Sergey P. Verevkin, Artemiy A. Samarov, Sergey V. Vostrikov
The reversible hydrogenation/dehydrogenation of aromatic molecules, known as liquid organic hydrogen carriers, is considered as an attractive option for the safe storage and release of elemental hydrogen. The recently reported efficient synthetic routes to obtain methoxy-biphenyls in high yield make them promising candidates for hydrogen storage. In this work, a series of methoxy-substituted biphenyls and their structural parent compounds were studied. The absolute vapour pressures were measured using the transpiration method and the enthalpies of vaporisation/sublimation were determined. We applied a step-by-step procedure including structure–property correlations and quantum chemical calculations to evaluate the quality of thermochemical data on the enthalpies of phase transitions and enthalpies of formation of the studied methoxy compounds. The data sets on thermodynamic properties were evaluated and recommended for calculations in chemical engineering. A thermodynamic analysis of chemical reactions based on methoxy-biphenyls in the context of hydrogen storage was carried out and the energetics of these reactions were compared with the energetics of reactions of common LOHCs. The influence of the position of the methoxy groups in the rings on the enthalpies of the reactions relevant for hydrogen storage was discussed.
{"title":"Thermodynamics of Reversible Hydrogen Storage: Are Methoxy-Substituted Biphenyls Better through Oxygen Functionality?","authors":"Sergey P. Verevkin, Artemiy A. Samarov, Sergey V. Vostrikov","doi":"10.3390/hydrogen4040052","DOIUrl":"https://doi.org/10.3390/hydrogen4040052","url":null,"abstract":"The reversible hydrogenation/dehydrogenation of aromatic molecules, known as liquid organic hydrogen carriers, is considered as an attractive option for the safe storage and release of elemental hydrogen. The recently reported efficient synthetic routes to obtain methoxy-biphenyls in high yield make them promising candidates for hydrogen storage. In this work, a series of methoxy-substituted biphenyls and their structural parent compounds were studied. The absolute vapour pressures were measured using the transpiration method and the enthalpies of vaporisation/sublimation were determined. We applied a step-by-step procedure including structure–property correlations and quantum chemical calculations to evaluate the quality of thermochemical data on the enthalpies of phase transitions and enthalpies of formation of the studied methoxy compounds. The data sets on thermodynamic properties were evaluated and recommended for calculations in chemical engineering. A thermodynamic analysis of chemical reactions based on methoxy-biphenyls in the context of hydrogen storage was carried out and the energetics of these reactions were compared with the energetics of reactions of common LOHCs. The influence of the position of the methoxy groups in the rings on the enthalpies of the reactions relevant for hydrogen storage was discussed.","PeriodicalId":13230,"journal":{"name":"Hydrogen","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135569497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hydrogen storage is a key enabling technology for the extensive use of hydrogen as energy carrier. This is particularly true in the widespread introduction of hydrogen in car transportation. Indeed, one of the greatest technological barriers for such development is an efficient and safe storage method. So, in this tutorial review the existing hydrogen storage technologies are described with a special emphasis on hydrogen storage in hydrogen cars: the current and the ongoing solutions. A particular focus is given on solid storage and some of the recent advances on plasma hydrogen ion implantation, which should allow not only the preparation of metal hydrides, but also the imagination of a new refluing circuit. From hydrogen discovery to its use as an energy vector in cars, this review wants to be as exhaustive as possible, introducing the basics of hydrogen storage, and discussing the experimental practicalities of car hydrogen fuel. It wants to serve as a guide for anyone wanting to undertake such a technology and to equip the reader with an advanced knowledge on hydrogen storage and hydrogen storage in hydrogen cars to stimulate further researches and yet more innovative applications for this highly interesting field.
