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Hydrogen energy has made significant progress as one of the technological pathways that can facilitate the green transformation of various sectors, including the chemical industry, steel production, transportation, and power generation. However, areas with high demand for hydrogen are typically located thousands of kilometers away from large-scale production facilities. Hydrogen transported from the most cost-competitive large production sites to areas that lack hydrogen resources requires converting gaseous hydrogen into a high-density liquid. Thus, global market trade is important for hydrogen carriers in long-distance and large-scale transportation. In this study, liquefied hydrogen (LH2) and ammonia (NH3), which are hydrogen-based energy carriers, are analyzed and compared in terms of economic costs, energy efficiency, and carbon dioxide (CO2) emissions. It has been demonstrated that the LH2 supply chain is more energy-efficient and has higher CO2 emissions compared to the NH3 supply chain. Furthermore, this study shows that the levelized cost of hydrogen transportation (LCoHT) delivered from Australia to Ningbo, China, is lower for NH3 (19.95 yuan/kg-H2) compared to LH2 (22.83 yuan/kg-H2). Meanwhile, the LCoHT for the two supply chains is in a similar range (27.82 yuan/kg-H2 and 21.53 yuan/kg-H2 for LH2 and NH3, respectively) from Norway to Ningbo, China. The impacts of important parameters on the LCoHT, energy efficiency, and CO2 emissions of the LH2/NH3 supply chain are also considered through a sensitivity analysis. [ABSTRACT FROM AUTHOR]

Aromatic esters such as phenyl acetates are of interest as promising liquid organic hydrogen carriers (LOHCs) due to the presence of double bonds. However, the key factor for the development of green hydrogen fuel is the production of LOHCs from renewable sources. Since the synthesis and isolation of such esters is a complex task, understanding the relationship between the chemical structures of aromatic esters and their thermodynamic properties is of great importance for their further practical use as LOHCs. Obtaining reliable thermodynamic and thermochemical properties of phenyl and benzyl phenyl acetates formed the basis of this work. Vapour pressures, enthalpies of vaporisation, and enthalpies of formation were systematically studied. An approach based on the structure–property correlation was used to confirm these quantities. Additionally, the high-level quantum-chemical method G4 was used to estimate the enthalpy of formation in the gas phase. The final stage was the assessment of the energetics of chemical reactions based on aromatic esters and their partially and fully hydrogenated analogues. [ABSTRACT FROM AUTHOR]

Liquid hydrogen is a promising energy carrier in the global hydrogen value chain with the advantages of high volumetric energy density/purity, low operating pressure, and high flexibility in delivery. Safe and high-efficiency storage and transportation are essential in the large-scale utilization of liquid hydrogen. Aiming at the two indicators of the hold time and normal evaporation rate (NER) required in standards, this paper focuses on the thermal behaviors of fluid during the no-vented storage of liquid hydrogen and thermal insulations applied for the liquid hydrogen tanks, respectively. After presenting an overview of experimental/theoretical investigations on thermal behaviors, as well as typical forms/testing methods of performance of thermal insulations for liquid hydrogen tanks, seven perspectives are proposed on the key challenges and recommendations for future work. This work can benefit the design and improvement of high-performance LH2 tanks. [ABSTRACT FROM AUTHOR]

This paper investigated the opportunities and challenges of integrating ports into hydrogen (H2) supply chains in the context of Australia and Japan because they are leading countries in the field and are potential leaders in the upcoming large-scale H2 trade. Qualitative interviews were conducted in the two countries to identify opportunities for H2 ports, necessary infrastructure and facilities, key factors for operations, and challenges associated with the ports' development, followed by an online survey investigating the readiness levels of H2 export and import ports. The findings reveal that there are significant opportunities for both countries' H2 ports and their respective regions, which encompass business transition processes and decarbonisation. However, the ports face challenges in areas including infrastructure, training, standards, and social licence, and the sufficiency and readiness levels of port infrastructure and other critical factors are low. Recommendations were proposed to address the challenges and barriers encountered by H2 ports. To optimise logistics operations within H2 ports and facilitate effective integration of H2 applications, this paper developed a user-oriented working process framework to provide guidance to ports seeking to engage in the H2 economy. Its findings and recommendations contribute to filling the existing knowledge gap pertaining to H2 ports. [ABSTRACT FROM AUTHOR]

Aviation is a contributor to global warming. Hydrogen-powered aircraft are seen as an important option to decarbonise parts of commercial aviation. Airports have a pivotal role in facilitating the development of ground infrastructure. This paper provides a broader perspective on the supply and handling of liquid hydrogen, and necessary airport developments, to enable hydrogen-powered aviation. Hydrogen-related airport development projects at Rotterdam The Hague Airport (RTHA) are presented and discussed, and a detailed overview of the airport's liquid hydrogen (LH2) storage facility is given. To link the ongoing developments to future needs, a LH2 demand scenario for RTHA is determined for the years 2040 and 2050. Based on this demand, analysis of levelised cost of hydrogen for relevant value chains were conducted. This study exemplifies that the LH2 value chain for an airport depends on individual characteristics of the airport and its surroundings. The hydrogen demand, the airport's proximity to larger hydrogen hubs (import and/or production hubs) and the availability of local renewable resources, which influence electricity price and hydrogen production and liquefaction costs, are key parameters and heavily influence the airport LH2 value chain. Conceptualisation and future development of hydrogen infrastructure for airport supply should take into account the above factors. LH2 demand at RTHA in the year 2050 is predicted to range between 8–14kt. Under the given electricity price assumptions, local production and liquefaction of hydrogen at the airport is not seen as a viable option, as cost savings can be achieved by making use of the Port of Rotterdam's large hydrogen production and import cluster nearby. The work shows that trailer-based logistics for both the delivery of LH2 to the airport and subsequent usage of these trailers in the storage and dispensing process at the airport seems the most viable for RTHA (and airports that show similarities). This further indicates that current small-scale LH2 demonstration at airports provides important lessons for scaling up. [ABSTRACT FROM AUTHOR]

To achieve net-zero objectives, the expansion of renewable energy sources is anticipated to be accompanied by an increased use of carbon-free fuels, such as hydrogen. Internationally, there are proposals for transporting hydrogen by synthesizing it into carriers like ammonia or Liquid Organic Hydrogen Carriers (LOHCs). However, considering the energy consumption required for hydrogenation and dehydrogenation processes and the need for high-purity hydrogen production, the development of liquid hydrogen transportation technologies is becoming increasingly important. Liquid hydrogen, with a density approximately one-sixth that of liquid natural gas and a boiling point roughly 90 K lower, poses significant challenges in suppressing and managing boil-off gas during transportation. Slush hydrogen, a mixture of liquid and solid phases, offers potential benefits. with an approximate 15% increase in density and an 18% increase in thermal capacity compared to liquid hydrogen. The latent heat of fusion of solid hydrogen effectively suppresses boil-off gas (BOG), and the increased density can reduce transportation costs. This study experimentally validated the long-duration storage and transportation concept of slush hydrogen by adapting NASA's (National Aeronautics and Space Administration) proposed IRAS (Integrated Refrigeration and Storage) technology for compact and mobile tanks. Slush hydrogen was successfully produced by reaching the triple point of hydrogen, resulting in a composition of 47% solid and 53% liquid, with a density of approximately 80.9 kg/m3. Most importantly, methodologies were presented to observe and measure whether the hydrogen was indeed in the slush state and to determine its density. Additionally, CFD (Computational Fluid Dynamics) analysis was performed using solid hydrogen properties, and the results were compared with experimental values. Notably, this analytical technique can be utilized in designing large-capacity tanks for storing slush hydrogen. [ABSTRACT FROM AUTHOR]

