Amount Of Hydrogen Research Articles

Enhancing solar energy output for green hydrogen production: a comparative study on bifacial solar panels in Nepalese cities at household-scale

ABSTRACT Increasing need for renewable energy, especially solar energy holds even greater significance in developing countries like Nepal. Therefore, an on-grid 5-kW solar power plant has been examined in 9 important and populous cities of Nepal. The PVsyst v7.1 software was used for simulation, and to optimise the results, Bifacial solar panels were employed. The economic results were considered in both Fixed Tilted Plane and Seasonal Tilt Adjustment modes. After the simulation, it was found that Dadeldhura has the highest injected electricity into the grid, equivalent to 9.23 MW/year, prevented CO2 emissions of 9.036 tons annually, and the payback period for this city is 8.5 years. Nepal has a great chance to produce green hydrogen, and in the investigated cities, the total amount of hydrogen produced is equal to 1.416 tons/year, of which the highest and lowest shares of hydrogen production belong to Dadeldhura (175.7 kg) and Biratnagar (137.2 kg), respectively. Therefore, the construction of home solar power plants in Nepal is highly cost-effective. The government can not only recover the entire investment in a short period but also contribute to the city grid during peak consumption times. This initiative can enable the entire country to benefit from green energy.

Silver Electrodes Are Highly Selective for CO in CO2 Electroreduction due to Interplay between Voltage Dependent Kinetics and Thermodynamics.

Electrochemical reduction is a promising way to make use of CO2 as feedstock for generating renewable fuel and valuable chemicals. Several metals can be used as the electrocatalyst to generate CO and formic acid, but hydrogen formation is an unwanted side reaction that can even be dominant. The lack of selectivity is, in general, a significant problem, but silver-based electrocatalysts have been shown to be highly selective, with faradaic efficiency of CO production exceeding 90%, when the applied voltage is below -1 V vs RHE. In this voltage range, only a small amount of hydrogen and formate is formed. We present calculations of the activation free energy for the various elementary steps as a function of applied voltage at the three low index facets, Ag(111), Ag(100) and Ag(110), as well as experimental measurements on polycrystalline electrodes, to identify the reason for this high selectivity. The formation of formic acid is suppressed, even though it is thermodynamically favored, because of the low coverage of adsorbed hydrogen and kinetic hindrance to the formation of the HCOO* intermediate, while *COOH, a key intermediate in CO formation, is thermodynamically unstable until the applied voltage reaches -1 V vs RHE, at which point the kinetics for its formation are more favorable than for hydrogen. The calculated results are consistent with experimental measurements carried out for acidic conditions and provide an atomic scale insight into the high CO selectivity of silver-based electrocatalysts.

Enhancing solar-driven hydrogen production through photoelectrochemical methods via dual transition metal doping of titanium oxide to form an impurity energy band

Developing a photoanode that is stable, efficient, and cost-effective for photoelectrochemical water splitting poses a significant challenge. To address this, we have successfully synthesized cobalt and chromium-doped Titanium dioxide (CoCrTiO2) using the hydrothermal method. This innovative approach results in an efficient, stable, and economical material. The introduction of Co and Cr through doping creates an intermediate band energy within TiO2, thereby enhancing charge separation and movement. The performance of CoCrTiO2 in the photoelectrochemical water splitting process is noteworthy. At 0 V vs Ag/AgCl, CoCrTiO2 exhibits a photocurrent density of 3.45 mAcm−2, representing an impressive 8.5 times increase compared to bare TiO2. Furthermore, when employed as a photoanode, CoCrTiO2 demonstrates a significant increase in hydrogen production. The amount of hydrogen generated is measured at 67.8 μmolecm−2, surpassing bare TiO2 by a factor of 5.6. Analysis data strongly supports CoCrTiO2 as an excellent candidate for advancing the field of photoelectrochemical water splitting due to its exceptional performance characteristics.

