- Home
- A-Z Publications
- Publications
Publications
Investigation of Hydrogen Leaks from Double Ferrule Fittings
Sep 2021
Publication
The use of hydrogen is expected to increase rapidly in the future. Leakage of hydrogen pipework are the main forms of safety problems in hydrogen utilization. In this paper a numerical model of hydrogen leakage and diffusion in pipe joints was established. The Schlieren + high-speed camera is used in experiments to observe the leakage of hydrogen in the pipe joints. In addition the shape and size of the scratches in the tube were statistically analyzed. Finally the leakage characteristics of double ferrule joints with scratches are experimentally analyzed. For the two scratch sizes the critical pressure values for the vortex transition are 0.2 MPa and 0.03 MPa. Through our experimental process some practical experience and suggestions are given.
A Promising Cobalt Catalyst for Hydrogen Production
Mar 2022
Publication
In this work a metal cobalt catalyst was synthesized and its activity in the hydrogen production process was tested. The substrates were water and ethanol. Activity tests were conducted at a temperature range of 350–600 °C water to ethanol molar ratio of 3 to 5 and a feed flow of 0.4 to 1.2 mol/h. The catalyst had a specific surface area of 1.75 m2/g. The catalyst was most active at temperatures in the range of 500–600 °C. Under the most favorable conditions the ethanol conversion was 97% the hydrogen production efficiency was 4.9 mol (H2)/mol(ethanol) and coke production was very low (16 mg/h). Apart from hydrogen and coke CO2 CH4 CO and traces of C2H2 and C2H4 were formed.
The Roles of Nuclear Energy in Hydrogen Production
Dec 2021
Publication
Fossil resources are unevenly distributed on the earth and are finite primary energy which is widely used in the fields of industry transportation and power generation etc.<br/>Primary energies that can replace fossil resources include renewable energy and nuclear energy. Hydrogen has the potential to be secondary energy that can be widely used in industry for various purposes. Nuclear energy can be used for producing hydrogen; it is becoming more important to convert this primary energies into hydrogen. This paper describes the roles of nuclear energy as a primary energy in hydrogen production from the viewpoint of the basics of energy form conversion.
Accurate Predictions of the Effect of Hydrogen Composition on the Thermodynamics and Transport Properties of Natural Gas
Mar 2024
Publication
This work demonstrates the need for accurate thermodynamic models to reliably quantify changes in the thermophysical properties of natural gas when blended with hydrogen. For this purpose a systematic evaluation was carried out on the predictive accuracy of three well-known models the Peng−Robinson equation of state (EoS) the multiparameter empirical GERG-2008 model and the molecular-based polar softSAFT EoS in describing the thermodynamic behavior of mixtures of hydrogen with commonly found components in natural gas. Deviations between the calculated properties and experimental data for phase equilibria critical loci second-order derivative properties and viscosities are used to determine the accuracy of the models with polar soft-SAFT performing either equally or better than the other two examined models. The evaluation for the effect of H2 content on the properties of methane simulated as natural gas at conditions for transportation reveals higher changes in blend density and speed of sound with increasing H2 content within 5% change per 5 mol % H2 added while viscosity is the least affected property changing by 0.4% for every 5 mol % H2.