The inefficient storage hydrogen is the bottleneck that restricts the large-scale application of green hydrogen energy. Compared with the existing hydrogen storage technologies, naphthalene-decalin organic liquid hydrogen storage, as a highly promising hydrogen storage technology, is expected to provide a new and efficient solution for future energy storage and utilization. The naphthalene-decalin hydrogen storage system can enhance the hydrogen storage capacity of organic liquids, improve the hydrogenation/dehydrogenation cycle and increase economic efficiency. The research progress on naphthalene-decalin organic liquid hydrogen storage technology was reviewed, and the mechanisms of naphthalene hydrogenation and decalin dehydrogenation were analyzed, and the structures of catalysts, processes and technical economy of naphthalene hydrogenation and decalin dehydrogenation were discussed, and the main challenges of naphthalene-decalin organic liquid hydrogen storage technology were summarized. Starting from the key points of demand, through in-depth exploration of the mechanism of decalin dehydrogenation, highly efficient catalysts from the atomic point of view are designed and structures of catalyst surface are constructed to improve the efficiency of decalin dehydrogenation and promote the commercialization of naphthalene-decalin organic liquid hydrogen storage technology. [ABSTRACT FROM AUTHOR]

To address the high energy consumption and low efficiency of hydrogen liquefaction, a novel hydrogen liquefaction process based on liquefied natural gas (LNG) terminals is proposed. The process utilizes LNG cold energy for precooling and mixed refrigerants for cooling, converting hydrogen at 25, 2.1 MPa with parahydrogen concentration (mole fraction, the same below) of 25.00% into liquid hydrogen at -252.4, 130 kPa with parahydrogen concentration of 98.01%. The process, with a handling capacity of 50 t/d, can support 5 104 to 10 104 hydrogen-powered vehicles. By leveraging the pressure energy of natural gas expansion while maintaining the gas grid entry pressure, the energy consumption of hydrogen liquefaction is reduced. The process was simulated using Aspen HYSYS software. With minimized specific energy consumption as the objective function, MATLAB software was used to optimize key process parameters. Exergy efficiency, figure of merit and coefficient of performance were used as evaluation indicators for energy analysis of the system. The results show that the optimized process reduces specific energy consumption (5.257 kW·h/kg) by 28.09%, which is 17.86% lower than the European IDEALHY project and below the levels reported for similar processes in the literature. The exergy efficiency, figure of merit and coefficient of performance are 45.73%, 0.4573, and 0.2346, respectively, which increase by 39.04% 39.04% and 39.06% compared to before optimization. The exergy efficiency is higher than that reported for most similar processes in the literature. The lower liquefaction pressure of hydrogen is more favorable for equipment manufacturing and safe operation. The process is reasonable and highly efficient, which can provide a reference for hydrogen liquefaction at LNG terminals. [ABSTRACT FROM AUTHOR]

Orthohydrogen and parahydrogen (hereinafter referred to as "orthohydrogen-parahydrogen") conversion reaction affects the liquefaction process of hydrogen at low temperature and is an important step in the storage and transportation of liquid hydrogen. Traditional iron-based catalysts face problems such as the aggregative growth of active species, the insufficient resistance ability of water and the poor tolerance ability of high temperature. To solve above problems, α-Fe2O3 was encapsulated into amorphous silica with abundant pore structures, and the encapsulated α-Fe2O3@SiO2 catalyst with high catalytic performance in orthohydrogen-parahydrogen conversion was prepared. SEMXRD and H2-TPR were used to investigate the effects of the encapsulated structure on surface morphologies, crystal structures and reduction abilities of catalysts. The catalytic performances of catalysts were evaluated by test device, and the relationship between the encapsulated structure and catalytic performance was analyzed and summarized. The results show that the encapsulated structure can optimize the pore structure of the catalyst, regulate the electronic property of active sites, improve the structural stability and high temperature tolerance ability of the catalyst, and thereby improve the catalytic performance. When the volume space velocity is 600 min-1, under the action of α-Fe2O3@SiO2 and α-Fe2O3/SiO2 (without encapsulation), parahydrogen volume fractions at the outlet of the device are 41.8% and 37.6%, and the orthohydrogen conversion rates are 22.4% and 16.8%, respectively, indicating that encapsulated iron-based catalysts have high potential for application in the field of orthohydrogenparahydrogen conversion. [ABSTRACT FROM AUTHOR]

ObjectivesLiquid storage and transportation is one of the effective ways to realize large-scale and long-distance storage and transportation of hydrogen and ensure the large-scale application of hydrogen energy. At present, there is relatively little research on the preparation, storage, transportation, and refueling of liquid hydrogen in China. Therefore, the current development status analysis of key technologies in these fields was conducted.MethodsThe advantages and disadvantages of high pressure gaseous storage, liquid hydrogen storage and solid hydrogen storage technologies were compared. The main liquefaction methods, liquid hydrogen storage insulation technologies and key materials in the process of liquid hydrogen preparation were reviewed. The characteristics of different transportation modes and equipments of liquid hydrogen were analyzed. The construction of liquid hydrogen hydrogenation station was combed, and the liquid hydrogen filling technologies were compared. The main application fields and industrialization modes of liquid hydrogen were expounded, and a statistical analysis of the patent technologies of liquid hydrogen storage and transportation in China in recent years was carried.ResultsThe “neck-stuck” difficulties faced by the development of liquid hydrogen storage and transportation in China and the urgent need for technical research directions were proposed.ConclusionsThe results can provide reference for the key technology research and equipment development of liquid hydrogen.

Cavitation occurs in the micro-clearance of liquid-hydrogen-lubricated bearings owing to the pressure drop caused by high-speed shearing. The pressure undulation caused by cavitation collapse results in bearing surface erosion and significantly affects the bearing performance. In this study, a modified Z-G-B cavitation model was used to study the crushing process of a single liquid hydrogen bubble in a shear micro-clearance. Fast Fourier transform (FFT) and wavelet transform (WT) were applied to study the frequency characteristics of the pressure, mass transfer rate, and vapor mass fraction during bubble rupture in shearing micro-clearance. To obtain a deeper insight into the details of the effect of the shear micro-clearance structure on bubble collapse, the relationship between the flow field energy, attenuation rate, and frequency was investigated. The proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) methods were used to analyze the energy of each order mode of the flow field. The analysis results of the bubble vibration intensity with respect to time and frequency provide a theoretical basis for the optimization of the bearing structure.

Liquid hydrogen is a promising energy carrier in the global hydrogen value chain with the advantages of high volumetric energy density/purity, low operating pressure, and high flexibility in delivery. Safe and high-efficiency storage and transportation are essential in the large-scale utilization of liquid hydrogen. Aiming at the two indicators of the hold time and normal evaporation rate (NER) required in standards, this paper focuses on the thermal behaviors of fluid during the no-vented storage of liquid hydrogen and thermal insulations applied for the liquid hydrogen tanks, respectively. After presenting an overview of experimental/theoretical investigations on thermal behaviors, as well as typical forms/testing methods of performance of thermal insulations for liquid hydrogen tanks, seven perspectives are proposed on the key challenges and recommendations for future work. This work can benefit the design and improvement of high-performance LH2 tanks.

