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Some Issues Concerning the CFD Modelling of Confined Hydrogen Releases
Sep 2017
Publication
In SUSANA E.U. project a rather broad CFD benchmarking exercise was performed encompassing a number of CFD codes a diversity of turbulence models... It is concluded that the global agreement is good. But in this particular situation the experimental data to compare with were known to the modelers. In performing this exercise the present authors explored the influence of some modelling choices which may have a significant impact on the results (apart from the traditional convergence testing and mass conservation) especially in the situation where little relevant data are available. The configuration investigated is geometrically simple: a vertical round hydrogen jet in a square box. Nevertheless modelling aspects like the representation of the source and of the boundary conditions have a rather strong influence on the final results as illustrated in this communication. In other words the difficulties may not be so much in the intrinsic capabilities of the code (which SUSANA tends to show) but more in the physical representation the modelers have. Even in the specific situation addressed in this communication although looking simple it may not be so obvious to grasp correctly the leading physical processes.
Hydrogen Effects in Non-ferrous Alloys: Discussion
Jun 2017
Publication
This is a transcript of the discussion session on the effects of hydrogen in the non-ferrous alloys of zirconium and titanium which are anisotropic hydride-forming metals. The four talks focus on the hydrogen embrittlement mechanisms that affect zirconium and titanium components which are respectively used in the nuclear and aerospace industries. Two specific mechanisms are delayed hydride cracking and stress corrosion cracking.
This article is a transcription of the recorded discussion of the session ‘Hydrogen in non-ferrous alloys’ at the Royal Society Discussion Meeting Challenges of Hydrogen in Metals 16–18 January 2017. The text is approved by the contributors. M.P. transcribed the session. M.A.S. 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 the session ‘Hydrogen in non-ferrous alloys’ at the Royal Society Discussion Meeting Challenges of Hydrogen in Metals 16–18 January 2017. The text is approved by the contributors. M.P. transcribed the session. M.A.S. assisted in the preparation of the manuscript.
Link to document download on Royal Society Website
Bioanode as a Limiting Factor to Biocathode Performance in Microbial Electrolysis Cells
Mar 2017
Publication
The bioanode is important for a microbial electrolysis cell (MEC) and its robustness to maintain its catalytic activity affects the performance of the whole system. Bioanodes enriched at a potential of +0.2 V (vs. standard hydrogen electrode) were able to sustain their oxidation activity when the anode potential was varied from -0.3 up to +1.0 V. Chronoamperometric test revealed that the bioanode produced peak current density of 0.36 A/m2 and 0.37 A/m2 at applied potential 0 and +0.6 V respectively. Meanwhile hydrogen production at the biocathode was proportional to the applied potential in the range from -0.5 to -1.0 V. The highest production rate was 7.4 L H2/(m2 cathode area)/day at -1.0 V cathode potential. A limited current output at the bioanode could halt the biocathode capability to generate hydrogen. Therefore maximum applied potential that can be applied to the biocathode was calculated as -0.84 V without overloading the bioanode.
Risk Identification for the Introduction of Advanced Science and Technology: A Case Study of a Hydrogen Energy System for Smooth Social Implementation
May 2020
Publication
A method of risk identification is developed by comparing existing and advanced technologies from the viewpoint of comprehensive social risk. First to analyze these values from a multifaceted perspective we constructed a questionnaire based on 24 individual values and 26 infrastructural values determined in a previous study. Seven engineering experts and six social science experts were then asked to complete the questionnaire to compare and analyze a hydrogen energy system (HES) and a gasoline energy system (GES). Finally the responses were weighted using the analytic hierarchy process. Three important points were identified and focused upon: the distinct disadvantages of the HES compared to the GES judgments that were divided between experts in the engineering and social sciences fields and judgments that were divided among experts in the same field. These are important risks that should be evaluated when making decisions related to the implementation of advanced science and technology.
An Energy Autonomous House Equipped with a Solar PV Hydrogen Conversion System
Dec 2015
Publication
The use of RES in buildings is difficult for their random nature; therefore the plants using photovoltaic solar collectors must be connected to a power supply or interconnected with Energy accumulators if the building is isolated. The conversion of electricity into hydrogen technology is best suited to solve the problem and allows you to transfer the solar energy captured from day to night from summer to winter. This paper presents the feasibility study for a house powered by PV cogeneration solar collectors that reverse the electricity on the control unit that you command by a PC to power the household using a heat pump an electrolytic cell for the production of hydrogen to accumulate; control units sorting to the utilities the electricity produced by the fuel cell. The following are presented: The Energy analysis of the building the plant design economic analysis.
