Hydrogen Safety Research: State-Of-The-Art

2021

2015

International audienceSince a few years, hydrogen appears as a practical energy vector and some hydrogen applications are already on the market. However these applications are still considered dangerous, hazardous events like explosion could occur and some accidents, like the Hindenburg disaster, are still in the mind. Objectively, hydrogen ignites easily and explodes violently. Safety engineering has to be particularly strong and demonstrative; a method of precise identification of accidental scenarios (“probabilities”; “severity”) is developed in this article. This method, derived from ARAMIS method, permits to identify and to estimate the most relevant safety barriers and therefore helps future users choose appropriate safety strategies

2019

This paper is intended to be a brief survey of the state of the art about the safety aspects of industrial application using hydrogen. Although hydrogen has been used in the industry for a long time in chemistry, in metallurgy and more recently in the space industry and in electronics, new fields of application emerged at the turn of the century in the energy sector, broadening considerably both the technologies spectrum concerned but also the public exposed to the risks. Experts of the domain admit that the extent of the spreading of hydrogen technologies depends very much on the safety demonstration rendering the implementation acceptable to the public. Considerable effort was done along the two last decades both to develop risk assessment methods specific to hydrogen technologies and to understand better the key physical phenomena: material embrittlement, formation of explosive atmospheres, ignition, high pressure jet fires, unstable combustion, venting, etc. Major outcomes are r...

Process Safety Progress, 2008

Computational fluid dynamics calculations for gas explosion safety have been widely used for doing risk assessments within the oil and gas industry for more than a decade. On the basis of predicted consequences of a range of potential accident scenarios a risk level is predicted. The development of applications using hydrogen as a clean energy carrier has accelerated in recent years, and hydrogen may be used widely in the future. Because of the very high reactivity of hydrogen, safe handling is critical. For most applications it is not realistic to perform an extensive risk assessment similar to what is done for large petrochemical installations. On the other hand, simplified methods, like venting guidelines, may have a questionable validity for hydrogen. The use of simple methods, if these actually are conservative, will in general predict too high consequences for the majority of scenarios, as these are not able to represent actual geometry and physics of the explosion. In this article a three-step approach is proposed. The initial approach will be to carry out a ''worstcase'' calculation evaluating the consequences if a full stoichiometric gas cloud is ignited. Mitigation measures can also be considered. As a second step, if potential consequences of the initial approach are not acceptable, the assumptions are refined and more calculations are performed to make the evaluations more realistic and reduce unnecessary conservatism of the chosen worst-case scenarios. Typically a number of dispersion calculations will be performed to generate likely gas clouds, which are subsequently ignited. If estimated consequences are still not acceptable, a more comprehensive study, including ventilation, dispersion, and explosion, is performed to evaluate the probability for unacceptable events.

Chemical Engineering Transactions, 2016

This paper describes a general analysis methodology which was developed for consistent and mechanistic modeling of hydrogen behavior in complex industrial accident scenarios. The methodology includes four steps: 1. Three-dimensional CFD simulation of the time and space dependent hydrogen concentration in the computational domain. 2. Application of experiment-based criteria which allow to estimate the fastest possible combustion regime for the given H2-air-distribution and geometrical constraint. 3. Numerical simulation of the identified combustion regime with a validated 3D combustion code; output from this step are mechanical and thermal loads to surrounding structures. 4. Consequence analysis with respect to a) structural response of the pressure loaded building using 3d-FEM or simpler models and b) health effects on persons. As an example for the analysis procedure the blow-down of 31 kg of hydrogen from a large electrical generator located in a 160,000 cubic meter turbine hall i...

2010

International Journal of Hydrogen Energy, 2017

The "SUpport to SAfety aNAlysis of Hydrogen and Fuel Cell Technologies" (SUSANA) project aims to support stakeholders using Computational Fluid Dynamics (CFD) for safety engineering design and assessment of FCH systems and infrastructure through the development of a model evaluation protocol. The protocol covers all aspects of safety assessment modelling using CFD, from release, through dispersion to combustion (self-ignition, fires, deflagrations, detonations, and Deflagration to Detonation Transition-DDT) and not only aims to enable users to evaluate models but to inform them of the state of the art and best practices in numerical modelling. The paper gives an overview of the SUSANA project, including the main stages of the model evaluation protocol and some results from the ongoing benchmarking activities.

2011

The report describes the findings of a workshop that was held at the Institute for Energy and Transport (JRC) in Petten Netherlands, on the topic “Gap analysis of CFD modelling of hydrogen release and combustion”. The main topic was divided in 6 sub-topics: release and dispersion,auto-ignition, fires, deflagrations, detonations and DDT, and accident consequences. For each sub-topic, the main gaps in CFD modelling were identified and prioritised.Hydrogen is expected to play an important role in the energy mix of a future low carbon society, (the European Strategic Energy Technology Plan of the European Commission (COM 2007 - 723) and in the Hydrogen, Fuel Cells & Infrastructure Technologies Program-Multi-Year Research, Development, and Demonstration Plan of the USA Department of Energy (DoE 2007).Hydrogen safety issues must be addressed in order to ensure that the wide spread deployment and use of hydrogen and fuel cell technologies can occur with the same or lower level of hazardsan...

Health and Safety Executive, 2020

Hydrogen storage is now, and will continue to be a key topic for established and developing applications moving forward. The main priorities identified for hydrogen storage are: 1 st priority: tank fire resistance (previously identified as a priority in 2016). 2 nd priority: non-destructive testing techniques for manufacturing and regular inspection. 3 rd priority: understanding the effects of tank overheating on the structural performance and lifetime of the tank (also highlighted as a key priority by session chair to underpin refuelling protocols). (4) Key Session Topic: ACCIDENT PHYSICS of GASEOUS HYDROGEN For the accident physics of gaseous hydrogen the top three priorities from a list of five are: 1 st priority: premixed combustion associated with large scale problems with obstacles, flame acceleration and particularly deflagration-detonation-transition (DDT). 2 nd priority: hydrogen venting. 3 rd priority: ignition statistical approaches and spontaneous ignition. These priorities are key to growing application inventories and preventing and understanding the consequences of accidental releases in these new and developing scenarios. (5) Key Session Topic: ACCIDENT PHYSICS of LIQUID HYDROGEN For the accident physics of liquid hydrogen the top three priorities from an extensive list of 15 are: 1 st priority: multi-phase accumulations with explosion potential. 2 nd priority: combustion properties of cold gas clouds, especially in congested areas. 3 rd priority: knowledge and experience related to releases of large quantities. Obviously, this is an highly important area with a number of outstanding issues, many of which are beginning to be addressed by international efforts, such as the FCH JU project PRESLHY or the Norwegian project SH2IFT. These efforts are essential, as LH2 is key to a number of applications, as noted with the strong overlap in priorities with aerospace and maritime, and others that will need larger hydrogen inventories and corresponding scaling-up of supply infrastructure. (6) Key Session Topic: MATERIALS The rapid development and deployment of hydrogen applications leads to an expectation that the materials that enable the novel use of hydrogen today must become the normal, common place and safe materials (or their equivalents) for tomorrow. To meet this expectation, it is essential that the characteristics and long term performance and reliability of materials across all applications is understood, evidenced, catalogued and applied. With this in mind, the materials prioritisation exercise is divided into two sub-chapters, as it was in 2016.