP). FIP is formulated based on the experimental observations of several crack initiation sites along the grain boundaries their normal direction with respect to loading direction and the accumulated plastic strain in nickel polycrystalline samples. Developed simulation framework correctly accounts cyclic stress-strain behavior and multiple fatigue crack initiation sites observed experimentally in the presence of hydrogen.
The Role of κ-Carbides as Hydrogen Traps in High-Mn Steels
Jul 2017
Publication
Since the addition of Al to high-Mn steels is known to reduce their sensitivity to hydrogen-induced delayed fracture we investigate possible trapping effects connected to the presence of Al in the grain interior employing density-functional theory (DFT). The role of Al-based precipitates is also investigated to understand the relevance of short-range ordering effects. So-called E21-Fe3AlC κ-carbides are frequently observed in Fe-Mn-Al-C alloys. Since H tends to occupy the same positions as C in these precipitates the interaction and competition between both interstitials is also investigated via DFT-based simulations. While the individual H–H/C–H chemical interactions are generally repulsive the tendency of interstitials to increase the lattice parameter can yield a net increase of the trapping capability. An increased Mn content is shown to enhance H trapping due to attractive short-range interactions. Favorable short-range ordering is expected to occur at the interface between an Fe matrix and the E21-Fe3AlC κ-carbides which is identified as a particularly attractive trapping site for H. At the same time accumulation of H at sites of this type is observed to yield decohesion of this interface thereby promoting fracture formation. The interplay of these effects evident in the trapping energies at various locations and dependent on the H concentration can be expressed mathematically resulting in a term that describes the hydrogen embrittlement
Aging Effects on Modelling and Operation of a Photovoltaic System with Hydrogen Storage
Jun 2021
Publication
In this work the aging effects on modelling and operation of a photovoltaic system with hydrogen storage in terms of energy production decrease and demand for additional hydrogen during 10 years of the system operation was analysed for the entire energy system for the first time. The analyses were performed with the support of experimental data for the renewable energy system composed of photovoltaic modules fuel cell electrolysers hydrogen storage and hydrogen backup.<br/>It has been found that the total degradation of the analysed system can be described by the proposed parameter – unit additional hydrogen consumption ratio. The results reveal a 33.2–36.2% increase of the unit fuel requirement from an external source after 10 years in reference to the initial condition. Degradation of the components can on the other hand be well described with the unit hydrogen consumption ratio by fuel cell for electricity or the unit electricity consumption ratio by electrolyser for hydrogen production which has been found to vary for the electrolyser in the range of 4.6–4.9% and for the fuel cell stack in the range of 13.4–15.1% during the 10 years of the system operation. The analyses indicate that this value depends on the load profile and PV module types and the system performance decline is non-linear."
Hydrogen Diffusion in Coal: Implications for Hydrogen Geo-storage
Oct 2021
Publication
Hypothesis: Hydrogen geo-storage is considered as an option for large scale hydrogen storage in a full-scale hydrogen economy. Among different types of subsurface formations coal seams look to be one of the best suitable options as coal’s micro/nano pore structure can adsorb a huge amount of gas (e.g. hydrogen) which can be withdrawn again once needed. However literature lacks fundamental data regarding H2 diffusion in coal. Experiments: In this study we measured H2 adsorption rate in an Australian anthracite coal sample at isothermal conditions for four different temperatures (20 C 30 C 45 C and 60 C) at equilibrium pressure 13 bar and calculated H2 diffusion coefficient (DH2 ) at each temperature. CO2 adsorption rates were measured for the same sample at similar temperatures and equilibrium pressure for comparison. Findings: Results show that H2 adsorption rate and consequently DH2 increases by temperature. DH2 values are one order of magnitude larger than the equivalent DCO2 values for the whole studied temperature range 20–60 C. DH2 / DCO2 also shows an increasing trend versus temperature. CO2 adsorption capacity at equilibrium pressure is about 5 times higher than that of H2 in all studied temperatures. Both H2 and CO2 adsorption capacities at equilibrium pressure slightly decrease as temperature rises.
