Production of ultra-dense hydrogen H(0): A novel nuclear fuel

Condensation of hydrogen Rydberg atoms (highly electronically excited) into the lowest energy state of condensed hydrogen i.e. the ultra-dense hydrogen phase, H(0), has gained increased attention not only from the fundamental aspects but also from the applied point of view. The physical properties of ultra-dense hydrogen H(0) were recently reviewed (Physica Scripta 2019 https://doi.org/10.1088/1402-4896/ab1276), summarizing the results reported in 50 publications during the last ten years. The main application of H(0) so far is as the fuel and working medium in nuclear particle generators and nuclear fusion reactors which are under commercial development. The first fusion process showing sustained operation above break-even was published in 2015 (AIP Advances) and used ultra-dense deuterium D(0) as fuel. The first generator giving a high-intensity muon flux intended for muon-catalyzed fusion reactors was patented in 2017, using H(0) as the working medium. Here, we first focus on the different nuclear processes using hydrogen isotopes for energy generation, and then on the detailed processes of formation of H(0). The production of H(0) employs heterogeneous catalysts which are active in hydrogen transfer reactions. Iron oxide-based, alkali promoted catalysts function well, but also platinum group metals and carbon surfaces are active in this process. The clusters of highly excited Rydberg hydrogen atoms H(l) are formed upon interaction with alkali Rydberg matter. The final conversion step from ordinary hydrogen Rydberg matter H(l) to H(0) is spontaneous and does not require a solid surface. It is concluded that the exact choice of catalyst is not very important. It is also concluded that the crucial feature of the catalyst is to provide excited alkali atoms at a sufficiently high surface density and in this way enabling formation and desorption of H(0) clusters. Finally, the relation to industrial catalytic processes which use H(0) formation catalysts is described and some important consequences like the muon and neutron radiation from H(0) are discussed.     

Enhancement of heat transfer in hydrogen storage tank with hydrogen absorbing alloy (optimum fin layout)

Optimization of the fin layout in a metal hydride (MH) bed has been sought to enhance poor heat transmission in a hydrogen storage tank, and to obtain a maximum hydrogen absorption rate with a smaller volume of fins. Two different fin configurations, radial and circular fins, in a vertical cylindrical reactor vessel were tested with a La‐Ni‐based AB5 type hydrogen storage alloy. A two‐dimensional transient heat conduction analysis, coupled with predicted temperature and concentration of absorbed hydrogen in the bed for the exothermic hydride reaction, was used to evaluate enhancement of the hydrogen absorption time. The estimated temperature and concentration agreed within 6 K and 8.5%, respectively, with our experimental results. The effect of thickness and the spacing and shape of fins on the hydrogen absorption time were analytically evaluated, so that the optimum range of the each fin layout was obtained by the trade off between absorption time and reduction in the MH volume due to the volume occupied by fins. The hydrogen absorption time for the recommended layout of circular fins was reduced to approximately one‐third of that without fins. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res, 37(3): 165–183, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20195     

In situ hydrogen plasma treatment for improved transport of (4 0 0) oriented polycrystalline silicon films

Polycrystalline silicon (poly-Si) films were deposited on glass by very high-frequency (100 MHz) plasma enhanced chemical vapor deposition from a gaseous mixture of SiF₄ and H₂ with small amounts of SiH₄. (2 2 0) oriented films prepared at small SiF₄/H₂ ratios (<30/40 sccm) showed intrinsic transport properties of poly-Si. However, the room temperature dark conductivity (σ_d) of the (4 0 0) oriented film was very high for intrinsic poly-Si, 7.2×10⁻⁴S/cm. This conductivity exhibited a T^−1/4 behavior, suggesting a high defect density at the grain boundaries. It was found that in situ hydrogen plasma treatment successfully produced (4 0 0) oriented poly-Si with a reasonably low σ_d of 4.5×10⁻⁷S/cm and a good photoconductivity of 1.3×10⁻⁴S/cm.     