Chemical Utilization of Hydrogen from Fluctuating Energy Sources- Catalytic Transfer Hydrogenation from Charged Liquid Organic Hydrogen Carrier Systems
Nov 2015
Publication
Liquid Organic Hydrogen Carrier (LOHC) systems offer a very attractive way for storing and distributing hydrogen from electrolysis using excess energies from solar or wind power plants. In this contribution an alternative high-value utilization of such hydrogen is proposed namely its use in steady-state chemical hydrogenation processes. We here demonstrate that the hydrogen-rich form of the LOHC system dibenzyltoluene/perhydro-dibenzyltoluene can be directly applied as sole source of hydrogen in the hydrogenation of toluene a model reaction for large-scale technical hydrogenations. Equilibrium experiments using perhydro-dibenzyltoluene and toluene in a ratio of 1:3 (thus in a stoichiometric ratio with respect to H2) yield conversions above 60% corresponding to an equilibrium constant significantly higher than 1 under the applied conditions (270 °C).
Wood Cellulose as a Hydrogen Storage Material
Apr 2020
Publication
Hydrogen has become a strong candidate to be a future energy storage medium but there are technological challenges both in its production and storage. For storage a search for lightweight abundant and non-toxic materials is on the way. An abundant natural material such as wood cellulose would make an ideal storage medium from a sustainability perspective. Here using a combination of static DFT calculations and ab initio molecular dynamics simulations at different temperatures it is shown that wood cellulose has the ability to uptake H2 via a physisorption mechanism based on dispersion interactions of the van der Waals type involving the O-atoms of the d-glucose rings. The absorption causes little to no disturbances on the cellulose structure and H2 is highly mobile in the material. At an external pressure of H2(g) of 0.09 atm and T = 25 °C cellulose has a theoretical gravimetric density of hydrogen storage of ≈1%.
An Ammonia-Hydrogen Energy Roadmap for Carbon Neutrality: Opportunity and Challenges in China
Nov 2021
Publication
China has promised to reach the peak carbon dioxide emission (ca. 10 billion tons) by 2030 and carbon neutrality by 2060. To realize these goals it is necessary to develop hydrogen energy and fuel cell techniques. However the high cost and low intrinsic safety of high-pressure hydrogen storage limit their commercialization. NH3 is high in hydrogen content easily liquefied at low pressure and free of carbon and the technology of NH3 synthesis has been commercialized nationwide. It is worth noting that the production of NH3 in China is about 56 million tons per year accounting for 35% of worldwide production. Hence with the well established infrastructure for NH3 synthesis and transportation and the demand for clean energy in China it is feasible to develop a green and economical energy roadmap viz. “Clean low-pressure NH3 synthesis → Safe and economical NH3 storage and transportation → Carbon-free efficient NH3-H2 utilization” for low-carbon or even carbon-free energy production.<br/>Currently the academic and industrial communities in China are striving to make technological breakthroughs in areas such as photocatalytic water splitting electrocatalytic water splitting mild-condition NH3 synthesis low-temperature NH3 catalytic decomposition and indirect or direct NH3 fuel cells with significant progress.<br/>Taking full advantage of the NH3 synthesis industry and readjusting the industrial structure it is viable to achieve energy saving and emission reduction in NH3 synthesis industry (440 million tons CO2 per year) as well as promote a new energy industry and ensure national energy security. Therefore relevant academic and industrial communities should put effort on mastering the key technologies of “Ammonia-Hydrogen” energy conversion and utilization with complete self-dependent intellectual property. It is envisioned that through the establishment of “Renewable Energy-Ammonia-Hydrogen” circular economy a green technology chain for hydrogen energy industry would pose as a promising pathway to achieve the 2030 and 2060 goals.
Business Energy and Industrial Strategy Committee Inquiry into Post-Pandemic Economic Growth
Sep 2020
Publication
The Hydrogen Taskforce welcomes the opportunity to submit evidence to the Business Energy and
Industrial Strategy Committee’s inquiry into post-pandemic economic growth.