{"title":"Hydrogen Storage as a Key Energy Vector for Car Transportation: A Tutorial Review","authors":"Marie-Charlotte Dragassi, Laurent Royon, Michaël Redolfi, Souad Ammar","doi":"10.3390/hydrogen4040051","DOIUrl":"https://doi.org/10.3390/hydrogen4040051","url":null,"abstract":"Hydrogen storage is a key enabling technology for the extensive use of hydrogen as energy carrier. This is particularly true in the widespread introduction of hydrogen in car transportation. Indeed, one of the greatest technological barriers for such development is an efficient and safe storage method. So, in this tutorial review the existing hydrogen storage technologies are described with a special emphasis on hydrogen storage in hydrogen cars: the current and the ongoing solutions. A particular focus is given on solid storage and some of the recent advances on plasma hydrogen ion implantation, which should allow not only the preparation of metal hydrides, but also the imagination of a new refluing circuit. From hydrogen discovery to its use as an energy vector in cars, this review wants to be as exhaustive as possible, introducing the basics of hydrogen storage, and discussing the experimental practicalities of car hydrogen fuel. It wants to serve as a guide for anyone wanting to undertake such a technology and to equip the reader with an advanced knowledge on hydrogen storage and hydrogen storage in hydrogen cars to stimulate further researches and yet more innovative applications for this highly interesting field.","PeriodicalId":13230,"journal":{"name":"Hydrogen","volume":"284 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135729824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Proton-conducting ceramic membranes show high hydrogen ion conductivity in the temperature range of 300–700 °C. They are attracting significant attention due to their relevant characteristics compared to both higher-temperature oxygen ion-conducting ceramic membranes and lower-temperature proton-conducting polymers. The aim of this review is to integrate the fundamentals of proton-conducting ceramic membranes with two of their relevant applications, i.e., membrane reactors (PCMRs) for methane steam reforming (SMR) and electrolysis (PCEC). Both applications facilitate the production of pure H2 in the logic of process intensification via decarbonized heat. Firstly, an overview of various types of hydrogen production is given. The fundamentals of proton-conducting ceramic membranes and their applications in PCMRs for SMR and reversible PCEC (RePCEC), respectively, are given. In particular, RePCECs are of particular interest when renewable power generation exceeds demand because the excess electrical energy is converted to chemical energy in the electrolysis cell mode, therefore representing an appealing solution for energy conversion and grid-scale storage.
{"title":"Proton-Conducting Ceramic Membranes for the Production of Hydrogen via Decarbonized Heat: Overview and Prospects","authors":"Maria Giovanna Buonomenna","doi":"10.3390/hydrogen4040050","DOIUrl":"https://doi.org/10.3390/hydrogen4040050","url":null,"abstract":"Proton-conducting ceramic membranes show high hydrogen ion conductivity in the temperature range of 300–700 °C. They are attracting significant attention due to their relevant characteristics compared to both higher-temperature oxygen ion-conducting ceramic membranes and lower-temperature proton-conducting polymers. The aim of this review is to integrate the fundamentals of proton-conducting ceramic membranes with two of their relevant applications, i.e., membrane reactors (PCMRs) for methane steam reforming (SMR) and electrolysis (PCEC). Both applications facilitate the production of pure H2 in the logic of process intensification via decarbonized heat. Firstly, an overview of various types of hydrogen production is given. The fundamentals of proton-conducting ceramic membranes and their applications in PCMRs for SMR and reversible PCEC (RePCEC), respectively, are given. In particular, RePCECs are of particular interest when renewable power generation exceeds demand because the excess electrical energy is converted to chemical energy in the electrolysis cell mode, therefore representing an appealing solution for energy conversion and grid-scale storage.","PeriodicalId":13230,"journal":{"name":"Hydrogen","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135918541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Goitom K. Gebremariam, Aleksandar Z. Jovanović, Igor A. Pašti
Amid global energy challenges, the hydrogen evolution reaction (HER) is gaining traction for green hydrogen production. While catalyst research is ongoing, recognizing electrolyte effects remains crucial for sustainable hydrogen production via renewable-powered water electrolysis. This review delves into the intricate effects of electrolytes on the kinetics of the HER. It examines key factors including the pH, cations, anions, impurities, and electrolyte concentration. This review discusses the notion that the electrolyte pH alters catalyst–electrolyte interactions and proton concentrations, thereby influencing factors such as the hydrogen binding energy, water adsorption, and overall reaction kinetics. Moreover, this review provides a briefing on the notion that electrolyte cations such as Li+ can impact the HER positively or negatively, offering opportunities for improvement based on the metal substrate. Interestingly, there is a potential that the HER can be tuned using Li+ ions to modify the M–H bond energy, demonstrating a flexibility beyond the pH levels and counter-ions. The varied adsorption energies of metal cations on metal electrodes are also found to influence the HER kinetics. The effects of electrolyte anions and impurities are also discussed, emphasizing both the positive and negative impacts on HER kinetics. Moreover, it is pointed out that the electrolyte-engineering approach enhances the HER kinetics without permanent catalyst surface modifications. This review underscores the importance of the electrolyte composition, highlighting both the challenges and potential solutions in advancing HER research for sustainable energy production.