Research on Carbide Characteristics and Their Influence on the Properties of Welding Joints for 2.25Cr1Mo0.25V Steel
Feb 2021
Publication
The carbide characteristics of 2.25Cr1Mo0.25V steel have an extremely important influence on the mechanical properties of welding joints. In addition hydrogen resistance behavior is crucial for steel applied in hydrogenation reactors. The carbide morphology was observed by scanning electron microscopy (SEM) and the carbide microstructure was characterized by transmission electron microscopy (TEM). Tensile and impact tests were carried out and the influence of carbides on properties was studied. A hydrogen diffusion test was carried out and the hydrogen brittleness resistance of welding metal and base metal was studied by tensile testing of hydrogenated samples to evaluate the influence of hydrogen on the mechanical properties. The research results show that the strength of the welding metal was slightly higher and the Charpy impact value was significantly lower compared to the base metal. The hydrogen embrittlement resistance of the welding metal was stronger than that of the base metal. The presence of more carbides and inclusions was the main cause of the decreased impact property and hydrogen brittleness resistance of the welding metal. These conclusions have certain reference value for designing and manufacturing hydrogenation reactors. View Full-Text
Research on the Concept of Hydrogen Supply Chains and Power Grids Powered by Renewable Energy Sources: A Scoping Review with the Use of Text Mining
Jan 2022
Publication
The key direction of political actions in the field of sustainable development of the energy sector and economy is the process of energy transformation (decarbonization) and increasing the share of renewable energy sources (RES) in the supply of primary energy. Regardless of the indisputable advantages RES are referred to as unstable energy sources. A possible solution might be the development of the concept of hydrogen supply chains especially the so-called green hydrogen obtained in the process of electrolysis from electricity produced from RES. The aim of the research undertaken in the article is to identify the scope of research carried out in the area of hydrogen supply chains and to link this research with the issues of the operation of electricity distribution networks powered by RES. As a result of the scoping review and the application of the text-mining method using the IRaMuTeQ tool which includes the analysis of the content of 12 review articles presenting the current research achievements in this field over the last three years (2016–2020) it was established that the issues related to hydrogen supply chains including green hydrogen are still not significantly associated with the problem of the operation of power grids. The results of the conducted research allow formulating recommendations for further research areas.
Recent Advances in Pd-Based Membranes for Membrane Reactors
Jan 2017
Publication
Palladium-based membranes for hydrogen separation have been studied by several research groups during the last 40 years. Much effort has been dedicated to improving the hydrogen flux of these membranes employing different alloys supports deposition/production techniques etc. High flux and cheap membranes yet stable at different operating conditions are required for their exploitation at industrial scale. The integration of membranes in multifunctional reactors (membrane reactors) poses additional demands on the membranes as interactions at different levels between the catalyst and the membrane surface can occur. Particularly when employing the membranes in fluidized bed reactors the selective layer should be resistant to or protected against erosion. In this review we will also describe a novel kind of membranes the pore-filled type membranes prepared by Pacheco Tanaka and coworkers that represent a possible solution to integrate thin selective membranes into membrane reactors while protecting the selective layer. This work is focused on recent advances on metallic supports materials used as an intermetallic diffusion layer when metallic supports are used and the most recent advances on Pd-based composite membranes. Particular attention is paid to improvements on sulfur resistance of Pd based membranes resistance to hydrogen embrittlement and stability at high temperature.
Effect of α′ Martensite Content Induced by Tensile Plastic Prestrain on Hydrogen Transport and Hydrogen Embrittlement of 304L Austenitic Stainless Steel
Aug 2018
Publication
Effects of microstructural changes induced by prestraining on hydrogen transport and hydrogen embrittlement (HE) of austenitic stainless steels were studied by hydrogen precharging and tensile testing. Prestrains higher than 20% at 20 °C significantly enhance the HE of 304L steel as they induce severe α′ martensite transformation accelerating hydrogen transport and hydrogen entry during subsequent hydrogen exposure. In contrast 304L steel prestrained at 50 and 80 °C and 316L steel prestrained at 20 °C exhibit less HE due to less α′ after prestraining. The increase of dislocations after prestraining has a negligible influence on apparent hydrogen diffusivity compared with pre-existing α′. The deformation twins in heavily prestrained 304L steel can modify HE mechanism by assisting intergranular (IG) fracture. Regardless of temperature and prestrain level HE and apparent diffusivity ( Dapp ) increase monotonously with α′ volume fraction ( fα′ ). Dapp can be described as log Dapp=log(Dα′sα′/sγ)+log[fα′/(1−fα′)] for 10%<fα′<90% with Dα′ is diffusivity in α′ sα′ and sγ are solubility in α′ and austenite respectively. The two equations can also be applied to these more typical duplex materials containing both BCC and FCC phases.
