Publications

A novel approach has been developed for quantitative evaluation of the susceptibility of steels and alloys to hydrogen embrittlement. The approach uses a combination of hydrogen thermal desorption spectroscopy (TDS) analysis with recent advances in machine learning technology to develop a regression artificial neural network (ANN) model predicting hydrogen-induced degradation of mechanical properties of steels. We describe the thermal desorption data processing artificial neural network architecture development and the learning process beneficial for the accuracy of the developed artificial neural network model. A data augmentation procedure was proposed to increase the diversity of the input data and improve the generalization of the model. The study of the relationship between thermal desorption spectroscopy data and the mechanical properties of steel evidences a strong correlation of their corresponding parameters. A prototype software application based on the developed model is introduced and is openly available. The developed prototype based on TDS analysis coupled with ANN is shown to be a valuable engineering tool for steel characterization and quantitative prediction of the degradation of steel properties caused by hydrogen.

Abatement of greenhouse gas emissions and diversification of energy sources will probably lead to an economy based on hydrogen. In order to evaluate safety conditions during transport and distribution experimental data is needed on the detonation of Hydrogen/Natural gas blend mixtures. The aim of this study is to constitute detonation and deflagration to detonation transition (DDT) database of H2/CH4-air mixtures. More precisely the detonability of such mixtures is evaluated by the detonation cell size and the DDT run up distance measurements. Large experimental conditions are investigated (i) various equivalence ratios from 0.6 to 3 (ii) various H2 molar fraction x ( ( )2 2 4x H H CH= + ) from 0.5 to 1 (iii) different initial pressure P0 from 0.2 to 2 bar at fixed ambient temperature T0=293 K. Detonation pressures P velocities D and cell sizes ? were measured in two smooth tubes with different i.d. d (52 and 106 mm). For DDT data minimum DDT run up distances LDDT were determined in the d=52 mm tube containing a 2.8 m long Schelkin spiral with a blockage ratio BR = 0.5 and a pitch equal to the diameter. Measured detonation velocities D are very close to the Chapman Jouguet values (DCJ). Concerning the effect of detonation cell size ? follows a classical U shaped- curve with a minimum close to =1 and concerning the effect of x ? decreases when x increases. The ratio ik L?= obtained from different chemical kinetics (Li being the ZND induction length) is well approximated by the value 40 in the range 0.5 < x < 0.9 and 50 for x 0.9. Minimum DDT run up distance LDDT varies from 0.36 to 1.1m when x varies from 1 to 0.8. The results show that LDDT obeys the linear law LDDT ~ 30-40? previously validated in H2/Air mixtures. Adding Hydrogen in Natural Gas promotes the detonability of the mixtures and for x 0.65 these mixtures are considered more sensitive than common heavy Alkane-Air mixtures.

Around 20% of the nation’s carbon emissions are generated by domestic heating. Analysis of the many ways the energy system might be adapted to meet carbon targets shows that the elimination of emissions from buildings is more cost effective than deeper cuts in other energy sectors such as transport. This effectively means that alternatives need to be found for domestic natural gas heating systems. Enhanced construction standards are ensuring that new buildings are increasingly energy efficient but the legacy building stock of around 26 million homes has relatively poor thermal performance and over 90% are expected to still be in use in 2050. Even if building replacement was seen as desirable the cost is unaffordable and the carbon emissions associated with the construction would be considerable.

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In order to simulate an accidental hydrogen release from the low pressure pipe system of a hydrogen vehicle a systematic study on the nature of transient hydrogen jets into air and their combustion behaviour was performed at the FZK hydrogen test site HYKA. Horizontal unsteady hydrogen jets with an amount of hydrogen up to 60 STP dm3 and initial pressures of 5 and 16 bar have been investigated. The hydrogen jets were ignited with different ignition times and positions. The experiments provide new experimental data on pressure loads and heat releases resulting from the deflagration of hydrogen-air clouds formed by unsteady turbulent hydrogen jets released into a free environment. It is shown that the maximum pressure loads occur for ignition in a narrow position and time window. The possible hazard potential arising from an ignited free transient hydrogen jet is described.

The facility will be built from a range of decommissioned transmission assets to create a representative whole-network which will be used to trial hydrogen and will allow for accurate results to be analysed. Blends of hydrogen up to 100% will then be tested at transmission pressures to assess how the assets perform.<br/>The hydrogen research facility will remain separate from the main National Transmission System allowing for testing to be undertaken in a controlled environment with no risk to the safety and reliability of the existing gas transmission network.<br/>Ofgem’s Network Innovation Competition will provide £9.07m of funding with the remaining amount coming from the project partners.<br/>The aim is to start construction in 2021 with testing beginning in 2022.

