Topic Editors

Department of Innovation Engineering, University of Salento, Via per Arnesano 73100 Lecce, Italy
Department of Mechanical and Product Design Engineering, Swinburne University of Technology, Hawthorn, VIC 3122, Australia

Hydrogen—The New Energy Vector for the Transition of Industries "Hard to Abate"

Abstract submission deadline
31 May 2024
Manuscript submission deadline
31 August 2024
Viewed by
10669

Topic Information

Dear Colleagues,

The industrial sector accounts for the largest share of global energy consumption. Given a continuously increasing demand for industrial products, the key for industrial decarbonization is decoupling its production from the produced CO2 emissions. The replacement of traditional energy production based on carbon sources with renewables is insufficient for the inversion of global warming. A major transformation and redesign of the global energy system is required towards decarbonisation and to achieve the Paris Agreement targets. This Grand transition is a complex and pressing issue, where global joint efforts and system solutions are essential; with hydrogen being one of them.

The present Topic aims to describe hydrogen properties as crucial energy vectors of the future. Present hydrogen production routes and methods of utilization will be underlined. Hydrogen will become a crucial energy vector and the other leg of the energy transition alongside renewable electricity by replacing coal, oil, gas, and conventional hydrogen across different segments of the economy. As an energy carrier, hydrogen’s versatility will be underlined as a key actor in decarbonization. Its energy storage capability during renewable production peaks is a crucial factor of its potential introduction in many civil and industrial sectors. Obviously, this depends on its “color”, which influences the new acceptability because of the major or minor weight of traditional carbon sources. As a matter of fact, the largest amount of attention will be devoted at the so called “green hydrogen” production route, which is based on renewables or on carbon-free power sources. Among the main civil and industrial applications, the role of hydrogen for the “hard to abate” industry decarbonization will be largely emphasized.

Hydrogen storage in innovative materials will be reviewed as a great solution for large scale production. In the present issue, the production routes based on hydrocarbons or clean sources will be also reviewed and compared. The properties of hydrogen as an energy carrier that is useful for the efficient reduction of iron ores will be described in the present issue. The basic mechanisms related to the direct reduction of iron ores through hydrogen will be detailed and analyzed. The kinetic analysis of hydrogen metallurgy in a wide range of conditions will be reviewed. Thermodynamic analysis in various gas mixture conditions employed during iron ore reduction will be detailed. A large amount of attention will be devoted to the energy efficiency of the reduction processes as a function of the different reducing gases that are employed. All of the previous factors will be described from the macro to the atomic scale.

The hydrogen production from non-renewable sources continues to grow all around the world because of the continuous need for such energetic vectors in modern industry. The decomposition of basic hydrocarbons for t hydrogen synthesis will be described in the present issue. First of all, the coal gasification procedure and reactors will be reviewed. Steam reforming and syngas production will be described in depth. The process performance will be analyzed and compared to those belonging to traditional conventional routes.

The decarbonization of human activities requires that hydrogen be produced through sustainable routes. One of the most promising ways to achieve this is through the electrolysis of water with the energy sources provided by renewables. The main available technologies that are available for hydrogen production through electrolysis will be reviewed in the present issue. The fundamentals of water electrolysis will be described. The problematics related to the desalinization and purification of sea water for its employment in water electrolyzers will be described. The fundamental aspects related to the choice of high-temperature or low-temperature technologies will be analyzed. The key aspects of the integration of water electrolysis with renewable sources will be discussed.

Hydrogen production and storage are the main issues related to its large-scale utilization. The large-scale implementation of water electrolysis for the production of green H2 has mainly been hampered by cost issues. In the present issue, the main costs issues that are related to the hydrogen economy transition will be analyzed. The fundamental aspects of hydrogen production costs by each route will be highlighted. The forecasts related to new energy solutions for hydrogen production will be analyzed. The economic issues related to hydrogen production to direct reduction reactors will be underlined.