Evidence Base Utilised to Justify a Hydrogen Blend Gas Network Safety Case
Sep 2021
Publication
Blending hydrogen with natural gas up to 20 % mol/mol has been identified as a key enabler of hydrogen deployment within the UK gas network. This work outlines the evidence base generated to form the basis of safety submitted to the Health and Safety Executive (HSE) to justify a demonstration of hydrogen blending on a live public gas network within the UK supplying a hydrogen blend to 668homes over the course of 10 months. An evidence base to demonstrate that gas users are not prejudiced by the addition of hydrogen is required by the Gas Safety (Management) Regulations [1] to allow hydrogen distribution above the 0.1 mol% limit specified within the regulations. The technical evidence generated to support the safety case presented to the HSE concerned the implications of introducing a hydrogen blend on appliance operation materials gas characteristics and operational procedures. The outputs of the technical evidence workstreams provided input data to a Quantitative Risk Assessment (QRA) of the GB gas distribution network. The QRA was developed in support of the safety case to allow a causal understanding of public risk to be understood where harm due to gas usage was defined as risk to life caused either by carbon monoxide poisoning or as a result of fires/explosions. Public records were used to calibrate and validate the base risk model to understand the dynamics of public risk due to natural gas usage. The experimental and analytical results of the technical workstreams were then used to derive risk model inputs relating to a hydrogen blend. This allowed a quantified comparison of risk to be understood to demonstrate parity of safety between natural gas and a hydrogen blend. This demonstration of risk parity is a condition precedent of allowing the distribution and utilisation of hydrogen blends within the GB gas network.
Everything About Hydrogen Podcast: Storage for the Future!
Jan 2022
Publication
For our first episode of 2022 we invited Jørn Helge Dahl Global Director of Sales&Marketing at Hexagon Purus to talk about hydrogen storage with the EAH podcast and to explain the types of solutions available today Hexagon's history and plans for the future alongside some commentary on US hydrogen strategy from the gang.
The podcast can be found on their website
The podcast can be found on their website
Research Efforts for the Resolution of Hydrogen Risk
Jan 2015
Publication
During the past 10 years the Korea Atomic Energy Research Institute (KAERI) has performed a study to control hydrogen gas in the containment of the nuclear power plants. Before the Fukushima accident analytical activities for gas distribution analysis in experiments and plants were primarily conducted using a multidimensional code: the GASFLOW. After the Fukushima accident the COM3D code which can simulate a multi-dimensional hydrogen explosion was introduced in 2013 to complete the multidimensional hydrogen analysis system. The code validation efforts of the multidimensional codes of the GASFLOW and the COM3D have continued to increase confidence in the use of codes using several international experimental data. The OpenFOAM has been preliminarily evaluated for APR1400 containment based on experience from coded validation and the analysis of hydrogen distribution and explosion using the multidimensional codes the GASFLOW and the COM3D. Hydrogen safety in nuclear power has become a much more important issue after the Fukushima event in which hydrogen explosions occurred. The KAERI is preparing a large-scale test that can be used to validate the performance of domestic passive autocatalytic recombiners (PARs) and can provide data for the validation of the severe accident code being developed in Korea
Golden Hydrogen
Nov 2022
Publication
Hydrogen is a colorless compound to which symbolic colors are attributed to classify it according to the resources used in production production processes such as electrolysis and energy vectors such as solar radiation. Green hydrogen is produced mainly by electrolysis of water using renewable electricity from an electricity grid powered by wind geothermal solar or hydroelectric power plants. For grid-powered electrolyzers the tendency is to go larger to reach the gigawatt-scale. An evolution in the opposite direction is the integration of the photophysics of sunlight harvesting and the electrochemistry of water molecule splitting in solar hydrogen generator units with each unit working at kilowatt-scale or less. Solar hydrogen generators are intrinsically modular needing multiplication of units to reach gigawatt-scale. To differentiate these two fundamentally different technologies the term ‘golden hydrogen’ is proposed referring to hydrogen produced by modular solar hydrogen generators. Decentralized modular production of golden hydrogen is complementary to centralized energy-intensive green hydrogen production. The differentiation between green hydrogen and golden hydrogen will facilitate the introduction of the additionality principle in clean hydrogen policy.
