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Techno-economic calculations of small-scale hydrogen supply systems for zero emission transport in Norway
Jun 2019
Publication
In Norway where nearly 100% of the power is hydroelectric it is natural to consider water electrolysis as the main production method of hydrogen for zero-emission transport. In a start-up market with low demand for hydrogen one may find that small-scale WE-based hydrogen production is more cost-efficient than large-scale production because of the potential to reach a high number of operating hours at rated capacity and high overall system utilization rate. Two case studies addressing the levelized costs of hydrogen in local supply systems have been evaluated in the present work: (1) Hydrogen production at a small-scale hydroelectric power plant (with and without on-site refuelling) and (2) Small hydrogen refuelling station for trucks (with and without on-site hydrogen production). The techno-economic calculations of the two case studies show that the levelized hydrogen refuelling cost at the small-scale hydroelectric power plant (with a local station) will be 141 NOK/kg while a fleet of 5 fuel cell trucks will be able to refuel hydrogen at a cost of 58 NOK/kg at a station with on-site production or 71 NOK/kg at a station based on delivered hydrogen. The study shows that there is a relatively good business case for local water electrolysis and supply of hydrogen to captive fleets of trucks in Norway particularly if the size of the fleet is sufficiently large to justify the installation of a relatively large water electrolyzer system (economies of scale). The ideal concept would be a large fleet of heavy-duty vehicles (with a high total hydrogen demand) and a refuelling station with nearly 100% utilization of the installed hydrogen production capacity.
Minimum Entropy Generation in a Heat Exchanger in the Cryogenic Part of the Hydrogen Liquefaction Process: On the Validity of Equipartition and Disappearance of the Highway
May 2019
Publication
Liquefaction of hydrogen is a promising technology for transporting large quantities of hydrogen across long distances. A key challenge is the high power consumption. In this work we discuss refrigeration strategies that give minimum entropy production/exergy destruction in a plate-fin heat exchanger that cools the hydrogen from 47.8 K to 29.3 K. Two reference cases are studied; one where the feed stream enters at 20 bar and one where it enters at 80 bar. Catalyst in the hot layers speeds up the conversion of ortho-to para-hydrogen. Optimal control theory is used to formulate a minimization problem where the objective function is the total entropy production the control variable is the temperature of the refrigerant and the constrains are the balance equations for energy mass and momentum in the hot layers. The optimal refrigeration strategies give a reduction of the total entropy production of 8.7% in the 20-bar case and 4.3% in the 80-bar case. The overall heat transfer coefficient and duty is higher in the 20 bar case which compensates for the increase in entropy production due to a thermal mismatch that is avoided in the 80 bar case. This leads the second law efficiency of the 20 bar case (91%) to be similar to the 80 bar case (89%). We demonstrate that equipartition of the entropy production and equipartition of the thermal driving force are both excellent design principles for the process unit considered with total entropy productions deviating only 0.2% and 0.5% from the state of minimum entropy production. Equipartition of the thermal driving force i.e. a constant difference between the inverse temperatures of the hot and cold layers represents a particularly simple guideline that works remarkably well. We find that both heat transfer and the spin-isomer reaction contribute significantly to the entropy production throughout the length of the process unit. Unlike previous examples in the literature the process unit considered in this work is not characterized by a “reaction mode” at the inlet followed by a “heat transfer mode”. Therefore it does not follow a highway in state space i.e. a band that is particularly dense with energy efficient solutions. By artificially increasing the spin-isomer conversion rate the highway appears when the conversion rate becomes sufficiently high.
Pathways to Hydrogen as an Energy Carrier
Feb 2007
Publication
When hydrogen is used as an alternative energy carrier it is very important to understand the pathway from the primary energy source to the final use of the carrier. This involves for example the understanding of greenhouse gas emissions associated with the production of hydrogen and throughout the lifecycle of a given utilization pathway as well as various energy or exergy1 efficiencies and aspects involved. This paper which is based on a talk given at the Royal Society in London assesses and reviews the various production pathways for hydrogen with emphasis on emissions energy use and energy efficiency. The paper also views some aspects of the breaking of the water molecule and examines some new emerging physical evidence which could pave the way to a new and more feasible pathway.