超临界水中生物质气化制氢的反应路径

超临界水中生物质气化制氢技术因其具有良好的环保性、产氢高等特点已成为氢能领域的研究热点之一。文中对超临界水中生物质气化制氢反应路径的研究结果进行了总结，归纳了生物质及其模型化合物葡萄糖在亚临界和超临界水中分解气化的可能的反应路径以及反应过程中产生的一系列中间产物，讨论了影响反应的主要因素。     

Biological hydrogen production from sweet sorghum syrup by mixed cultures using an anaerobic sequencing batch reactor (ASBR)

Continuous biological hydrogen production from sweet sorghum syrup by mixed cultures was investigated by using anaerobic sequencing batch reactor (ASBR). The ASBR was conducted based on the optimum condition obtained from batch experiment i.e. 25 g/L of total sugar concentration, 1.45 g/L of FeSO₄ and pH of 5.0. Feasibility of continuous hydrogen fermentation in ASBR operation at room temperature (30 ± 3 °C) with different hydraulic retention time (HRT) of 96, 48, 24 and 12 hr and cycle periods consisting of filling (20 min), settling (20 min), and decanting (20 min) phases was analyzed. Results showed that hydrogen content decreased with a reduction in HRT i.e. from 42.93% (96 hr HRT) to 21.06% (12 hr HRT). Decrease in HRT resulted in a decrease of solvents produced which was from 10.77 to 2.67 mg/L for acetone and 78.25 mg/L to zero for butanol at HRT of 96 hr-12 hr, respectively. HRT of 24 hr was the optimum condition for ASBR operation indicated by the maximum hydrogen yield of 0.68 mol H₂/mol hexose. The microbial determination in DGGE analysis indicated that the well-known hydrogen producers Clostridia species were dominant in the reacting step. The presence of Sporolactobacillus sp. which could excrete the bacteriocins causing the adverse effect on hydrogen-producing bacteria might responsible for the low hydrogen content obtained.     

Pure hydrogen production in a Pd-Ag multi-membranes module by methane steam reforming

An experimental test campaign has been carried out in order to investigate the performances in terms of pure hydrogen production of a multi-membrane module coupled with a methane reforming fixed bed reactor. The effect of operating parameters such as the temperature, the pressure, the water/methane feed flow rates and the feed molar ratio has been studied. The hydrogen produced into the traditional reformer has been recovered in the shell side of the membrane module by vacuum pumping. The membrane module consists of 19 Pd/Ag permeator tubes of wall thickness 150 μm, diameter 10 mm and length 250 mm: these dense permeators permitted to separate ultra-pure hydrogen.The experiments have been carried out with the reaction pressure of 100-490 kPa, the temperature of the reformer of 570-720 °C and the temperature of the Pd/Ag membranes module of 300-400 °C. A water/methane stream of molar ratio of 4/1 and 5/1 has been fed into the methane reformer at GSHV of 1547.6 and 1796.1 L_(STP) kg⁻¹ h⁻¹. Hydrogen yield value of about 3 has been measured at reaction pressure of 350 kPa, temperature reformer of 720 °C and methane feed flow rate of 6.445 × 10⁻⁴ mol s⁻¹.     

Overview of hydrogen production research in the Clean Energy Research Laboratory (CERL) at UOIT

This paper discusses new hydrogen production methods that have been actively investigated both theoretically and experimentally at UOIT and some recent findings through experimental measurements and analysis. A major cluster of activities at UOIT has developed novel hydrogen production systems from electrolysis to thermochemical cycles and from integrated cycles to solar-light based hydrogen production processes. The results confirm that both thermochemical cycles and photochemical processes offer promising potential for sustainable hydrogen production.     

Formate detection by potassium permanganate for enhanced hydrogen production in Escherichia coli

Mutagenesis of Escherichia coli for hydrogen production is difficult since there is no high-throughput screen. Here we describe a method for rapid detection of enhanced hydrogen production by engineered strains by detecting formate via potassium permanganate; in E. coli, hydrogen is synthesized from formate using the formate hydrogen lyase system.     

