Hydrogen safety

Fundamental and applied sciences are employed for ensuring a safe and efficient green transition using hydrogen.

Background

Despite several decades of research on hydrogen releases, there are still important gaps to be filled.

The main knowledge gaps relate to jet releases above ground. Those are mostly related to radiation, where the treatment thus far has been oversimplified, where the difference between the infrared blackbody radiation of hydrocarbon flames and the lesser, but more energetic, radiation from hydrogen flames has been disregarded. This is despite the fact that the damage mechanism is different, e.g. radiative absorptivity of exposed surfaces as well as the radiative transport with interaction with air humidity etc.

Pressure waves from hydrogen explosions also differs considerably from conventional hydrocarbons, mainly because of the higher flame speed for hydrogen combustion. The probability for ignition is also higher for hydrogen releases due to the low minimum ignition energy as well as due to the wide explosion range. The interaction between pressure waves and constructions needs to be understood in better detail given the particular characteristics of hydrogen explosions.

Well-established safety distances are of paramount importance for the wide implementation of hydrogen technologies in society since it affects both the design and location of new facilities. The less knowledge there is, the higher the requirements for safety/protective measures typically become. Some guidance can be obtained from the examination of similar activities, but as the assessment must be made on a case-by-case basis the possibility of analogously applying the process from another type of activity is limited. For hydrogen applications, the lack of a coherent regulatory framework amplifies these challenges, creating a situation characterized by a high level of uncertainty and thereby considerable costs, seriously threatening the investments. Also guidelines and tactics for the rescue services is today characterized by a high level on uncertainty, resulting in over-conservative decision making.

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Aim & Objectives

The aim is to develop pre-normative results regarding heat emission and pressure waves from hydrogen jet flames and explosions, and their interaction with the surrounding environment, such as humans and building structures. These results will constitute the underpinning bases for the development of balanced and knowledge-based guidelines and regulations on Swedish and European level, with emphasis on possibilities for accelerating the establishment of hydrogen infrastructure, with a sufficient level of safety. The methods used are molecular quantum physics and chemical kinetics, combined with computational fluid dynamics (CFD) and finite element analysis (FEA). Combustion/explosions are modelled with CFD, with adaption of existing models to the specifics of hydrogen. FEA is used for calculating the structural response engineering. This numerical modelling is be employed in the modelling of thermal and pressure loads from hydrogen jet flames and explosions, and the interaction of these loads on structures and humans. The models will be used for knowledge-based input to regulatory standardization bodies, and for ongoing projects where detailed simulations are of relevance for expedient implementation of project plans.

Financiers: Tillväxtverket and the EU Just Transition Fund.

Researchers: Lucas Andersson, Andrea Correa, Joakim Sandström, Oisik Das, Rhoda Afriyie Mensah and Michael Försth.

Read more about the university's hydrogen investment Center for Hydrogen Energy Systems Sweden - CH2ESS here.