Publications

We analyze the feasibility of a novel hydrogen fuel cell electric generator to provide power with zero noise and emissions for myriad ground based applications. The hydrogen fuel cell electric generator utilizes a novel scalable apparatus that safely generates hydrogen (H2) on demand according to a novel method using a controlled chemical reaction between water (H2O) and sodium (Na) metal that yields hydrogen gas of sufficient purity for direct use in fuel cells without risk of contaminating sensitive catalysts. The sodium hydroxide (NaOH) byproduct of the hydrogen producing reaction is collected within the apparatus for later reprocessing by electrolysis to recover the Na reactant. The detailed analysis shows that the novel hydrogen fuel cell electric generator will be capable of meeting the clean power requirements for residential and commercial buildings including single family homes and light commercial establishments under a wide range of geographic and climatic conditions.

(Mg-10wt.%Ni)-10wt.%Ce (Mg10Ni10Ce) was ball-milled with SnO2 nanotubes and Mg10Ni10Ce-xSnO2 (x=0 5 10 and 15wt.%) composites have been prepared. The phase compositions microstructures morphologies and hydrolysis H2 generation performance in different aqueous systems (distilled water tap water and simulated seawater) have been investigated and the corresponding hydrolysis mechanism of Mg10Ni10Ce and Mg10Ni10Ce-SnO2 has been proposed. Adding a small amount of SnO2 nanotubes can significantly enhance the hydrolysis reaction of Mg10Ni10Ce especially the initial hydrolysis kinetics and the final H2 generation yield. Unfortunately the Mg10Ni10Ce-xSnO2 hardly react with distilled water at room temperature. The hydrolysis reaction rate of Mg10Ni10Ce-5SnO2 composite in tap water is still very slow with only 17.3% generation yield after 1 hour at 303 K. Fortunately in simulated seawater (3.5wt.% NaCl solution) the hydrolytic H2 generation behavior of the Mg10Ni10Ce-5SnO2 composite has been greatly improved which can release as high as 468.6 mL/g H2 with about 60.9% generation yield within 30 s at 303 K. The Cl- destroys the passivation layer on Mg-Ni-Ce alloy surface and the added SnO2 nanotubes accelerate the hydrolysis reaction rate and enhance the H2 generation yield. The Mg10Ni10Ce-5SnO2 composite can rapidly generate a large amount of H2 in simulate seawater in a short time which is expected to be applied on portable H2 generators in the future.

Climate change and global warming pose great sustainability challenges to the aviation industry. Alternatives to petroleum-based fuels (hydrogen natural gas etc.) have emerged as promising aviation fuels for future aircraft. The present study aimed to contribute to the understanding of the impact of material selection on aviation sustainability accounting for the type of fuel implemented and circular economy aspects. In this context a decision support tool was introduced to aid decisionmakers and relevant stakeholders to identify and select the best-performing materials that meet their defined needs and preferences expressed through a finite set of conflicting criteria associated with ecological economic and circularity aspects. The proposed tool integrates life-cycle-based metrics extending to both ecological and economical dimensions and a proposed circular economy indicator (CEI) focused on the material/component level and linked to its quality characteristics which also accounts for the quality degradation of materials which have undergone one or more recycling loops. The tool is coupled with a multi-criteria decision analysis (MCDA) methodology in order to reduce subjectivity when determining the importance of each of the considered criteria.

The site at the Health and Safety Executive’s Science and Research Centre in Buxton will carry out controlled tests to establish the critical safety evidence proving that a 100% hydrogen gas network is equally as safe as the natural gas grid heating our homes and businesses today. The results will be critical in determining if it is safe to convert millions of homes across the country from natural gas to hydrogen. H21 which is led by Northern Gas Networks (NGN) the gas distributor for the North of England in partnership with Cadent SGN and Wales & West Utilities HSE Science and Research Centre and DNV-GL is part of a number of gas industry projects designed to support conversion of the UK gas networks to carry 100% hydrogen. Currently about 30% of UK carbon emissions are from the heating of homes businesses and industry. H21 states that a large-scale conversion of the gas grid from natural gas to hydrogen is vital to meeting the Government’s Net Zero targets.

Developing low-cost high-performance catalysts is of fundamental significance for electrochemical energy conversion and storage. In recent years metal@carbon core@shell nanocomposites have emerged as a unique class of functional nanomaterials that show apparent electrocatalytic activity towards a range of reactions such as hydrogen evolution reaction oxygen evolution reaction oxygen reduction reaction and CO2 reduction reaction that are important in water splitting fuel cells and metal-air batteries. The activity is primarily attributed to interfacial charge transfer from the metal core to the carbon shell that manipulate the electronic interactions between the catalyst surface and reaction intermediates and varies with the structures and morphologies of the metal core (elemental composition core size etc.) and carbon shell (doping layer thickness etc.). Further manipulation can be achieved by the incorporation of a third structural component. A perspective is also included highlighting the current gap between theoretical modeling and experimental results and technical challenges for future research.