Gas Turbine Enclosures: Determining Ventilation Safety Criteria using Hydrogen Explosion Modelling
Sep 2021
Publication
Dilution ventilation is the current basis of safety following a flammable gas leak within a gas turbine enclosure and compliance requirements are defined for methane fuels in ISO 21789. These requirements currently define a safety criteria of a maximum flammable gas cloud size within an enclosure. The requirements are based on methane explosion tests conducted during a HSE Joint Industry Project which identified typical pressures associated with a range of gas cloud sizes. The industry standard approach is to assess the ventilation performance of specific enclosure designs against these requirements using CFD modelling. Gas turbine manufacturers are increasingly considering introducing hydrogen/methane fuel mixtures and looking towards operating with hydrogen alone. It is therefore important to review the applicability of current safety standards for these new fuels as the pressure resulting from a hydrogen explosion is expected to be significantly higher than that from a methane explosion. In this paper we replicate the previous methane explosion tests for hydrogen and hydrogen/methane fuel mixtures using the explosion modelling tool FLACS CFD. The results are used to propose updated limiting safety criteria for hydrogen fuels to support ventilation CFD analysis for specific enclosure designs. It is found that significantly smaller gas cloud sizes are likely to be acceptable for gas turbines fueled by hydrogen however significantly more hydrogen than methane is required per unit volume to generate a stoichiometric cloud (as hydrogen has a lower stoichiometric air fuel ratio than methane). This effect results in the total quantity of gas in the enclosure (and as such detectability of the gas) being broadly similar when operating gas turbines on hydrogen when compared to methane.
Optimization of Component Sizing for a Fuel Cell-Powered Truck to Minimize Ownership Cost
Mar 2019
Publication
In this study we consider fuel cell-powered electric trucks (FCETs) as an alternative to conventional medium- and heavy-duty vehicles. FCETs use a battery combined with onboard hydrogen storage for energy storage. The additional battery provides regenerative braking and better fuel economy but it will also increase the initial cost of the vehicle. Heavier reliance on stored hydrogen might be cheaper initially but operational costs will be higher because hydrogen is more expensive than electricity. Achieving the right tradeoff between these power and energy choices is necessary to reduce the ownership cost of the vehicle. This paper develops an optimum component sizing algorithm for FCETs. The truck vehicle model was developed in Autonomie a platform for modelling vehicle energy consumption and performance. The algorithm optimizes component sizes to minimize overall ownership cost while ensuring that the FCET matches or exceeds the performance and cargo capacity of a conventional vehicle. Class 4 delivery truck and class 8 linehaul trucks are shown as examples. We estimate the ownership cost for various hydrogen costs powertrain components ownership periods and annual vehicle miles travelled.
Hydrogen Generation in Europe: Overview of Costs and Key Benefits
May 2021
Publication
The European Commission published its hydrogen strategy for a climate-neutral Europe on the 8th July 2020. This strategy brings different strands of policy action together covering the entire value chain as well as the industrial market and infrastructure angles together with the research and innovation perspective and the international dimension in order to create an enabling environment to scale up hydrogen supply and demand for a climate-neutral economy. The strategy also highlights clean hydrogen and its value chain as one of the essential areas to unlock investment to foster sustainable growth and jobs which will be critical in the context of recovery from the COVID-19 crisis. It sets strategic objectives to install at least 6 GW of renewable hydrogen electrolysers by 2024 and at least 40 GW of renewable hydrogen electrolysers by 2030 and foresees industrial applications and mobility as the two main lead markets. This report provides the evidence base established on the latest publicly available data for identifying investment opportunities in the hydrogen value chain over the period from 2020 to 2050 and the associated benefits in terms of jobs. Considering the dynamics and significant scale-up expected over a very short period of time multiple sources have been used to estimate the different values consistently and transparently. The report covers the full value chain from the production of renewable electricity as the energy source for renewable hydrogen production to the investment needs in industrial applications and hydrogen trucks and buses. Although the values range significantly across the different sources the overall trend is clear. Driving hydrogen development past the tipping point needs critical mass in investment an enabling regulatory framework new lead markets sustained research and innovation into breakthrough technologies and for bringing new solutions to the market a large-scale infrastructure network that only the EU and the single market can offer and cooperation with our third country partners. All actors public and private at European national and regional level must work together across the entire value chain to build a dynamic hydrogen ecosystem in Europe.
