The utilisation of hydrogen in ships has important potential in terms of achieving the decarbonisation of waterway transport, which produces approximately 3% of the world’s total emissions. However, the utilisation of hydrogen drives in maritime and inland shipping is conditioned by the efficient and safe storage of hydrogen as an energy carrier on ship decks. Regardless of the type, the constructional design and the purpose of the aforesaid vessels, the preferred method for hydrogen storage on ships is currently high-pressure storage, with an operating pressure of the fuel storage tanks amounting to tens of MPa. Alternative methods for hydrogen storage include storing the hydrogen in its liquid form, or in hydrides as adsorbed hydrogen and reformed fuels. In the present article, a method for hydrogen storage in metal hydrides is discussed, particularly in a certified low-pressure metal hydride storage tank—the MNTZV-159. The article also analyses the 2D heat conduction in a transversal cross-section of the MNTZV-159 storage tank, for the purpose of creating a final design of the shape of a heat exchanger (intensifier) that will help to shorten the total time of hydrogen absorption into the alloy, i.e., the filling process. Based on the performed 3D calculations for heat conduction, the optimisation and implementation of the intensifier into the internal volume of a metal hydride alloy will increase the performance efficiency of the shell heat exchanger of the MNTZV-159 storage tank. The optimised design increased the cooling power by 46.1%, which shortened the refuelling time by 41% to 2351 s. During that time, the cooling system, which comprised the newly designed internal heat transfer intensifier, was capable of eliminating the total heat from the surface of the storage tank, thus preventing a pressure increase above the allowable value of 30 bar.

The present article discusses the potential for hydrogen separation using a metal hydride separator, which facilitates the generation of hydrogen contained in syngas following the thermal recovery of wastes. The article provides a detailed description of the separator heat balance using analytical calculations and optimised calculations, and by applying numerical methods. The proposed concept of a separator intended for hydrogen separation from syngas offers a solution to a problem associated with the use of metal hydride alloy powders; in particular, their low thermal conductivity. In order to eliminate big temperature differences in the alloy, a heat transfer intensifier was implemented in the metal hydride alloy volume; the intensifier was made of metal and exhibited high thermal conductivity. For the purpose of comparing the thermal fields, the first stage comprised the creation of a numerical simulation of hydrogen absorption without the use of an intensifier. Subsequently, three different geometries were created for an intensifier intended to remove heat from the metal hydride alloy powder towards the separator cover, and the effects of these three geometries were analysed. The implementation of heat transfer intensifiers into the metal hydride alloy powder improved the heat removal by as much as 43.9% and increased the thermal field homogeneity by 77%. A result of the heat removal optimisation was an increase in the hydrogen absorption kinetics and the efficiency of the separator operation.

The present article describes the measurements of flow rates of the inward air leakage through the skin–facepiece interface of a protective half-mask with replaceable filters. The measurements were carried out while applying an indirect method in which the pressure drops in a compressed air container were measured, and subsequently, the total flow rate of the leak was calculated. This methodology facilitated measuring extremely low air flow rates at the atmospheric pressure of 3.2 × 10⁻⁶ m³·s⁻¹. A numerical analysis of the inward air leakage through the gaps between the face and the facepiece of the mask was carried out with the aim of identifying the cross-sectional area of the leak. With the tested mask, which was made of Santoprene 8281-45MED, the leakage measured during inhalation was 0.21%, which corresponded to the cross-sectional area of only 0.14 mm².

Synthesis gases produced in the processes of the high-temperature gasification of otherwise unusable waste, with the use of technologically efficient and cost-effective separation methods, may represent a reliable source of hydrogen intended for applications in the industry and the transport segments. One of the possible solutions to the separation of hydrogen from a mixture of gases is the use of metal hydride (MH) alloys, which are capable of binding hydrogen into their structure. This is the subject of the present article, in which a new design is presented for a fully functional system and a hydrogen separator unit, and the potential application of a commonly available metal hydride alloy in the separation of hydrogen from a binary mixture containing carbon dioxide and hydrogen is discussed. Load testing of the selected type of metal hydride alloy with a high concentration of carbon dioxide in the mixture, representing 40 vol. % and 4 vol. %, was performed. In addition, testing the alloy’s ability to separate hydrogen from a mixture containing H₂ and CO₂ was conducted using small alloy samples and a newly designed hydrogen separator unit. The resulting higher purity of hydrogen after the separation was confirmed by an experiment, in which the hydrogen concentration in the resulting mixture increased by 2.7 vol. %. The purity of the desorbed hydrogen amounted to 99.4 vol. %. The testing also confirmed a high degree of degradation of the alloy, caused by the poisoning effect of CO₂ on the selected alloy type. There was also a significant decrease in the absorption ability of the alloy—from 1.7 wt. % to 1.2 wt. %—and a significant extension of the absorption time caused by the slower kinetics of the hydrogen storage, which occurred as early as after ten absorption–desorption cycles.

