Poland

This paper demonstrates experimental and numerical study on spontaneous ignition of H2–N2 mixtures during high-pressure release into air through the tubes of various diameters and lengths. The mixtures included 5% and 10% (vol.) N2 addition to hydrogen being at initial pressure in range of 4.3–15.9 MPa. As a point of reference pure hydrogen release experiments were performed with use of the same experimental stand experimental procedure and extension tubes. The results showed that N2 addition may increase the initial pressure necessary to self-ignite the mixture as much as 2.12 or 2.85 – times for 5% and 10% N2 addition respectively. Additionally simulations were performed with use of Cantera code (0-D) based on the ideal shock tube assumption and with the modified KIVA3V code (2-D) to establish the main factors responsible for ignition and sustained combustion during the release.

A new method of hydrogen generation from water by irradiation with CW infrared laser diode of graphene scaffold immersed in solution is reported. Hydrogen production was extremely efficient upon admixing NaCl into water. The efficiency of hydrogen production increased exponentially with laser power. It was shown that hydrogen production was highly efficient when the intense white light emission induced by laser irradiation of graphene foam was occurring. The mechanism of laser-induced dissociation of water is discussed. It was found that hydrogen production was extremely high at about 80% and assisted by a small emission of O2 CO and CO2 gases.

Type IV pressure vessels are commonly used for hydrogen on-board stationary or bulk storages. During their lifetime they can be submitted to mechanical impacts creating damage within the composite structure not necessarily correlated to what is visible from the outside. When an impact is suspected or when a cylinder is periodically inspected it is necessary to determine whether it can safely stay in service or not. The FCH JU project Hypactor aims at creating a large database of impacts characterized by various non destructive testing (NDT) methods in order to provide reliable pass-fail criteria for damaged cylinders. This paper presents some of the tests results investigating short term burst) and long term (cycling) performance of impacted cylinders and the recommendations that can be made for impact testing and NDT criteria calibration.

With regard to the goals of the European HySafe Network research facilities are essential for the experimental investigation of relevant phenomena for testing devices and safety concepts as well as for the generation of validation data for the various numerical codes and models. The integrating activity ‘Integration of Experimental Facilities (IEF)’ has provided basic support for jointly performed experimental work within HySafe. Even beyond the funding period of the NoE HySafe in the 6th Framework Programme IEF represents a long lasting effort for reaching sustainable integration of the experimental research capacities and expertise of the partners from different research fields. In order to achieve a high standard in the quality of experimental data provided by the partners emphasis was put on the know-how transfer between the partners. The strategy for reaching the objectives consisted of two parts. On the one hand a documentation of the experimental capacities has been prepared and analysed. On the other hand a communication base has been established by means of biannual workshops on experimental issues. A total of 8 well received workshops has been organised covering topics from measurement technologies to safety issues. Based on the information presented by the partners a working document on best practice including the joint experimental knowledge of all partners with regard to experiments and instrumentation was created. Preserving the character of a working document it was implemented in the IEF wiki website which was set up in order to provide a central communication platform. The paper gives an overview of the IEF network activities over the last 5 years.

Hydrogen vehicles may emerge as a leading contender to replace today’s internal combustion engine powered vehicles. A Phenomena Identification and Ranking Table exercise conducted as part of the European Network of Excellence on Hydrogen Safety (HySafe) identified the use of hydrogen vehicles in road tunnels as a topic of important concern. An internal project called HyTunnel was duly established within HySafe to review identify and analyse the issues involved and to contribute to the wider activity to establish the true nature of the hazards posed by hydrogen vehicles in the confined space of a tunnel and their relative severity compared to those posed by vehicles powered by conventional fuels including compressed natural gas (CNG). In addition to reviewing current hydrogen vehicle designs tunnel design practice and previous research a programme of experiments and CFD modelling activities was performed for selected scenarios to examine the dispersion and explosion hazards potentially posed by hydrogen vehicles. Releases from compressed gaseous hydrogen (CGH2) and liquid hydrogen (LH2) powered vehicles have been studied under various tunnel geometries and ventilation regimes. The findings drawn from the limited work done so far indicate that under normal circumstances hydrogen powered vehicles do not pose a significantly higher risk than those powered by petrol diesel or CNG but this needs to be confirmed by further research. In particular obstructions at tunnel ceiling level have been identified as a potential hazard in respect to fast deflagration or even detonation in some circumstances which warrants further investigation. The shape of the tunnel tunnel ventilation and vehicle pressure relief device (PRD) operation are potentially important parameters in determining explosion risks and the appropriate mitigation measures.

The detonation propensity of hydrogen-air mixtures with addition of methane ethane or propane in wide range of compositions is analyzed. The analysis concerned the detonation cell width ignition delay time RSB and parameters. Results are presented as a function of hydrogen molar fraction. Computations were performed with the use of three Cantera 2.1.1. scripts in the Matlab R2010b environment. The validated mechanisms of chemical reactions based on data available in the literature were used. Six mechanisms were assessed: GRI-Mech 3.0 LLNL SanDiego Wang POLIMI and AramcoMech. In conclusion the relation between detonation propensity parameters is discussed.