{"title":"The Effect of Electrolytes on the Kinetics of the Hydrogen Evolution Reaction","authors":"Goitom K. Gebremariam, Aleksandar Z. Jovanović, Igor A. Pašti","doi":"10.3390/hydrogen4040049","DOIUrl":"https://doi.org/10.3390/hydrogen4040049","url":null,"abstract":"Amid global energy challenges, the hydrogen evolution reaction (HER) is gaining traction for green hydrogen production. While catalyst research is ongoing, recognizing electrolyte effects remains crucial for sustainable hydrogen production via renewable-powered water electrolysis. This review delves into the intricate effects of electrolytes on the kinetics of the HER. It examines key factors including the pH, cations, anions, impurities, and electrolyte concentration. This review discusses the notion that the electrolyte pH alters catalyst–electrolyte interactions and proton concentrations, thereby influencing factors such as the hydrogen binding energy, water adsorption, and overall reaction kinetics. Moreover, this review provides a briefing on the notion that electrolyte cations such as Li+ can impact the HER positively or negatively, offering opportunities for improvement based on the metal substrate. Interestingly, there is a potential that the HER can be tuned using Li+ ions to modify the M–H bond energy, demonstrating a flexibility beyond the pH levels and counter-ions. The varied adsorption energies of metal cations on metal electrodes are also found to influence the HER kinetics. The effects of electrolyte anions and impurities are also discussed, emphasizing both the positive and negative impacts on HER kinetics. Moreover, it is pointed out that the electrolyte-engineering approach enhances the HER kinetics without permanent catalyst surface modifications. This review underscores the importance of the electrolyte composition, highlighting both the challenges and potential solutions in advancing HER research for sustainable energy production.","PeriodicalId":13230,"journal":{"name":"Hydrogen","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135855292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Olga Kanz, Karsten Bittkau, Kaining Ding, Uwe Rau, Angèle Reinders
The global interest in hydrogen as an energy carrier is steadily increasing. In this study, multiple scenarios of liquid hydrogen exports from Africa to Germany are analyzed by life cycle assessment (LCA) to quantify the global warming potential (GWP) of 1 kg hydrogen. The investigation is driven by the promise that hydrogen can be sustainably and economically produced by photovoltaic (PV)-powered electrolysis in Africa, benefiting from the geographical location near the equator and, consequently, higher solar irradiation levels. Given the absence of a pipeline network, shipping hydrogen emerges as the most efficient short-term transportation option to Germany. In this paper, supply locations—Morocco, Senegal, and Nigeria—are evaluated by means of an LCA and compared to hydrogen supply from Germany. Results show that emissions from hydrogen production and transportation by ship from Morocco range from 3.32 to 3.41 kgCO2-eq/kgH2. From Senegal, the range is 3.88 to 3.99 kgCO2eq/kgH2, and from Nigeria, it falls between 4.38 and 4.27 kgCO2-eq/kgH2. These emission levels are influenced by factors such as the GWP of PV electricity, the efficiency of the electrolyzer, and the transportation distance. Interestingly, the analysis reveals that PV-powered electrolysis of hydrogen in Germany, including 300 km distribution, causes, in most scenarios, a lower GWP in the range of 3.48 to 3.61 kgCO2-eq/kgH2 than hydrogen from the analyzed African regions. Opting for grid electricity instead of PV (with a value of 0.420 kgCO2-eq/kWh) for hydrogen production in Germany yields a GWP ranging from 24.35 to 25.42 kgCO2-eq/kgH2. Hence, we can conclude that in any event, PV-powered hydrogen electrolysis has a low environmental impact not only within Africa but also in Germany. However, it is crucial to carefully consider the balance of the GWP of production versus transportation given the distance between a hydrogen production site and the location of consumption.