Hydrogen is commonly perceived as the key player in the transition towards a low-carbon future. Nevertheless, H 2 low energy density hinders its easy storage and transportation. To address this issue, different alternatives (liquefied hydrogen, ammonia and liquid organic hydrogen carriers) are explored as hydrogen vectors. The techno-economic assessment of H 2 transport through these carriers is strongly dependent on the basis of design adopted, such that it is difficult to draw general conclusions. In this respect, this work is aimed at performing a sensitivity analysis on the hypotheses introduced in the layout of H 2 value chains. Different scenarios are discussed, depending on harbour-to-harbour distances, cost of utilities and raw materials and H 2 application to the industrial or mobility sector. The most cost-effective carrier is selected for each case-study: NH 3 is the most advantageous for industrial sector, while LH 2 holds promises for mobility. Critical issues are pointed out for future large-scale applications. [Display omitted] • NH 3, liquefied H 2 , toluene and dibenzyltoluene assessment as H 2 carrier. • H 2 application to both the industrial and mobility sectors. • Sensitivity study on harbour-to-harbour distance, utilities and raw materials cost. • NH 3 is the most cost-effective H 2 carrier for industrial applications. • LH 2 is the most cost-effective H 2 carrier for mobility applications. [ABSTRACT FROM AUTHOR]

An accurate prediction of non-isothermal gas–liquid interfaces in cryogenic two-phase flows is crucial for the high-efficiency energy storage, transportation, and utilization of liquid hydrogen. However, temperature difference and interfacial mass and energy transport can change the thermodynamic state of gas–liquid interfaces and thereby impact the distribution. And the lower surface tension coefficient and viscosity of liquid hydrogen, compared to room-temperature fluids, increase the likelihood of the instability and breakage of non-isothermal interfaces. Conventional numerical methods suffer from a scarcity of precision and the propagation of spurious velocities in predicting such flows. In this study, a new numerical framework called cryoFoam was developed based on an open source CFD code OpenFOAM to address the issue of the inaccurate capture of non-isothermal cryogenic interfaces. A practical interface-capturing model involving phase change was implemented to achieve the uniform distribution of surface forces in both gas and liquid phases. The tangential surface force was incorporated into the governing equations to realize thermocapillary convection. The Schrage model, a widely-used phase change model, was employed to deal with condensation and evaporation. The performance of the solver was assessed using five benchmarks which involve thermocapillary flows and phase changes in liquid hydrogen, liquid oxygen, liquid nitrogen, and liquid methane. The results show that the new method can reduce large spurious velocities and prevent the distortion of isotherms near the curved interface in cryogenic fluids. It demonstrates higher precision than the traditional VOF method in predicting cryogenic thermocapillary convection and interfacial energy transport. • A new CFD code was developed to model the non-isothermal two-phase flows in liquid hydrogen. • A practical interface-capturing model involving phase change was implemented. • The tangential surface force was employed to realize thermocapillary convection. • Spurious velocities and the distortion of isotherms in liquid hydrogen were reduced. • The method presents high accuracy in predicting mass and energy transport at cryogenic interfaces. [ABSTRACT FROM AUTHOR]

The release of hydrogen from liquid organic hydrogen carriers (LOHC) takes place in an endothermal dehydrogenation reaction that is accompanied by a strong volume expansion. This leads to complex hydrodynamic properties that change drastically along the reactor axis due to product gas evolution. Consequently, heat transfer into the catalytic fixed-bed exhibits a pronounced local dependency. For a better understanding of such multiphase dehydrogenation systems, we have performed heat transport measurements in the presence of the chemical reaction, namely during the dehydrogenation of perhydro benzyltoluene (H12-BT) and perhydro dibenzyltoluene (H18-DBT). The results reveal that overall heat transfer coefficients show a clear local dependency on the axial coordinate. Moreover, the two carriers were found to differ significantly in their thermal behavior. Based on a global analysis, two main regimes can be distinguished in the dehydrogenation reactor: 1.) With the LOHC mixture being primarily in the liquid phase, heat transport is dominated and intensified by the hydrogen release; 2.) With an increasing proportion of LOHC vapor in the reactor, the heat transport is dominated by the gas phase, resulting in significantly lower thermal parameters. • Local and global heat transport analysis for hydrogen release from LOHC systems. • Examination of heat transfer parameters in presence of the chemical reaction. • Hydrogen release amplifies or hinders heat transport depending on hydrodynamic regime. [ABSTRACT FROM AUTHOR]

We report an exploration of liquid hydrogen (LH 2) tank technology, determining if improving LH 2 tank weight, multiplicity or shape enables more hydrogen to be stored on hydrogen vessels. The improvements investigated are well beyond the current LH 2 technology state-of-the-art. The platform for this study is a monohull H 2 Baseline research vessel powered 100% by hydrogen. Regarding weight reductions, we found that the research vessel does not benefit significantly from large weight reductions of the LH 2 tanks. A 50% reduction in mass of the inner pressure vessel led to a 3.1% reduction in the total research vessel weight. Reducing the LH 2 tank weight to the asymptotic limit of zero results in a 7.1% reduction in the overall research vessel weight. This maritime application, while benefitting from a reduction in LH 2 tank weight, is not a strong driver for LH 2 tank weight improvements. The two large LH 2 tanks of the H 2 Baseline Vessel can be replaced with a multitude of smaller LH 2 tanks. In two Multiplicity design variants, the total amount of stored LH 2 was ∼5–9% less than that of the H 2 Baseline Vessel, which does not motivate conducting the needed R&D that would drive the technology to smaller high-performing LH 2 tanks. We did find a significant benefit to improving the shape of LH 2 tanks, towards prismatic tanks that would better match the vessel hullform. Considering a "Shape Variant" that included space-consuming features such as tank connection spaces, manifolding and ventilation, we found a 26% improvement in stored LH 2 compared to the H 2 Baseline Vessel. The large improvement in storage capacity could warrant further LH 2 tank R&D that can enable high performing prismatic LH 2 tanks, such as pressure vessel steel developments allowing for higher strength/ductility at 20 K, improved insulation systems, methods for efficiently building prismatic tanks with insulation systems fit for 20 K service and flare-less techniques for managing heat leak (venting). The results are reviewed considering the current regulatory restrictions as well as prevailing limitations in LH 2 tank manufacturing. • Watercraft are not a strong driver for reducing the mass of LH 2 tanks. • There is no benefit to deploying smaller LH 2 tanks with multiplicity on ships. • Improved shape of LH 2 tanks allows more hydrogen to be stored on ships. • Future LH 2 tank R&D needs to consider prevailing regulatory restrictions. [ABSTRACT FROM AUTHOR]

Due to excellent performance, hydrogen is treated as the most promising energy carrier. However, during the storage of liquid hydrogen, there are still some thorny issues that need to be addressed urgently, such as fluid thermal stratification and sloshing phenomenon. To efficiently grasp fluid sloshing mechanical characteristics, a simple visual sloshing experiment rig was established by using a rectangle transparent water vessel. The variations of the interface shape and the impact force during sloshing were monitored and analyzed. The effects of sloshing frequency, horizontal acceleration, and initial liquid height on fluid sloshing mechanical mechanism were investigated. The results show that when the external sloshing excitation is close to the first order natural frequency, obvious interface fluctuation and large amplitude sloshing force variation are observed. The present work is of significance to strengthen the understanding of fluid sloshing mechanical performance and may lay a solid foundation for fluid sloshing suppression and long‐term storage of cryogenic fuels. [ABSTRACT FROM AUTHOR]

In the pursuit of enhancing the applications of hydrogen as an energy carrier, this research delved into the utilization of a singular hybrid catalyst capable of performing both dehydrogenation and hydrogenation processes for Liquid Organic Hydrogen Carriers (LOHCs). This study presents the synthesis and characterization of a hybrid catalyst, combining an organometallic pincer complex with Pd−Ru heterostructures supported on γ‐alumina. Unlike conventional transition and noble metal nanoparticles, the use of a pincer complex offers exceptional thermal stability due to its aryl backbone, which is advantageous for various endothermic dehydrogenation reactions of hydrocarbons in LOHCs. This pioneering hybrid catalyst is a novel approach, demonstrating a proof of concept. In this study, we utilized the hybrid catalyst to investigate the dehydrogenation and hydrogenation of a lower enthalpic system, specifically the cyclooctane−cyclooctene system. The dehydrogenation of cyclooctane was conducted at 443 K using tertiary butyl ethylene as a sacrificial hydrogen acceptor, while the hydrogenation of cyclooctene reaction catalyzed by Pd−Ru nanostructures occurred at 298 K and 1 atm H2. The results showed successful tandem dehydrogenation‐hydrogenation reactions. However, challenges were noted in terms of catalytic activity and recyclability, providing valuable insights for further refinement and optimization. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) is being acknowledged as the future energy carrier due to its high energy density and potential to mitigate the intermittency of other renewable energy sources. H2 also ensures a clean, carbon‐neutral, and sustainable environment for current and forthcoming generations by contributing to the global missions of decarbonization in the transportation, industrial, and building sectors. Several H2 storage technologies are available and have been employed for its secure and economical transport. The existing H2 storage and transportation technologies like liquid‐state, cryogenic, or compressed hydrogen are in use but still suffer from significant challenges regarding successful realization at the commercial level. These factors affect the overall operational cost of technology. Therefore, H2 storage demands novel technologies that are safe for mobility, transportation, long‐term storage, and yet it is cost‐effective. This review article presents potential opportunities for H2 storage technologies, such as physical and chemical storage. The prime characteristics and requirements of H2 storage are briefly explained. A detailed discussion of chemical‐based hydrogen storage systems such as metal hydrides, chemical hydrides (CH3OH, NH3, and HCOOH), and liquid organic hydrogen carriers (LOHCs) is presented. Furthermore, the recent developments and challenges regarding hydrogen storage, their real‐world applications, and prospects have also been debated. [ABSTRACT FROM AUTHOR]

