Poland

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?

Underground hydrogen storage in geological structures is considered appropriate for storing large amounts of hydrogen. Using the geological Konary structure in the deep saline aquifers an analysis of the influence of depth on hydrogen storage was carried out. Hydrogen injection and withdrawal modeling was performed using TOUGH2 software assuming different structure depths. Changes in the relevant parameters for the operation of an underground hydrogen storage facility including the amount of H2 injected in the initial filling period cushion gas working gas and average amount of extracted water are presented. The results showed that increasing the depth to approximately 1500 m positively affects hydrogen storage (flow rate of injected hydrogen total capacity and working gas). Below this depth the trend was reversed. The cushion gas-to-working gas ratio did not significantly change with increasing depth. Its magnitude depends on the length of the initial hydrogen filling period. An increase in the depth of hydrogen storage is associated with a greater amount of extracted water. Increasing the duration of the initial hydrogen filling period will reduce the water production but increase the cushion gas volume.

Green hydrogen supply chain includes supply sources production and distribution of hydrogen produced from renewable energy sources (RES). It is a promising scientific and application area as it is related to the problem of instability of power grids supplied with RES. The article presents the conceptual assumptions of the research on the design of a functional multi-criteria model of the stabilization model architecture of energy distribution networks based on a hydrogen energy buffer taking into account the applicable use of hydrogen. The aim of the research was to identify the variables contributing to the stabilization of the operation of distribution networks. The method used to obtain this result was a systematic review of the literature using the technique of in-depth analysis of full-text articles and expert consultations. The concept of a functional model was described as a matrix in two dimensions in which the identified variables were embedded. The first dimension covers the phases of the supply chain: procurement and production along with storage and distribution. The second dimension divides the separate factors into technical economic and logistic. The research was conducted in the context of system optimization from the point of view of the operator of the energy distribution system. As a result of the research several benefits resulting from stabilization using a hydrogen buffer were identified. Furthermore the model may be used in designing solutions stabilizing the operation of power grids in which there are surpluses of electricity produced from RES. Due to the applied multidimensional approach the developed model is recommended for use as it enables the design of solutions in a systemic manner. Due to the growing level of energy obtained from renewable energy sources the issue of stabilizing the energy network is becoming increasingly important for energy network distributors.

The study focuses on the aspect of using the structure of gasars i.e. materials with directed open porosity as a potential hydrogen storage. The structure of the tested gasar is composed of a large number of thin open tubular pores running through the entire longitudinal section of the sample. This allows hydrogen to easily penetrate into the entire sample volume. The analysis of pore distribution showed that the longest diffusion path needed for full penetration of the metal structure with hydrogen is about L = 50–70 μm regardless of the external dimensions of the sample. Attempts to hydrogenate the magnesium gasar structure have shown its ability to accumulate hydrogen at a level of 1 wt%. The obtained results were compared with the best result was obtained for the ZK60 alloy after equal channel angular pressing (ECAP) and crushed to a powder form. The result obtained exceeded 4 wt% of hydrogen accumulated in the metal structure at theoretical 6.9 wt% maximum capacity. A model analysis of the theoretic absorption capacity of pure magnesium was also carried out based on the concentration of vacancies in the metal structure. The theoretical results obtained correlate well with experimental data.

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.

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.

This work is aimed at solving the problem of converting diesel power drives to diesel– hydrogen fuels which are more environmentally friendly and less expensive alternatives to diesel fuel. The method of increasing the energy efficiency of diesel fuels has been improved. The thermochemical essence of using methanol as an alternative fuel to increase energy efficiency based on the provisions of thermotechnics is considered. Alternative methanol fuel has been chosen as the initial product for the hydrogen conversion process and its energy value cost and temperature conditions have been taken into account. Calculations showed that the caloric effect from the combustion of the converted mixture of hydrogen H2 and carbon monoxide CO exceeds the effect from the combustion of the same amount of methanol fuel. Engine power and fuel energy were increased due to the thermochemical regeneration of engine exhaust gas heat. An experimental setup was created to study the operation of a converted diesel engine on diesel–hydrogen products. Experimental studies of power and environmental parameters of a diesel engine converted for diesel–hydrogen products were performed. The studies showed that the conversion of diesel engines to operate using diesel– hydrogen products is technically feasible. A reduction in energy consumption was accompanied by an improvement in the environmental performance of the diesel–hydrogen engine working together with a chemical methanol conversion thermoreactor. The formation of carbon monoxide occurred in the range of 52–62%; nitrogen oxides in the exhaust gases decreased by 53–60% according to the crankshaft speed and loading on the experimental engine. In addition soot emissions were reduced by 17% for the engine fueled with the diesel–hydrogen fuel. The conversion of diesel engines for diesel–hydrogen products is very profitable because the price of methanol is on average 10–20% of the cost of petroleum fuel.

The article discusses issues related to the operation of fuel cells stack fed with hydrogen at low temperature. The test object was a Toyota Mirai passenger car equipped with this type of powertrain. Tests were carried out in a thermoclimatic chamber at the Cracow University of Technology. They had an initial character and their aim was to evaluate the work of individual subassemblies of the propulsion system including the hydrogen supply system in terms of operational safety.

The energy approach for determining the durability of structural elements at high temperature creep and hydrogen activity was proposed. It has been shown that the approach significantly simplifies research compared with the known ones. Approbation of the approach was carried out on the example of determining the indicators of durability of the Bridgman sample under conditions of creep and different levels of hydrogenation of the metal. It was shown that with an increase of hydrogen concentration in the metal from 2 to 10 ppm the durability of the test sample decreased from 22 to 58%.

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.