{"title":"Life Cycle Global Warming Impact of Long-Distance Liquid Hydrogen Transport from Africa to Germany","authors":"Olga Kanz, Karsten Bittkau, Kaining Ding, Uwe Rau, Angèle Reinders","doi":"10.3390/hydrogen4040048","DOIUrl":"https://doi.org/10.3390/hydrogen4040048","url":null,"abstract":"The global interest in hydrogen as an energy carrier is steadily increasing. In this study, multiple scenarios of liquid hydrogen exports from Africa to Germany are analyzed by life cycle assessment (LCA) to quantify the global warming potential (GWP) of 1 kg hydrogen. The investigation is driven by the promise that hydrogen can be sustainably and economically produced by photovoltaic (PV)-powered electrolysis in Africa, benefiting from the geographical location near the equator and, consequently, higher solar irradiation levels. Given the absence of a pipeline network, shipping hydrogen emerges as the most efficient short-term transportation option to Germany. In this paper, supply locations—Morocco, Senegal, and Nigeria—are evaluated by means of an LCA and compared to hydrogen supply from Germany. Results show that emissions from hydrogen production and transportation by ship from Morocco range from 3.32 to 3.41 kgCO2-eq/kgH2. From Senegal, the range is 3.88 to 3.99 kgCO2eq/kgH2, and from Nigeria, it falls between 4.38 and 4.27 kgCO2-eq/kgH2. These emission levels are influenced by factors such as the GWP of PV electricity, the efficiency of the electrolyzer, and the transportation distance. Interestingly, the analysis reveals that PV-powered electrolysis of hydrogen in Germany, including 300 km distribution, causes, in most scenarios, a lower GWP in the range of 3.48 to 3.61 kgCO2-eq/kgH2 than hydrogen from the analyzed African regions. Opting for grid electricity instead of PV (with a value of 0.420 kgCO2-eq/kWh) for hydrogen production in Germany yields a GWP ranging from 24.35 to 25.42 kgCO2-eq/kgH2. Hence, we can conclude that in any event, PV-powered hydrogen electrolysis has a low environmental impact not only within Africa but also in Germany. However, it is crucial to carefully consider the balance of the GWP of production versus transportation given the distance between a hydrogen production site and the location of consumption.","PeriodicalId":13230,"journal":{"name":"Hydrogen","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135251441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grace Russell, Adam D. Thomas, Alexander Nenov, Georgia Mannings, John T. Hancock
Cancer is a leading cause of mortality worldwide. B-cells are a keystone of the adaptive immune response and are essential for the presentation of tumor-associated antigens to various types of T-cells. Approximately 1.5% of global cancer cases, including breast and gastric carcinomas and both Hodgkin’s and non-Hodgkin’s lymphomas, are linked with prior Epstein–Barr Virus (EBV) infection. Such properties make EBV-infected lymphocytes ideal models for understanding the effect of oxyhydrogen gas on dysfunctional cell cycling. The aim of this study is to assess the effects of the direct infusion of oxyhydrogen gas on the replicative capacity of EBV-immortalised B-lymphocytes. Oxyhydrogen gas was directly infused into cell culture media. Cells were incubated in 95% air and 5% CO2 for up to 72 h. Cell enumeration was assessed with and without the addition of mitogenic growth stimuli, and subsequent cell-cycle analysis was performed. Cell enumeration: An initial trend of replicative inhibition of TK6 cells is noted with a single oxyhydrogen treatment at the 24 and 48 h time points. The daily addition of oxyhydrogen-infused media showed statistically relevant data at 24 and 48 h but not at 72 h. In mitogen-stimulated cells, a non-statistical trend of inhibition was observed at 24, 48 and 72 h. Analysis details a significant increase in DNA in the Sub G1 phase, indicating increased apoptosis.