Autothermal hydrogen release from liquid organic hydrogen carrier systems

A typical feature that the LOHC technology shares with other types of chemical hydrogen storage is that the release of hydrogen from the carrier requires an input of heat. In many use cases where waste heat from external sources is not available (e.g. in heavy-duty mobility), this is seen as a major drawback. In this paper, we show that autothermal LOHC dehydrogenation offers a very attractive way to overcome this drawback. In detail, we demonstrate autothermal hydrogen release from dicyclohexylmethane using diphenylmethane oxidation to benzophenone as source of heat. The full storage cycle involves benzophenone hydrodeoxygenation to dicyclohexylmethane, dicyclohexylmethane dehydrogenation to diphenylmethane, and diphenylmethane oxidation to benzophenone. We studied both the individual reaction steps using pure feedstocks and the integral cycle in which the intermediates and by-products of each reaction remain in the system for the subsequent reaction step. Although no efforts have yet been made to develop special catalyst materials for this purpose, the results with the applied commercial hydrodeoxygenation (Pd/C), dehydrogenation (Pt on alumina) and partial oxidation (VOx/TiO2) catalysts are already very promising. The storage cycle can be closed with high selectivity and with only minor total oxidation losses. The proposed concept of autothermal LOHC dehydrogenation offers the potential to increase the amount of useable hydrogen from a given amount of charged hydrogen carrier by up to 30%.

Study on the effects of aging on the pyrolysis of plastic and the synergistic mechanisms of co-pyrolysis with lignite

Co-pyrolysis of waste plastic with low-rank coal explored how photoaging impacts the pyrolysis of plastics and delves into the synergistic mechanisms involved in co-pyrolysis. The results of elemental analysis, X-ray powder diffraction and Fourier transform infrared spectroscopy showed that photoaging primarily involves oxidizing and breaking the aliphatic chains in polyethylene (PE), as well as generating oxygen-containing functional groups like hydroxyl (-OH), carbonyl (-C=O), and ether (-C-O), thereby reducing the crystallinity of PE. The results of individual plastic pyrolysis showed that photoaging is beneficial to the generation of gas and tar. Pyrolysis tar of PE samples contains significant amounts of alcohols, and olefins and alkynes (O&As). The results of co-pyrolysis indicated that photoaging can enhance the yields of gas and oil from the co-pyrolysis between PE and Naomaohu (NMH) coal. Co-pyrolysis effectively reduced the relative content of O&As in the tar from the pyrolysis of PE samples alone by 8.0%-29.0%. The synergistic mechanism of co-pyrolysis between aged PE and NMH involved supplying a significant quantity of hydrogen and hydroxyl radicals by NMH, which react with alkyl radicals generated from PE pyrolysis, leading to the production of additional alkanes and alcohols. These findings offered new insights for a deeper understanding of the co-pyrolysis behaviors between waste plastic and lignite.

Construction of Au nanoparticles decorated on ZnFe2O4@ZnIn2S4 core-shell structure to enhance photocatalytic hydrogen production

Developing effective photocatalysts for water splitting is essential to generating H2 energy sources. Herein, a novel ZnFe2O4@ZnIn2S4/Au ternary composite (abbreviated as ZFO@ZIS/Au) was successfully designed and fabricated by loading Au nanoparticles on the ZFO@ZIS surfaces for effective photocatalytic H2 generation for the first time. Attributed to the synergistic effect of the traditional II-type heterojunction charge transfer and Au nanoparticles as co-catalysts, the ZFO@ZIS/Au heterojunction generated greater amounts of hydrogen under visible light irradiation. The ZFO-7%@ZIS/Au-2 catalyst displayed the highest H2 production rate of 1145.38 μmol∙g-1∙h-1, which was almost 3.87 times more than the ZIS value. Furthermore, several characterization techniques were performed to investigate the catalysts and evaluate the catalyst's photocatalytic activity when exposed to visible light. Lastly, a detailed discussion of the corresponding photocatalytic H2 production process of the as-prepared ZFO@ZIS/Au heterojunction was provided. The distinctive research might offer a potential approach for modifying zinc ferrate for photocatalytic hydrogen production.

