United States

Reversible solid oxide cells (r-SOCs) can be operated in either solid oxide fuel cell or solid oxide electrolysis cell mode. They are expected to become important in the support of renewable energy due to their high efficiency for both power generation and hydrogen generation. The exchange current density is one of the most important parameters in the quantification of electrode performance in solid oxide cells. In this study four different fuel electro Read More

In the transition to a hydrogen economy it is likely that hydrogen will be used or stored in close proximity to other flammable fuels and gases. Accidents can occur that result in the release of two or more fuels such as hydrogen and natural gas that can mix and form a hazard. A series of five medium-scale semi-open-space deflagration experiments have been conducted with hydrogen natural gas and air mixtures. The natural gas consisted of 90% methan Read More

We present results from hydrogen dispersion simulations from a pressurized reservoir at constant flow rate in the presence and absence of a wall. The dispersion simulations are performed using a commercial finite volume solver. Validation of the approach is discussed. Constant concentration envelopes corresponding to the 2% 4% and 15% hydrogen concentration in air are calculated for a subcritical vertical jet and for an equivalent subcritical ho Read More

Recent research efforts to develop advanced–/ultrahigh–strength medium-Mn steels have led to the development of a variety of alloying concepts thermo-mechanical processing routes and microstructural variants for these steel grades. However certain grades of advanced–/ultrahigh–strength steels (A/UHSS) are known to be highly susceptible to hydrogen embrittlement due to their high strength levels. Hydrogen embrittlement characteristics of mediu Read More

Experimental data obtained for hydrogen mixtures in a room-size enclosure are presented and compared with data for propane and methane mixtures. This set of data was also used to develop a three-dimensional gas dynamic model for the simulation of gaseous combustion in vented enclosures. The experiments were performed in a 64 m3 chamber with dimensions of 4.6 × 4.6 × 3.0 m and a vent opening on one side and vent areas of either 2 Read More

Knowledge of the concentration field and flammability envelope from small-scale leaks is important for the safe use of hydrogen. These small-scale leaks may occur from leaky fittings or o-ring seals on liquid hydrogen-based systems. The present study focuses on steady-state leaks with large amounts of pressure drop along the leak path such that hydrogen enters the atmosphere at near atmospheric pressure (i.e. Very low Mach number). A three- Read More

Experimental data from vented explosion tests using lean hydrogen–air mixtures with concentrations from 12 to 19% vol. are presented. A 63.7-m3 chamber was used for the tests with a vent size of either 2.7 or 5.4 m2. The tests were focused on the effect of hydrogen concentration ignition location vent size and obstacles on the pressure development of a propagating flame in a vented enclosure. The dependence of the maximum pressure generated on th Read More

Hydrogen is being considered as a pathway to decarbonize large energy systems and for utility-scale energy storage. As these applications grow transportation infrastructure that can accommodate large quantities of hydrogen will be needed. Many millions of tons of hydrogen are already consumed annually some of which is transported in dedicated hydrogen pipelines. The materials and operation of these hydrogen pipeline systems however Read More

Hydrogen is seen as the future automobile energy storage media due to its inherent cleanliness upon oxidation and its ready utilization in fuel cell applications. Its physical storage in light weight low volume systems is a key technical requirement. In searching for ever higher gravimetric and volumetric density hydrogen storage materials and systems it is inevitable that higher energy density materials will be studied and used. To make safe and co Read More

A best practice is a technique or methodology that has reliably led to a desired result. A wealth of experience regarding the safe use and handling of hydrogen exists as a result of an extensive history in a wide variety of industrial and aerospace settings. Hydrogen Safety Best Practices (www.h2bestpractices.org) captures this vast knowledge base and makes it publicly available to those working with hydrogen and related systems Read More

The objective of this work was to enable the safe design of hydrogen pressure vessels by measuring the fatigue crack growth rates of ASME code-qualified steels in high-pressure hydrogen gas. While a design framework has recently been established for high-pressure hydrogen vessels a material property database does not exist to support the design calculations. This study addresses such voids in the database by measuring the fatigue crack growth Read More

The ignition limits of hydrogen/air mixtures in turbulent jets are necessary to establish safety distances based on ignitable hydrogen location for safety codes and standards development. Studies in turbulent natural gas jets have shown that the mean fuel concentration is insufficient to determine the flammable boundaries of the jet. Instead integration of probability density functions (PDFs) of local fuel concentration within the quiescent flammability limits Read More