Investigation of the Hydrogen Embrittlement Susceptibility of T24 Boiler Tubing in the Context of Stress Corrosion Cracking of its Welds
Dec 2018
Publication
For the membrane and spiral walls of the new USC boilers the advanced T24 material was developed. In 2010 however extensive T24 tube weld cracking during the commissioning phase of several newly built boilers was observed. As the dominant root cause Hydrogen Induced - Stress Corrosion Cracking was reported. An investigation into the interaction of the T24 material with hydrogen was launched in order to compare its hydrogen embrittlement susceptibility with that of the T12 steel commonly used for older boiler evaporators. Both base materials and simulated Heat Affected Zone (HAZ) microstructures were tested. Total and diffusible hydrogen in the materials after electrochemical charging were measured. Thermo Desorption Spectrometry was used to gain insights into the trapping behaviour and the apparent diffusion coefficient at room temperature was determined. Based on the hardness and the diffusible hydrogen pick-up capacity of the materials it was concluded that T12 is less susceptible to hydrogen embrittlement than T24 as base material as well as in the HAZ condition and that the HAZ of T24 is more susceptible to hydrogen embrittlement than the base material both in the as welded and in the Post Weld Heat Treated (PWHT) condition. However based on the results of this investigation it could not be determined if the T24 HAZ is less susceptible to hydrogen embrittlement after PWHT.
Influence of Pressure, Temperature and Organic Surface Concentration on Hydrogen Wettability of Caprock; Implications for Hydrogen Geo-storage
Sep 2021
Publication
Hydrogen (H2) as a cleaner fuel has been suggested as a viable method of achieving the decarbonization objectives and meeting increasing global energy demand. However successful implementation of a full-scale hydrogen economy requires large-scale hydrogen storage (as hydrogen is highly compressible). A potential solution to this challenge is injecting hydrogen into geologic formations from where it can be withdrawn again at later stages for utilization purposes. The geostorage capacity of a porous formation is a function of its wetting characteristics which strongly influence residual saturations fluid flow rate of injection rate of withdrawal and containment security. However literature severely lacks information on hydrogen wettability in realistic geological and caprock formations which contain organic matter (due to the prevailing reducing atmosphere). We therefore measured advancing (θa) and receding (θr) contact angles of mica substrates at various representative thermo-physical conditions (pressures 0.1-25 MPa temperatures 308–343 K and stearic acid concentrations of 10−9 - 10−2 mol/L). The mica exhibited an increasing tendency to become weakly water-wet at higher temperatures lower pressures and very low stearic acid concentration. However it turned intermediate-wet at higher pressures lower temperatures and increasing stearic acid concentrations. The study suggests that the structural H2 trapping capacities in geological formations and sealing potentials of caprock highly depend on the specific thermo-physical condition. Thus this novel data provides a significant advancement in literature and will aid in the implementation of hydrogen geo-storage at an industrial scale.
Techno-economic Feasibility of Road Transport of Hydrogen Using Liquid Organic Hydrogen Carriers
Sep 2020
Publication
The cost of storing and transporting hydrogen have been one of the main challenges for the realization of the hydrogen economy. Liquid organic hydrogen carriers (LOHC) are a promising novel solution to tackle these challenges. In this paper we compare the LOHC concept to compressed gas truck delivery and on-site production of hydrogen via water electrolysis. As a case study we consider transportation of by-product hydrogen from chlor-alkali and chlorate plants to a single industrial customer which was considered to have the greatest potential for the LOHC technology to enter the markets. The results show that the LOHC delivery chain could significantly improve the economics of long distance road transport. For economic feasibility the most critical parameters identified are the heat supply method for releasing hydrogen at the end-user site and the investment costs for LOHC reactors.
Electrochemical Fracture Analysis of In-service Natural Gas Pipeline Steels
Dec 2018
Publication
Long-term operation of natural gas transit pipelines implies aging hydrogen-induced and stress corrosion cracking and it causes hydrogen embrittlement of steels degradation of mechanical properties associated to a safe serviceability of pipelines and failure risk increase. The implementation of effective diagnostic measures of pipelines steels degradation would allow planning actions in order to reduce a risk of fracture. In this paper a new scientific and methodical approach based on the electrochemical analysis of fracture surface for evaluation of in-service degradation of operated pipeline steels was developed. It was suggested that carbon diffusion to grain boundaries and to defects inside grains intensified by hydrogen under long-term operation led to formation of nanoparticles of carbides which resulted in intergranular cracking of operated pipeline steels under service and their transgranular cracking under impact toughness testing. Therefore fracture surface was enriched by carbon compounds and electrochemical characteristics were sensitive to this. In-service degradation of ferrite-pearlite pipeline steels was accompanied by a sharp shift in open-circuit potential of the fracture surface (brittle fracture) of specimens after impact toughness tests compared with that of polished steel surfaces. A significant difference between potentials of the fracture surface and the polished steel surface (over 60 mV in 0.3% NaCl solution) of specimens made of ferrite-pearlite pipeline steels observed after their long-term operation was evidently due to the increased content of carbon compounds on the fracture surface. Mechanism of ferrite-pearlite pipeline steels embrittlement under operation consisted in carbides enrichment not only grain boundaries but also intragranular defects has been revealed as it is indicated by an increase of carbon content on transgranular fracture surfaces determined electrochemically.