HyResponder is a European Hydrogen Train the Trainer programme for responders. This paper describes the key outputs of the project and the steps taken to develop and implement a long-term sustainable train the trainer programme in hydrogen safety for responders across Europe and beyond. This FCH2 JU (now Clean Hydrogen Joint Undertaking) funded project has built on the successful outcomes of the previous HyResponse project. HyResponder has developed further and updated educational, operational, and virtual reality training for trainers of responders to reflect the state-of-the-art in hydrogen safety, including liquid hydrogen, and expand the programme across Europe and specifically within the 10 countries represented directly within the project consortium: Austria, Belgium, the Czech Republic, France, Germany, Italy, Norway, Spain, Switzerland, and the United Kingdom. For the first time, four levels of educational materials from fire fighter through to specialist have been developed. The digital training resources are available on the e-Platform (https://hyresponder.eu/e-platform/). The revised European Emergency Response Guide is now available to all stakeholders. The resources are intended to be used to support national training programs. They are available in 8 languages: Czech, Dutch, English, French, German, Italian, Norwegian and Spanish. Through the HyResponder activities, trainers from across Europe have undertaken joint actions which are in turn being used to inform the delivery of regional and national training both within and beyond the project. The established pan-European network of trainers is shaping the future in the important for inherently safer deployment of hydrogen systems and infrastructure across Europe and enhancing the reach and impact of the programme. • Responders across 10 European countries have been trained in hydrogen safety. • Translated teaching materials are available in 8 languages. • A unique operational training platform for responders has been extended. • Operational, virtual reality and educational training materials have been revised. • A revised European Emergency Response guide is available on an e-Platform. [ABSTRACT FROM AUTHOR]

Liquid hydrogen leaks can lead to the formation of solid-air deposition near the leakage source, and oxygen enrichment may exacerbate the risk of ignition of liquid hydrogen and combustible clouds. This study, based on NASA's large-scale liquid hydrogen leakage experiments, constructed a three-dimensional model to dissect the evaporation/condensation and melting/solidification processes of air components (water, oxygen, and nitrogen), aiming to analyze the phase transitions of each air component and study the concentration and extent changes of condensed air components and solid-air deposition over time. The findings indicated that after the leakage stopped, the concentrations of liquid nitrogen and oxygen initially increased and then decreased below the leakage source, related to the heat absorption from liquid hydrogen evaporation and ground heat exchange, while the range of solid-air deposition gradually diminished. This model provides a reliable prediction of solid-air deposition formation, offering a reference for further research. [Display omitted] • Condensation and solidification processes of nitrogen and oxygen are considered separately. • The concentration and range of liquid nitrogen and liquid oxygen continue to increase after the leakage is stopped. • The solidification range of nitrogen and oxygen decreases after the liquid hydrogen evaporates completely. • Thermal conductivity of ground conditions affects the duration of solid-air deposition. [ABSTRACT FROM AUTHOR]

Many countries, especially those with a high energy demand but insufficient renewable resources are currently investigating the role that imported low carbon hydrogen may play in meeting future energy requirements and emission reduction targets. A future hydrogen economy is uncertain and predicated on reduced price of hydrogen delivered to customers. Current hydrogen production, steam reforming of natural gas or coal gasification, is co-located to its end-use as a chemical feedstock. Large-scale multi-source value chains of hydrogen needed to support its use for energy are still at concept phase. This research investigates the combination of technical and economic factors which will determine the viability and competitiveness of two competing large scale renewable hydrogen value chains via ammonia and liquid hydrogen. Using a techno-economic model, an evaluation of whether green hydrogen exports to Germany from countries with low-cost renewable electricity production, but high-costs of storage, distribution and transport will be economically competitive with domestic renewable hydrogen production is conducted. The model, developed in Python, calculates costs and energy losses for each step in the value chain. This includes production from an optimised combination of solar and/or wind generation capacity, optimised storage requirements, conversion to ammonia or liquid hydrogen, distribution, shipping, and reconversion. The model can easily be applied to any scenario by changing the inputs and was used to compare export from Chile, Namibia, and Morocco with production in Germany using a 1 GW electrolyser and 2030 cost scenario in each case. • Electrolyser utilisation is more important than renewable energy storage when determining the LCOH. • The lowest cost LCOE for green hydrogen production does not always result in the LCOH. • The reconversion of ammonia back to hydrogen significantly increases the cost of energy to the end user. [ABSTRACT FROM AUTHOR]

The study presents a thermodynamic and economic assessment of different hydrogen storage solutions for heating purposes, powered by PV panels, of a 10-apartment residential building in Milan, and it focuses on compressed hydrogen, liquid hydrogen, and metal hydride. The technical assessment involves using Python to code thermodynamic models to address technical and thermodynamic performances. The economic analysis evaluates the CAPEX, the ROI, and the cost per unit of stored hydrogen and energy. The study aims to provide an accurate assessment of the thermodynamic and economic indicators of three of the storage methods introduced in the literature review, pointing out the one with the best techno-economic performance for further development and research. The performed analysis shows that compressed hydrogen represents the best alternative but its cost is still too high for small residential applications. Applying the technology to a big system case would enable the solution making it economically feasible. • Evaluation of H2 storage for residential heating. • Analysis of compressed, liquid, and metal hydride H2 storage. • Evaluation criteria based on thermodynamics and economic metrics. • Compressed hydrogen is the most feasible storage: energy intensity of 1.31 kWh/kg and cost of 3 €/kg. • Discussion and analysis of scale-up potential for economic feasibility. [ABSTRACT FROM AUTHOR]

Hydrogen is a promising solution for the decarbonisation of several hard-to-abate end uses, which are mainly in the industrial and transport sectors. The development of an extensive hydrogen delivery infrastructure is essential to effectively activate and deploy a hydrogen economy, connecting production, storage, and demand. This work adopts a mixed-integer linear programming model to study the cost-optimal design of a future hydrogen infrastructure in presence of cross-sectoral hydrogen uses, taking into account spatial and temporal variations, multiple production technologies, and optimised multi-mode transport and storage. The model is applied to a case study in the region of Sicily in Italy, aiming to assess the infrastructural needs to supply the regional demand from transport and industrial sectors and to transfer hydrogen imported from North Africa towards Europe, thus accounting for the region's role as transit point. The analysis integrates multiple production technologies (electrolysis supplied by wind and solar energy, steam reforming with carbon capture) and transport options (compressed hydrogen trucks, liquid hydrogen trucks, pipelines). Results show that the average cost of hydrogen delivered to demand points decreases from 3.75 €/kg H2 to 3.49 €/kg H2 when shifting from mobility-only to cross-sectoral end uses, indicating that the integrated supply chain exploits more efficiently the infrastructural investments. Although pipeline transport emerges as the dominant modality, delivery via compressed hydrogen trucks and liquid hydrogen trucks remains relevant even in scenarios characterised by large hydrogen flows as resulting from cross-sectoral demand, demonstrating that the system competitiveness is maximised through multi-mode integration. [Display omitted] • A hydrogen supply chain model is extended to study delivery to multi-sector demand. • Industrial uses impose flat profiles with large quantities, while mobility demand is more variable. • The cost-optimal hydrogen infrastructure relies on combined transport modes. • Cross-sectoral deployment of hydrogen has positive impact on the cost of infrastructure. [ABSTRACT FROM AUTHOR]