Hydrogen is a notoriously difficult substance to store yet has endless energy applications. Thus the study of long-term hydrogen storage and high-pressure bulk hydrogen storage have been the subject of much research in the last several years. To create a research path forward it is important to know what research has already been done and what is already known about hydrogen storage. In this review several approaches to hydrogen storage are a Read More

For hydrogen fuelled vehicles to attain significant market penetration it is essential that any potential risks be controlled within acceptable levels. To achieve this goal on-board vehicle hydrogen storage systems should undergo risk analyses during early concept development and design phases. By so doing the process of eliminating safety-critical failure modes will help guide storage system development and be more efficient to implement than if underta Read More

We have analyzed vacuum insulation failure in an automotive cryogenic pressure vessel (also known as cryo-compressed vessel) storing hydrogen (H2). Vacuum insulation failure increases heat transfer into cryogenic vessels by about a factor of 100 potentially leading to rapid pressurization and venting to avoid exceeding maximum allowable working pressure (MAWP). H2 release to the environment may be dangerous if the vehicle is located in a clo Read More

Hydrogen sensors are recognized as an important technology for facilitating the safe implementation of hydrogen as an alternative fuel and there are numerous reports of a sensor alarm successfully preventing a potentially serious event. However gaps in sensor metrological specifications as well as in their performance for some applications exist. The U.S. Department of Energy (DOE) Fuel Cell Technologies Office published a short list of critical gaps i Read More

Hydrogen has the potential to be used by many countries as part of decarbonising the future energy system. Hydrogen can be used as a fuel ‘vector’ to store and transport energy produced in low-carbon ways. This could be particularly important in applications such as heating and transport where other solutions for low and zero carbon emission are difficult. To enable the safe uptake of hydrogen technologies it is important to develop the international scien Read More

In conjunction with John Zink Co. LLC the Chevron Energy Technology Company conducted a three part study evaluating potential issues with switching refinery process heaters from fuel gas to hydrogen fuel for the purpose of greenhouse gas emissions reduction via CO2 capture and storage.The focus was on the following areas:Heater performanceBurner performance and robustnessFuel gas system retrofit requirementsThis paper will summarize th Read More

Various studies and market trends show that the number of hydrogen fuelling stations will increase to the thousands in the US by 2050. NFPA 2 Hydrogen Technologies Code (NFPA2) the nationally adopted primary code governing hydrogen safety is relatively new and hydrogen vehicle technology is a relatively new and rapidly developing technology. In order to effectively aid and accelerate the deployment of standardized retail hydrogen fuelling facilities Read More

Reliable methods are needed to predict ignition boundaries that result from compressed hydrogen bulk storage leaks without complex modelling. To support the development of these methods a new high-pressure stagnation chamber has been integrated into Sandia National Laboratories’ Turbulent Combustion Laboratory so that relevant compressed gas release scenarios can be replicated. For the present study a jet with a 10:1 pressure ratio issuing fro Read More

The U.S. Department of Energy supports the implementation of hydrogen fuel cell technologies by providing hydrogen safety and emergency response training to first responders. A collaboration was formed to develop and deliver a one-day course that uses a mobile fuel cell vehicle (FCV) burn prop designed and built by Kidde Fire Trainers. This paper describes the development of the training curriculum including the design and operation of the FCV pro Read More

Hydrogen is seen as an ideal energy carrier for stationary and mobile applications. However the use of high energy density materials such as hydrides comes with the drawback of risks associated to their high reactivity towards air and water exposure. We have developed novel strategies to mitigate these risks. These strategies were evaluated using standard UN tests and isothermal calorimetric measurements. Cycling experiments were conducted to ass Read More

Radiative heat fluxes from small to medium-scale hydrogen jet flames (<10 m) compare favorably to theoretical predictions provided the product species thermal emittance and optical flame thickness are corrected for. However recent heat flux measurements from two large-scale horizontally orientated hydrogen flames (17.4 and 45.9 m respectively) revealed that current methods underpredicted the flame radiant fraction by 40% or more. Newly Read More

Refueling infrastructure for use in gaseous hydrogen powered vehicles requires extensive manifolding for delivering the hydrogen from the stationary fuel storage at the refueling station to the vehicle as well as from the mobile storage on the vehicle to the fuel cell or combustion engine. Manifolds for gas handling often use welded construction (as opposed to compression fittings) to minimize gas leaks. Therefore it is important to understand the eff Read More

Previous studies have shown that the two-layer model more accurately predicts hydrogen dispersion than the conventional notional nozzle models without significantly increasing the computational expense. However the model was only validated for predicting the concentration distribution and has not been adequately validated for predicting the velocity distributions. In the present study particle imaging velocimetry (PIV) was used to measure the velo Read More