Hydrogen production capabilities of lichens micro-ecosystem under extreme salinity, crystalline salt exposure, and simulated Mars-like conditions

This work aims to demonstrate the extremophilic behavior of the lichen Pleurosticta acetabulum at extreme salinities, while maintaining its metabolic capacity to produce hydrogen. Lichen is a special micro-ecosystem that includes mostly a fungus and a green alga or cyanobacterium, as well as a microbiome. The peculiarity of this symbiotic system is its ability to dry out completely and stay inactive to survive harsh conditions. Lichens that had been dehydrated for six months revived quickly when rehydrated, restoring their photosynthetic efficiency and ability to produce hydrogen. The lichen microbiome was crucial for hydrogen production, especially through dark fermentation. The experiments of this work showed that lichen during its exposure to different salinity conditions (0%NaCl – control, 3,5%NaCl – sea salt concentration, 36%NaCl – saturated salt concentration), but also after exposure to crystalline salt (100%NaCl) could maintain the structure and the functionality of its photosynthetic apparatus. This was tested using chlorophyll a fluorescence induction measurements. Based on the results of thermal conductivity gas chromatography (GC-TCD) for the determination of hydrogen production, it was shown that despite being exposed to extreme salinity conditions, lichens maintained its ability to produce hydrogen. The experimental combination of lichen exposure to extreme salinities (up to 100% NaCl), with an extreme atmosphere (100% CO2) and low atmospheric pressure (<10mbar), simulating Mars conditions, highlighted the functional potential of the lichen for survival in a Mars-like environment. This lichen’s ability to withstand extreme conditions and to produce large amounts of hydrogen, makes it a promising candidate for future biotechnological applications, even in challenging environments like Mars, opening new astrobiological and astrobiotechnological perspectives.

Low-carbon optimal dispatch of park integrated energy system considering coordinated ammonia production from multiple hydrogen energy

The utilization of ammonia energy has garnered considerable global attention as a viable approach to alleviate pressure on energy supply within park integrated energy systems (PIES) and enhance energy efficiency. However, the introduction of ammonia production requires the system to increase large amounts of hydrogen, diversifying the sources of hydrogen and challenging the coordinated operation of PIES. In this paper, the inertia characteristics of the gas and thermal energy delivery process are utilized to increase the flexibility of the PIES operation. A technological framework for coordinated ammonia production from multi-hydrogen energy in PIES under consideration of having inertia characteristics and a low-carbon operation strategy for ammonia-doped combustion in thermal generation is constructed. Limiting carbon emissions through a stepped carbon trading mechanism in this strategy. In addition, while addressing the ammonia-doped requirement for thermal generation combustion, and by flexibly setting the ammonia doping ratio of thermal generation combustion, the operation of PIES under different ammonia-doped ratios has been analyzed in detail. The results demonstrate that the proposed model enhances the utilization of renewable energy, leading to reduction in total economic costs by 4.52 % and total carbon emissions by 24.81 %. This makes the operation of PIES more economical, low-carbon, and flexible.

Optimal pH condition for hydrogen production using δ-FeOOH under UV irradiation

δ-FeOOH was synthesized to produce hydrogen and its properties were investigated. Although δ-FeOOH has a band gap energy that absorbs sufficient visible light, it cannot produce hydrogen in the visible-light region. However, δ-FeOOH can successfully produce hydrogen under UV. These results indicate that the hydrogen production reaction with δ-FeOOH under UV irradiation is related to the photo-Fenton reaction. The hydrogen production ability was investigated by controlling the pH of the solution, which is an important factor in the photo-Fenton reaction. As the pH of the solution decreased, the amount of hydrogen produced increased. The crystal structures of δ-FeOOH before and after hydrogen production were compared, and it was confirmed that the two crystal structures were identical. This result represents that the photo-Fenton reaction is a circular reaction, and δ-FeOOH can produce hydrogen semi-permanently under UV.

