Safe Use Of Hydrogen Research Articles

Strain and defect engineering of high-performance monolayer two-dimensional material/Ag nanoparticles optoelectronic FET sensor through multiple laser shock

The development of sensor devices that detect low-concentrations hydrogen at room temperature is becoming increasingly important for the safe use of hydrogen. In this study, the introduction of strain and defects in two-dimensional materials has been realised by laser shock and its application in gas sensing. The strain and defect density of monolayer MoS2 increase after multiple laser shock, providing more active sites for gas adsorption and improving the ability to adsorb hydrogen atoms. Under the synergistic effect of strain and defects, the response of non-noble metal nanoparticles/MoS2 photoelectric hydrogen sensors is accelerated, and their sensing performance (83% for 200 ppm) is 9.5 times higher than that of pure MoS2 devices (8.7% for 200 ppm) at room temperature (25 ℃). As a proof of concept, laser shock induced 2D material strain and defect engineering has opened up new ideas for improving the performance of photoelectric gas sensors at room temperature.

Experimental and numerical studies on hydrogen leakage and dispersion evolution characteristics in space with large aspect ratios

Green hydrogen is a clean energy, and its application scenarios have become increasingly diverse with the development of hydrogen energy equipment. To ensure the safe use of hydrogen, it is essential to study the leakage and dispersion characteristics of hydrogen in different spaces. In this work, the experimental and numerical simulation studies on hydrogen leakage and dispersion were conducted in spaces with large aspect ratios. The research found that hydrogen leakage and dispersion can be divided into three typical stages: buoyancy-dominated stage, horizontal spreading stage, and vertical filling stage. The relationship between the concentration rise rate of hydrogen and the leakage rate and leakage direction in the third stage is established. As the leakage speed increases, the dispersion time of hydrogen decreases, leading to significant differences in concentration distribution. Changes in the leakage direction will influence the interaction between hydrogen and the walls, subsequently altering the dispersion behavior of hydrogen. Changes in leakage speed and direction do not affect the sequence of hydrogen dispersion to specific points in space. Based on the characteristics of hydrogen dispersion, a subjective-objective integrated hydrogen weighted concentration calculation method was proposed in this study. The hydrogen weighted concentration can be effectively characterized the leakage and dispersion characteristics of hydrogen. The value always approaches 50% of the average concentration, which can be used for determining the warning threshold or specifying emergency strategies.

Optics-mechanics synergistic fiber optic sensor for hydrogen detection.

As a carbon-free energy carrier and an attractive alternative energy source, hydrogen energy has great development potential for future considerations, and it may be the ultimate answer to the global energy crisis. Due to the high combustibility of hydrogen, hydrogen sensors will be a vital component of safe use of hydrogen. Among the various sensors, the optical hydrogen sensor can meet the requirements of intrinsic safety, online detection, surrounding immunity, and lack of spark. Hence, we demonstrate a miniature optics-mechanics synergistic fiber optic hydrogen sensor by using Pd nanofilm, it has a large response range (0.5%-3.5%), high sensitivity of -0.334 nm/1% concentration and a short response time (10s)/recovery time (25s). Experimental results reveal that the proposed optics-mechanics synergistic fiber optic hydrogen sensor is reusable, durable, and low temperature sensitive. In this optics-mechanics synergistic fiber optic hydrogen sensor, nano Pd film with a large surface-to-volume ratio allows for rapid hydrogen dissociation, and Pd lattice expansion caused by Pd-hydrogen reaction is effectively transduced into optical change. This proposed sensor integrated Pd nanofilm with optical fiber by using an optics-mechanics synergistic strategy, resulting in a compact and all-optical solution for the safe measurement of hydrogen concentration, which can be used in hazardous or space-limited environments.

Development of a CFD-Suitable Deep Neural Network Model for Laminar Burning Velocity

Hydrogen is a valued resource for today’s industry. As a fuel, it produces large amounts of energy and creates water during the process, unlike most other polluting energy sources. However, the safe use of hydrogen requires reliable tools able to accurately predict combustion. This study presents the implementation of a deep neural network of laminar burning velocity of hydrogen into an open-source CFD solver flameFoam. DNN was developed based on a previously created larger DNN, which was too large for CFD applications since the calculations took around 40 times longer compared to the Malet correlation. Therefore, based on the original model, a faster, but still accurate, DNN was developed and implemented into flameFoam starting with version 0.10. The paper presents the adaptation of the original DNN into a CFD-applicable version and the initial test results of the CFD–DNN simulation.