甲烷部分氧化制氢机理及方法

就甲烷部分氧化制氢的机理和方法进行了讨论,对甲烷部分氧化制氢各种工艺的研究现状进行了阐述,能对寻找经济性较好的制氢方法有所启发,引发对甲烷部分氧化制氢机理和方法的讨论与研究：     

Characterization of hydrogen production by Platymonas Subcordiformis in torus photobioreactor

Platymonas subcordiformis, a marine green alga, was demonstrated to photo-biologically produce hydrogen when regulated by a kind of proton uncoupler CCCP (Carbonyl Cyanide m-Chlorophenylhydrazone). In this paper, hydrogen production experiments by P. subcordiformis were carried out in a torus photobioreactor equipped with a mass spectrometer and other necessary sensors so that instantaneous gas components could be measured and other successive physiological states could be well recorded.     

Hydrogen production by aluminum corrosion in hydrochloric acid and using inhibitors to control hydrogen evolution

This study reports on the systematic assessment of hydrogen (H₂) production by corrosion of aluminum alloy (AA) in hydrochloric acid (HCl) at different temperature. Rare earth inhibitors, lanthanum (La) and cerium (Ce) have been applied to control the H₂ production process. The production process is based on electrochemical reaction of aluminum (anodic reaction) in the HCl solution, which has a high concentration of hydrogen ions (H⁺), the H⁺ ions are reduced and H₂ is evolved. Preliminary results showed that an increase in temperature of working solution produced an increase of the H₂ production rate. The H₂ production rate increases because acid can prevent aluminum passivation during H₂ evolution. The rare earth inhibitors La and Ce control the H₂ evolution, especially, when using mixture of both inhibitors. This result demonstrates a synergistic effect between the La and the Ce inhibitors. X-ray diffraction studies were performed on the surface structure before and after immersion, and a scanning electron microscope (SEM) was used to study the morphology of the AA.     

Reducing the hydrogen production cost by operating alkaline electrolysis as a discontinuous process in the French market context

The possible reduction of the hydrogen production cost when operating alkaline electrolysers in a discontinuous way, in order to benefit from low electricity prices, is investigated. Beside the insights about the electricity market (prices do not correlate the demand; they are related to the supply-and-demand hardness), advances in modelling discontinuous operation are proposed. An optimum production cost is found that induces a profit of 4%, with regard to a plant that would work continuously. Specific attention should be given to related overcosts: additional degradation due to frequent transitions from the minimum electrolyser load to the nominal one, higher maintenance needs, and hydrogen storage costs. Such an operating mode would also greatly benefit from a reduction of the electrolyser prices. However, the state-of-the-art as regards the electrolyser minimum loads and transition time appears satisfactory.     

Metal nanoparticle preparation within modifiable p(4-VP) microgels and their use in hydrogen production from NaBH4 hydrolysis

Composite poly(4-vinyl pyridine)-silica (p(4-VP)–Si) nanoparticles were synthesized, employing trimethoxy vinyl silane (TMVS) as silica forming agent using ethylene glycol dimethacrylate (EGDMA) as the cross-linker, and ammonium persulfate (APS) as the initiator in an oil-in-water micro emulsion system. Porous p(4-VP) nanoparticles were generated from p(4-VP)–Si by treatment with hydrofluoric acid (HF). The size of p(4-VP)-based particles ranged between 300 and 500 nm. The porous p(4-VP) particles have a surface area of 42.26 m²/g. We also report preparation of various metal nanoparticles, such as Co and Ni, inside bare p(4-VP), p(4-VP)–Si and porous p(4-VP) nanoparticles by absorption from the corresponding metal ions aqueous solution and then reduction with NaBH₄. Atomic Absorption Spectroscopy (AAS) was used to determine the metal particle content of the p(4-VP)-based nanoparticles. The hydrogen production rate of Co-containing p(4-VP) was found to be superior to Ni-containing p(4-VP) under the same conditions. Cobalt-containing p(4-VP)–Si and porous p(4-VP) microgel composites can generate hydrogen faster than Co-containing p(4-VP). Moreover, p(4-VP)-based microgels showed seven fold hydrogen production rate, and almost five fold turn over frequency (TOF) than p(AMPS) microgels in terms of catalytic performances reported earlier.     