Exergy Analysis of Hydrogen-Rich Syngas Production System Utilizing Palm Oil Empty Fruit Bunch using Pyrolysis Connected with Steam Methane Reformer

Fossil fuel consumption on a large scale continues to increase yearly, causing a shortage of energy sources. Hydrogen can help to overcome the shortage of energy sources. It can be produced from renewable energy sources, such as oil palm Empty Fruit Bunch (EFB) as biomass using pyrolysis processes equipped with steam methane reformer and water gas shift reactions. This research was conducted to determine the amount of hydrogen that can be produced and to analyze the exergy of the existing systems in the hydrogen production process. Aspen Plus has been used to design and analyze pyrolysis processes, steam methane reform, and water gas shift reactions. The results showed that when 6.54 kg Empty Fruit Bunch was used as raw material in a pyrolysis reactor, hydrogen could be produced in the amounts of 0.435 kg. The exergy values of raw materials and fuels are relatively high because the chemical exergy values of the compounds contained therein are also high. Based on the calculations, it is found that the combustion process is the process that experiences the most significant exergy destruction. The exergy efficiency of this hydrogen production process system is 22.77%.

Substituted Indole Derivatives against Leucine Transporter (LeuT) as SSRI Antidepressant: Molecular Dynamics Study

Molecular docking and molecular dynamics on substituted indole derivatives-Leucine Trasporter had been performed. Indole derivatives with methoxy and fluorine group are chosen and specific amino acid residue Arg30 and Asp404 are π-alkyl and π-cation interactions. The suggested molecule containing methoxy groups has an RMSD value of 1.95 Å, a binding energy of-4.00 kcal mol-1, and an inhibition constant of 1.17 μM. The hypothesized fluorine-containing compound's RMSD value, binding energy, and inhibition constant were each 1.88 Å; -5.97 kcal mol-1; and 41.88 μM, respectively. The substituted indole derivative with the methoxy group was stable, according to the findings of a 200-ns molecular dynamics simulation, while the substituted indole derivative with the fluorine group was less stable. Based on the examination of RMSD, RMSF, RoG, the quantity of hydrogen, and the level of contact stability of the ligands with the particular amino acid residues for the antidepressant drug, the dynamical interaction of ligands against LeuT was determined.

Experimental Investigation and Chemical Kinetics Analysis of Carbon Dioxide Inhibition on Hydrogen-Enriched Liquefied Petroleum Gas (LPG) Explosions

The utilization of hydrogen-enriched liquefied petroleum gas (LPG) is an effective means of reducing carbon emissions, but the special physical and chemical properties of hydrogen have raised concerns among the public. To delve into the intricate chemical kinetic mechanisms governing the inhibitory effect of CO2 on the explosion of hydrogen-enriched LPG, this study systematically investigated the influence of varying CO2 concentrations (3%, 6%, and 9%) on the explosion characteristics of hydrogen-enriched LPG (hydrogen ratio ranging from 0 to 0.5) within a 20 L spherical explosion chamber. Subsequently, a chemical kinetic analysis was conducted, focusing on the explosion reaction dynamics of the H2/LPG/CO2/Air mixture, encompassing temperature sensitivity assessments and the production rates of key free radicals. The findings reveal that although hydrogen incorporation does not significantly alter the maximum explosion pressure of LPG, it markedly accelerates the explosion reaction rate, posing a challenge for CO2 in effectively inhibiting the explosion of hydrogen-enriched LPG. CO2 functions as a stabilizing third body within the reaction system, diminishing the collision frequency among free radicals, hydrogen molecules, hydrocarbon molecules, and oxygen molecules, thereby slowing down the reaction rate. As the proportion of hydrogen increases, the concentration of ·H radicals, known for their high reactivity, escalates, rapidly completing the propagation phase of the chain reaction and intensifying the overall generation rates of critical free radicals, including ·H, ·O, and ·OH. Notably, the key reaction H+O2⇋O+OH, which governs the reaction temperature, undergoes significant enhancement, further accelerating the explosion reaction rate and ultimately diminishing the inhibitory efficacy of CO2 against the hydrogenated LPG explosion. Furthermore, as the amount of hydrogen added increases, hydrogen’s competitiveness for oxygen within the reaction system markedly improves, attenuating the oxidation of hydrocarbons. Concurrently, the alkane recombination reaction, exemplified by C3H6+CH3(+M)⇋sC4H9(+M), is strengthened. These insights provide valuable understanding of the complex interactions and mechanisms during the explosion of hydrogen-enriched LPG in the presence of CO2, with implications for the safe application of hydrogen-enriched LPG.