Progress and prospects of research on hydrogen sensors

<p indent="0mm">The development of hydrogen energy industry is of great significance to the construction of a clean, low-carbon, safe and efficient modern energy system, the realization of the “dual carbon” goal and the high-quality economic development. The safe use of hydrogen has always been a concern. Hydrogen sensors can quickly and accurately measure hydrogen concentration, and effectively prevent hydrogen leakage, explosion and other safety problems in the process of production, storage, transportation and use. In recent years, with the popularization and application of hydrogen energy and the rapid development of Internet of Things technology, the requirements for hydrogen sensors in security, remote monitoring and distributed measurement are increasing. In this paper, the principle, applicability and research status of different types of hydrogen sensors are reviewed and analyzed, and the development trend of hydrogen sensors is forecasted. Hydrogen sensors can be divided into catalytic, electrical, optical fiber, acoustic and other types according to sensing principles. The catalytic hydrogen sensor has simple structures, fast response and high sensitivity. However, the catalytic hydrogen sensor is greatly affected by the temperature and humidity, and it has poor gas selectivity and high working temperature, which leads to potential safety hazards. The electrical hydrogen sensor has simple structures, long service life, and is easy to be integrated and miniaturized. However, electrical signals are prone to environmental interference and lead to signal drift, and electrical sparks may be generated during the detection of electrical signals, which can cause explosions in the detection of combustible gas. Compared with traditional electrical sensors, fiber optic hydrogen sensors have higher security and anti-interference, and are convenient to realize distributed measurement and other excellent performance, which has become a research hotspot. The fiber optic hydrogen sensor is small in size, intrinsically safe, anti-electromagnetic interference, and it can realize distributed spatial multi-point measurement. However, it is difficult to achieve commercial production due to its high cost, complex signal processing and expensive instruments for detection. The acoustic hydrogen sensor has high sensitivity and fast response time, but is greatly affected by temperature and humidity. The future challenges and opportunities for hydrogen sensors are also discussed in the last section. Under the background of Internet of Things and the era of big data, the research of hydrogen sensors will be gradually toward miniaturization, integration and distributed sensing. Moreover, it is necessary to realize hydrogen detection at high temperature and humidity. Future research in this field may focus on the following four aspects: (1) Reducing the cross sensitivity of temperature, humidity and other gases; (2) new hydrogen-sensitive materials such as nanomaterials and graphene; (3) performance optimization of hydrogen sensors at high temperature; (4) signal detection and demodulation device of fiber optic sensors.

Estimation of the efficiency of combining a npp with a hydrogen facility under conditions of safe use of hydrogen in a steam turbine cycle

THE PURPOSE. System efficiency and competitiveness assess of a new scheme for combining a nuclear power plant with a hydrogen complex based on additional heating of feed water and superheating of live steam in front of the high-pressure cylinder of a steam turbine. METHODS. Basic laws of thermodynamics were applied when developing and substantiating a new scheme for combining a nuclear power plants (NPP) with a hydrogen facility; theoretical regularities were applied of heat engineering; basic regularity were applied of fatigue wear of power equipment and assessment of its working resourse; basic regularities were applied for the assessment of operating costs and net present value (NPV). RESULTS. A new scheme is presented of the combination of a nuclear power plant with a hydrogen facility and a description of its operating principle on the example of a two-circuit nuclear power plant with a VVER-1000 reactor and a C-1000-60 / 1500 turbine. The data are presented on an increase in the productivity of steam generators at nuclear power plants with additional heating of feed water in the range of 235-250 ° C from its nominal value of 230 ° C. The temperature was estimated of live steam superheat depending on the temperature of the additional heating of the feed water. The results are presented of the calculation of the generated peak power by the power unit and the efficiency of conversion of the night off-peak power of the NPP into peak power, as well as the efficiency of the power unit of the NPP depending on the temperature of additional heating of the feed water. Main regularities are given for taking into account the fatigue wear of the main equipment of the hydrogen facility, including the rotor of the NPP turbine in the conditions of the stress-cyclic operation. The results are presented of assessing the cost of peak electricity NPP in combination with a hydrogen facility in comparison with a pumped storage power plant (PSPP) both for the current period and for the future until 2035. CONCLUSION. Hydrogen facility efficiency and competitiveness depends significantly on the intensity of the use of the main equipment in the conditions of the intense-cyclic operation. The hydrogen facility will competitiveness noticeably increase in comparison with the PSPP in the future. Efficiency of the NPP power unit and NPV is highest when the feed water is heated to 235 ° C and superheating of live steam in front of the high-pressure cylinder of the C-1000-60/1500 turbine up to 470°C.The hydrogen facility competes with the PSPP with her specific capital investment at the level of 660 USD / kW, provided that the boosting capabilities of the turbine are used with live steam overheating at 300 ° C and additional heating of feed water to 235°C on the current period. The PSPP does not compete with the hydrogen facility both for the current period and in the future with her specific capital investment of $ 1,500 / kW and above.