Link to document download on Royal Society Website
Link to document download on Royal Society Website
Influence of hydraulic sequential tests on the burst strength of Type-4 compressed hydrogen containers
Sep 2019
Publication
One of the topics for the revision deliberation of GTR13 on hydrogen and fuel cell vehicles is the study of an appropriate initial burst pressure of the containers. The purpose of this study is to investigate the influence of the hydraulic sequential tests on the residual burst pressure in order to examine the appropriate initial burst pressure correlated with the provisions for the residual burst pressure at the Endof-Life (EOL). Specifically we evaluated any deterioration and variations of burst pressure due to hydraulic sequential tests on 70MPa compressed-hydrogen containers. When the burst pressure after the hydraulic sequential testing (EOL) was compared with the initial burst pressure at the beginning of life (BOL) the pressure proved to have decreased by a few percent while the variation increased. In the burst test it was observed that the rupture originated in the cylindrical part in all the BOL containers while in some of the EOL containers the rupture originated in the dome part. Since the dome part is a section that suffers an impact of vertical drop test it is conceivable that some sort of damage occurred in the CFRP. Therefore it was assumed that this damage was the main causal factor for the decrease in the burst pressure and the increase of the burst pressure variation at the dome part.
Oxford Energy Podcast – Hydrogen in Europe
Apr 2021
Publication
The EU and a number of its member states have now published hydrogen strategies and Europe continues to lead the way in the decarbonisation of its gas sector. In this latest OIES Energy Podcast James Henderson talks with Martin Lambert and Simon Schulte about their latest paper entitled “Contrasting European Hydrogen Pathways” which examines the plans in six major EU countries. They discuss the outlook for various forms of hydrogen supply contrasting the potential for green hydrogen from renewable energy with the outlook for blue hydrogen using steam-reforming of methane as well as hydrogen generated from surplus nuclear energy. They also examine the potential sources of demand considering existing use of hydrogen in industrial processes as well as the potential for hydrogen to displace hydrocarbons in the steel and cement industries. Finally the podcast also looks at the potential for imports of hydrogen and its distribution within Europe while also considering some key milestones that can provide indicators of how the region’s hydrogen plans are playing out.
The podcast can be found on their website
The podcast can be found on their website
Meeting Net Zero with Decarbonised Gas
Aug 2019
Publication
Although the UK has done a great job of decarbonising electricity generation to get to net zero we need to tackle harder-to-decarbonise sectors like heat transport and industry. Decarbonised gas – biogases hydrogen and the deployment of carbon capture usage and storage (CCUS) – can make our manufacturing more sustainable minimise disruption to families and deliver negative emissions.
Carbon Negative Transportation Fuels - A Techno-Economic-Environmental Analysis of Biomass Pathways for Transportation
Feb 2022
Publication
Global warming and fossil fuel depletion have necessitated alternative sources of energy. Biomass is a promising fuel source because it is renewable and can be carbon negative even without carbon capture and storage. This study considers biomass as a clean renewable source for transportation fuels. An Aspen Plus process simulation model was built of a biomass gasification biorefinery with Fischer-Tropsch (FT) synthesis of liquid fuels. A GaBi life cycle assessment model was also built to determine the environmental impacts using a cradle-to-grave approach. Three different product pathways were considered: Fischer-Tropsch synthetic diesel hydrogen and electricity. An offgas autothermal reformer with a recycle loop was used to increase FT product yield. Different configurations and combinations of biorefinery products are considered. The thermal efficiency and cost of production of the FT liquid fuels are analyzed using the Aspen Plus process model. The greenhouse gas emissions profitability and mileage per kg biomass were compared. The mileage traveled per kilogram biomass was calculated using modern (2019-2021) diesel electric and hydrogen fuel cell vehicles. The overall thermal efficiency was found to be between 20-41% for FT fuels production between 58-61% for hydrogen production and around 25-26% for electricity production for this biorefinery. The lowest production costs were found to be $3.171/gal of FT diesel ($24.304/GJ) $1.860/kg of H2 ($15.779/GJ) and 13.332¢/kWh for electricity ($37.034/GJ). All configurations except one had net negative carbon emissions over the life cycle of the biomass. This is because carbon is absorbed in the trees initially and some of the carbon is sequestered in ash and unconverted char from the gasification process furthermore co-producing electricity while making transportation fuel offsets even more carbon emissions. Compared to current market rates for diesel hydrogen and electricity the most profitable biorefinery product is shown to be hydrogen while also having net negative carbon emissions. FT diesel can also be profitable but with a slimmer profit margin (not considering government credits) and still having net negative carbon emissions. However our biorefinery could not compete with current commercial electricity prices in the US. As oil hydrogen and electricity prices continue to change the economics of the biorefinery and the choice product will change as well. For our current biorefinery model hydrogen seems to be the most promising product choice for profit while staying carbon negative while FT diesel is the best choice for sequestering the most carbon and still being profitable. All code and data are given.
