Gap Analysis of CFD Modelling of Accidental Hydrogen Release and Combustion

The report describes the findings of a workshop that was held at the Institute for Energy (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.JRC.DDG.F.2-Cleaner energ

Prioritisation of Research and Development for modelling the safe production, storage, delivery and use of hydrogen.

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 hazards and associated risk compared to the conventional fossil fuel technologies. Hydrogen safety is a EU Policy relevant issue as it is stated in the priority 3 Action 2 (Continuous improvement in safety and security) of the EU “Energy 2020 A strategy for competitive, sustainable and secure energy”: “The same security and safety considerations will also be upheld in the development and deployment of new energy technologies (hydrogen safety, safety of CO2 transportation network, CO2 storage, etc…)” Computational Fluid Dynamics (CFD) is one of the tools to investigate safety issues related to the production, storage, delivery and use of hydrogen. CFD techniques can provide a wealthy amount of information on the dynamics of hypothetical hydrogen accident and its consequences. The CFD-based consequence analysis is then used in risk assessments. This report describes the output of a workshop organised at the Institute for Energy and Transport (JRC) in Petten, Netherlands to identify the gaps and issues in CFD modelling of hydrogen release and combustion. A hydrogen accident usually follows a typical sequence of events: an unintended release, the mixing of hydrogen with air to form a flammable mixture, the ignition of the flammable cloud and depending on the conditions, and a fire or an explosion (deflagration or/and detonation). For each stage of the accident, the critical CFD issues have been identified and prioritised. Beyond the specific issues of CFD modelling that are described for each accident stage in the report, some general modelling issues can be found in all stages: • lack of an extensive validation of CFD codes/models that covers all the relevant range of conditions that can be found in hypothetical accident scenarios e.g. in terms of geometrical lay-out, leak flow rates. • lack of a CFD validation protocol for hydrogen like it exists for Liquefied Natural Gas (LNG): the Model Evaluation Protocols (MEP) for assessment of models for accident consequences, with guidance on evaluating models in terms of scientific assessment, verification and validation. • lack of a database of experiments for validation of hydrogen models. • in some cases, lack of complete and accurate experimental data for the CFD validation. The goals of this work were to perform a state of the art review in CFD modelling of hypothetical accidents scenarios related to hydrogen technologies and identify and prioritise the gaps in the field. The report is based on a dedicated workshop organised in Petten with the participation of external experts an extensive literature review performed by experts in the field and the direct expertise and experience of the experts. The experts were carefully selected according to their experience/expertise, number of scientific publications and participations to International Conferences, seminars, workshops and to international and/or European co-funded projects such as HySafe (Hydrogen Safety), HyApproval (Approval of Hydrogen Re-fuelling Stations), European Integrated Hydrogen Projects. By performing a state of the art review of CFD modelling for hydrogen safety issues, a consensus was reached among the scientific experts as to the main gaps in the field and on the priority of the research needs.JRC.F.2-Cleaner energ

Statistics, lessons learned and recommendations from analysis of HIAD 2.0 database

The manuscript firstly describes the data collection and validation process for the European Hydrogen Incidents and Accidents Database (HIAD 2.0), a public repository tool collecting systematic data on hydrogen-related incidents and near-misses. This is followed by an overview of HIAD 2.0, which currently contains 706 events. Subsequently, the approaches and procedures followed by the authors to derive lessons learned and formulate recommendations from the events are described. The lessons learned have been divided into four categories including system design; system manufacturing, installation and modification; human factors and emergency response. An overarching lesson learned is that minor events which occurred simultaneously could still result in serious consequences, echoing James Reason's Swiss Cheese theory. Recommendations were formulated in relation to the established safety principles adapted for hydrogen by the European Hydrogen Safety Panel, considering operational modes, industrial sectors, and human factors. This workprovide an important contribution to the safety of systems involving hydrogen, benefitting technical safety engineers, emergency responders and emergency services. The lesson learned and the discussion derived from the statistics can also be used in training and risk assessment studies, being of equal importance to promote and assist the development of sound safety culture in organisations

Conformation-sensitive Antibodies against Alzheimer Amyloid-β by Immunization with a Thioredoxin-constrained B-cell Epitope Peptide

Immunotherapy against the amyloid-beta (Abeta) peptide is a valuable potential treatment for Alzheimer disease (AD). An ideal antigen should be soluble and nontoxic, avoid the C-terminally located T-cell epitope of Abeta, and yet be capable of eliciting antibodies that recognize Abeta fibrils and neurotoxic Abeta oligomers but not the physiological monomeric species of Abeta. We have described here the construction and immunological characterization of a recombinant antigen with these features obtained by tandem multimerization of the immunodominant B-cell epitope peptide Abeta1-15 (Abeta15) within the active site loop of bacterial thioredoxin (Trx). Chimeric Trx(Abeta15)n polypeptides bearing one, four, or eight copies of Abeta15 were constructed and injected into mice in combination with alum, an adjuvant approved for human use. All three polypeptides were found to be immunogenic, yet eliciting antibodies with distinct recognition specificities. The anti-Trx(Abeta15)4 antibody, in particular, recognized Abeta42 fibrils and oligomers but not monomers and exhibited the same kind of conformational selectivity against transthyretin, an amyloidogenic protein unrelated in sequence to Abeta. We have also demonstrated that anti-Trx(Abeta15)4, which binds to human AD plaques, markedly reduces Abeta pathology in transgenic AD mice. The data indicate that a conformational epitope shared by oligomers and fibrils can be mimicked by a thioredoxin-constrained Abeta fragment repeat and identify Trx(Abeta15)4 as a promising new tool for AD immunotherapy

Coalition Formation and the Ancillary Benefits of Climate Policy

Several studies found ancillary benefits of environmental policy to be of considerable size. These additional private benefits imply not only higher cooperative but also noncooperative abatement targets. However, beyond these largely undisputed important quantitative effects, there are qualitative and strategic implications associated with ancillary benefits: climate policy is no longer a pure but an impure public good. In this paper, we investigate these implications in a setting of non-cooperative coalition formation. In particular, we address the following questions. 1) Do ancillary benefits increase participation in international environmental agreements? 2) Do ancillary benefits raise the success of these treaties in welfare terms