Pd Nanocluster/Monolayer MoS2 Heterojunctions for Light-Induced Room-Temperature Hydrogen Sensing.

Developing sensing approaches that can exploit visible light for the detection of low-concentration hydrogen at room temperatures has become increasingly important for the safe use of hydrogen in many applications. In this study, heterostructures composed of monolayer MoS2 and Pd nanoclusters (Pd/MoS2) acting as photo- and hydrogen-sensitizers are successfully fabricated in a facile and scalable manner. The uniform deposition of morphologically isotropic Pd nanoclusters (11.5 ± 2.2 nm) on monolayer MoS2 produces a plethora of active heterojunctions, effectively suppressing charge carrier recombination under light illumination. The dual photo- and hydrogen-sensitizing functionality of Pd/MoS2 can enable its use as an active sensing layer in optoelectronic hydrogen sensors. Gas-sensing examinations reveal that the sensing performance of Pd/MoS2 is enhanced three-fold under visible light illumination (17% for 140 ppm of H2) in comparison with dark light (5% for 140 ppm of H2). Photoactivation is also found to enable excellent sensing reversibility and reproducibility in the obtained sensor. As a proof-of-concept, the integration of Pd nanoclusters and monolayer MoS2 can open a new avenue for light-induced hydrogen gas sensing at room temperature.

Hydrogen wide area monitoring of LH2 releases

The characterization of liquid hydrogen (LH2) releases has been identified as an international research priority to expand the safe use of hydrogen as an energy carrier. The elucidation of LH2 release behavior will require the development of dispersion and other models, guided and validated by empirical field measurements such as those afforded by Hydrogen Wide Area Monitoring (HyWAM). HyWAM can be defined as the quantitative spatial and temporal three-dimensional monitoring of planned or unintentional hydrogen releases. With support provided through the FCH JU Prenormative Research for the Safe Use of Liquid Hydrogen (PRESLHY) program, HSE performed a series of LH2 releases to characterize the dispersion and pooling behavior of cold hydrogen releases. The NREL Sensor Laboratory developed a HyWAM system based upon a distributed array of point sensors that is amenable for profiling cold hydrogen plumes. The NREL Sensor Laboratory and HSE formally committed to collaborate on profiling the LH2 releases. This collaboration included the integration of the NREL HyWAM into the HSE LH2 release hardware. This was achieved through a deployment plan jointly developed by the NREL and HSE personnel. Under this plan, the NREL Sensor Laboratory provided multiple HyWAM modules that accommodated 32 sampling points for near-field hydrogen profiling during the HSE PRESLHY LH2 releases. The NREL HyWAM would be utilized throughout the LH2 release study performed under PRESLHY by HSE, including Work Package 3 (WP3—Release and Mixing--Rainout) and subsequent work packages (WP4—Ignition and WP5—Combustion). Under the auspices of the PRESLHY WP6 (Implementation), data and findings from the HSE LH2 Releases are to be made available to stakeholders in the hydrogen community. Comprehensive data analysis and dissemination is ongoing, but the integration of the NREL HyWAM into the HSE LH2 Release Apparatus and its performance as well as some key outcomes of the LH2 releases in WP3 are presented.