This article presents an analysis of three different approaches to the identification of the thickness of the fouling layer inside the pipes of natural gas (NG) coolers. At present, there is no existing simple analytical procedure for the identification of the fouling layer thickness. The authors of this article describe in detail the balance method, which required the use of a large number of physical parameters, changes in their sizes depending on the output temperature of the gas, the temperature of the cooling air, the air quantity, as well as the physical properties of both media. The computational model was robust, and its disadvantage was the iterative computation. The second analysed method was a dimensional analysis. It was applied using the Buckingham’s theorem to express the individual similarity criteria. In this method, 10 simplexes and two complexes were created. The fouling layer thickness, expressed using a derived criterial equation, exhibited real results. The third analysed method was based on analysing selected physical parameters with the use of a multiple regression analysis in MinitabX 18 software. The analysis showed that the fouling layer thickness depended on fewer parameters than the number of parameters assumed in the dimensional analysis or the balance method. The standard deviation that was identified in the multiple linear regression for a double crossflow cooler was 0.0667 and the value of reliability (the coefficient of determination of the multiple linear regression) R² was 0.9985.

Hydrogen storage and separation remain major technical challenges limiting the broader implementation of hydrogen-based energy systems. Metal–hydride alloys offer a promising solution because they enable reversible hydrogen storage within their crystal structure and can selectively absorb hydrogen from multicomponent gas mixtures. However, the practical application of metal–hydride systems requires storage vessels that combine sufficient mechanical strength with effective heat removal, as hydrogen absorption is accompanied by significant heat generation that can reduce the reaction rate and usable storage capacity. This study addresses hydrogen storage within the crystal structure of metal alloys and introduces the potential of metal–hydride (MH) alloys for hydrogen separation from gas mixtures. It subsequently presents the structural design and strength assessment of a low-pressure, double-walled, tubular steel MH storage vessel intended for hydrogen storage in a MnTiVFeZr-based alloy. Structural simulations were performed in ANSYS 2025 R2 Static Structural at three operating pressures: 3, 5, and 7 MPa. For all three simulated pressure conditions, the gravimetric hydrogen storage capacity of the alloy was 0.992 ± 0.016 wt.%. Following the selection of the most suitable design with an operating pressure of 3 MPa, an analytical calculation was performed to verify the results obtained from the numerical analysis. The storage vessel was subsequently manufactured and subjected to experimental strength validation using the test procedures specified in the STN EN 13322-2 standard. The design of the low-pressure tubular steel MH storage vessel also incorporates an efficient thermal management system based on a combination of active and passive cooling modules. The passive cooling module takes the form of an internal heat-transfer enhancement element, which is inserted into the primary storage vessel together with the MH alloy. The active cooling module uses a coolant flowing around the outer wall of the primary vessel. The optimal design of the aluminium passive cooling module was selected from four variants based on a steady-state temperature-field analysis conducted in ANSYS CFX. The selected module was subsequently manufactured and integrated into the proposed storage vessel. The vessel equipped with the passive cooling element was then subjected to experimental temperature measurements during hydrogen absorption by the MH alloy. The experimentally obtained data were compared with the numerical simulation results to evaluate the temperature fields within the vessel and the heat dissipation from the core of the MH storage system during hydrogen absorption. The main contribution of this work is the development of a mechanically validated and thermally managed tubular metal–hydride vessel that integrates structural design, numerical optimisation, manufacturing, and full-scale experimental testing within a single methodology. The proposed approach provides a practical basis for the further development and scaling of low-pressure metal–hydride systems for hydrogen storage, purification, and separation applications.