The paper presents an overview of the main achievements of the internal project InsHyde of the HySafe NoE. The scope of InsHyde was to investigate realistic small-medium indoor hydrogen leaks and provide recommendations for the safe use/storage of indoor hydrogen systems. Additionally InsHyde served to integrate proposals from HySafe work packages and existing external research projects towards a common effort. Following a state of the art review InsHyde activities expanded into experimental and simulation work. Dispersion experiments were performed using hydrogen and helium at the INERIS gallery facility to evaluate short and long term dispersion patterns in garage like settings. A new facility (GARAGE) was built at CEA and dispersion experiments were performed there using helium to evaluate hydrogen dispersion under highly controlled conditions. In parallel combustion experiments were performed by FZK to evaluate the maximum amount of hydrogen that could be safely ignited indoors. The combustion experiments were extended later on by KI at their test site by considering the ignition of larger amounts of hydrogen in obstructed environments outdoors. An evaluation of the performance of commercial hydrogen detectors as well as inter-lab calibration work was jointly performed by JRC INERIS and BAM. Simulation work was as intensive as the experimental work with participation from most of the partners. It included pre-test simulations validation of the available CFD codes against previously performed experiments with significant CFD code inter-comparisons as well as CFD application to investigate specific realistic scenarios. Additionally an evaluation of permeation issues was performed by VOLVO CEA NCSRD and UU by combining theoretical computational and experimental approaches with the results being presented to key automotive regulations and standards groups. Finally the InsHyde project concluded with a public document providing initial guidance on the use of hydrogen in confined spaces.

This article presents a power to SNG (synthetic natural gas) system that converts hydrogen into SNG via a methanation process. In our analysis detailed models for all the elements of the system are built. We assume a direct connection between a wind farm and a hydrogen generator. For the purposes of our calculations we also assume that the hydrogen generator is powered by the renewable source over a nine-hour period per day (between 21:00 and 06:00) and this corresponds to the off-peak period in energy demand. In addition a hydrogen tank was introduced to maximize the operating time of the methanation reactor. The cooperation between the main components of the system were simulated using Matlab software. The primary aim of this paper is to assess the influence of various parameters on the operation of the proposed system and to optimize its yearly operation via a consideration of the most important constraints. The analyses also examine different nominal power values of renewables from 8 to 12 MW and hydrogen generators from 3 to 6 MW. Implementing the proposed configuration taking into account the direct connection of the hydrogen generator and the methanation reactor showed that it had a positive effect on the dynamics and the operating times of the individual subsystems within the tested configuration

This is article presents the results of the testing of the addition of a hydrogen-to-nitrogen-rich natural gas of the Lw group and its influence on the operation of selected gas-fired domestic appliances. The tests were performed on appliances used for the preparation of meals and hot water production for hygienic and heating purposes. The characteristics of the tested gas appliances are also presented. The burners and their controllers with which the tested appliances were equipped were adapted for the combustion of Lw natural gas. The tested appliances reflected the most popular designs for domestic gas appliances in their group used both in Poland and in other European countries. The tested appliances were supplied with nitrogen-rich natural gas of the Lw group and a mixture of this gas with hydrogen at 13.2% content. The article presents the approximate percentage compositions of the gases used during the tests and their energy parameters. The research was focused on checking the following operating parameters and the safety of the tested appliances: the rated heat input thermal efficiency combustion quality ignition flame stability and transfer. The article contains an analysis of the test results referring in detail to the issue of decreasing the heat input of the appliances by lowering the energy parameters of the nitrogen-rich natural gas of the Lw group mixture with a hydrogen addition and how it influenced the thermal efficiency achieved by the appliances. The conclusions contain an explanation regarding among other things how the design of an appliance influences the thermal efficiency achieved by it in relation to the heat input decrease. In the conclusions on the basis of the research results answers have been provided to the following questions: (1) Whether the hydrogen addition to the nitrogen-rich natural gas of the Lw group will influence the safe and proper operation of domestic gas appliances; (2) What hydrogen percentage can be added to the nitrogen-rich natural gas of the Lw group in order for the appliances adapted for combusting it to operate safely and effectively without the need for modifying them?

An experimental study of flame propagation acceleration and transition to detonation in hydrogen-air mixture in 2 m long rectangular cross section channel filled with obstacles located at the bottom wall was performed. The initial conditions of the hydrogen-air mixture were 0.1 MPa and 293 K. Three different cases of obstacle height (blockage ratio 0.25 0.5 and 0.75) and four cases of obstacle density were studied with the channel height equal to 0.08 m. The channel width was 0.11 m in all experiments. The propagation of flame and pressure waves was monitored by four pressure transducers and four in house ion probes. The pairs of transducers and probes were placed at various locations along the channel in order to get information about the progress of the phenomena along the channel. To examine the influence of mixture composition on flame propagation and DDT the experiments were performed for the compositions of 20% 25% and 29.6% of H2 in air by volume. As a result of the experiments the deflagration and detonation regimes and velocities of flame propagation in the obstructed channel were determined.