Evaluation of electricity generation subsystem of power-to-gas-to-power unit using gas expander and heat recovery steam generator

Power-to-hydrogen technology allows the effective use of electricity produced during the energy demand valleys, mainly in stochastic renewable energy sources. The dynamics of implementing such systems in the economy is correlated with the development of technologies enabling safe use of hydrogen. Currently, planning investments in power-to-hydrogen requires considering the risks associated with the possibility of reduced hydrogen demand. A way of protection against permanent or periodic reduction in the demand for hydrogen may be investments in electricity generation systems, which, thanks to the use of by-product of the electrolysis process - oxygen, can allow using of not only hydrogen but also natural gas. This paper discusses the thermodynamic and economic study of a hydrogen-to-power system using methanation and oxy-combustion combined cycle. The thermodynamic calculations focus on analysis of heat recovery steam generator (HRSG) structures and determining the energy efficiency of the system. The obtained energy storage efficiency are in the range of 16.29–24.95%. Within economic considerations, an electricity generation unit consisting of methanation and single-pressure HRSG systems cooperating with 100 MW hydrogen generators unit is considered. Sensitivity analyzes are performed and the value of investment outlays in hydrogen production unit and the price of electricity are decision variables.

Developments of MEMS Gas Sensors Based on Tin Oxide semiconductors: Application to Battery-Powered Household Gas Alarms

Developments of MEMS Gas Sensors Based on Tin Oxide semiconductors: Application to Battery-Powered Household Gas Alarms

Technologies for the Safe Use of Hydrogen and Construction of the Safety Standards System

The industry of hydrogen energy for fuel cell electric vehicles (FCEVs) is in a rapid start-up stage in China. Understanding of the danger of hydrogen and safe use of the hydrogen energy are the basis for the healthy development of the FCEV industry. In this study, we analyze the physical and chemical properties of hydrogen and the compatibility issues for hydrogen and materials and then propose three basic principles for the safe use of hydrogen. Subsequently, the research outputs and technical measures for the safe use of high-pressure hydrogen energy in Japan are thoroughly introduced and some suggestions are presented for the safe use of hydrogen in accordance with the Chinese situation. First, China should conduct overall planning and design, increase investment in science and technology, and form a research system that takes the National Hydrogen Safety Laboratory as the main body and has active participation from social science and technology forces. Moreover, it should perfect its hydrogen safety standards system for vehicles and build a 70 MPa hydrogen-related equipment manufacturing system.

Science-based framework for ensuring safe use of hydrogen as an energy carrier and an emission-free transportation fuel

The objective of this research is to examine the safety-related characteristics of candidate hydrogen storage materials being considered for use in light-duty fuel-cell vehicles (LD-FCV) under the U.S. Department of Energy (DOE) Hydrogen Program. This research aims to provide useful meaning to the general DOE safety target by establishing a link between the safety-related characteristics of candidate storage materials and satisfaction of DOE safety target. Accordingly, a science-based framework has been developed and consists of standardized materials tests (based on internationally accepted ASTM and United Nations testing protocols), novel risk mitigation strategies, and subscale system demonstration. The examined storage materials include NaAlH4, AlH3, 2LiBH4 + MgH2, 3Mg(NH2)2·8LiH, NH3BH3, and activated carbon (Maxsorb AX-21). The scope of safety tests covers conditions that the storage material may encounter during postulated accident scenarios such as dust cloud explosion, materials reactivity in air and other fluids, hot-surface contact, mechanical impact, and fast depressurization. The generated results uncovered potential fire and explosion risks under accidental conditions. The generated insights can be useful for assigning realistic probability values needed for quantifying risk scenarios, characterizing material’s hazard class, and supporting current and new hydrogen safety codes and standards. For risk mitigation, this study showed that powder compaction could be effective in suppressing pyrophoricity of hydride powders such as NaAlH4. Also, the study has experimentally demonstrated that adding (NH4)H2PO4 as a flame retardant to the hydride powder before compaction could suppress sensitivity of hydrides like NaAlH4 to ignite due to mechanical impact. The results also revealed that Maxsorb AX-21 to be a safer hydrogen storage medium compared to the examined hydrides which exhibited potential safety concerns under certain accident conditions.