Sulfide Stress Cracking of C-110 Steel in a Sour Environment
Jul 2021
Publication
The scope of this study includes modeling and experimental investigation of sulfide stress cracking (SSC) of high-strength carbon steel. A model has been developed to predict hydrogen permeation in steel for a given pressure and temperature condition. The model is validated with existing and new laboratory measurements. The experiments were performed using C-110 grade steel specimens. The specimens were aged in 2% (wt.) brine saturated with mixed gas containing CH4 CO2 and H2S. The concentration H2S was maintained constant (280 ppm) while varying the partial pressure ratio of CO2 (i.e. the ratio of partial pressure of CO2 to the total pressure) from 0 to 15%. The changes occurring in the mechanical properties of the specimens were evaluated after exposure to assess material embrittlement and SSC corrosion. Besides this the cracks developed on the surface of the specimens were examined using an optical microscope. Results show that the hydrogen permeation and subsequently SSC resistance of C-110 grade steel were strongly influenced by the Partial Pressure Ratio (PPR) of CO2 when the PPR was between 0 and 5%. The PPR of CO2 had a limited impact on the SSC process when it was between 10 and 15 percent.
The UK Carbon Capture, Usage and Storage (CCUS) Deployment Pathway: An Action Plan
Nov 2018
Publication
CCUS has economy-wide qualities which could be very valuable to delivering clean industrial growth. It could deliver tangible results in tackling some of the biggest challenges we face in decarbonising our economy contributing to industrial competitiveness and generating new economic opportunities – a key part of our modern Industrial Strategy.
Our vision is to become a global leader in CCUS unlocking the potential of the technology and securing the added value which it can bring to our industrial centres and businesses all across the UK.
Our ambition is that the UK should have the option to deploy CCUS at scale during the 2030s subject to the costs coming down sufficiently.
Our Industrial Strategy set out four Grand Challenges to put the UK at the forefront of the industries of the future. The Clean Growth Grand Challenge seeks to maximise the advantages for UK industry from the global shift to clean growth. CCUS can be an important part of achieving these objectives.
Our vision is to become a global leader in CCUS unlocking the potential of the technology and securing the added value which it can bring to our industrial centres and businesses all across the UK.
Our ambition is that the UK should have the option to deploy CCUS at scale during the 2030s subject to the costs coming down sufficiently.
Our Industrial Strategy set out four Grand Challenges to put the UK at the forefront of the industries of the future. The Clean Growth Grand Challenge seeks to maximise the advantages for UK industry from the global shift to clean growth. CCUS can be an important part of achieving these objectives.
Corrosion Mechanisms of High-Mn Twinning-Induced Plasticity (TWIP) Steels: A Critical Review
Feb 2021
Publication
Twinning-induced plasticity (TWIP) steels have higher strength and ductility than conventional steels. Deformation mechanisms producing twins that prevent gliding and stacking of dislocations cause a higher ductility than that of steel grades with the same strength. TWIP steels are considered to be within the new generation of advanced high-strength steels (AHSS). However some aspects such as the corrosion resistance and performance in service of TWIP steel materials need more research. Application of TWIP steels in the automotive industry requires a proper investigation of corrosion behavior and corrosion mechanisms which would indicate the optimum degree of protection and the possible decrease in costs. In general Fe−Mn-based TWIP steel alloys can passivate in oxidizing acid neutral and basic solutions however they cannot passivate in reducing acid or active chloride solutions. TWIP steels have become as a potential material of interest for automotive applications due to their effectiveness impact resistance and negligible harm to the environment. The mechanical and corrosion performance of TWIP steels is subjected to the manufacturing and processing steps like forging and casting elemental composition and thermo-mechanical treatment. Corrosion of TWIP steels caused by both intrinsic and extrinsic factors has posed a serious problem for their use. Passivity breakdown caused by pitting and galvanic corrosion due to phase segregation are widely described and their critical mechanisms examined. Numerous studies have been performed to study corrosion behaviour and passivation of TWIP steel. Despite the large number of articles on corrosion few comprehensive reports have been published on this topic. The current trend for development of corrosion resistance TWIP steel is thoroughly studied and represented showing the key mechanisms and factors influencing corrosion processes and its consequences on TWIP steel. In addition suggestions for future works and gaps in the literature are considered.