A General Vision for Reduction of Energy Consumption and CO2 Emissions from the Steel Industry
Aug 2020
Publication
The 2018 IPCC (The Intergovernmental Panel on Climate Change’s) report defined the goal to limit global warming to 1.5 ◦C by 2050. This will require “rapid and far-reaching transitions in land energy industry buildings transport and cities”. The challenge falls on all sectors especially energy production and industry. In this regard the recent progress and future challenges of greenhouse gas emissions and energy supply are first briefly introduced. Then the current situation of the steel industry is presented. Steel production is predicted to grow by 25–30% by 2050. The dominant iron-making route blast furnace (BF) especially is an energy-intensive process based on fossil fuel consumption; the steel sector is thus responsible for about 7% of all anthropogenic CO2 emissions. In order to take up the 2050 challenge emissions should see significant cuts. Correspondingly specific emissions (t CO2/t steel) should be radically decreased. Several large research programs in big steelmaking countries and the EU have been carried out over the last 10–15 years or are ongoing. All plausible measures to decrease CO2 emissions were explored here based on the published literature. The essential results are discussed and concluded. The specific emissions of “world steel” are currently at 1.8 t CO2/t steel. Improved energy efficiency by modernizing plants and adopting best available technologies in all process stages could decrease the emissions by 15–20%. Further reductions towards 1.0 t CO2/t steel level are achievable via novel technologies like top gas recycling in BF oxygen BF and maximal replacement of coke by biomass. These processes are however waiting for substantive industrialization. Generally substituting hydrogen for carbon in reductants and fuels like natural gas and coke gas can decrease CO2 emissions remarkably. The same holds for direct reduction processes (DR) which have spread recently exceeding 100 Mt annual capacity. More radical cut is possible via CO2 capture and storage (CCS). The technology is well-known in the oil industry; and potential applications in other sectors including the steel industry are being explored. While this might be a real solution in propitious circumstances it is hardly universally applicable in the long run. More auspicious is the concept that aims at utilizing captured carbon in the production of chemicals food or fuels e.g. methanol (CCU CCUS). The basic idea is smart but in the early phase of its application the high energy-consumption and costs are disincentives. The potential of hydrogen as a fuel and reductant is well-known but it has a supporting role in iron metallurgy. In the current fight against climate warming H2 has come into the “limelight” as a reductant fuel and energy storage. The hydrogen economy concept contains both production storage distribution and uses. In ironmaking several research programs have been launched for hydrogen production and reduction of iron oxides. Another global trend is the transfer from fossil fuel to electricity. “Green” electricity generation and hydrogen will be firmly linked together. The electrification of steel production is emphasized upon in this paper as the recycled scrap is estimated to grow from the 30% level to 50% by 2050. Finally in this review all means to reduce specific CO2 emissions have been summarized. By thorough modernization of production facilities and energy systems and by adopting new pioneering methods “world steel” could reach the level of 0.4–0.5 t CO2/t steel and thus reduce two-thirds of current annual emissions.
The Impact of Fuel Cell Electric Freight Vehicles on Fuel Consumption and CO2 Emissions: The Case of Italy
Oct 2022
Publication
The Italian Recovery and Resilience Plan promotes among its many actions the use of hydrogen by the deployment of refuelling stations for heavy-duty vehicles predicting a 5–7% penetration rate of fuel cell electric vehicles (FCEVs) for long-distance freight transport. In this work the impact of this action on the reduction of greenhouse gas emissions and consumption was estimated assuming the plan’s objectives are met. To achieve this aim a national simulation model of the road freight transport system was implemented consisting of a graph of the national road network and an inter-provincial origin-destination matrix; the graph was based on data available from OpenStreetMap while the interprovincial matrix was estimated from the interregional matrix with the use of two linear regression models one for emitted goods and one for attracted goods. The simulation of the system made it possible to estimate the impact of this action on CO2 emissions and fuel consumption under three different scenarios. From 2025 to 2040 a reduction in CO2 emissions ranging from around 9 to around 16.5 million tonnes was estimated and a reduction in consumption ranging from around 3 billion to around 5.6 billion litres of diesel. These results show how this action can be seen as one of the bricks contributing to the fight against global warming.
