Hydrogen Safety Codes and Standards R&D - Release Behavior
Abstract not provided.
Publications
Hydrogen Safety Codes and Standards R&D - Release Behavior
Abstract not provided.
Quarterly Progress Report: Hydrogen Safety Codes & Standards Program Q1FY2011
Abstract not provided.
Evaluation of Light-Off Limits for a Novel Oxy-Combustion Process for Advanced EOR
Abstract not provided.
Update on Sandia Hydrogen Releases Program
Abstract not provided.
Risk-informed separation distances for hydrogen gas storage facilities
The use of risk information in establishing code and standard requirements enables: (1) An adequate and appropriate level of safety; and (2) Deployment of hydrogen facilities are as safe as gasoline facilities. This effort provides a template for clear and defensible regulations, codes, and standards that can enable international market transformation.
Risk associated with the use of barriers in hydrogen refueling stations
Abstract not provided.
Risk associated with the use of barriers in hydrogen refueling stations
Abstract not provided.
Hydrogen release behavior
The summary of this presentation is: (1) Barrier walls are used to reduce setbacks by factor of 2; (2) We found no ignition-timing vs. over-pressure sensitivities for jet flow obstructed by barrier walls; (3) Cryogenic vapor cloud model indicates hazard length scales exceed the room-temperature release; validation experiments are required to confirm; (4) Light-up maps developed for lean limit ignition; flammability factor model provides good indication of ignition probability; and (5) Auto-ignition is enhanced by blunt-body obstructions - increases gas temperature and promotes fuel/air mixing.
Risk associated with the use of barriers in hydrogen refueling stations
Separation distances are used in hydrogen refueling stations to protect people, structures, and equipment from the consequences of accidental hydrogen releases. Specifically, hydrogen jet flames resulting from ignition of unintended releases can be extensive in length and pose significant radiation and impingement hazards. Depending on the leak diameter and source pressure, the resulting separation distances can be unacceptably large. One possible mitigation strategy to reduce exposure to hydrogen flames is to incorporate barriers around hydrogen storage, process piping, and delivery equipment. The effectiveness of barrier walls to reduce hazards at hydrogen facilities has been previously evaluated using experimental and modeling information developed at Sandia National Laboratories. The effect of barriers on the risk from different types of hazards including direct flame contact, radiation heat fluxes, and overpressures associated with delayed hydrogen ignition has subsequently been evaluated and used to identify potential reductions in separation distances in hydrogen facilities. Both the frequency and consequences used in this risk assessment and the risk results are described. The results of the barrier risk analysis can also be used to help establish risk-informed barrier design requirements for use in hydrogen codes and standards.
Analyses to support development of risk-informed separation distances for hydrogen codes and standards
The development of a set of safety codes and standards for hydrogen facilities is necessary to ensure they are designed and operated safely. To help ensure that a hydrogen facility meets an acceptable level of risk, code and standard development organizations are tilizing risk-informed concepts in developing hydrogen codes and standards.
Results from an analytical investigation of small-scale releases from liquid hydrogen storage systems
A need exists for developing codes and standards to support the wide-spread delivery of liquid hydrogen bulk fuel and fueling station storage. To develop these codes and standards the consequences of planned and unplanned hydrogen releases must be understood. The systems under consideration are mainly those used in supplying hydrogen for transportation. These systems include production storage tanks, tanker trucks and tanks located at vehicle fueling stations. Typically these systems store hydrogen in the saturated state at approximately 11 atmospheres. Storage vessels are heavily insulated and sometimes actively cooled to minimize the rate of hydrogen boil-off (intended hydrogen release).
Risk-informed separation distances for use in NFPA hydrogen codes and standards
17th World Hydrogen Energy Conference 2008, WHEC 2008
The development of separation distances for hydrogen facilities can be determined in several ways. A conservative approach is to use the worst possible accidents in terms of consequences. Such accidents may be of very low frequency and would likely never occur. Although this approach bounds separation distances, the resulting distances are generally prohibitive. The current separation distances in hydrogen codes and standards do not reflect this approach. An alternative deterministic approach that is often utilized by standards development organizations and allowed under some regulations is to select accident scenarios that are more probable but do not provide bounding consequences. In this approach, expert opinion is generally used to select the accidents used as the basis for the prescribed separation distances.
Hydrogen Release Behavior
Abstract not provided.
Hydrogen Release Behavior -- 2008 Hydrogen Program Annual Merit Review
Abstract not provided.
Recent Research and Development on Barrier Walls for Unintended Releases of Hydrogen
Abstract not provided.
Hydrogen Safety Codes and Standards Q1FY08 Progress Report
Abstract not provided.
Investigation of Small-Scale Unintended Releases of Hydrogen: Buoyancy Effects
International Journal of Hydrogen Energy
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Hydrogen Codes and Standards Quartery Report Q4FY07
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Characterization of high-pressure, underexpanded hydrogen-jet flames
International Journal of Hydrogen Energy
Measurements were performed to characterize the dimensional and radiative properties of large-scale, vertical hydrogen-jet flames. This data is relevant to the safety scenario of a sudden leak in a high-pressure hydrogen containment vessel and will provide a technological basis for determining hazardous length scales associated with unintended hydrogen releases at storage and distribution centers. Jet flames originating from high-pressure sources up to 413 bar (6000 psi) were studied to verify the application of correlations and scaling laws based on lower-pressure subsonic and choked-flow jet flames. These higher pressures are expected to be typical of the pressure ranges in future hydrogen storage vessels. At these pressures the flows exiting the jet nozzle are categorized as underexpanded jets in which the flow is choked at the jet exit. Additionally, the gas behavior departs from that of an ideal-gas and alternate formulations for non-ideal gas must be introduced. Visible flame emission was recorded on video to evaluate flame length and structure. Radiometer measurements allowed determination of the radiant heat flux characteristics. The flame length results show that lower-pressure engineering correlations, based on the Froude number and a non-dimensional flame length, also apply to releases up to 413 bar (6000 psi). Similarly, radiative heat flux characteristics of these high-pressure jet flames obey scaling laws developed for low-pressure, smaller-scale flames and a wide variety of fuels. The results verify that such correlations can be used to a priori predict dimensional characteristics and radiative heat flux from a wide variety of hydrogen-jet flames resulting from accidental releases.
Hydrogen Safety Codes and Standards R&D
Abstract not provided.
Project SA5: Hydrogen Release Behavior
Abstract not provided.
Hydrogen Codes and Standards Q2FY07 Report
Abstract not provided.
Investigation of Small-Scale Unintended Releases of Hydrogen: Momentum-Dominated Regime
International Journal of Hydrogen Energy
Abstract not provided.
High pressure hydrogen jets in the presence of a surface
Abstract not provided.
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