Experimental kinetics and dynamics of hydrogen production on glucose by hydrogen forming bacteria (HFB) culture

The kinetic study was performed using a modified “initial rate-method” and the dynamic ones by the relaxation time methodology. The approach was tested on glucose as sole carbon source while the hydrogen forming bacteria HFB were obtained by acid treatment of anaerobic sludge. A large spectrum of substrate concentration from 5 g/l to 90 g/l was experimentally tested. During the test biogas evolution, gas composition, glucose concentration as well as pH and Red-Ox Potential (ROP) were monitored. At the end of the tests ethanol and VFA were measured to evaluate a reference molar H₂ yield (Y*). The biogas composition ranged in (40–60%) for H₂ and rest CO₂, no CH₄ was observed. A first order kinetic equation for glucose with a kinetic constant of 0.0041 h⁻¹ and an inhibited kinetic equation for biogas evolution with a maximum production rate of 100 ml/l h were set-up. The dynamic study evidences the strong role of the pH in the regulation of activity of the Ferrodoxin and Hydrogenase pools. Lastly a test with a bioreactor of 2 l with pH adjustments validated the dynamics of the system showing an increase of 2.8 times of efficiency of glucose conversion into H₂ compared with tests without pH adjustments and agitation.     

The optical absorption and hydrogen production by water splitting of (Si,Fe)-codoped anatase TiO2 photocatalyst

The electronic and optical properties are studied using the density functional theory in (Si,Fe)-codoped anatase TiO₂. The calculated results suggest that the synergistic effects of (Si,Fe) codoping can effectively induce the redshift of optical absorption edge, which leads to higher visible-light photocatalytic activity for hydrogen production by water splitting than pure anatase TiO₂. To verify the reliability of our calculated results, nanocrystalline (Si,Fe)-codoped TiO₂ is synthesized by a sol-gel-solvothermal method, and excellent absorption performance and photocatalytic activity for hydrogen production by water splitting are observed in our experiments.     

Technological development of hydrogen production by solid oxide electrolyzer cell (SOEC)

High-temperature solid oxide electrolyzer cell (SOEC) has great potential for efficient and economical production of hydrogen fuel. In this paper, the state-of-the-art SOEC technologies are reviewed. The developments of the important steam electrolyzer components, such as the ionic conducting electrolyte and the electrodes, are summarized and discussed. YSZ and LSGM are promising electrolyte materials for SOEC working at high and intermediate temperatures, respectively. When co-doping or a blocking layer is applied, SDC or GDC are possible electrolyte materials for intermediate-temperature SOEC. Ni–YSZ remains to be the optimal cathode material. Although LSM–YSZ is widely used as SOEC anode, other materials, such as LSF–YSZ, may be better choices and need to be further studied. Considering the cell configuration, planar SOECs are preferred due to their better manufacturability and better electrochemical performance than tubular cells. Anode depolarization is an effective method to reduce the electrical energy consumption of SOEC hydrogen production. Although some electrochemical models and fluid flow models are available, the present literature is lacking detailed modeling analyses of the coupled heat/mass transfer and electrochemical reaction phenomena of the SOEC. Mathematical modeling studies of SOEC with novel structures and anode depolarization processes will be fruitful for the development of SOEC. More works, both experimental and theoretical, are needed to further develop SOEC technology to produce hydrogen more economically and efficiently for the coming hydrogen economy.     

