Lithuania

Development of technologically and economically feasible solutions for hydrogen storage stimulates progress in hydrogen economy. High gravimetric and volumetric capacities of magnesium hydride makes it promising material capable to accelerate implementation of hydrogen-based technologies in our daily life. However widely discussed limitations of sorption kinetics and thermodynamic properties must be managed in MgH2. This work investigates two steps hydrogenation when process of hydrogen absorption is followed after hydrogen plasma activation. Such technique initiates creation of new channels for enhanced hydrogen sorption. Moreover synthesis of negligible amount of hydride acts as positive factor for further hydrogenation.

The paper presents the experimental research results of heavy-duty vehicle (public transport bus) fuelled with natural gas and hydrogen fuel mixtures. Spark ignition six cylinder engine tested with different hydrogen additions (from 5% up to 20% according to volume) in the natural gas fuel. The tests were performed on heavy-duty vehicle’s dyno test stand in company “SG dujos Auto” research laboratory. The tests were carried out at three load points and one engine speed. Engine had originally a port fuel injection and exhaust gas recirculation system. Experiments showed that engine fuelled with hydrogen addition was able to achieve lower fuel consumption and brake specific fuel consumption. It was also possible to achieve small increase of engine efficiency. The exhaust gas measurements showed that hydrogen addition in natural gas reduced the CO CO2 and HC emissions because of the H/C atom ratio change in fuel mixture and improved combustion process. The NOx emission level was decreasing although bigger amounts of hydrogen were used in natural gas fuel.

Due to practical computational resource limits current simulations of premixed turbulent combustion experiments are often performed using simplified turbulence treatment. From all available RANS models k-ε and k-ω SST are the most widely used. k-ω SST model is generally expected to be more accurate in bounded geometries since it corresponds to k-ε model further from the walls but switches to more appropriate k-ω model near the walls. However k-ε is still widely used and in some instances is shown to provide better results. In this paper we perform RANS simulations of premixed hydrogen flame propagation in an acceleration tube using k-ε and k-ω SST models. Accuracy of the models is assessed by comparing obtained results with the experiment. In order to better understand differences between k-ε and k-ω-SST results parameters of main k-ω-SST model features are examined. The distribution of the blending functions values and corresponding zones of are analysed in relation to flame position and resulting observed propagation velocity. We show that in the simulated case biggest difference between k-ω-SST and k-ε model results can be attributed to turbulent eddy viscosity limiting by shear strain rate in the k-ω-SST model.

Currently hydrogen and electric drives used in various means of transport is a leading topic in many respects. This article discusses the most important aspects of the operation of vehicles with electric drives (passenger cars) and hydrogen drives. In both cases the official reason for using both drives is the possibility of independence from fossil fuel supplies especially oil. The desire for independence is mainly dictated by political considerations. This article discusses the acquisition of basic raw materials for the construction of lithium-ion batteries in electric cars as well as methods for obtaining hydrogen as a fuel. The widespread use of electric passenger cars requires the construction of a network of charging stations. This article shows that taking into account the entire production process of electric cars including lithium-ion batteries the argument that they are ecological cannot be used. Additionally it was indicated that there is no concept for the use of used accumulator batteries. If hydrogen drives are used in trains there is no need to build the traction network infrastructure and then continuously monitor its technical condition and perform the necessary repairs. Of course the necessary hydrogen tanks must be built but there must be similar tanks to store oil for diesel locomotives. This paper also deals with other possibilities of hydrogen application for transformational usage e.g. the use of combustion engines driven with liquid hydrogen. Unfortunately an optimistic approach to this issue does not allow for a critical view of the whole matter. In public discussion there is no room for scientific arguments and emotions to dominate.

This article presents a 3D model of a yellow hydrogen generation system that uses the electricity produced by a photovoltaic carport. The 3D models of all key system components were collected and their characteristics were described. Based on the design of the 3D model of the photovoltaic carport the amount of energy produced monthly was determined. These quantities were then applied to determine the production of low-emission hydrogen. In order to increase the amount of low-emission hydrogen produced the usage of a stationary energy storage facility was proposed. The Metalog family of probability distributions was adopted to develop a strategic model for low-emission hydrogen production. The hydrogen economy of a company that uses small amounts of hydrogen can be based on such a model. The 3D modeling and calculations show that it is possible to design a compact low-emission hydrogen generation system using rapid prototyping tools including the photovoltaic carport with an electrolyzer placed in the container and an energy storage facility. This is an effective solution for the climate and energy transition of companies with low hydrogen demand. In the analytical part the Metalog probability distribution family was employed to determine the amount of monthly energy produced by 6.3 kWp photovoltaic systems located in two European countries: Poland and Italy. Calculating the probability of producing specific amounts of hydrogen in two European countries is an answer to a frequently asked question: In which European countries will the production of low-emission hydrogen from photovoltaic systems be the most profitable? As a result of the calculations for the analyzed year 2023 in Poland and Italy specific answers were obtained regarding the probability of monthly energy generation and monthly hydrogen production. Many companies from Poland and Italy are taking part in the European competition to create hydrogen banks. Only those that offer low-emission hydrogen at the lowest prices will receive EU funding.