- Release of Hydrogen
- Safety Related Aspects of Liquid Hydrogen (LH2)
- Explosion Protection for Hydrogen Applications
The field of competence is centred around the safe operation of hydrogen plants and the safety of processes for the production, transport and conversion of liquid and gaseous hydrogen and hydrogen mixtures.
The activities focus on the safety-related properties of hydrogen or hydrogen mixtures, explosion protection, consequence considerations in accident scenarios and the design of safety-related measures and concepts.
The research work includes practical experimental investigations from laboratory to real scale and the derivation of protective measures. In addition, calculation models and estimation procedures are used and further developed, e.g. to evaluate the possible effects of accident scenarios.
Release of Hydrogen
The release of hydrogen is one of the most important scenarios to be considered in the context of risk assessment and the assessment of accidental consequences. If the released hydrogen ignites, flame jets or gas cloud explosions can occur.
At BAM's Test Site for Technical Safety (TTS) south of Berlin, hydrogen releases at high pressure are investigated experimentally on a real scale. The dispersion of hydrogen and hydrogen mixtures as well as the effects of free-jet flames on the environment are studied for various realistic release scenarios. Parameters such as pressure, leak size or orientation of the release can be varied.
Mathematical simulation models are used to calculate the extension of explosive atmospheres as well as the heat radiation and extension of free-jet flames. These models are continuously developed and validated by experimental results.
These calculations are required for the design of protective measures in accordance with corresponding regulations, e.g., for the definition of hazardous areas with potentially explosive atmospheres or for the determination of safety distances.
Safety Related Aspects of Liquid Hydrogen (LH2)
Liquefaction makes it possible to store large quantities of hydrogen in a smaller space and at low pressure and to transport large amounts over long distances. Due to the cryogenic state of liquid hydrogen (LH2), it differs significantly from gaseous hydrogen in some properties and hazards; a circumstance that must be considered e.g., in evaluating hydrogen releases or in the development of safety concepts. To ensure a high level of safety in the use of LH2, a wide range of investigations are taking place at BAM.
One focus is on the safety of tanks for storing LH2. Typically, double-walled tanks with thermal insulation based on vacuum and insulating materials are used for this purpose. This type of insulation makes it possible to guarantee the cryogenic state of LH2 over a long period of time and is potentially used in land, sea, and air transport. To be able to evaluate the behaviour of tanks and their insulation in a fire event as well as the resulting consequences, laboratory and real-scale experiments take place at the Test Site for Technical Safety (TTS). The data obtained provide information on the course of incidents and are also used to develop models.
Another focus is the accidental release of LH2 on and under water, which is researched at the BAM TTS on a real scale. There are great differences to the release on land, e.g., due to higher evaporation mass flows and possible pressure waves with explosive character (Rapid Phase Transition). Such incidents are of great importance for maritime transport, where large quantities of LH2 are handled and transported and where a single incident can have potentially devastating consequences for the environment and society.
Explosion Protection for Hydrogen Applications
According to European directives (ATEX), the use of hydrogen and hydrogen mixtures requires measures for explosion protection to be taken. The explosion protection measures are divided into primary (avoidance of explosive mixtures), secondary (avoidance of ignition sources) and constructive (explosion-proof design) measures.
In the laboratories and test facilities of BAM, safety related tests on hydrogen mixtures are carried out in connection with explosion protection as close to practice as possible. At BAM's Test Site for Technical Safety (TTS), corresponding investigations are also carried out on a real scale. In addition, safety-related characteristics such as explosion limits, ignition temperatures or explosion pressures at process pressures and temperatures are determined experimentally and corresponding test methods are further developed.
Overall, all three types of explosion protection measures are taken into account. Among other things, the explosibility of gas mixtures, the effectiveness of non-electrical ignition sources and the design of bursting discs as a constructive explosion protection measure are examined.
The results of the investigations are implemented in regulations, codes and standards for explosion protection. Safety parameters for explosion protection are evaluated and included in the CHEMSAFE database. By means of the database, the safety of hydrogen mixtures can be assessed, for example.