It is the Taskforce’s view that:
You can download the whole document from the Hydrogen Taskforce website here
Industrial Strategy Committee’s inquiry into post-pandemic economic growth.
It is the Taskforce’s view that:
- 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;
- Other economies are moving ahead in the development of this sector and the UK must respond;
- The post pandemic economic recovery planning should reflect the need to achieve deep decarbonisation and support wider objectives such as achieving net zero and levelling up the
- economy; and
- The hydrogen sector is well-placed to play a key role in the UK’s economic recovery with the right policies and financial structures in place.
- 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 per cent hydrogen heating through supporting public trials and
- mandating 100 per cent hydrogen-ready boilers by 2025; and
- Commit to the support of 100 Hydrogen Refuelling Stations (HRS) by 2025 to support the rollout of hydrogen transport.
You can download the whole document from the Hydrogen Taskforce website here
Hydrogen Technologies Safety Guide
Jan 2015
Publication
The purpose of this guide is to provide basic background information on hydrogen technologies. It is not intended to be a comprehensive collection of hydrogen technologies safety information. It is intended to provide project developers code officials and other interested parties the background information to be able to put hydrogen safety in context. For example code officials reviewing permit applications for hydrogen projects will get an understanding of the industrial history of hydrogen basic safety concerns and safety requirements.
Cryogenic Hydrogen Jets: Flammable Envelope Size and Hazard Distances for Jet Fire
Sep 2019
Publication
Engineering tools for calculation of hazard distances for cryogenic hydrogen jets are currently missing. This study aims at the development of validated correlations for calculation of hazard distances for cryogenic unignited releases and jet fires. The experiments performed by Sandia National Laboratories (SNL) on jets from storage temperature in the range 46-295 K and pressure up to 6 bar abs are used to expand the validation domain of the correlations. The Ulster’s under-expanded jet theory is applied to calculate parameters at the real nozzle exit. The similarity law for concentration decay in momentum-dominated jets is shown to be capable to reproduce experimental data of SNL on 9 unignited cryogenic releases. The accuracy of the similarity law to predict experimentally measured axial concentration decay improves with the increase of the release diameter. This is thought due to decrease of the effect of friction and minor losses for large release orifices. The dimensionless flame length correlation is applied to analyse 30 cryogenic jet fire tests. The deviation of calculated flame length from measured in experiments is mostly within acceptable accuracy for engineering correlations 20% similarly to releases from storage and equipment at atmospheric temperatures. It is concluded that the similarity law and the dimensionless flame correlation can be used as universal engineering tools for calculation of hazard distances for hydrogen releases at any storage temperature including cryogenic.
Development of Risk Mitigation Guidance for Sensor Placement Inside Mechanically Ventilated Enclosures – Phase 1
Sep 2019
Publication
Guidance on Sensor Placement was identified as the top research priority for hydrogen sensors at the 2018 HySafe Research Priority Workshop on hydrogen safety in the category Mitigation Sensors Hazard Prevention and Risk Reduction. This paper discusses the initial steps (Phase 1) to develop such guidance for mechanically ventilated enclosures. This work was initiated as an international collaborative effort to respond to emerging market needs related to the design and deployment equipment for hydrogen infrastructure that is often installed in individual equipment cabinets or ventilated enclosures. The ultimate objective of this effort is to develop guidance for an optimal sensor placement such that when integrated into a facility design and operation will allow earlier detection at lower levels of incipient leaks leading to significant hazard reduction. Reliable and consistent early warning of hydrogen leaks will allow for the risk mitigation by reducing or even eliminating the probability of escalation of small leaks into large and uncontrolled events. To address this issue a study of a real-world mechanically ventilated enclosure containing GH2 equipment was conducted where CFD modelling of the hydrogen dispersion (performed by AVT and UQTR and independently by the JRC) was validated by the NREL Sensor laboratory using a Hydrogen Wide Area Monitor (HyWAM) consisting of a 10-point gas and temperature measurement analyzer. In the release test helium was used as a hydrogen surrogate. Expansion of indoor releases to other larger facilities (including parking structures vehicle maintenance facilities and potentially tunnels) and incorporation into QRA tools such as HyRAM is planned for Phase 2. It is anticipated that results of this work will be used to inform national and international standards such as NFPA 2 Hydrogen Technologies Code Canadian Hydrogen Installation Code (CHIC) and relevant ISO/TC 197 and CEN documents.