Safety and Environmental Standards for Fuel Storage Sites
Jan 2009
Publication
The main purpose of this report is to specify the minimum standards of control which should be in place at all establishments storing large volumes of gasoline.<br/>The PSLG also considered other substances capable of giving rise to a large flammable vapour cloud in the event of a loss of primary containment. However to ensure priority was given to improving standards of control to tanks storing gasoline PSLG has yet to determine the scale and application of this guidance to such substances. It is possible that a limited number of other substances (with specific physical properties and storage arrangements) will be addressed in the future.<br/>This report also provides guidance on good practice in relation to secondary and tertiary containment for facilities covered by the CA Control of Major Accident Hazards (COMAH) Parts of this guidance may also be relevant to other major hazard establishments.
Tracking the Evolution of a Single Composite Particle During Redox Cycling for Application in H2 Production
Mar 2020
Publication
Composite materials consisting of metal and metal oxide phases are being researched intensively for application in various energy conversion and storage technologies. In these applications composites are often expected to operate under redox conditions at elevated temperature. The understanding of the dynamics of composite phase and morphology evolution during redox cycling is still very limited yet critical to maximising performance and increasing durability. Here we track the microstructural evolution of a single composite particle over 200 redox cycles for hydrogen production by chemical looping using multi-length scale X-ray computed tomography. We show that redox cycling triggers a centrifugal redispersion of the metal phase and a centripetal clustering of porosity both seemingly driven by the asymmetric nature of oxygen exchange in composites. We show that initially the particle develops a large amount of internal porosity which boosts activity but on the long term this facilitates structural and compositional reorganisation and eventually degradation. We also correlate the microstructural data with phase and activity analysis to identify structure-property correlations which not only provide valuable insight into the evolution of composite materials under redox conditions but also for the design of new composite materials with enhanced durability.
Hydrogen Taskforce: The Role of Hydrogen in Delivering Net Zero
Feb 2020
Publication
Hydrogen is essential to the UK meeting its net zero emissions target. We must act now to scale hydrogen solutions and achieve cost effective deep decarbonisation. With the support of Government UK industry is ready to deliver.
The potential to deploy hydrogen at scale as an energy vector has risen rapidly in the political and industrial consciousness in recent years as the benefits and opportunities have become better understood. Early stage projects across the globe have demonstrated the potential of hydrogen to deliver deep decarbonisation reduce the cost of renewable power and balance energy supply and demand. Governments and major industrial and commercial organisations across the world have set out their ambition to deploy hydrogen technologies at scale. This has created a growing confidence that hydrogen will present both a viable decarbonisation pathway and a global market opportunity. Hydrogen will have an important role to play in meeting the global climate goals set out in the Paris Climate Agreement and due to be discussed later this year at COP26.
The UK’s commitment to a net zero greenhouse gas emissions target has sharpened the conversation around hydrogen. Most experts agree that net zero by 2050 cannot be achieved through electrification alone and as such there is a need for a clean molecule to complement the electron. Hydrogen has properties which lend themselves to the decarbonisation of parts of the energy system which are less well suited to electrification such as industrial processes heating and heavy and highly utilised vehicles. Hydrogen solutions can be scaled meaning that the contribution of hydrogen to meeting net zero could be substantial.
A steady start has been made to exploring the hydrogen opportunity. Partnerships between policymakers and industry exist on several projects which are spread out right across the country from London to many industrial areas in the north east and north west. Existing projects include the early stage roll out of transport infrastructure and vehicles feasibility studies focused on large scale hydrogen production technologies projects exploring the decarbonisation of the gas grid and the development of hydrogen appliances.
The Government recently announced new funding for hydrogen through the Hydrogen Supply Programme and Industrial Fuel Switching Competition. These programmes are excellent examples of collaboration between Government and industry in driving UK leadership in hydrogen and developing solutions that will be critical for meeting net zero.
If the UK is going to meet net zero and capitalise on the economic growth opportunities presented by domestic and global markets for hydrogen solutions and expertise it is critical that the 2020s deliver a step change in hydrogen activity building on the unique strengths and expertise developed during early stage technology development.
The Hydrogen Taskforce brings together leading companies pushing hydrogen into the mainstream in the UK to offer a shared view of the opportunity and a collective position on the next steps that must be taken to ensure that the UK capitalises on this opportunity. There are questions to be answered and challenges that must be overcome as hydrogen technologies develop yet by focusing on what can be done today the benefits of hydrogen can be immediately realised whilst industry expertise and knowledge is built.