Integrating experimental and machine learning approaches for predictive analysis of photocatalytic hydrogen evolution using Cu/g-C3N4

This study addresses environmental issues like global warming and wastewater generation by exploring waste-to-energy strategies that produce renewable hydrogen and treat wastewater simultaneously. Cu/g-C3N4 is used to evolve hydrogen from sucrose solution and the impact of reaction parameters such as pH (3, 5, and 7), Cu loading (5, 10, and 15 wt%), catalyst amount (0.1, 0.2, and 0.3 g/L), and oxidant (H2O2) concentration (0, 10, and 20 mM) on the evolved hydrogen amount is examined. Characterization study confirmed successful incorporation of Cu without significantly altering g-C3N4 properties. The highest hydrogen production (1979.25 μmol g−1·h−1) is achieved with 0.3 g/L catalyst, 20 mM H2O2, 5 % Cu loading, and pH 3. The experimental study concludes that Cu/g-C3N4 is an effective photocatalyst for renewable hydrogen production. In addition to the experimental investigations, various machine learning (ML) models, including Random Forest, Decision Tree, XGBoost, among others, are employed to analyze the impact of reaction parameters and forecast the quantities of produced hydrogen. Alongside these individual models, an ensemble approach is proposed and utilized. The R2 values of these ML models ranged from 0.9454 to 0.9955, indicating strong predictive performance across the board. Additionally, these models exhibited low error rates, further confirming their reliability in predicting hydrogen evolution.

Improvement of hydrogen reciprocating compressor efficiency: A novel capacity control system and its multi-objective optimization

To enhance the operational efficiency of hydrogen compressors and reduce the costs associated with the storage and transportation of hydrogen, this paper has developed a novel capacity control system (CCS). This system ensures that the compressor accurately compresses hydrogen according to actual demand, driven by an electromagnetic actuator, which simplifies the system design and enhances operational precision. To optimize the system's performance, a multi-objective optimization was conducted. Initially, a hydrogen compressor backflow working model and a comprehensive evaluation index system were established. Subsequently, a three-tier computational multi-objective optimization framework was proposed based on the working model, ultimately determining the optimal combination of key system parameters. A prototype was manufactured and subjected to validation testing and a full life cycle analysis. The results indicate that the developed system can accurately regulate the amount of compressed hydrogen within a range of 0%–100% load. Compared to traditional systems, for the same compressor group, carbon emissions and costs were reduced by 41.93% and 36.49%, respectively. The optimized design of the internal and external resistance angles and the limiter plate thickness are 11°, 16°, and 1 mm, respectively. Compared to the baseline state, the specific energy consumption of the hydrogen compressor per unit of exhaust volume has been reduced by 28.22%. Additionally, during the ejection and retraction processes of the actuator, the peak vibration impact on the hydrogen compressor has been reduced by 77.6% and 73.3%, respectively, achieving optimal comprehensive performance.

Evaluation of Hydrogen Permeation in Fretting Corrosion Interfaces with Ti-6Al-4V Alloy and Varying Lubricants Using a Modified Devanathan-Stachurski Cell