Technical and economic evaluation of solar hydrogen production by supercritical water gasification of biomass in China

A novel thermochemical method for solar hydrogen production was proposed by state key laboratory of multiphase flow in power engineering (SKLMFPE) of Xi’an Jiaotong University. In this paper, a technical and economic evaluation of the new solar hydrogen production technology was conducted. Firstly, the advantages of this new solar hydrogen production process, compared with other processes, were assessed and thermodynamic analysis of the new process was carried out. The results show that biomass gasification in supercritical water driven by concentrating solar energy may be used to achieve high efficiency solar thermal decomposition of water and biomass for hydrogen production. Secondly, the hydrogen production cost was analyzed using the method of the total annual revenue requirement. The estimated hydrogen production cost was 38.46RMB/kg for the experimental demonstration system with a treatment capacity of 1 ton wet biomass per hour, and it would be decreased to 25.1 RMB/kg if the treatment capacity of wet biomass increased from 1 t/h to 10 t/h. A sensitivity analysis was also performed and influence of parameters on the hydrogen production cost was studied. The results from technical and economic evaluation show that supercritical water gasification of biomass driven by concentrated solar energy is a promising technology for hydrogen production and it is competitive compared to other solar hydrogen production technologies.     

Study of hydrogen production system by using PV solar energy and PEM electrolyser in Algeria

Hydrogen fuel can be produced by using solar electric energy from photovoltaic (PV) modules for the electrolysis of water without emitting carbon dioxide or requiring fossil fuels.     

Optimizing energy harvest in wastewater treatment by combining anaerobic hydrogen producing biofermentor (HPB) and microbial fuel cell (MFC)

This study focused on the optimization of energy harvest from wastewater treatment by integrating two novel biotechnologies: anaerobic hydrogen production and microbial fuel cell (MFC). The simultaneous production of hydrogen and electricity from wastewater was examined at continuous flow at different organic loading rates (OLR) by changing chemical oxygen demand (COD) and hydraulic retention time (HRT). The experimental results showed that the specific hydrogen yield (SHY, mole H₂/mole glucose) increased with the decrease in OLR, and reached at the maximum value of 2.72 mol H₂/mole glucose at the lowest OLR of 4 g/L.d. The effluent from hydrogen producing biofermentor (HPB) was fed to a single chamber MFC (SCMFC), obtaining the highest power density and coulombic efficiency (CE) of 4200 mW/m³ and 5.3%, respectively. The energy conversion efficiency (ECE) increased with OLR and reached the peak value of 4.24% at the OLR of 2.35 g/L.d, but decreased with higher OLR. It was demonstrated that the combination of HPB and MFC improved the ECE and COD removal with the maximum total ECE of 29% and COD removal of 71%. The kinetic analysis was conducted for the HPB-MFC hybrid system. The maximum hydrogen production was projected to be 2.85 mol H₂/mole glucose. The maximum energy recovery and COD removal efficiency from MFC were projected to be 559 J/L and 97%, respectively.     

Experimental research on catalysts and their catalytic mechanism for hydrogen production by gasification of peanut shell in supercritical water

Peanut shell, mixed with sodium carboxymethyl-cellulose, was gasified at a temperature of 450°C and a pressure range from 24 to 27 MPa with the presence of different catalysts, including K₂CO₃, ZnCl₂ and Raney-Ni. The experimental results show that different catalysts have greatly different effects on the reaction. Gasification efficiency (GE), hydrogen gasification efficiency (GHE), carbon gasification efficiency (GCE), yield of hydrogen production and potential yield of hydrogen production are applied to describe the catalytic efficiency. From the result of gaseous components, ZnCl₂ has the highest hydrogen selectivity, K₂CO₃ is lower, and Raney-Ni is the lowest, but Raney-Ni is the most favorable to gasify biomass among the three catalysts, and its G _E, G _HE, G _CE reach 126.84%, 185.71%, 94.24%, respectively. As expected, hydrogen selectivity increased and CH₄ reduced rapidly when the mixture of ZnCl₂ and Raney-Ni is used under the same condition. The optimization mixture appeared when 0.2 g of ZnCl₂ was added to 1 g of Raney-Ni, 43.56 g·kg⁻¹ of hydrogen production was obtained. In addition, the catalytic mechanisms of different catalysts were analyzed, and the possible reaction pathway was brought forward, which helped to explain the experiment phenomena and results correctly. __________ Translated from Journal of Xi’an Jiaotong University, 2006, 40(9): 1 263–1 267 [译自: 西安交通大学学报]