Methylcyclohexane (MCH) dehydrogenation is an equilibrium‐limited reaction that requires high temperatures (>300 °C) for complete conversion. However, high‐temperature operation can degrade catalytic activity and produce unwanted side products. Thus, a hybrid zeolite membrane (Z) is prepared on the inner surface of a tubular support and used it as a wall in a membrane reactor (MR) configuration. Pt/C catalysts is packed diluted with quartz sand inside the Z‐coated tube and applied the MR for MCH dehydrogenation at low temperatures (190–250 °C). Z showed a remarkable H2‐permselectivity in the presence of both toluene and MCH, yielding separation factors over 350. The Z‐based MR achieved higher MCH conversion (75.3% ± 0.8% at 220 °C) than the conventional packed‐bed reactor (56.4% ± 0.3%) and the equilibrium state (53.2%), owing to the selective removal of H2 through Z. In summary, the hybrid zeolite MR enhances MCH dehydrogenation at low temperatures by overcoming thermodynamic limitations and improves the catalytic performance and product selectivity of the reaction. [ABSTRACT FROM AUTHOR]

During liquid hydrogen bunkering into a cryogenic tank, boil-off losses occur due to the high thermal gradient between liquid hydrogen and the warm surface of the tank. This leads to gaseous hydrogen release. Such losses constitute a significant drawback in using hydrogen as a fuel for maritime applications where bunkering operations are regularly carried out, thereby constituting a significant loss along the liquid hydrogen pathway. Due to the inherently low temperature of liquid hydrogen, boil-off losses are always present. Some boil-off losses cannot be eliminated because they are thermodynamically constrained or intrinsic to the system's design. Boil-off recovery methods can be implemented to capture the boil-off; however, those solutions come with an additional cost and system complexities. Hence, this paper investigates the feasibility of minimizing boil-off losses during the first bunkering of liquid hydrogen or refilling of liquid hydrogen in an empty cryogenic tank by first precooling the cryogenic tank surface to decrease the thermal gradient between the liquid hydrogen and the tank surface/wall. In this paper, different media for precooling a cryogenic tank are evaluated to assess the boil-off reduction potential and the associated costs in order to identify the most suitable solution. The assessment has been carried out based on analytical formulation. [ABSTRACT FROM AUTHOR]

This review aims to summarize the recent advancements and prevailing challenges within the realm of hydrogen storage and transportation, thereby providing guidance and impetus for future research and practical applications in this domain. Through a systematic selection and analysis of the latest literature, this study highlights the strengths, limitations, and technological progress of various hydrogen storage methods, including compressed gaseous hydrogen, cryogenic liquid hydrogen, organic liquid hydrogen, and solid material hydrogen storage, as well as the feasibility, efficiency, and infrastructure requirements of different transportation modes such as pipeline, road, and seaborne transportation. The findings reveal that challenges such as low storage density, high costs, and inadequate infrastructure persist despite progress in high-pressure storage and cryogenic liquefaction. This review also underscores the potential of emerging technologies and innovative concepts, including metal–organic frameworks, nanomaterials, and underground storage, along with the potential synergies with renewable energy integration and hydrogen production facilities. In conclusion, interdisciplinary collaboration, policy support, and ongoing research are essential in harnessing hydrogen's full potential as a clean energy carrier. This review concludes that research in hydrogen storage and transportation is vital to global energy transformation and climate change mitigation. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carrier (LOHC) technology has unique advantages in hydrogen storage and transportation. However, the lack of research on the continuous dehydrogenation process of LOHCs has hindered the design and application of industrial dehydrogenation processes. In this work, a highly active dehydrogenation catalyst 1.5 wt% Pd/activated carbon (Pd/C) and a commercial catalyst 5 wt% Pd/Al2O3 were used for the continuous dehydrogenation of dodecahydro‐N‐ethylcarbazole (12H‐NEC). Based on a tubular reactor and lab‐scale apparatus, 1.5 wt% Pd/C catalyst achieved a maximum dehydrogenation conversion of 98.3% and a maximum NEC selectivity of 95.3%, while dehydrogenation conversion and NEC selectivity with 5 wt% Pd/Al2O3 were 98.3% and 97.6%, respectively. It showed the equally excellent performance between Pd/C and Pd/Al2O3, and the former has less Pd loading than the latter, with the potential of reducing the production cost of the dehydrogenation catalyst. The dehydrogenation results also indicated the difference in catalytic performance between the two kinds of catalysts. The obtained kinetics data were analyzed, and the dynamics of continuous dehydrogenation were studied to provide fundamental information for dehydrogenation scale‐up. [ABSTRACT FROM AUTHOR]

Liquid hydrogen leakage and diffusion accidents pose serious threats to the safety of personnel and equipment. In the present work, three-dimensional CFD models for liquid hydrogen spills in unstable, neutral and stable atmospheric boundary layers are developed, and the effects of atmospheric boundary layer on prediction accuracy is validated. Spread characteristics of hydrogen vapor cloud under different atmospheric boundary layers are then numerically analyzed. Modeling the stability of atmospheric boundary layer can improve the accuracy and reliability of the prediction results for liquid hydrogen spills. Wind velocity and its gradient, as well as the vertical distribution of air temperature, act upon the spread characteristics of hydrogen vapor cloud. The unstable atmospheric boundary layer could promote the upward movement and the expansion of hydrogen vapor cloud to some extent. The stable atmospheric boundary layer promotes the vertical spread process in early stage, while presents hindering effects as the spill continues. Cloud heights at the end of the spill are respectively 48.6 m, 45.5 m and 30.2 m, under the unstable, neutral, and stable atmospheric boundary layers. In addition, wind flow in stable atmospheric boundary layer has obvious dragging effect on the lateral edge of hydrogen vapor cloud. • Models for liquid hydrogen spill in various atmospheric boundary layers are built. • Cloud spread characteristics under different atmosphere stabilities are analyzed. • Modeling atmosphere stability improves accuracy for spill prediction. • Unstable atmosphere promotes the upward movement and expansion of vapor cloud. • Stable atmosphere hinders cloud spread process in late stage of spill. [ABSTRACT FROM AUTHOR]

Liquid hydrogen storage equipment is insulated using high-vacuum multi-layer insulation. This insulation is manufactured from materials that emit hydrogen gas, which degrades the insulating properties. Palladium oxide is widely used in liquid hydrogen storage as an effective hydrogen absorber. This study investigates the adsorption principle of H 2 molecules on the surface of PdO(101) crystals. The mechanism of hydrogen adsorption on the PdO(101) surface was investigated by analyzing the adsorption energy, stable adsorption configuration, and electronic structure of the H 2 /PdO(101) system. The dissociative chemisorption of hydrogen on the PdO (101) surface has been investigated using temperature-programmed desorption (TPD) and density functional theory (DFT) calculations. It is determined that greater than 90% of the hydrogen dissociation occurs at temperatures below ∼100K. The dissociative chemisorption of hydrogen on the PdO(101) surface was found to occur at temperatures below ∼100K. The majority of the dissociated hydrogen reacts and produces water on the surface during TPD, which desorbs above ∼300K. The results indicate that Pd cus is the most stable adsorption site for H 2 on the PdO(101) surface, with an adsorption energy of −0.56 eV, resulting in weak chemisorption. Once the activation energy is reached, H 2 and Pd cus form a stable structure. The movement of H atoms between Pd cus sites generates a negative heat of reaction. The adsorption energy of H atoms at the O cus site (−3.26 eV) is higher than that at the Pd cus site (−3.21 eV). Hydroxylated PdO(101) promotes water production. The combination of H atoms and hydroxides to produce water overcomes the potential barrier of 0.69 eV, resulting in the production of Pd and H 2 O. • DFT calculations were used to study the adsorption mechanism of H 2 molecules on the PdO(101) surface. • The TPD process found that H2 dissociates readily at temperatures below 100 K. • 3.The stable adsorption sites for H 2 molecules were identified as the unsaturated Pd sites on the surface of PdO (101). • On PdO(101), H 2 dissociates into two H atoms and adsorbs stably on the Pd cus site. • The hydroxylated PdO (101) continues to adsorb H 2 eventually producing Pd and water. [ABSTRACT FROM AUTHOR]