Prof. Dr. Pasquale Cavaliere
Prof. Dr. Geoffrey Brooks
Topic Editors

Keywords

  • global warming
  • energy
  • CO2 emissions
  • energy transition
  • hydrogen
  • renewables
  • decarbonization
  • steel industry
  • hydrogen storage
  • energy carrier
  • hydrogen "color"
  • iron ores reduction
  • hydrogen reduction
  • energy efficiency
  • non-renewable sources

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Energies
energies
3.2 5.5 2008 16.1 Days CHF 2600 Submit
Materials
materials
3.4 5.2 2008 13.9 Days CHF 2600 Submit
Catalysts
catalysts
3.9 6.3 2011 14.3 Days CHF 2700 Submit
Metals
metals
2.9 4.4 2011 15 Days CHF 2600 Submit
Hydrogen
hydrogen
- - 2020 14.4 Days CHF 1000 Submit

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Published Papers (7 papers)

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16 pages, 9331 KiB  
Article
In-Situ Hydrogen Charging Effect on the Fracture Behaviour of 42CrMo4 Steel Submitted to Various Quenched and Tempering Heat Treatments
by Atif Imdad and Francisco Javier Belzunce Varela
Hydrogen 2023, 4(4), 1035-1050; https://doi.org/10.3390/hydrogen4040060 - 11 Dec 2023
Viewed by 741
Abstract
Research into safer, durable steels to be used in hydrogen-rich environments has been gaining importance in recent years. In this work, 42CrMo4 steel was subjected to quenched and tempered heat treatments using different temperature and time durations, in order to obtain different tempered [...] Read more.
Research into safer, durable steels to be used in hydrogen-rich environments has been gaining importance in recent years. In this work, 42CrMo4 steel was subjected to quenched and tempered heat treatments using different temperature and time durations, in order to obtain different tempered martensite microstructures. Tensile tests on smooth and notched specimens were then performed in the air as well as with in situ electrochemical hydrogen charging using two different hydrogenated conditions. The harmful effects of hydrogen are more evident in tensile tests performed on notched specimens. The harder (stronger) the steel, the more hydrogen embrittlement occurs. As the steel’s internal local hydrogen concentration rises, its strength must be gradually reduced in order to choose the best steel. The observed embrittlement differences are explained by modifications in the operative failure micromechanisms. These change from ductile (microvoid coalescence) in the absence of hydrogen, or under low hydrogen levels in the case of the softest steels, to brittle (cleavage or even intergranular fracture) under the most severe conditions. Full article
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11 pages, 4131 KiB  
Article
Comparison of Microstructures of Magnetite Reduced by H2 and CO under Microwave Field
by Meijie Zhou, Liqun Ai, Lukuo Hong, Caijiao Sun, Yipang Yuan and Shuai Tong
Metals 2023, 13(8), 1367; https://doi.org/10.3390/met13081367 - 29 Jul 2023
Cited by 1 | Viewed by 775
Abstract
The reduction of magnetite in H2 and CO atmospheres was compared using a microwave-heating technique. The reduction of magnetite in a mixed H2 + CO atmosphere was compared with respect to the effects of a microwave field and a conventional field. [...] Read more.
The reduction of magnetite in H2 and CO atmospheres was compared using a microwave-heating technique. The reduction of magnetite in a mixed H2 + CO atmosphere was compared with respect to the effects of a microwave field and a conventional field. Microstructural changes were observed using an electron microscope. The results show that the metallization rate and reduction degree of the H2-reduced magnetite are much higher than those of the magnetite reduced by CO at 900–1100 ℃. The Fe phase generated by H2 reduction forms a cavity structure, and the Fe phase generated by CO reduction forms a dense block. Under conventional heating conditions, the higher the H2 content in a pure CO atmosphere, the better the reduction effect. Under the effect of a microwave field, the atmosphere with the highest reduction rate was 50% H2 + 50% CO. Compared with conventional heating, the bubble holes formed by reduced iron in microwave field are larger under the same conditions. Full article
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20 pages, 2643 KiB  
Article
NOx Emission Limits in a Fuel-Flexible and Defossilized Industry—Quo Vadis?
by Nico Schmitz, Lukas Sankowski, Elsa Busson, Thomas Echterhof and Herbert Pfeifer
Energies 2023, 16(15), 5663; https://doi.org/10.3390/en16155663 - 27 Jul 2023
Viewed by 1578
Abstract