Titanium alloys are commonly used in biomedical applications for structural components such as hip femoral stems and acetabular cup shells. Whilst the fretting-corrosion degradation of titanium (Ti)-alloys has been well documented, the role of hydrogen permeation within these contacts has not received much attention despite evidence in clinical retrieval studies. This is likely due to the complexity of measurement and simulation. The aim of this study was to better understand the effect of tribological and electrochemical mechanisms on hydrogen permeation. A novel detection cell based on the Devanathan-Stachurski (DS) cell was designed to investigate hydrogen permeation in fretting corrosion contacts found in titanium-aluminum-vanadium (Ti-6Al-4V) alloy. Hydrogen permeation was found to be dependent on the amplitude of fretting displacement. Hydrogen permeation was not detected at lower amplitudes (10 and 50 μm); whereas, a significant increase in hydrogen permeation was found at 150 μm displacements. Furthermore, hydrogen permeation was found to be affected by the components of the tested physiological saline solution. Presence of hydrogen permeation was noticed in 0.9% sodium chloride (NaCl) and physiological saline combined with albumin protein. However, the amount of permeated hydrogen was reduced (38%) when hydrogen peroxide (H2O2) was added. While corrosion rate and hydrogen permeation increased (6%) significantly when both albumin and H2O2 were added to the solution. These results show that fretting induced hydrogen ingress can be simulated and detected in situ within simulated aqueous environments. Furthermore, a framework to assess the interactions between fretting and hydrogen ingress, which can be translated to other industrial challenges, has been developed.

Creating an intermediate energy band to boost the photoelectrochemical efficiency of TiO2 for solar-driven hydrogen production

The utilization of photoelectrochemical processes for hydrogen generation from water and solar energy offers a promising avenue to replace non-renewable energy sources. Nevertheless, achieving high-performance photoanode electrodes poses a significant challenge. In this study, we present the synthesis cerium and chromium-doped TiO2 (CeCrTiO2) is produced through a simple, scalable, and cost-effective hydrothermal method on a fluorine-doped tin oxide (FTO) substrate. the introduction of Ce and Cr impurities is highlighted for its role in creating an impurity band within CeCrTiO2. This impurity band is instrumental in enhancing the separation and movement of electrons and holes, contributing to the improved performance of CeCrTiO2 as a photoanode in photoelectrochemical applications. Hence, the photocurrent density value of CeCrTiO2 is 4.5 times higher than that of bare TiO2. This suggests that CeCrTiO2 exhibits improved efficiency in generating a photocurrent when exposed to light, indicating enhanced photoelectrochemical performance. The amount of hydrogen produced by CeCrTiO2 is noted to be 4.88 times greater than that of bare TiO2. This highlights the material's effectiveness in harnessing solar energy to drive the water-splitting reaction, leading to a higher yield of hydrogen gas. The synthesis of CeCrTiO2 through a hydrothermal method results in a photoanode with significantly enhanced performance, positioning it as a promising candidate for advancing photoelectrochemical processes aimed at replacing non-renewable energy sources.

A Study of Heat Recovery and Hydrogen Generation Systems for Methanol Engines

Biofuels are the most essential types of alternative fuels, which currently have significant potential to reduce CO2 emissions compared to fossil fuels. Methanol is a more efficient fuel than petrol due to its physicochemical properties, such as a higher latent heat of vaporization, research octane number, and heat of combustion of the fuel–air mixture. Also, biomethanol is cheaper than traditional petrol and diesel fuel for agricultural countries. The authors have proposed a new approach to improve the characteristics and efficiency of methanol diesel engines by using biomethanol mixed with hydrogen instead of pure biomethanol. Using a hydrogen–biomethanol mixture in modern engines is an effective method because hydrogen is a carbon-free, low-ignition, highest-flame-rate, high-octane fuel. A small quantity of hydrogen added to biomethanol and its combustion in an engine with a heat exchanger increases the combustion temperature and heat release, increases engine power, and reduces fuel consumption. This article presents experimental results of methanol combustion and a hydrogen-in-methanol mixture if hydrogen was retained due to the utilization of the heat of the exhaust gases. The tests were carried on a single-cylinder experimental engine with an injection of liquid methanol and gaseous hydrogen mixtures. The experiments showed that green hydrogen generated onboard the car due to the utilization of heat significantly reduced fuel costs of engines of vehicles and technological installations. It was established a hydrogen gaseous mixture addition of up to 5% by mass to methanol requires a corresponding change in the coefficient of excess air to λ = 1.25. Also, using an additional hydrogen mixture requires adjustment at the ignition moment in the direction of its decrease by 4–5 degrees of the engine crankshaft. Hydrogen gas mixture addition reduced methanol consumption, reaching a maximum reduction of 24%. The maximum increase in power was 30.5% based on experimental data. The reduction in the specified fuel consumption, obtained after experimental tests of the methanol research engine on the stand, can be implemented on the vehicle engines and technological installations equipped with an onboard heat recovery system. Such a system, due to the utilization of heat and the supply of additional hydrogen, can be implemented for engines that work on any alternative or traditional fuels.