Hydrogen Permeation Studies of Composite Supported Alumina-carbon Molecular Sieves Membranes: Separation of Diluted Hydrogen from Mixtures with Methane
Jun 2020
Publication
One alternative for the storage and transport of hydrogen is blending a low amount of hydrogen (up to 15 or 20%) into existing natural gas grids. When demanded hydrogen can be then separated close to the end users using membranes. In this work composite alumina carbon molecular sieves membranes (Al-CMSM) supported on tubular porous alumina have been prepared and characterized. Single gas permeation studies showed that the H2/CH4 separation properties at 30 °C are well above the Robeson limit of polymeric membranes. H2 permeation studies of the H2–CH4 mixture gases containing 5–20% of H2 show that the H2 purity depends on the H2 content in the feed and the operating temperature. In the best scenario investigated in this work for samples containing 10% of H2 with an inlet pressure of 7.5 bar and permeated pressure of 0.01 bar at 30 °C the H2 purity obtained was 99.4%.
Mobile Phone Infrastructure Development: Lessons for the Development of a Hydrogen Infrastructure
Apr 2014
Publication
The development of new infrastructure is often a consideration in the introduction of new innovations. Currently there is some confusion around how to develop a hydrogen infrastructure to support the introduction of FCVs. Lessons can be learned from similar technology introduction in the past and therefore this paper investigates how mobile phone infrastructure was developed allowing the mass-market penetration of mobile phones. Based on this successful infrastructural development suggestions can be made on the development of a hydrogen infrastructure. It is suggested that a hydrogen infrastructure needs to be pre-developed 3–5 years before the market introduction of FCVs can successfully occur. A lack of infrastructural pre-development will cause to the market introduction of FCVs to fail.
An Investigation of Gaseous Hydrogen Storage Characterizations of Mg–Y–Ni–Cu Alloys Synthesized by Melt Spinning
Aug 2018
Publication
Melt spinning was successfully utilized to prepare Mg25−xYxNi9Cu (x = 0 1 3 5 7) alloys producing nanocrystalline and amorphous structures with improved hydrogenation and dehydrogenation performances. The influence of spinning rate on hydrogenation and dehydrogenation thermodynamics and kinetics was studied in detail. XRD and TEM were utilized to characterize the alloy structures. Hydrogenation and dehydrogenation performances were investigated by Sievert apparatus DSC and TGA connected to a H2 detector. Dehydrogenation activation energies were estimated using both Arrhenius and Kissinger methods. Results show that melt spinning significantly decreases thermodynamic parameters (ΔH and ΔS) and ameliorates desorption kinetics. Dehydrogenation activation energy markedly lowers with increase in spinning rate and is the real driver of amelioration of dehydrogenation kinetics caused by increasing Y content.
Unattended Hydrogen Vehicle Fueling Challenges and Historical Context
Sep 2019
Publication
Hydrogen fuelling in the US is unattended activity although this precedent is not without several challenges that have been addressed in the past decade. This paper provides the recent history and the generic safety case which has established this precedent for hydrogen. The paper also explores the longer history of unattended gasoline fuelling and attempts to help place hydrogen fuelling into the longer history of fuelling personal vehicles.
Oxford Energy Podcast – Energy Transition Post-Pandemic in the Gulf: Clean Energy, Sustainability and Hydrogen
Jun 2021
Publication
The COVID-19 pandemic has exacerbated challenges faced by hydrocarbon exporters in the Gulf owing to the global push to transition to cleaner energy sources. In this podcast Manal Shehabi (OIES) discusses with David Ledesma a recent OIES-KFAS workshop held in April 2021 titled “Energy Transition Post-Pandemic in the Gulf States” held with support from the Kuwait Foundation for the Advancement of Sciences (KFAS). They discuss separate but interrelated issues on clean energy economic and climate sustainability and hydrogen. Specially they examine how the global energy transition outlook has changed post-pandemic along with its impacts on Gulf States’ economies and energy transition projects. They explain implications to Gulf states’ sustainability evaluating whether these countries are fiscally sustainable post-pandemic and their urgent need for energy and economic diversification. They focus in on the possibility of the Gulf States’ using hydrogen to diversify both in domestic and export markets evaluating opportunities and challenges for both blue and green hydrogen. A preliminary case study on the economics of hydrogen in Kuwait is highlighted as indication of whether Gulf states can produce green hydrogen competitively. They conclude with policy recommendations to increase economic sustainability and resilience post-pandemic both through the energy transition and responses to it.