The demand for hydrogen in South Korea is projected to reach 3.9 Mt by 2030, of which 2.96 Mt clean hydrogen is aimed by 2030. As such, we conduct an economic analysis of a low greenhouse gas emission hydrogen supply chain in South Korea using several H 2 transportation methods in this study. The types of supply chains considered are green and blue ammonia; green and blue liquid hydrogen (LH 2) imported from the Gulf Cooperation Council (GCC) region; and blue hydrogen produced in South Korea. A base-case analysis shows that the imported blue ammonia scenario is the most cost-effective option with 3.40 USD/kg H2 , followed by the domestic blue hydrogen with 4.33 USD/kg H2, and imported green ammonia with 4.56 USD/kg H2. In environmental analysis, imported green ammonia shows the lowest CO 2 footprint with 4.20 kg CO2 /kg H2 , followed by imported green LH 2 with 6.26 kg CO2 /kg H2 , and domestic blue hydrogen with 7.34 kg CO2 /kg H2. • Imported blue ammonia scenario is the most cost-effective option at 3.40 USD/kg H2 • Cost reduces further when ammonia is used for power generation or as a marine fuel • Imported blue and green LH 2 show a far higher hydrogen supply cost than the others • Electrolysis has largest portion of hydrogen supply cost • Imported green ammonia shows the lowest CO 2 footprint with 4.20 kg CO2 /kg H2 [ABSTRACT FROM AUTHOR]

During hydrogenation and dehydrogenation reactions of liquid organic hydrogen carriers (LOHC), their thermophysical properties change significantly as a function of the degree of hydrogenation (DoH). Compared with conventional techniques, Raman spectroscopy offers a contactless methodology for online process monitoring without the need of sampling. This work demonstrates the application of Raman spectroscopy for the determination of the DoH under process-relevant conditions for LOHC systems based on diphenylmethane (DPM) and benzyltoluene (BT) up to 473 K. For the DPM-based system, a previous study is extended by examining the influence of process-like disturbances. For the BT-based system, a novel approach using indirect hard modeling of the unpolarized Raman spectra is applied, which results in strongly reduced uncertainties and insensitivity towards process-like disturbances, e.g. reaction by-products. For a corresponding testing set exhibiting a pronounced fluorescent background in the Raman spectra, the DoH is determined with an average absolute deviation of 0.0057. [Display omitted] • Accurate determination of the degree of hydrogenation (DoH) by Raman spectroscopy. • Sound methodology for the inline and online monitoring of LOHC reaction processes. • Investigation of the influence of process conditions on the evaluation of the DoH. • Analysis even possible in the presence of convection and reaction by-products. [ABSTRACT FROM AUTHOR]

Addressing the urgent need to reduce global CO 2 emissions, there is a growing emphasis on transitioning from the current fossil fuel-dependent energy system to an environmentally sustainable hydrogen-based economy, devoid of carbon emissions. However, the inherent challenges in the conventional storage and transportation of elemental hydrogen have impeded progress. To overcome this hurdle and achieve a seamless transition to a cost-effective hydrogen storage solution, researchers propose the use of liquid organic hydrogen carriers (LOHCs). These carriers involve chemically binding elemental hydrogen within hydrogen-deficient organic molecules, allowing for efficient storage and retrieval of hydrogen under low pressure conditions. An attractive feature of LOHCs is their compatibility with existing infrastructure such as storage tanks, ships, and fueling stations, facilitating a smoother transition. This contribution delves into the crucial role of various catalyst materials in enhancing the hydrogenation activity of various LOHCs such as benzene, toluene, N-ethylcarbazole (NEC) and dibenzyltoluene (DBT). Through the exploration of catalytic aspects, this review investigates the effect of noble metal, transition metal, and multimetallic catalysts, providing valuable insights into their design and optimization. These efforts aim to achieve efficient and sustainable hydrogen storage within the LOHC framework. The findings presented in this study aim to contribute to the development of economically viable solutions for hydrogen storage and utilization, thereby aiding the seamless transition toward a hydrogen-based energy economy. The roles of catalyst materials in enhancing the hydrogenation activity of various LOHCs such as toluene, benzene, N-ethlycarbazole and dibenzyltoluene are studied. By investigating various catalytic aspects, it offers valuable insights into the design and optimization of catalysts for efficient hydrogen storage within the LOHC framework. [Display omitted] [ABSTRACT FROM AUTHOR]

The desublimation crystallization of trace impurity gas at the temperature of liquid hydrogen and liquid oxygen is a common problem in cryogenic engineering, which usually leads to the failure of cryogenic liquid transportation. Liquid hydrogen and liquid oxygen are important aerospace propellants. In the pressurization process of cryogenic liquid propellant, a small amount of water vapor and other gases in the pressurized gas would appear desublimation and crystallization at low temperature. Inevitably, as the tail gas of hydrogen combustion, water vapor sometimes diffused into cryogenic liquid. This kind of desublimation crystallization was accompanied by heat and mass transfer, accompanied by gas-solid phase transition, moving boundary, random and extremely complicated crystallization growth process. It was of great engineering practical significance to study the heat and mass transfer mechanism and law of this complex desublimation phase change phenomenon for the progress and development of engineering technologies such as refrigeration, cryogenics and aerospace. In this paper, based on the homogeneous desublimation theory, the pressurization system of liquid oxygen tank with oxygen containing trace water vapor was taken as the research object, and the basic data of ice crystal formation and growth during pressurization, such as crystallization quantity, crystallization speed and size distribution, were calculated theoretically. It provided a theoretical basis for the experimental study of the real dynamic characteristics and laws of desublimation crystallization in the propulsion system. The research methods and conclusions in this paper also had some guiding significance for the use of liquid hydrogen in the storage, transportation and use of the hydrogen energy. • Provided a challenging crystallography study on the space application of liquid hydrogen and liquid oxygen. • Described the complicated desublimation crystallization with accompanied by heat and mass transfer. • Provided dynamic characteristics of crystallization quantity, crystallization speed and size distribution. • Simulated the nucleation and ice growth accurately for many generations crystals evolved. • Suitable for crystallization of trace impurities during liquid hydrogen storage and transportation. [ABSTRACT FROM AUTHOR]

This study introduces an electro-dehydrogenation method for converting amines into nitriles in aqueous environments, simultaneously releasing two moles of H2 using nickel electrodes. This eco-friendly process is selective and operates at room temperature, in contrast to traditional thermal methods that require high temperatures and where condensation products are usually observed. Detailed impedance spectroscopy analysis reveals that the dehydrogenation of amines in aqueous media is facilitated by efficient charge transfer, with the diffusion of amines to the electrode surface identified as the kinetically slowest step. Our study underscores the potential of electrochemistry to enhance the reversible dehydrogenation and hydrogenation of the amine/nitrile pair. By demonstrating the practicality and efficiency of this approach, we highlight the amine/nitrile pair as a promising candidate for liquid organic hydrogen carriers. This has significant implications for the future of hydrogen storage and transport technologies, paving the way for more sustainable and efficient energy solutions. [ABSTRACT FROM AUTHOR]