Hydrodynamic simulations of white dwarf–white dwarf mergers and the origin of R Coronae Borealis stars

ABSTRACT We study the properties of double white dwarf (DWD) mergers by performing hydrodynamic simulations using the new and improved adaptive mesh refinement code octo-tiger. We follow the orbital evolution of DWD systems of mass ratio $q=0.7$ for tens of orbits until and after the merger to investigate them as a possible origin for R Coronae Borealis (RCB) type stars. We reproduce previous results, finding that during the merger, the helium WD donor star is tidally disrupted within 20–80 min since the beginning of the simulation onto the accretor carbon–oxygen WD, creating a high temperature shell around the accretor. We investigate the possible helium burning in this shell and the merged object’s general structure. Specifically, we are interested in the amount of oxygen-16 dredged-up from the accretor to the hot shell and the amount of oxygen-18 produced. This is critical as the discovery of very low oxygen-16 to oxygen-18 ratios in RCB stars pointed out the merger scenario as a favourable explanation for their origin. A small amount of hydrogen in the donor may help keep the oxygen-16 to oxygen-18 ratios within observational bounds, even if moderate dredge-up from the accretor occurs. In addition, we perform a resolution study to reconcile the difference found in the amount of oxygen-16 dredge-up between smoothed-particle hydrodynamics and grid-based simulations.

Producing aromatic‐rich oil through microwave‐assisted catalytic pyrolysis of low‐density polyethylene over Ni/Co/Cu‐doped Ga/ZSM‐5 catalysts

AbstractMicrowave (MW)‐assisted catalytic pyrolysis represents a promising method for transforming petroleum‐based plastic waste into valuable chemicals, offering a pathway towards more sustainable circular economy. In this study, catalytic pyrolysis of low‐density polyethylene (LDPE) was conducted under MW irradiation. The influence of various catalyst types (HZSM‐5, Ga/ZSM‐5, Ga/Ni/ZSM‐5, Ga/Co/ZSM‐5, and Ga/Cu/ZSM‐5) on product yield and distribution was examined. The results revealed that the Ga/ZSM‐5 catalyst yielded the maximum liquid oil, approximately 41%. Ga/Ni/ZSM‐5 performed excellently in the production of long‐chain olefins, constituting about 27% of the liquid fraction. However, Ga/Co/ZSM‐5 led to the production of heavy pyrolysis oil containing nearly 25% long‐chain paraffins, rendering it unsuitable for producing high‐value chemicals. Conversely, the Ga/Cu/ZSM‐5 catalyst yielded an aromatic‐rich pyrolysis oil, with benzene derivatives constituting approximately 90% of the liquid oil fraction, thus proving to be a suitable catalyst for the intended application. The liquid product distribution was compared with a petroleum assay by SimDist, and this suggested that utilizing the HZSM‐5 catalyst could yield an 86.4% naphtha fraction. The study also revealed that the Ga/Cu/ZSM‐5 catalyst generated the largest amounts of hydrogen and syngas, as determined by a MicroGC analysis of the gas products. This catalyst also exhibited the maximum coke deposition (1.35%) postreaction, which was attributed to its high aromatic hydrocarbon content in the pyrolysis oil and maximal hydrogen release. A comparison of fresh and spent catalyst properties was conducted to gain insights into catalyst activity and to correlate the effects of metal doping on product distribution. These findings underscore the potential of MW‐assisted catalytic pyrolysis, particularly with the Ga/Cu/ZSM‐5 catalyst, for the efficient conversion of plastic waste into valuable chemicals, thereby contributing to sustainable resource utilization and environmental conservation.

Probabilistic Analysis of Low-Emission Hydrogen Production from a Photovoltaic Carport

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.