{"title":"The Therapeutic Potential of Oxyhydrogen Gas in Oncology: A Study on Epstein–Barr Virus-Immortalised B-Lymphoblastoid (TK6) Cells","authors":"Grace Russell, Adam D. Thomas, Alexander Nenov, Georgia Mannings, John T. Hancock","doi":"10.3390/hydrogen4040047","DOIUrl":"https://doi.org/10.3390/hydrogen4040047","url":null,"abstract":"Cancer is a leading cause of mortality worldwide. B-cells are a keystone of the adaptive immune response and are essential for the presentation of tumor-associated antigens to various types of T-cells. Approximately 1.5% of global cancer cases, including breast and gastric carcinomas and both Hodgkin’s and non-Hodgkin’s lymphomas, are linked with prior Epstein–Barr Virus (EBV) infection. Such properties make EBV-infected lymphocytes ideal models for understanding the effect of oxyhydrogen gas on dysfunctional cell cycling. The aim of this study is to assess the effects of the direct infusion of oxyhydrogen gas on the replicative capacity of EBV-immortalised B-lymphocytes. Oxyhydrogen gas was directly infused into cell culture media. Cells were incubated in 95% air and 5% CO2 for up to 72 h. Cell enumeration was assessed with and without the addition of mitogenic growth stimuli, and subsequent cell-cycle analysis was performed. Cell enumeration: An initial trend of replicative inhibition of TK6 cells is noted with a single oxyhydrogen treatment at the 24 and 48 h time points. The daily addition of oxyhydrogen-infused media showed statistically relevant data at 24 and 48 h but not at 72 h. In mitogen-stimulated cells, a non-statistical trend of inhibition was observed at 24, 48 and 72 h. Analysis details a significant increase in DNA in the Sub G1 phase, indicating increased apoptosis.","PeriodicalId":13230,"journal":{"name":"Hydrogen","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135591383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luís Carmo-Calado, Manuel Jesús Hermoso-Orzáez, Daniel Diaz-Perete, José La Cal-Herrera, Paulo Brito, Julio Terrados-Cepeda
The present study compares the performance of bubbling-bed updraft and a fixed-bed downdraft gasification systems for producing hydrogen-rich (H2) syngas from olive pomace on a semi-industrial scale. The focus is on examining the effects of temperature and efficiency ratio (ER) on the composition, low heat value (LHV), carbon conversion efficiency (CCE), and cold gas efficiency (CGE) of the produced syngas. The results presented for the fixed bed show the concentration of H2 (15.6–16.52%), CGE (58.99–66.80%), CCE (69.07–71.86%), and LHV (4.82–5.70 MJ/Nm3). The CGE reaches a maximum of 66.80% at a temperature of 700 °C and an ER of 0.20, while the syngas yield (2.35 Nm3/kg) presents a maximum at a temperature 800 °C and an ER of 0.21, with a tendency to decrease with the increase in the temperature. For the bubbling fluidized bed, results were shown for the concentration of H2 (12.54–12.97%), CGE (70.48–89.51%), CCE (75.83–78.49%), and LHV (6.10–6.93 MJ/Nm3), where, at a temperature of 700 °C and an ER of 0.23, the CGE is 89.51% and the LHV is 6.93 MJ/Nm3, with a tendency to decrease with the increase in the temperature, while the maximum syngas yield (2.52 Nm3/kg) occurs at a temperature of 800 °C and an ER of 0.23. Comparing the two gasification processes, the fixed bed has a higher concentration of H2 at all the temperatures and ERs of the experiments; however, the bubbling fluidized bed has a higher CGE. These findings have implications for applications involving syngas, such as energy production and chemical synthesis, and can guide process optimization and enhance energy efficiency. The information obtained can also contribute to emission mitigation strategies and improvements in syngas-based synthesis reactors.