Pd on MoO3 nanoplates as small-polaron-resonant eye-readable gasochromic and electrical hydrogen sensor

Hydrogen is a renewable, efficient, and clean energy carrier that can replace petroleum as the future of energy. Eventually, efficient hydrogen detection will become an important requirement for the successful and safe use of hydrogen as a fuel. Among the various hydrogen detection schemes available, gasochromic sensors have major advantages of being intrinsically safe, free of electric contacts in the sensing area, easy to use, and inexpensive. In view of these advantages, we developed an irreversible gasochromic and electrical sensor composed of MoO3 nanoplates and Pd nanoparticles fabricated via green deposition. The amount, distribution, and particle size of the Pd nanoparticles can be controlled easily by modifying the deposition condition, which is necessary for efficient hydrogen sensing. The developed gasochromic sensor was found to change color from white to dark blue upon hydrogen exposure, owing to the polaron-resonance effect; this effect is induced by the coupling of atomic free d-electrons in reduced Mo ion states with H+ ions. Hydrogen concentrations as low as up to 0.1% could be easily detected by the developed sensor. The simple and green fabrication process and detection scheme make the developed sensor highly cost effective and widely applicable in various areas of the hydrogen industry.

On-board hydrogen production for auxiliary power in passenger aircraft

This paper presents the potential of a method for on-demand hydrogen generation from the reaction of activated aluminum powder and water for commercial aircraft applications. The hydrogen produced on-board during flight can be used in a fuel cell to generate electric energy. Results of an investigation of the reaction between aluminum and urine show that, in addition to fresh water, the waste water available on-board the aircraft can be used for hydrogen generation. High reaction rates producing about 200–600 ml/min/g Al of hydrogen at a high yield of about 90% was demonstrated. The possibility to use the available waste water leads to high specific electric energy of up to about 850 Wh/kg. In addition, the aluminum–water reaction enables safe use of hydrogen. A comparison to the traditional hydrogen storage methods is also presented.

Simulation analysis on the risk of hydrogen releases and combustion in subsea tunnels

Hydrogen is considered to be a very promising potential energy carrier due to its excellent characteristics such as abundant resources, high fuel value, clean and renewable. Its safety features greatly influence the potential use. Several safety problems need to be analyzed before using in transportation industry. With the development of the tunnel transportation technology, the safe use of hydrogen in tunnels will receive a lot of research attentions. In this article, the risk associated with hydrogen release from onboard high-pressure vessels and the induced combustion in tunnels was analyzed using the Partially Averaged Navier–Stokes (PANS) turbulence model. The influences of the tunnel ventilation facilities on the hydrogen flow characteristics and the flammable hydrogen cloud sizes were studied. The tunnel layouts were designed according to the subsea tunnel. And a range of longitudinal ventilation conditions had been considered to investigate the hydrogen releases and the sizes of the flammable hydrogen cloud. Then the hydrogen combustion simulation was carried out after the fixed leaking time. The overpressures induced after the ignition of leaking hydrogen were studied. The influences of ventilation and ignition delay time on the overpressure were also investigated. The main aim was to research the phenomena of hydrogen releases and combustion risk inside subsea tunnels, and to lay the foundation of risk assessment methodology developed for hydrogen energy applications on transportation.

Fabrication of highly sensitive and selective H2 gas sensor based on SnO2 thin film sensitized with microsized Pd islands

Ultrasensitive and selective hydrogen gas sensor is vital component in safe use of hydrogen that requires a detection and alarm of leakage. Herein, we fabricated a H2 sensing devices by adopting a simple design of planar-type structure sensor in which the heater, electrode, and sensing layer were patterned on the front side of a silicon wafer. The SnO2 thin film-based sensors that were sensitized with microsized Pd islands were fabricated at a wafer-scale by using a sputtering system combined with micro-electronic techniques. The thicknesses of SnO2 thin film and microsized Pd islands were optimized to maximize the sensing performance of the devices. The optimized sensor could be used for monitoring hydrogen gas at low concentrations of 25–250ppm, with a linear dependence to H2 concentration and a fast response and recovery time. The sensor also showed excellent selectivity for monitoring H2 among other gases, such as CO, NH3, and LPG, and satisfactory characteristics for ensuring safety in handling hydrogen. The hydrogen sensing characteristics of the sensors sensitized with Pt and Au islands were also studied to clarify the sensing mechanisms.