Electromagnetic induction heating could eliminate the limitations associated with conventional heating methods for endothermic dehydrogenation reactions of liquid organic hydrogen carriers—it may offer faster heating rates, while directing the heat from the core of the inductively active materials to the catalyst and the surrounding fluid. A 5 wt% Pt/γ-Al 2 O 3 prepared by wet impregnation, was used as a wash-coat to produce an inductively active catalyst in which stainless steel (SS) pellets were used. Different configurations were considered, for comparison: SS pellets alone, Pt/γ-Al 2 O 3 coated SS pellets, a mixture of 5 wt% Pt/γ-Al 2 O 3 pellets and SS pellets. An induction heating set-up for the catalytic dehydrogenation of perhydro-benzyltoluene (H12-BT) was built (use was made of an inductive coil covering a glass batch reactor. Increasing the n (Pt)/ n (H12-BT) ratio lowered the catalyst productivity (gH 2 gPt−1min−1) by 7.4%, but enhanced the H12-BT conversion and selectivity towards the product benzyltoluene (H0-BT). Remarkably, there are no by-products in either the liquid or gas phases at high conversion (>90%). • A suitable set-up of an inductively heated batch-type reactor was developed. • Induction heating dehydrogenation was confirmed by the production of hydrogen gas and benzyltoluene (H0-BT). • Higher Pt molar ratio in coated stainless-steel pellets, increased conversion and selectivity. • There is absence of by-products in both liquid and gas phase at a conversion >90%. [ABSTRACT FROM AUTHOR]

The benzyltoluene (BT)-based liquid organic hydrogen carrier (LOHC) system currently considered for large-scale applications represents a mixture of regioisomers. To characterize this complex system, a comprehensive experimental database for various thermophysical properties of synthesized BT isomers and their mixtures without and with the presence of hydrogen (H 2) close to vapor-liquid equilibrium is established using optical and conventional techniques at process-relevant temperatures and pressures up to 573 K and 6 MPa. The surface tension varies by less than 4% among the dehydrogenated (H0-BT) or hydrogenated (H12-BT) isomers. The density and viscosity of mixtures of H0-BT or H12-BT isomers can be described by simple mixing rules with average absolute relative deviations of 0.022% and 0.38%. With increasing H 2 pressure, the viscosity remains nearly constant, while the interfacial tension decreases by up to 5%. The thermal and mutual diffusivity of H12-ortho-BT containing dissolved H 2 at 6 MPa decrease and increase with increasing temperature. [Display omitted] • Synthesis of high-purity regioisomers of LOHC system based on benzyltoluene (BT). • Optical and conventional techniques applied up to 573 K and 6 MPa hydrogen (H 2). • Minor variation in density and surface tension among BT or its hydrogenated isomers. • Large effect of isomeric mixture composition on viscosity with variations up to 33%. • First temperature-dependent data for thermal and Fick diffusivity of BT-H 2 system. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carrier (LOHC) systems offer a particularly interesting option for chemical hydrogen storage. In order to characterize and understand the endothermal hydrogen release from the carrier liquid and to evaluate suitable catalyst materials, knowledge of the temperature fields in the dehydrogenation reactor is important. One suitable technique for planar temperature sensing in reacting systems is phosphor thermometry. It is based on the excitation of a luminescent material by a laser pulse and detection of the subsequent phosphorescence signal. We investigated the luminescence of the thermographic phosphor (Sr,Ca)SiAIN3:Eu2+ ("SCASN:Eu2+") dispersed in the H0-DBT / H18-DBT LOHC system in a temperature range from 400 to 600 K. A measurement cell enables repeatable and homogeneous measurement conditions of the hydrogen release reaction. A catalytic plate was put inside the heated LOHC. Temperature fields during the hydrogen release reaction were measured for the first time using the phosphorescence decay time (PDT) and the phosphorescence intensity ratio method (PIR). As expected, a strong cooling at the catalyst surface during the endothermal hydrogen release reaction could be observed, which was quantified to be in the range of 40 K. [ABSTRACT FROM AUTHOR]

Based on the costs to produce PTX products, a simple computational model is presented to determine the costs to ship and to reform them into hydrogen. In this model, wind farms are the sole energy source for PTX production. As an example, the costs of transporting power‐to‐X (PTX) products NH3, MeOH, liquid organic hydrogen carrier (LOHC), and Fischer‐Tropsch diesel from Chile (Haru Oni) and Morocco (Tarfaya) are determined. These costs are compared with those of hydrogen production at three domestic locations with very good to very moderate wind conditions in the order Dornum (North German coast), Senftenberg (Lausitz), and Ludwigshafen (Rhine Graben). In addition, a cost comparison for Fischer‐Tropsch diesel is made and land requirements for domestic production are determined. [ABSTRACT FROM AUTHOR]

A calculation method for optimizing the LCOE and the cost of subsequent PTX production from wind power is presented, based on Weibull parameters and cost functions. The PTX products methanol, ammonia and synthetic diesel are considered, as well as hydrogen, which is converted into an easily transportable form by hydrogenation of a liquid organic hydrogen carrier (LOHC). Haru‐Oni in Chile and Tarfaya in Morocco were chosen as examples of production sites with excellent wind conditions. These are compared with three domestic sites with very good to very moderate wind conditions in the order Dornum (North German coast), Senftenberg (Lausitz) and Ludwigshafen (Rhine Graben). [ABSTRACT FROM AUTHOR]

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This paper describes design, manufacture, and testing of a linerless composite vessel for liquid hydrogen, having 0.3 m diameter and 0.9 m length. The vessel consists of a composite cylinder manufactured by wet filament winding of thin-ply composite bands, bonded to titanium end caps produced by additive manufacturing. The aim was to demonstrate the linerless design concept with a thin-ply composite for the cylinder. The investigation is limited to the internal pressure vessel, while real cryogenic tanks also involve an outer vessel containing vacuum for thermal insulation. Thermal stresses dominate during normal operation (4 bar) and the layup was selected for equal hoop strains in the composite cylinder and end caps during filling with liquid hydrogen. Two vessels were tested in 20 cycles, by filling and emptying with liquid nitrogen to 4 bar, without signs of damage or leakage. Subsequently, one vessel was tested until burst at almost 30 bar. [ABSTRACT FROM AUTHOR]

We report time resolved observations of the crystallization from liquid hydrogen, supercooled to temperatures below the melting point, using 11.2 keV X-ray diffraction from the Linac Coherent Light Source (LCLS). Changes to the metastable solid and liquid structure factors have been dynamically measured. This allows for a direct determination of the lowest energy crystal polymorphs, the stacking probabilities, as well as the liquid and solid densities and temperatures. Such measurements provide experimental evidence of an Arrhenius-like growth kinetics along the stacking direction during supercooling. [ABSTRACT FROM AUTHOR]

Hydrogen is an ideal energy source and plays an important role in increasingly global energy issues and environmental problems. Liquid hydrogen (LH2) has many advantages over other storage methods, especially in terms of energy density. However, it may cause enormous harm once it leaks accidently. LH2 leakage is a complex multiphase process involving evaporation, condensation, transfer of mass and heat, and dispersion. In order to study LH2 transportation and storage systems safety, a research project has been carried out to develop a 3D numerical model using an open-source CFD code, OpenFoam, for investigating LH2 accidental release scenarios. Since the release of LH2 is a very complex process, our strategy is to study it step by step. Therefore, in this paper we present our research work at the first stage, a dispersion process of room-temperature gaseous hydrogen without multiphase flow. A small-scale hydrogen release conducted by Sandia National Laboratories is simulated. In this experiment, room-temperature gaseous hydrogen is injected upwards into the air from a small hole with a 1.91 mm diameter. The situations of Froude (Fr) number = 99, 152, and 268 are studied, respectively. The behavior of hydrogen at different Fr numbers is discussed. When high-speed hydrogen enters the air, the speed and concentration of hydrogen decrease rapidly. In addition, the greater the speed, the faster it decays. The result shows a close range of hydrogen reach. Details about the numerical model are introduced. The simulation results are used to verify the validity of the developing numerical model for dispersion and mixing of multi-species. The simulated concentrations and velocity distribution are analyzed and compared with experimental data. The simulation shows a good agreement with the data of Sandia National Laboratories. The agreement between experiments and simulations is measured using the Pearson correlation coefficient (>0.98), which indicates excellent consistency. In the next step, we will integrate the multiphase flow and phase change into the current model. The phase change of liquid hydrogen and air will be simulated to study the release of liquid hydrogen. • Using the open-source CFD code OpenFOAM for simulation of hydrogen jet. • A good agreement between the simulations results and experimental data has been found in this paper. • When high-speed hydrogen is injected into the air, both velocity and concentration drop rapidly. • Final concentration is not sensitive to different injection velocity. [ABSTRACT FROM AUTHOR]