You can download the whole document from the Hydrogen Taskforce website here
The potential to deploy hydrogen at scale as an energy vector has risen rapidly in the political and industrial consciousness in recent years as the benefits and opportunities have become better understood. Early stage projects across the globe have demonstrated the potential of hydrogen to deliver deep decarbonisation reduce the cost of renewable power and balance energy supply and demand. Governments and major industrial and commercial organisations across the world have set out their ambition to deploy hydrogen technologies at scale. This has created a growing confidence that hydrogen will present both a viable decarbonisation pathway and a global market opportunity. Hydrogen will have an important role to play in meeting the global climate goals set out in the Paris Climate Agreement and due to be discussed later this year at COP26.
The UK’s commitment to a net zero greenhouse gas emissions target has sharpened the conversation around hydrogen. Most experts agree that net zero by 2050 cannot be achieved through electrification alone and as such there is a need for a clean molecule to complement the electron. Hydrogen has properties which lend themselves to the decarbonisation of parts of the energy system which are less well suited to electrification such as industrial processes heating and heavy and highly utilised vehicles. Hydrogen solutions can be scaled meaning that the contribution of hydrogen to meeting net zero could be substantial.
A steady start has been made to exploring the hydrogen opportunity. Partnerships between policymakers and industry exist on several projects which are spread out right across the country from London to many industrial areas in the north east and north west. Existing projects include the early stage roll out of transport infrastructure and vehicles feasibility studies focused on large scale hydrogen production technologies projects exploring the decarbonisation of the gas grid and the development of hydrogen appliances.
The Government recently announced new funding for hydrogen through the Hydrogen Supply Programme and Industrial Fuel Switching Competition. These programmes are excellent examples of collaboration between Government and industry in driving UK leadership in hydrogen and developing solutions that will be critical for meeting net zero.
If the UK is going to meet net zero and capitalise on the economic growth opportunities presented by domestic and global markets for hydrogen solutions and expertise it is critical that the 2020s deliver a step change in hydrogen activity building on the unique strengths and expertise developed during early stage technology development.
The Hydrogen Taskforce brings together leading companies pushing hydrogen into the mainstream in the UK to offer a shared view of the opportunity and a collective position on the next steps that must be taken to ensure that the UK capitalises on this opportunity. There are questions to be answered and challenges that must be overcome as hydrogen technologies develop yet by focusing on what can be done today the benefits of hydrogen can be immediately realised whilst industry expertise and knowledge is built.
You can download the whole document from the Hydrogen Taskforce website here
Sustainable Hydrogen Production: A Role for Fusion
Apr 2007
Publication
This Meeting Report summarises the findings of a two-day workshop in April 2007 at the Culham Science Centre and Worcester College Oxford which explored the potential for large-scale Hydrogen production through methods other than electrolysis.<br/>Operating at the cusp of research and policy-making the UK Energy Research Centre's mission is to be the UK's pre-eminent centre of research and source of authoritative information and leadership on sustainable energy systems. The Centre takes a whole systems approach to energy research incorporating economics engineering and the physical environmental and social sciences while developing and maintaining the means to enable cohesive research in energy. A key supporting function of UKERC is the Meeting Place based in Oxford which aims to bring together members of the UK energy community and overseas experts from different disciplines to learn identify problems develop solutions and further the energy debate.
Assessment of Hydrogen Direct Reduction for Fossil-free Steelmaking
Aug 2018
Publication
Climate policy objectives require zero emissions across all sectors including steelmaking. The fundamental process changes needed for reaching this target are yet relatively unexplored. In this paper we propose and assess a potential design for a fossil-free steelmaking process based on direct reduction of iron ore with hydrogen. We show that hydrogen direct reduction steelmaking needs 3.48 MWh of electricity per tonne of liquid steel mainly for the electrolyser hydrogen production. If renewable electricity is used the process will have essentially zero emissions. Total production costs are in the range of 361–640 EUR per tonne of steel and are highly sensitive to the electricity price and the amount of scrap used. Hydrogen direct reduction becomes cost competitive with an integrated steel plant at a carbon price of 34–68 EUR per tonne CO2 and electricity costs of 40 EUR/MWh. A key feature of the process is flexibility in production and electricity demand which allows for grid balancing through storage of hydrogen and hot-briquetted iron or variations in the share of scrap used.