Preventing hydrogen detonations in road tunnels hydrogen trap concept

During research of new possible sources of energy, hydrogen was identified as a very promising potential energy carrier. Because of its very good energy characteristics, it has received a lot of research attention while its safety features are the ones that were its drawback for potential use. Before it can be put in general use in transportation industry, there were safety problems identified as hazard which has to be further analysed. The main problem in the transport is the safe use of hydrogen in road tunnels where it should be safe in case of possible accidents where its release could end up in fire, deflagration and even detonation. In the article, concept of hydrogen trap on the ceiling is developed and described based on the available data and research results from which passive safety approach is suggested to be used in future designs of the road tunnels.

Evaluation of selectivity of commercial hydrogen sensors

The development of reliable hydrogen sensors is crucial for the safe use of hydrogen. One of the main concerns of end users is sensor reliability in the presence of species other than the target gas, which can lead to false alarms or undetected harmful situations. To assess the selectivity of commercial-off-the-shelf hydrogen sensors, a number of sensors of different technology types were exposed to various interferent gas species. Cross-sensitivity tests were performed in accordance with the recommendations of ISO 26142:2010, using the hydrogen sensor testing facilities of the National Renewable Energy Laboratory and the Joint Research Centre – Institute for Energy and Transport. Most of the sensor platform tested are unaffected by the exposure to the interferents. The metal-oxide and the thermal conductivity platform show a remarkable sensitivity to CH4. None of the platforms tested were permanently affected by the exposure to the cross-sensitive species.

Developments in gas sensor technology for hydrogen safety

Gas sensors are applied for facilitating the safe use of hydrogen in, for example, fuel cell and hydrogen fuelled vehicles. New sensor developments, aimed at meeting the increasingly stringent performance requirements in emerging applications, are reviewed. The strategy of combining different detection principles, i.e. sensors based on electrochemical cells, semiconductors or field effects in combination with thermal conductivity sensing or catalytic combustion elements, in one new measuring system is reported. This extends the dynamic measuring range of the sensor while improving sensor reliability to achieve higher safety integrity through diverse redundancy. The application of new nanoscaled materials, nanowires, carbon tubes and graphene as well as the improvements in electronic components and optical elements are evaluated in view of key operating parameters such as measuring range, sensor response time and low working temperature.

Web-based resources enhance hydrogen safety knowledge

The U.S. Department of Energy's Fuel Cell Technologies Program addresses key technical challenges and institutional barriers facing the development and deployment of hydrogen and fuel cell technologies with the goal of decreasing dependence on oil, reducing carbon emissions and enabling reliable power generation. The Safety, Codes & Standards program area seeks to develop and implement the practices and procedures that will ensure safety in the operation, handling and use of hydrogen and hydrogen systems for all projects and utilize these practices and lessons learned to promote the safe use of hydrogen. Enabling the development of codes and standards for the safe use of hydrogen in energy applications and facilitating the development and harmonization of international codes and standards are integral to this work.Web-based resources play a key role in reaching, educating and informing stakeholders whose contributions will help enable the deployment of new hydrogen and fuel cell technologies. This paper surveys eight web-based tools, each targeted to a specific stakeholder audience, that are integral resources for information on hydrogen-related safety, codes and standards work in the Fuel Cell Technologies Program.•Hydrogen Incident Reporting and Lessons Learned (http://h2incidents.org)•Hydrogen Safety Best Practices (http://h2bestpractices.org)•Hydrogen Safety Bibliographic Database (http://www.hydrogen.energy.gov/biblio_database.html)•Introduction to Hydrogen Safety for First Responders (http://www.hydrogen.energy.gov/firstresponders.html)•Introduction to Hydrogen for Code Officials (http://www.hydrogen.energy.gov/training/code_official_training/)•Permitting Hydrogen Facilities (http://www.hydrogen.energy.gov/permitting/)•Safety Training for Researchers (http://www.h2labsafety.org/)•Technical Reference for Hydrogen Compatibility of Materials (http://www.sandia.gov/matlsTechRef/)The development and use of each safety knowledge tool is described.