Hydrogen is widely recognized as an attractive energy carrier due to its low-level air pollution and its high mass-related energy density. However its wide flammability range and high burning velocity present a potentially significant hazard. A significant fraction of hydrogen is stored and transported as a cryogenic liquid. Therefore loss of hydrogen containments may lead to the formation of a pool on the ground. In general very large spills will give a pool whereas moderate sized spills may evaporate immediately. Accurate hazard assessments of storage systems require a proper prediction of the liquid hydrogen pool evaporation and spreading. A new pool model handling the spread and the evaporation of liquid spills on different surfaces has recently been developed in the 3D Computational Fluid Dynamics (CFD) tool FLACS [1-4]. As the influence of geometry on the liquid spread is taken into account in the new pool model realistic industrial scenarios can be investigated. The model has been validated for LNG spills on water with the Burro and Coyote experiments [56]. The model has previously been tested for LH2 release in the framework of the EU-sponsored Network of Excellence HySafe where experiments carried out by BAM were modelled. In the large scale BAM experiments [7] 280 kg of liquid hydrogen was spilled in 6 tests adjacent to buildings. In these tests the pool spreading the evaporation and the cloud formation were investigated. Simulations of these tests are found to compare reasonably well with the experimental results. In the present work the model is extended and the liquid hydrogen spill experiments carried out by NASA are simulated with the new pool model. The large scale NASA experiments [89] consisted of 7 releases of liquefied hydrogen at White Sand New Mexico. The release test 6 is used. During these experiments cloud concentrations were measured at several distances downwind of the spill point. With the new pool model feature the FLACS tool is shown to be an efficient and accurate tool for the investigation of complex and realistic accidental release scenarios of cryogenic liquids.

Significant challenges still remain in the development of suitable materials for storing hydrogen for practical applications. Clathrate hydrates as a special inclusion compounds could be tailored by changing the storage pressure and temperature to adapt ambient conditions. In this work the hydrates were adopted to encage hydrogen in tetrahydrofuran (THF) aqueous solution with concentration of 3.0 mol%. The formation and dissociation behaviours were investigated by a high pressure micro-differential scanning calorimeter at the operating pressure of 18 MPa 25 MPa and 34 MPa. Experimental results show that the memory water only affects the hydrate formation behaviour instead of the hydrate dissociation behaviour. The dissociation temperature of the THF-H2 hydrate increases with the increase of the operating pressure and its dissociation equilibrium data can be obtained. The dissociation temperatures of the THF-H2 hydrate are 9.26 ℃ 10.94 ℃ and 12.67 ℃ at the operating pressure of 18 MPa 25 MPa and 34 MPa respectively. It is fundamental for performing the kinetics and microscopic experiments.

Hydrogen is widely recognised as an important option for future road transportation but a widespread infrastructure must be developed if the potential for hydrogen is to be achieved. This paper and related appendices which can be downloaded as Supplementary material present a mixed-integer linear programming model (called SHIPMod) that optimises a hydrogen supply chains for scenarios of hydrogen fuel demand in the UK including the spatial arrangement of carbon capture and storage infrastructure. In addition to presenting a number of improvements on past practice in the literature the paper focuses attention on the importance of assumptions regarding hydrogen demand. The paper draws on socio-economic data to develop a spatially detailed scenario of possible hydrogen demand. The paper then shows that assumptions about the level and spatial dispersion of hydrogen demand have a significant impact on costs and on the choice of hydrogen production technologies and distribution mechanisms.

The flame propagation regimes for the stoichiometric hydrogen-air mixtures in an obstructed semiconfined flat layer have been numerically investigated in this paper. Conditions defining fast or sonic propagation regime were established as a function of the main dimensions characterizing the system and the layout of the obstacles. It was found that the major dependencies were the following: the thickness of the layer of H2-air mixture the blockage ratio and the distance between obstacles and the obstacle size. A parametric study was performed to determine the combination of the above variables prone to produce strong combustions. Finally a criterion that separates experiments resulting in slow subsonic from fast sonic propagations regimes was proposed.

Australian Gas Infrastructure Group’s (AGIG’s) vision is to be the leading gas infrastructure business in Australia this means delivering for our customers being a good employer and being sustainably cost efficient. Establishing and developing a hydrogen industry is a key pathway for us to achieve our vision.



In South Australia AGIG is pioneering the introduction of hydrogen into its existing gas distribution networks through the Hydrogen Park South Australia (HyP SA) project. With safety our top priority we would like to give an overview of the safety considerations of our site our network methodology and the development of new safety procedures and culture regarding the production handling and reticulation of a 5% hydrogen blend.



We will cover three themes each having a safety story that is specific to the Australian context and to the project’s success:



The Production Plant and Site

Project site safety known hazards and risk mitigation electrical protection safety procedures lighting and security. Hydrogen storage filling and transportation.

The Network

Securing the network for an isolated safe demonstration footprint. Gas network and hydrogen safety considerations why 5%? Emergency procedures and crew training. New safety regulations blended networks. How does hydrogen perform in a blended gas with respect to leaks? How safe is the existing network and what sensors and controls are we using.

The Home

Introducing blended gas to existing homes. Appliance safety and failure mode analysis. Community engagement and education on a 5% renewable hydrogen gas blend and use in the home

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We aim to give a comprehensive overview of delivering a safe demonstration network for the HyP SA project in terms of the three main ecosystems that the hydrogen will be present our learnings so far and the development of the safety methodologies that will be applied in the industry in the future.