Numerical Simulations of Suppression Effect of Water Mist on Hydrogen Deflagration in Confined Spaces
Sep 2021
Publication
Hydrogen safety issues attract focuses increasingly as more and more hydrogen powered vehicles are going to be operated in traffic infrastructures of different kinds like tunnels. Due to the confinement feature of traffic tunnels hydrogen deflagration may pose a risk when a hydrogen leak event occurs in a tunnel e.g. failure of the hydrogen storage system caused by a car accident in a tunnel. A water injection system can be designed in tunnels as a mitigation measure to suppress the pressure and thermal loads of hydrogen combustion in accident scenarios. The COM3D is a fully verified three-dimensional finite-difference turbulent flow combustion code which models gas mixing hydrogen combustion and detonation in nuclear containment with mitigation device or other confined facilities like vacuum vessel of fusion and semi-confined hydrogen facilities in industry such as traffic tunnels hydrogen refueling station etc. Therefore by supporting of the European HyTunnel-CS project the COM3D is applied to simulate numerically the hydrogen deflagration accident in a tunnel model being suppressed by water mist injection. The suppression effect of water mist and the suppression mechanism is elaborated and discussed in the study.
Petroleum Sector-Driven Roadmap for Future Hydrogen Economy
Nov 2021
Publication
In the climate change mitigation context based on the blue hydrogen concept a narrative frame is presented in this paper to build the argument for solving the energy trilemma which is the possibility of job loss and stranded asset accumulation with a sustainable energy solution in gas- and oil-rich regions especially for the Persian Gulf region. To this aim scientific evidence and multidimensional feasibility analysis have been employed for making the narrative around hydrogen clear in public and policy discourse so that choices towards acceleration of efforts can begin for paving the way for the future hydrogen economy and society. This can come from natural gas and petroleum-related skills technologies experience and infrastructure. In this way we present results using multidimensional feasibility analysis through STEEP and give examples of oil- and gas-producing countries to lead the transition action along the line of hydrogen-based economy in order to make quick moves towards cost effectiveness and sustainability through international cooperation. Lastly this article presents a viewpoint for some regional geopolitical cooperation building but needs a more full-scale assessment.
Hydrogen Embrittlement in a 2101 Lean Duplex Stainless Steel
Sep 2019
Publication
Duplex Stainless Steels (DSSs) are an attractive class of materials characterized by a strong corrosion resistance in many aggressive environments. Thanks to the high mechanical performances DSSs are widely used for many applications in petrochemical industry chemical and nuclear plants marine environment desalination etc.<br/>Among the DSSs critical aspects concerning the embrittlement process it is possible to remember the steel sensitization and the hydrogen embrittlement.<br/>The sensitization of the DSSs is due to the peculiar chemical composition of these grades which at high temperature are susceptible to carbide nitrides and second phases precipitation processes mainly at grains boundary and in the ferritic grains. The hydrogen embrittlement process is strongly influenced by the duplex (austenitic-ferritic) microstructure and by the loading conditions.<br/>In this work a rolled lean ferritic-austenitic DSS (2101) has been investigated in order to analyze the hydrogen embrittlement mechanisms by means of slow strain rate tensile tests considering the steel after different heat treatments. The damaging micromechanisms have been investigated by means of the scanning electron microscope observations on the fracture surfaces.
Steel Manufacturing Clusters in a Hydrogen Economy – Simulation of Changes in Location and Vertical Integration of Steel Production in Northwestern Europe
Feb 2022
Publication
With the move to a hydrogen-based primary steel production envisioned for the near future in Europe existing regional industrial clusters loose major assets. Such a restructuring of industries may result in a new geographical distribution of the steel industry and also to another quality of vertical integration at sites. Both implications could turn out as drivers or barriers to invest in new technologies and are thus important in respect to vertical integration of sites and to regional policy. This paper describes an approach to model production stock invest for the steel industries in North-Western Europe. Current spatial structures are reproduced with capacity technical and energy efficiency data on the level of single facilities like blast furnaces. With the model developed both investments in specific technologies and at specific production sites can be modelled. The model is used to simulate different possible future scenarios. The case with a clear move to hydrogen-based production is compared to a reference scenario without technological shift. The scenarios show that existing trends like movement of production to the coast may be accelerated by the new technology but that sites in the hinterland can also adapt to a hydrogen economy. Possible effects of business cycles or a circular economy on regional value chains are explored with a Monte-Carlo analysis.