The podcast can be found on their website
The podcast can be found on their website
Energy White Paper: Powering our Net Zero Future
Dec 2020
Publication
The Prime Minister’s Ten Point Plan has set out the measures that will help ensure the UK is at the forefront of this revolution just as we led the first over two centuries ago. As nations move out of the shadow of coronavirus and confront the challenge of climate change with renewed vigour markets for new green products and services will spring up round the world. Taking action now will help ensure not just that we end our contribution to climate change by achieving our target of net zero emissions. It will help position UK companies and our world class research base to seize the business opportunities which flow from it creating jobs and wealth for our country.
Following on from the Ten Point Plan and the National Infrastructure Strategy the Energy White Paper provides further clarity on the Prime Minister’s measures and puts in place a strategy for the wider energy system that:
Following on from the Ten Point Plan and the National Infrastructure Strategy the Energy White Paper provides further clarity on the Prime Minister’s measures and puts in place a strategy for the wider energy system that:
- Transforms energy building a cleaner greener future for our country our people and our planet
- Supports a green recovery growing our economy supporting thousands of green jobs across the country in new green industries and leveraging new green export opportunities
- Creates a fair deal for consumers protecting the fuel poor providing opportunities to save money on bills giving us warmer more comfortable homes and balancing investment against bill impacts.
Thermal Radiation Properties of Large Hydrogen Leaks from Gas Distribution Networks
Sep 2019
Publication
Determination of the behaviour of hydrogen when leaking from pipework on gas distribution assets is essential in assessing the comparative risk associated with using pure hydrogen in place of natural gas in existing assets. Experimental work considering the behaviour of gaseous hydrogen when released in large volumes from gas distribution pipework at pressures of up to 7 barg through holes of up to 200mm in diameter in both buried and unburied scenarios is currently underway. The present paper presents and briefly discusses the results from a set of ignited 20mm diameter releases of hydrogen at pressures up to 7 barg vertically upwards from a pipe in an open excavation. Gaseous releases which find a direct route to atmosphere have the potential to create significant volumes of flammable gas and subsequently significant fires in the case of ignition. It is important to understand both the dispersion distances and thermal hazard field to be able to understand the comparative risk posed when compared to natural gas releases in similar situations. Results of current work completed to date are presented alongside comparisons with known properties of natural gas releases and the potential implications to the comparative risk of hydrogen network operation. The work has been conducted at the DNV GL Spadeadam Testing and Research Centre UK as part of the UK Gas Distribution Networks and Ofgem National Innovation Competition funded H21 project.
Achieving Carbon-neutral Iron and Steelmaking in Europe Through the Deployment of Bioenergy with Carbon Capture and Storage
Jan 2019
Publication
The 30 integrated steel plants operating in the European Union (EU) are among the largest single-point CO2 emitters in the region. The deployment of bioenergy with carbon capture and storage (bio-CCS) could significantly reduce their emission intensities. In detail the results demonstrate that CO2 emission reduction targets of up to 20% can be met entirely by biomass deployment. A slow CCS technology introduction on top of biomass deployment is expected as the requirement for emission reduction increases further. Bio-CCS could then be a key technology particularly in terms of meeting targets above 50% with CO2 avoidance costs ranging between €60 and €100 tCO2−1 at full-scale deployment. The future of bio-CCS and its utilisation on a larger scale would therefore only be viable if such CO2 avoidance cost were to become economically appealing. Small and medium plants in particular would economically benefit from sharing CO2 pipeline networks. CO2 transport however makes a relatively small contribution to the total CO2 avoidance cost. In the future the role of bio-CCS in the European iron and steelmaking industry will also be influenced by non-economic conditions such as regulations public acceptance realistic CO2 storage capacity and the progress of other mitigation technologies.
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