{"title":"Experimental Research on the Production of Hydrogen-Rich Synthesis Gas via the Air-Gasification of Olive Pomace: A Comparison between an Updraft Bubbling Bed and a Downdraft Fixed Bed","authors":"Luís Carmo-Calado, Manuel Jesús Hermoso-Orzáez, Daniel Diaz-Perete, José La Cal-Herrera, Paulo Brito, Julio Terrados-Cepeda","doi":"10.3390/hydrogen4040046","DOIUrl":"https://doi.org/10.3390/hydrogen4040046","url":null,"abstract":"The present study compares the performance of bubbling-bed updraft and a fixed-bed downdraft gasification systems for producing hydrogen-rich (H2) syngas from olive pomace on a semi-industrial scale. The focus is on examining the effects of temperature and efficiency ratio (ER) on the composition, low heat value (LHV), carbon conversion efficiency (CCE), and cold gas efficiency (CGE) of the produced syngas. The results presented for the fixed bed show the concentration of H2 (15.6–16.52%), CGE (58.99–66.80%), CCE (69.07–71.86%), and LHV (4.82–5.70 MJ/Nm3). The CGE reaches a maximum of 66.80% at a temperature of 700 °C and an ER of 0.20, while the syngas yield (2.35 Nm3/kg) presents a maximum at a temperature 800 °C and an ER of 0.21, with a tendency to decrease with the increase in the temperature. For the bubbling fluidized bed, results were shown for the concentration of H2 (12.54–12.97%), CGE (70.48–89.51%), CCE (75.83–78.49%), and LHV (6.10–6.93 MJ/Nm3), where, at a temperature of 700 °C and an ER of 0.23, the CGE is 89.51% and the LHV is 6.93 MJ/Nm3, with a tendency to decrease with the increase in the temperature, while the maximum syngas yield (2.52 Nm3/kg) occurs at a temperature of 800 °C and an ER of 0.23. Comparing the two gasification processes, the fixed bed has a higher concentration of H2 at all the temperatures and ERs of the experiments; however, the bubbling fluidized bed has a higher CGE. These findings have implications for applications involving syngas, such as energy production and chemical synthesis, and can guide process optimization and enhance energy efficiency. The information obtained can also contribute to emission mitigation strategies and improvements in syngas-based synthesis reactors.","PeriodicalId":13230,"journal":{"name":"Hydrogen","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135459214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
During severe accidents in light-water nuclear reactors, the release of hydrogen poses significant risks to the integrity of the containment and the surrounding infrastructure. To address this, passive autocatalytic re-combiners (PARs) have been adopted in several countries. However, it remains challenging to eliminate the production of flammable combinations and the potential for local flame explosions, even with PARs installed. Understanding the distribution and concentration of generated hydrogen, particularly in 100% fuel-clad coolant reactions, is therefore crucial. In this study, numerical investigations using ANSYS CFX, a commercially available code, are conducted to analyze the hydrogen generation and distribution in a 1000 MWe nuclear power plant. The results show the effectiveness of PARs through a comparative evaluation of reactors with PARs and without PARs installed. The simulated scenario involved the release of hydrogen from the reactor pressure vessel, resulting in a reduction in the maximum hydrogen concentration released from 17.85% in the containment model without PARs to 9.72% in the containment model with PARs installed after 22,000 s. These findings highlight the importance of understanding and controlling the hydrogen distribution in light-water nuclear reactors during severe accidents. This study is useful in informing the mitigation risks strategy for hydrogen release in light-water nuclear reactors.
{"title":"Mitigating Hydrogen Risks in Light-Water Nuclear Reactors: A CFD Simulation of the Distribution and Concentration","authors":"Joseph Amponsah, Archibong Archibong-Eso","doi":"10.3390/hydrogen4040045","DOIUrl":"https://doi.org/10.3390/hydrogen4040045","url":null,"abstract":"During severe accidents in light-water nuclear reactors, the release of hydrogen poses significant risks to the integrity of the containment and the surrounding infrastructure. To address this, passive autocatalytic re-combiners (PARs) have been adopted in several countries. However, it remains challenging to eliminate the production of flammable combinations and the potential for local flame explosions, even with PARs installed. Understanding the distribution and concentration of generated hydrogen, particularly in 100% fuel-clad coolant reactions, is therefore crucial. In this study, numerical investigations using ANSYS CFX, a commercially available code, are conducted to analyze the hydrogen generation and distribution in a 1000 MWe nuclear power plant. The results show the effectiveness of PARs through a comparative evaluation of reactors with PARs and without PARs installed. The simulated scenario involved the release of hydrogen from the reactor pressure vessel, resulting in a reduction in the maximum hydrogen concentration released from 17.85% in the containment model without PARs to 9.72% in the containment model with PARs installed after 22,000 s. These findings highlight the importance of understanding and controlling the hydrogen distribution in light-water nuclear reactors during severe accidents. This study is useful in informing the mitigation risks strategy for hydrogen release in light-water nuclear reactors.","PeriodicalId":13230,"journal":{"name":"Hydrogen","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136098865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work introduces state-of-the-art water detritiation processes and discusses the main technologies and materials adopted. Focus is given to the gas chromatography (GC) and the thermal cycling absorption process (TCAP), which are studied as potential back-end technologies for tritium recovery through a water detritiation system designed for a small-scale unit. GC and the TCAP are evaluated critically in order to establish their applicability for the final purification of the DT stream recovered at the bottom of the cryo-distillation column of a water detritiation unit. Both solutions (GC and the TCAP with an inverse column) exhibit safe and feasible operation modes and are characterised by a good technological level; furthermore, both of these processes meet the main design specifications required by the proposed application. However, the use of GC is preferred, since this system can operate with modest temperature cycling and producing streams (D2 and T2) of better purity.