Effect of Defects and Hydrogen on the Fatigue Limit of Ni-based Superalloy 718
Dec 2019
Publication
Tension-compression fatigue tests were performed on two types of Ni-based superalloy 718 with different microstructures to which small artificial defects of various shapes and sizes were introduced. Similar tests were also conducted on hydrogen-charged specimens with defects with a solute hydrogen content ranging from 26.3 to 91.0 mass ppm. In the non-charged specimens in particular the fatigue strength susceptibility to defects varied significantly according to the type of microstructural morphology i.e. a smaller grain size made the alloy more vulnerable to defects. The fatigue limit as a small-crack threshold was successfully predicted using the √area parameter model. Depending on the size of defects the fatigue limit was calculated in relation to three phases: (i) harmless-defect regime (ii) small-crack regime and (iii) large-crack regime. Such a classification enabled comprehensive fatigue limit evaluation in a wide array of defects taking into consideration (a) the defect size over a range of small crack and large crack and (b) the characteristics of the matrix represented by grain size and hardness. In addition the effect of defects and hydrogen on fatigue strength will be comprehensively discussed based on a series of experimental results.
Economic Optima for Buffers in Direct Reduction Steelmaking Under Increasing Shares of Renewable Hydrogen
Oct 2021
Publication
While current climate targets demand substantial reductions in greenhouse gas (GHG) emissions the potentials to further reduce carbon dioxide emissions in traditional primary steel-making are limited. One possible solution that is receiving increasing attention is the direct reduction (DR) technology operated either with renewable hydrogen (H2) from electrolysis or with conventional natural gas (NG). DR technology makes it possible to decouple steel and hydrogen production by temporarily using overcapacities to produce and store intermediary products during periods of low renewable electricity prices or by switching between H2 and NG. This paper aims to explore the impact of this decoupling on overall costs and the corresponding dimensioning of production and storage capacities. An optimization model is developed to determine the least-cost operation based on perfect-foresight. This model can determine the minimum costs for optimal production and storage capacities under various assumptions considering fluctuating H2 and NG prices and increasing H2 shares. The model is applied to a case study for Germany and covers the current situation the medium term until 2030 and the long term until 2050. Under the assumptions made the role of using direct reduced iron (DRI) storage as a buffer seems less relevant. DRI mainly serves as long-term storage for several weeks similar to usual balancing storage capacities. Storing H2 on the contrary is used for short-term fluctuations and could balance H2 demand in the hourly range until 2050. From an economic perspective DRI production using NG tends to be cheaper than using H2 in the short term and potential savings from the flexible operation with storages are small at first. However in the long term until 2050 NG and H2 could achieve similar total costs if buffers are used. Otherwise temporarily occurring electricity price spikes imply substantial increases in total costs if high shares of H2 need to be achieved.
Everything About Hydrogen Podcast: Costs, Cost, Costs!
Aug 2020
Publication
On this week's episode of Everything About Hydrogen the team are celebrating the show's one year anniversary with Randy MacEwen the CEO of Ballard Power Systems. On the show the team ask Randy to explain the stunning rise of hydrogen over the last 12-24 months how the use cases for hydrogen are evolving and how the growing capitalisation of listed businesses like Ballard is driving a change in the investor base across the hydrogen & fuel cell sector. We also dive into the future for Ballard where the challenges and focuses for the business lie while the team reflect on what has been a very intense year for the show and the hydrogen industry. All this and more!
The podcast can be found on their website
The podcast can be found on their website
No more items...