Numerical Prediction of Cryogenic Hydrogen Vertical Jets
Sep 2019
Publication
Comparison of Computational Fluid Dynamics (CFD) predictions with measurements is presented for cryo-compressed hydrogen vertical jets. The stagnation conditions of the experiments are characteristic of unintended leaks from pipe systems that connect cryogenic hydrogen storage tanks and could be encountered at a fuel cell refuelling station. Jets with pressure up to 5 bar and temperatures just above the saturation liquid temperature were examined. Comparisons are made to the centerline mass fraction and temperature decay rates the radial profiles of mass fraction and the contours of volume fraction. Two notional nozzle approaches are tested to model the under-expanded jet that was formed in the tests with pressures above 2 bar. In both approaches the mass and momentum balance from the throat to the notional nozzle are solved while the temperature at the notional nozzle was assumed equal to the nozzle temperature in the first approach and was calculated by an energy balance in the second approach. The two approaches gave identical results. Satisfactory agreement with the measurements was found in terms of centerline mass fraction and temperature. However for test with 3 and 4 bar release the concentration was overpredicted. Furthermore a wider radial spread was observed in the predictions possibly revealing higher degree of diffusion using the k-ε turbulence model. An integral model for cryogenic jets was also developed and provided good results. Finally a test simulation was performed with an ambient temperature jet and compared to the cold jet showing that warm jets decay faster than cold jets.
Environmental Audit Committee Inquiry into Hydrogen
Jun 2020
Publication
The Hydrogen Taskforce welcomes the opportunity to submit evidence to the Environmental Audit Committee’s inquiry into Hydrogen. It is the Taskforce’s view that:
You can download the whole document from the Hydrogen Taskforce website here
- Due to its various applications hydrogen is critical for the UK to reach net zero by 2050;
- The UK holds world-class advantages in hydrogen production distribution and application; and
- Other economies are moving ahead in the development of this sector and the UK must respond.
- Development of a cross departmental UK Hydrogen Strategy within UK Government;
- Commit £1bn of capex funding over the next spending review period to hydrogen production storage and distribution projects;
- Develop a financial support scheme for the production of hydrogen in blending industry power and transport;
- Amend Gas Safety Management Regulations (GSMR) to enable hydrogen blending and take the next steps towards 100% hydrogen heating through supporting public trials and mandating 100% hydrogen-ready boilers by 2025; and
- Commit to the support of 100 Hydrogen Refuelling Stations (HRS) by 2025 to support the roll-out of hydrogen transport.
You can download the whole document from the Hydrogen Taskforce website here
Hydrogen Embrittlement: Future Directions—Discussion
Jun 2017
Publication
The final session of the meeting consisted of a discussion panel to propose future directions for research in the field of hydrogen embrittlement and the potential impact of this research on public policy.
This article is a transcription of the recorded discussion of ‘Hydrogen Embrittlement: Future Directions’ at the Royal Society Scientific Discussion Meeting Challenges of Hydrogen and Metals Jan 16th–18th 2017. The text is approved by the contributors. H.L. transcribed the session and drafted the manuscript. Y.C. assisted in the preparation of the manuscript.
Link to document download on Royal Society Website
This article is a transcription of the recorded discussion of ‘Hydrogen Embrittlement: Future Directions’ at the Royal Society Scientific Discussion Meeting Challenges of Hydrogen and Metals Jan 16th–18th 2017. The text is approved by the contributors. H.L. transcribed the session and drafted the manuscript. Y.C. assisted in the preparation of the manuscript.