The reduction of CO2 emissions in hard-to-abate industries is described in several proposals on the European and National levels. In order to meet the defined goals, the utilization of sustainable, non-fossil fuels for process heat generation in industrial furnaces needs to [...] Read more.
The reduction of CO2 emissions in hard-to-abate industries is described in several proposals on the European and National levels. In order to meet the defined goals, the utilization of sustainable, non-fossil fuels for process heat generation in industrial furnaces needs to be intensified. The focus mainly lies on hydrogen (H2) and its derivates. Furthermore, biofuels, e.g., dimethyl ether (DME), are considered. Besides possible changes in the process itself when substituting natural gas (NG) with alternative fuels, the emission of nitrogen oxides (NOx) is a major topic of interest. In current European standards and regulations, the NOx emissions are specified in mg per m3 of dry off-gas and refer to a reference oxygen concentration. Within this study, this limit specification is investigated for its suitability for the use of various fuel-oxidizer combinations in industrial combustion applications. Natural gas is used as a reference, while hydrogen and DME are considered sustainable alternatives. Air and pure oxygen (O2) are considered oxidizers. It is shown that the current specification, which is built on the use of fossil fuels, leads to non-comparable values for alternative fuels. Therefore, alternative NOx limit definitions are discussed in detail. The most suitable alternative was found to be mg per kWh. This limit specification is finally being investigated for its compliance with current regulations on various aspects of Continuous Emission Monitoring Systems. Full article
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20 pages, 22980 KiB  
Article
Kinetics Study on the Hydrogen Reduction of Bauxite Residue-Calcite Sintered Pellets at Elevated Temperature
by Manish Kumar Kar, Casper van der Eijk and Jafar Safarian
Metals 2023, 13(4), 644; https://doi.org/10.3390/met13040644 - 23 Mar 2023
Cited by 1 | Viewed by 1231
Abstract
In this study, the isothermal reduction of bauxite residue-calcite sintered pellets by hydrogen at elevated temperatures and different gas flow rates was investigated. A thermogravimetric technique was applied to study the kinetics of the direct reduction by H2 at 500–1000 °C. It [...] Read more.
In this study, the isothermal reduction of bauxite residue-calcite sintered pellets by hydrogen at elevated temperatures and different gas flow rates was investigated. A thermogravimetric technique was applied to study the kinetics of the direct reduction by H2 at 500–1000 °C. It was observed that iron in sintered oxide pellets mainly exists in the form of brownmillerite, srebrodolskite and fayalite. The reduction of brownmillerite, the dominant Fe-containing phase, with hydrogen produces mayenite, calcite and metallic iron. X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence (XRF), BET surface area, pycnometer and mercury intrusion porosimeter analyses were adopted on reduced pellets to interpret the experimental results. The order of the reduction process changes from first-order reaction kinetics to second-order with an increasing reduction temperature. The change in reaction order may be due to sintering at higher reduction temperatures and corresponding physical and microstructural changes in pellets. The activation energy of reduction was calculated as 55.1–96.6 kJ/mol based on the experimental conditions and using different kinetic model equations. From the experimental observations, it was found that 1000 °C with 60 min is the most suitable condition for bauxite residue-CaO sintered pellets’ reduction with hydrogen. Full article
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18 pages, 6405 KiB  
Article
Characterization, Calcination and Pre-Reduction of Polymetallic Manganese Nodules by Hydrogen and Methane
by Ole Kristian Brustad, Jonas Låstad, Arman Hoseinpur and Jafar Safarian
Metals 2022, 12(12), 2013; https://doi.org/10.3390/met12122013 - 24 Nov 2022
Cited by 1 | Viewed by 1205
Abstract
A polymetallic manganese nodule was characterized and further calcined and pre-reduced by H2, CH4, and H2-CH4 mixtures at elevated temperatures. It was found that the main Mn and Fe elements coexisted in the ore in different [...] Read more.