This article comprehensively analyses a novel multi-generation energy system designed to produce liquid hydrogen. The versatile plant is strategically engineered to generate electrical energy, produce liquid hydrogen, and extract fresh water. Its operational characteristics are systematically examined across a range of scenarios. The primary discovery of this study is the assessment of the entire plant's energetic efficiencies, which stand at 55.91 % and 49.19 %, resulting in a total exergy destruction rate of 14365 kW. The investigation delves into the impact of critical parameters, such as reference temperature, combustion chamber temperature, and gas turbine pressure ratio, on the overall efficiency and effectiveness of the system. The study reveals that variations in these parameters have a noticeable effect on increasing total electricity output and hydrogen generation rates, ultimately enhancing overall thermodynamic efficiencies. The findings underscore the importance of elevating the reference temperature, gas turbine pressure ratio, and combustion chamber temperature for optimizing the operational parameters and efficiency of the proposed integrated energy plant. This research provides valuable insights for guiding the optimal operation of the energy system and achieving efficiency optimization. • A novel multigenerational facility is suggested for the production of liquid hydrogen. • An in-depth thermodynamic evaluation is provided to enhance the efficiency of the design. • The envisioned system generates four valuable outputs. • Parametric studies are presented to determine the optimal operating conditions. • The energetic and exergetic efficiencies for the study are 55.91 % and 49.19 %. [ABSTRACT FROM AUTHOR]

In the process of the on–board transportation of liquid hydrogen storage and transportation tanks, apart from considering the support strength and adiabatic performance, it is imperative to take into account the vibration characteristics of the carrying platform. The present work introduces a versatile support structure comprising a damping module and a ball contact insulation structure, enabling effective isolation of external vibrations while simultaneously providing support and insulation. The first step involves describing the principle of a flexible support structure and designing the mechanical structure. Subsequently, a damping analysis is conducted based on dynamic theory to establish the relationship between the spring and damping. Finally, the structural parameters of the dual–function strut are determined, followed by simulation of heat transfer performance. The results demonstrate that the dual–function strut exhibits exceptional vibration damping performance by reducing the amplitude of external vibrations greater than 5 Hz to less than 6%. Moreover, owing to the compact linear diameter spring structure of the vibration damping module and its ball contact effect, the thermal resistance of the dual–function strut is significantly enhanced, resulting in a mere heat leakage of only 22 W/m2 in a single rod section. [ABSTRACT FROM AUTHOR]

An essential part of addressing greenhouse gas emissions-related environmental issues is hydrogen energy. However, advances in technology are still needed for the industrial use of hydrogen, particularly in determining the most effective means of storage and transportation. As a result, the evolution, trends, updates, and research progress on hydrogen storage related topics were assessed in this bibliometric review, along with the difficulties posed by the application of various hydrogen storage technologies. Bibliometric analysis was performed using the R software's Biblioshiny package, and documents from 2013 to 2023 were chosen using the Scopus database using the PRISMA method. A total of 4456 documents were obtained within the period of study, with an annual growth rate of 21.7%. The study shows that themes such as dehydrogenation, hydrogenation, and hydrogen storage are well-developed themes in the area of the study. Emerging areas of study that have become areas of interest to researchers relative to hydrogen storage include themes such as metal hydrides and liquid hydrogen. Hydrogen evolution reactions, photocatalysis, oxygen evolution reactions, and electrocatalysts were found to be the actual themes of the field of study, i.e., niche themes. It is recommended that researchers focus more on liquid hydrogen storage and high-pressure gaseous systems and take the whole hydrogen energy utilization process into account. • This study employed the bibliometric and PRISMA method to review literature on hydrogen storage technologies. • A total of 4456 documents were reviewed between the period of 2013–2023. • Detailed review of various author keywords was reviewed to identify the focus of research in the area of study. • The period between 2016 and 2018 saw more intense research on themes like HER, methylcyclohexane. • Hybrid compressed hydrogen systems are expected to significantly contribute to the emerging hydrogen economy. [ABSTRACT FROM AUTHOR]

Background: Thermonuclear fusion is a widely discussed approach to energy production. In 2022, Energy Sustain. Soc. published L. Holmlid's paper (Energy Sustain Soc 12:14, 2022, 10.1186/s13705-022-00338-4) containing, in particular, critical statements about the plans for use of the T + D fusion in energy production. An analysis of these and several other statements of L. Holmlid is presented. This analysis complements a similar analysis performed by K. Hansen and J. Engelen (Energy Sustain Soc 13:14, 2023, 10.1186/s13705-023-00403-6). Main text: It is shown that several statements of L. Holmlid about D + T fusion and D + D fusion are mistaken or ungrounded. It is also shown that the statement of L. Holmlid about the products of annihilation of low-energy antiprotons with protons in ultra-dense hydrogen differs strongly from the data on the products of annihilation of stopped antiprotons with protons in liquid hydrogen and with nucleons of the nuclei of elements heavier than hydrogen. Conclusion: The statement "The use of all resources for fusion research on non-sustainable D + T fusion instead of sustainable muon-induced fusion may be a fatal mistake for humanity", made by L. Holmlid in his Reply (Energy Sustain Soc 13:25, 2023, 10.1186/s13705-023-00404-5) to the aforementioned paper by K. Hansen and J. Engelen, is mistaken. [ABSTRACT FROM AUTHOR]

The thermodynamic and transport properties of hydrogen isotopologues in the solid, liquid, and gas phases are crucial for hydrogen energy exploitation, such as the design of the fuel cycle of nuclear fusion reactors. However, experimental data for tritium-containing species are often not available. Alternatively, path integral (PI) simulation can evaluate hydrogen properties taking into account nuclear quantum effects; however, concerns about its reliability are present. This study proposes a method of Gaussian process regression (GPR) using both experimental and PI simulation data to obtain practically plausible estimates for all isotopologues. Using liquid viscosity and diffusivity as test cases, we demonstrate that the present method has high and robust predictive performance. The method has broad applicability and can also be used to design experiments and calculations to efficiently improve the regression model, and thus is expected to contribute to enhancing the availability and reliability of the hydrogen isotopologue property database. [Display omitted] • Experimental data on hydrogen properties are scarce for tritium-containing species. • Reliability of path-integral simulations is still limited. • Gaussian process regression can yield plausible predictions for all isotopologues. • The regression model can be efficiently improved using estimated model uncertainty. [ABSTRACT FROM AUTHOR]

This work reports on the development of a calibration approach of Raman spectroscopy for the determination of the concentration of dissolved hydrogen (H 2) in representative compounds and mixtures of liquid organic hydrogen carrier (LOHC) systems based on diphenylmethane and ortho -benzyltoluene (o-BT). Hydrogen solubility data are measured by the isochoric-saturation method at temperatures and pressures up to 473 K and 7 MPa where Raman spectra of the saturated liquid phase are recorded in parallel. By selecting an appropriate frequency range attributed to the LOHC signatures in isotropic spectra, a calibration which is independent of the LOHC system, the degree of hydrogenation of the LOHC samples, and temperature can be found. The transfer of the calibration to another setup is successfully tested up to 523 K and 6 MPa, where H 2 solubilities in the fully hydrogenated o-BT can be determined with an average absolute deviation of 0.009 from theoretically calculated data. [Display omitted] • Hydrogen (H 2) solubility measurements by the isochoric-saturation method. • H 2 solubility in diphenylmethane- and benzyltoluene-based systems up to 7 MPa. • Concentration of dissolved H 2 determined via Raman spectroscopy up to 523 K. • Calibration factor independent of temperature, degree of hydrogenation, and system. • Density insignificantly affected by pressure under saturation conditions with H 2. [ABSTRACT FROM AUTHOR]