Link to document download on Royal Society Website
Hydrogen Production and Subsequent Adsorption/Desorption Process within a Modified Unitized Regenerative Fuel Cell
Apr 2019
Publication
For sustainable and incremental growth mankind is adopting renewable sources of energy along with storage systems. Storing surplus renewable energy in the form of hydrogen is a viable solution to meet continuous energy demands. In this paper the concept of electrochemical hydrogen storage in a solid multi-walled carbon nanotube (MWCNT) electrode integrated in a modified unitized regenerative fuel cell (URFC) is investigated. The method of solid electrode fabrication from MWCNT powder and egg white as an organic binder is disclosed. The electrochemical testing of a modified URFC with an integrated MWCNT-based hydrogen storage electrode is performed and reported. Galvanostatic charging and discharging was carried out and results analyzed to ascertain the electrochemical hydrogen storage capacity of the fabricated electrode. The electrochemical hydrogen storage capacity of the porous MWCNT electrode is found to be 2.47 wt% which is comparable with commercially available AB5-based hydrogen storage canisters. The obtained results prove the technical feasibility of a modified URFC with an integrated MWCNT-based hydrogen storage electrode which is the first of its kind. This is surelya step forward towards building a sustainable energy economy
Production of Hydrogen by Chemical Looping Reforming of Methane and Biogas using a Reactive and Durable Cu-based Oxygen Carrier
Apr 2022
Publication
The objective of this work was to assess the suitability of a synthetic Cu-based oxygen carrier in a continuous pilot plant for the production of blue and green hydrogen through the autothermal Chemical Looping Reforming (CLRa). In CLRa methane is converted to a H2 + CO mixture through partial oxidation and reforming reactions in the fuel reactor. The degree of the partial oxidation of methane was defined by controlling the oxygen flow in the air reactor. Steam was used as reforming gas in natural gas to produce blue H2 but the existing CO2 in biogas was the reforming gas to produce green H2. Operating at 950 ◦C in the fuel and air reactors CH4 conversion and H2 yield parameters were 96 % and 2.60 mol of H2 per mole of CH4 respectively. These experimental results were close to the theoretical values that could be achieved in the CLRa process. Furthermore the physico-chemical characterization of the samples extracted from the pilot plant throughout the experimental campaign revealed that the Cu-based oxygen carrier maintained its mechanical integrity and chemical stability under harsh operating conditions. Therefore it can be concluded that Cu-based oxygen carriers can be considered a promising alternative to Ni-based materials for the production of blue and green hydrogen through the CLRa process.
How Hydrogen Empowers the Energy Transition
Jan 2017
Publication
This report commissioned by the Hydrogen Council and announced in conjunction with the launch of the initiative at the World Economic Forum in January 2017 details the future potential that hydrogen is ready to provide and sets out the vision of the Council and the key actions it considers fundamental for policy makers to implement to fully unlock and empower the contribution of hydrogen to the energy transition.
In this paper we explore the role of hydrogen in the energy transition including its potential recent achievements and challenges to its deployment. We also offer recommendations to ensure that the proper conditions are developed to accelerate the deployment of hydrogen technologies with the support of policymakers the private sector and society.
You can download the full report from the Hydrogen Council website here
In this paper we explore the role of hydrogen in the energy transition including its potential recent achievements and challenges to its deployment. We also offer recommendations to ensure that the proper conditions are developed to accelerate the deployment of hydrogen technologies with the support of policymakers the private sector and society.
You can download the full report from the Hydrogen Council website here
People’s Attitude to Energy from Hydrogen—From the Point of View of Modern Energy Technologies and Social Responsibility
Dec 2020
Publication
Energy from hydrogen is an appropriate technological choice in the context of sustainable development. The opportunities offered by the use of energy from hydrogen also represent a significant challenge for mobile technologies and daily life. Nevertheless despite a significant amount of research and information regarding the benefits of hydrogen energy it creates considerable controversy in many countries. Globally there is a lack of understanding about the production process of hydrogen energy and the benefits it provides which leads to concerns regarding the consistency of its use. In this study an original questionnaire was used as a research tool to determine the opinions of inhabitants of countries in which hydrogen energy is underutilized and where the infrastructure for hydrogen energy is underdeveloped. Respondents presented their attitude to ecology and indicated their knowledge regarding the operation of hydrogen energy and the use of hydrogen fuel. The results indicate that society is not convinced that the safety levels for energy derived from hydrogen are adequate. It can be concluded that knowledge about hydrogen as an energy source and the production safety and storage methods of hydrogen is very low. Negative attitudes to hydrogen energy can be an important barrier in the development of this energy in many countries.
Metallurgical Model of Diffusible Hydrogen and Non-Metallic Slag Inclusions in Underwater Wet Welding of High-Strength Steel
Nov 2020
Publication
High susceptibility to cold cracking induced by diffusible hydrogen and hydrogen embrittlement are major obstacles to greater utilization of underwater wet welding for high-strength steels. The aim of the research was to develop gas–slag systems for flux-cored wires that have high metallurgical activity in removal of hydrogen and hydroxyl groups. Thermodynamic modeling and experimental research confirmed that a decrease in the concentration of diffusible hydrogen can be achieved by reducing the partial pressure of hydrogen and water vapor in the vapor–gas bubble and by increasing the hydroxyl capacity of the slag system in metallurgical reactions leading to hydrogen fluoride formation and ionic dissolution of hydroxyl groups in the basic fluorine-containing slag of a TiO2–CaF2–Na3AlF6 system.
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