A polymetallic manganese nodule was characterized and further calcined and pre-reduced by H2, CH4, and H2-CH4 mixtures at elevated temperatures. It was found that the main Mn and Fe elements coexisted in the ore in different minerals, and the Mn/Fe ratio varies in the ore. Moreover, Cu, Ni and Co are distributed with Mn and Fe, and no known minerals of these elements were identified. The calcination of the ore was carried out through calcination in air in a muffle furnace, and under Ar in a thermogravimetry (TG) furnace. It was found that manganese and iron oxides are evolved from a variety of oxide and hydroxides in the ore during calcination. The pre-reduction of the calcined ore particles by H2 gas in the TG furnace indicated fast reduction by hydrogen. The pre-reduction of the calcined ore by H2, CH4, and H2-CH4 mixtures in a stationary bed reactor and further characterization of the products indicated the same products. It was found that the pre-reduction by all the applied gases at elevated temperatures yield a pre-reduced ore that contains metallic Fe, Cu, Ni, and Co, while MnO co-exist as the dominant phase. Full article
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17 pages, 6885 KiB  
Article
Isothermal Hydrogen Reduction of a Lime-Added Bauxite Residue Agglomerate at Elevated Temperatures for Iron and Alumina Recovery
by Olivia Bogen Skibelid, Sander Ose Velle, Frida Vollan, Casper Van der Eijk, Arman Hoseinpur-Kermani and Jafar Safarian
Materials 2022, 15(17), 6012; https://doi.org/10.3390/ma15176012 - 31 Aug 2022
Cited by 9 | Viewed by 1666
Abstract
The hydrogen reduction of bauxite residue lime pellets at elevated temperatures was carried out to recover iron and alumina from the bauxite residue in a new process route. Prior to the H2 reduction, oxide pellets were initially prepared via the mixing of [...] Read more.
The hydrogen reduction of bauxite residue lime pellets at elevated temperatures was carried out to recover iron and alumina from the bauxite residue in a new process route. Prior to the H2 reduction, oxide pellets were initially prepared via the mixing of an industrial bauxite residue with fine calcite powder followed by calcination and high-temperature sintering. The chemical, compositional, and microstructural properties of both oxide and reduced pellets were studied by advanced characterization techniques. It was found that iron in the oxide pellets is mainly in the form of brownmillerite, and calcium–iron–titanate phases, while upon reduction they are converted to wüstite and shulamitite intermediate phases and further to metallic iron. Moreover, it was found that the reduction at lower temperature of 1000 °C is faster than that at higher temperatures of 1100 °C and 1200 °C. The slower rate and extent of reduction at the higher temperatures is attributed to the porosity loss and reduction mechanism change to a diffusion-controlled process step. In addition, it was found that Al-containing phases in the raw materials are converted mainly to gehlenite in sintered pellets and further to the leachable mayenite phase. The alkaline leaching of selected reduced pellets by a sodium carbonate solution yielded up to 87% Al recovery into the solution, while the metallic iron was not affected. Full article
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18 pages, 10287 KiB  
Article
Metal Mesh and Narrow Band Gap Mn0.5Cd0.5S Photocatalyst Cooperation for Efficient Hydrogen Production
by Haifeng Zhu, Renjie Ding, Xinle Dou, Jiashun Zhou, Huihua Luo, Lijie Duan, Yaping Zhang and Lianqing Yu
Materials 2022, 15(17), 5861; https://doi.org/10.3390/ma15175861 - 25 Aug 2022
Cited by 5 | Viewed by 1484
Abstract
A novel co-catalyst system under visible-light irradiation was constructed using high-purity metal and alloy mesh and a Mn0.5Cd0.5S photocatalyst with a narrow band gap (1.91 eV) prepared by hydrothermal synthesis. The hydrogen production rate of Mn0.5Cd0.5 [...] Read more.
A novel co-catalyst system under visible-light irradiation was constructed using high-purity metal and alloy mesh and a Mn0.5Cd0.5S photocatalyst with a narrow band gap (1.91 eV) prepared by hydrothermal synthesis. The hydrogen production rate of Mn0.5Cd0.5S changed from 2.21 to 6.63 mmol·(g·h)−1 with the amount of thioacetamide, which was used as the sulphur source. The introduction of Ag, Mo, Ni, Cu, and Cu–Ni alloy meshes efficiently improved the H2 production rate of the co-catalyst system, especially for the Ni mesh. The improvement can reach an approximately six times greater production, with the highest H2 production rate being 37.65 mmol·(g·h)−1. The results showed that some bulk non-noble metal meshes can act as good or better than some noble metal nanoparticles deposited on the main photocatalyst for H2 evolution due to the promotion of photoinduced electron transfer, increase in redox reaction sites, and prevention of the recombination of carriers. Full article
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