The issue of spontaneous ignition of highly pressurized hydrogen release is of important safety concern e.g. in the assessment of risk and design of safety measures. This paper reports on recent numerical investigation of this phenomenon through releases via a length of tube. This mimics a potential accidental scenario involving release through instrument line. The implicit large eddy simulation (ILES) approach was used with the 5th-order weighted essentially non-oscillatory (WENO) scheme. A mixture-averaged multi-component approach was used for accurate calculation of molecular transport. The thin flame was resolved with fine grid resolution and the autoignition and combustion chemistry were accounted for using a 21-step kinetic scheme.<br/>The numerical study revealed that the finite rupture process of the initial pressure boundary plays an important role in the spontaneous ignition. The rupture process induces significant turbulent mixing at the contact region via shock reflections and interactions. The predicted leading shock velocity inside the tube increases during the early stages of the release and then stabilizes at a nearly constant value which is higher than that predicted by one-dimensional analysis. The air behind the leading shock is shock-heated and mixes with the released hydrogen in the contact region. Ignition is firstly initiated inside the tube and then a partially premixed flame is developed. Significant amount of shock-heated air and well developed partially premixed flames are two major factors providing potential energy to overcome the strong under-expansion and flow divergence following spouting from the tube.<br/>Parametric studies were also conducted to investigate the effect of rupture time release pressure tube length and diameter on the likelihood of spontaneous ignition. It was found that a slower rupture time and a lower release pressure will lead to increases in ignition delay time and hence reduces the likelihood of spontaneous ignition. If the tube length is smaller than a certain value even though ignition could take place inside the tube the flame is unlikely to be sufficiently strong to overcome under-expansion and flow divergence after spouting from the tube and hence is likely to be quenched.

Hydrogen mixed natural gas for combustion can improve combustion characteristics and reduce carbon emission which has important engineering application value. A casing swirl burner model is adopted to numerically simulate and research the natural gas hydrogen mixing technology for combustion in gas boilers in this paper. Under the condition of conventional air atmosphere and constant air excess coefficient the six working conditions for hydrogen mixing proportion into natural gas are designed to explore the combustion characteristics and the laws of pollution emissions. The temperature distributions composition and emission of combustion flue gas under various working conditions are analyzed and compared. Further investigation is also conducted for the variation laws of NOx and soot generation. The results show that when the boiler heating power is constant hydrogen mixing will increase the combustion temperature accelerate the combustion rate reduce flue gas and CO2 emission increase the generation of water vapor and inhibit the generation of NOx and soot. Under the premise of meeting the fuel interchangeability it is concluded that the optimal hydrogen mixing volume fraction of gas boilers is 24.7%.

Tecnalia is working in the development of gasification technology for the production of hydrogen from biomass. Biomass is an abundant and disperse renewable energy source that can be important for the production of hydrogen. The development of hydrogen system from biomass requires multifaceted studies on hydrogen production systems hydrogen separation methods and hydrogen safety aspects. Steam gasification of biomass produces a syngas with high hydrogen content but this syngas requires a post-treatment to clean and to separate the hydrogen. As a result of this analysis Tecnalia has defined a global process for the production cleaning enrichment and separation of hydrogen from the syngas produced from biomass gasification. But besides the technical aspects safety considerations affecting all the described processes have been identified. For that reason it is being developed a procedure to establish the technical requirements and the recommended practices to ensure the highest level of safety in the production and handing of hydrogen.

Unintentional leaks at hydrogen fuelling stations have the potential to form hydrogen jet flames which pose a risk to people and infrastructure. The heat flux from these jet flames are often used to develop separation distances between hydrogen components and buildings lot-lines etc. The heat flux and visible flame length is well understood for releases from round nozzles but real unintended releases would be expected to be be higher aspect-ratio cracks. In this work we measured the visible flame length and heat-flux characteristics of cryogenic hydrogen flames from high-aspect ratio nozzles. We compare this data to flames of both cryogenic and compressed hydrogen from round nozzles. The aspect ratio of the release does not affect the flame length or heat flux significantly for a given mass flow under the range of conditions studied. The engineering correlations presented in this work that enable the prediction of flame length and heat flux can be used to assess risk at hydrogen fuelling stations with liquid hydrogen and develop science-based separation distances for these stations.

Hydrogen technologies have been rapidly developing in the past few decades pushed by governments’ road maps for sustainability and supported by a widespread need to decarbonize the global energy sector. Recent scientific progress has led to better performances and higher efficiencies of hydrogen-related technologies so much so that their future economic viability is now rarely called into question. This article intends to study the integration of hydrogen systems in both gas and electric distribution networks. A preliminary analysis of hydrogen’s physical storage methods is given considering both the advantages and disadvantages of each one. After examining the preeminent ways of physically storing hydrogen this paper then contemplates two primary means of using it: integrating it in Power-to-Gas networks and utilizing it in Power-to-Power smart grids. In the former the primary objective is the total replacement of natural gas with hydrogen through progressive blending procedures from the transmission pipeline to the domestic burner; in the latter the set goal is the expansion of the implementation of hydrogen systems—namely storage—in multi-microgrid networks thus helping to decarbonize the electricity sector and reducing the impact of renewable energy’s intermittence through Demand Side Management strategies. The study concludes that hydrogen is assumed to be an energy vector that is inextricable from the necessary transition to a cleaner more efficient and sustainable future.