{"title":"Gas Chromatography and Thermal Cycling Absorption Techniques for Hydrogen Isotopes Separation in Water Detritiation Systems","authors":"Silvano Tosti","doi":"10.3390/hydrogen4030044","DOIUrl":"https://doi.org/10.3390/hydrogen4030044","url":null,"abstract":"This work introduces state-of-the-art water detritiation processes and discusses the main technologies and materials adopted. Focus is given to the gas chromatography (GC) and the thermal cycling absorption process (TCAP), which are studied as potential back-end technologies for tritium recovery through a water detritiation system designed for a small-scale unit. GC and the TCAP are evaluated critically in order to establish their applicability for the final purification of the DT stream recovered at the bottom of the cryo-distillation column of a water detritiation unit. Both solutions (GC and the TCAP with an inverse column) exhibit safe and feasible operation modes and are characterised by a good technological level; furthermore, both of these processes meet the main design specifications required by the proposed application. However, the use of GC is preferred, since this system can operate with modest temperature cycling and producing streams (D2 and T2) of better purity.","PeriodicalId":13230,"journal":{"name":"Hydrogen","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136236417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Considering the clean, renewable, and ecologically friendly characteristics of hydrogen gas, as well as its high energy density, hydrogen energy is thought to be the most potent contender to locally replace fossil fuels. The creation of a sustainable energy system is currently one of the critical industrial challenges, and electrocatalytic hydrogen evolution associated with appropriate safe storage techniques are key strategies to implement systems based on hydrogen technologies. The recent progress made possible through nanotechnology incorporation, either in terms of innovative methods of hydrogen storage or production methods, is a guarantee of future breakthroughs in energy sustainability. This manuscript addresses concisely and originally the importance of including nanotechnology in both green electroproduction of hydrogen and hydrogen storage in solid media. This work is mainly focused on these issues and eventually intends to change beliefs that hydrogen technologies are being imposed only for reasons of sustainability and not for the intrinsic value of the technology itself. Moreover, nanophysics and nano-engineering have the potential to significantly change the paradigm of conventional hydrogen technologies.
{"title":"A Brief on Nano-Based Hydrogen Energy Transition","authors":"Rui F. M. Lobo","doi":"10.3390/hydrogen4030043","DOIUrl":"https://doi.org/10.3390/hydrogen4030043","url":null,"abstract":"Considering the clean, renewable, and ecologically friendly characteristics of hydrogen gas, as well as its high energy density, hydrogen energy is thought to be the most potent contender to locally replace fossil fuels. The creation of a sustainable energy system is currently one of the critical industrial challenges, and electrocatalytic hydrogen evolution associated with appropriate safe storage techniques are key strategies to implement systems based on hydrogen technologies. The recent progress made possible through nanotechnology incorporation, either in terms of innovative methods of hydrogen storage or production methods, is a guarantee of future breakthroughs in energy sustainability. This manuscript addresses concisely and originally the importance of including nanotechnology in both green electroproduction of hydrogen and hydrogen storage in solid media. This work is mainly focused on these issues and eventually intends to change beliefs that hydrogen technologies are being imposed only for reasons of sustainability and not for the intrinsic value of the technology itself. Moreover, nanophysics and nano-engineering have the potential to significantly change the paradigm of conventional hydrogen technologies.","PeriodicalId":13230,"journal":{"name":"Hydrogen","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135827807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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