Energy Transition: Measurement Needs for Carbon Capture, Usage and Storage
Jan 2021
Publication
This latest report describes the potential for CCUS as an important technology during the UK’s energy transition and focuses on the role that metrology (the science of measurement) could play in supporting its deployment. High priority measurement needs and challenges identified within this report include:
- Measuring and comparing the efficiency of different capture techniques and configurations to provide confidence in investments into technologies;
- Improving equations of state to support the development of accurate models used for controlling operational conditions;
- Improving CO2 flow measurement to support fiscal and financial metering as well as process control and;
- Improving the understanding and validation of dispersion models for emitted CO2 including plume migration to support safety assessment.
Combined Soft Templating with Thermal Exfoliation Toward Synthesis of Porous g-C3N4 Nanosheets for Improved Photocatalytic Hydrogen Evolution
Apr 2021
Publication
Insufficient active sites and fast charge carrier recombination are detrimental to photocatalytic activity of graphitic carbon nitride (g-C3N4). In this work a combination of pore creating with thermal exfoliation was employed to prepare porous g-C3N4 nanosheets for photocatalytic water splitting into hydrogen. Hexadecyl trimethyl ammonium chloride (CTAC) as the soft template promoted the formation of porous g-C3N4 during the thermal condensation of melamine. On further post-synthesis calcination the porous g-C3N4 aggregates were exfoliated into discrete nanosheets accompanied by an increase in specific surface area and defects. Optimal porous g-C3N4 nanosheets achieved 3.6 times the photocatalytic hydrogen evolution rate for bulk counterpart. The enhanced photocatalytic activity may be ascribed to TCN-1%CTAC has larger specific surface area stronger optical absorption intensity and higher photogenerated electron–hole separation efficiency. The external quantum efficiency of TCN-1%CTAC was measured to be 3.4% at 420 nm. This work provides a simple combinatorial strategy for the preparation of porous g-C3N4 nanosheets with low cost environmental friendliness and enhanced photocatalytic activity.
Enhanced Hydrogen Storage of Alanates: Recent Progress and Future Perspectives
Feb 2021
Publication
The global energy crisis and environmental pollution have caused great concern. Hydrogen is a renewable and environmentally friendly source of energy and has potential to be a major alternative energy carrier in the future. Due to its high capacity and relatively low cost of raw materials alanate has been considered as one of the most promising candidates for hydrogen storage. Among them LiAlH4 and NaAlH4 as two representative metal alanates have attracted extensive attention. Unfortunately the high desorption temperature and sluggish kinetics restrict its practical application. In this paper the basic physical and chemical properties as well as the hydrogenation/dehydrogenation reaction mechanism of LiAlH4 and NaAlH4 are briefly reviewed. The recent progress on strategic optimizations toward tuning the thermodynamics and kinetics of the alanate including nanoscaling doping catalysts and compositing modification are emphatically discussed. Finally the coming challenges and the development prospects are also proposed in this review.
The Synergistic Effects of Alloying on the Performance and Stability of Co3Mo and Co7Mo6 for the Electrocatalytic Hydrogen Evolution Reaction
Oct 2020
Publication
Metal alloys have become a ubiquitous choice as catalysts for electrochemical hydrogen evolution in alkaline media. However scarce and expensive Pt remains the key electrocatalyst in acidic electrolytes making the search for earth-abundant and cheaper alternatives important. Herein we present a facile and efficient synthetic route towards polycrystalline Co3Mo and Co7Mo6 alloys. The single-phased nature of the alloys is confirmed by X-ray diffraction and electron microscopy. When electrochemically tested they achieve competitively low overpotentials of 115 mV (Co3Mo ) and 160 mV (Co7Mo6 ) at 10 mA cm−2 in 0.5 M H2SO4 and 120 mV (Co3Mo ) and 160 mV (Co7Mo6 ) at 10 mA cm−2 in 1 M KOH. Both alloys outperform Co and Mo metals which showed significantly higher overpotentials and lower current densities when tested under identical conditions confirming the synergistic effect of the alloying. However the low overpotential in Co3Mo comes at the price of stability. It rapidly becomes inactive when tested under applied potential bias. On the other hand Co7Mo6 retains the current density over time without evidence of current decay. The findings demonstrate that even in free-standing form and without nanostructuring polycrystalline bimetallic electrocatalysts could challenge the dominance of Pt in acidic media if ways for improving their stability were found.
No more items...