scholarly journals Generation of hydrogen by hydroheterogeneous compositions based on aluminum and alkali metals

2021 ◽  
Vol 7 (2) ◽  
pp. 133-138
Author(s):  
Sergey R. Askhadullin ◽  
Viktor K. Milinchuk
Keyword(s):  
Boric Acid ◽  
Alkali Metals ◽  
Hydrogen Generation ◽  
Nuclear Reactors ◽  
Total Concentration ◽  
Power Level ◽  
High Rate ◽  
Hydrogen Yield ◽  
Hydrogen Formation ◽  
Term Operation

The process of hydrogen formation and the associated risk of combustion and explosion is a complex problem concerned with the hydrogen and radiation safety of nuclear reactors. Lithium, potassium and sodium hydroxides are used in VVER reactors as corrective additives for keeping the hydrogen potential of the water coolant with boric acid at a controlled level of 5.8 to 10.3. In the process of investigating the interaction of aqueous solutions of the above hydroxides with aluminum, the most chemically active of these is lithium hydroxide; this reaction proceeds with hydrogen formed at a high rate at room temperature (in an exothermic mode). The processes of hydrogen generation in hydroheterogeneous compositions with potassium and sodium hydroxides proceed at an acceptable rate with heating to ~ 60 °C. The kinetics of hydrogen generation depends in a complex way on the content of boric acid, namely, the hydrogen yield is at a level of ~ 1000 ml at a low concentration of 0.01 to 0.05 g/l, and there is no hydrogen formation at a concentration of 0.6 g/l. According to the coolant quality standards, in the hot state of a VVER-1000 unit or in the reactor state at the minimum controlled power level, the total concentration of alkali metals is about 1 mg/dm3, i.e. two to three orders of magnitude as less as in the investigated compositions. The discovery of the influence of alkali metal hydroxides on the formation of hydrogen with the participation of structural materials based on the example of aluminum makes it possible to suggest that the hydroxides of these metals contained in the coolant in a small amount can also take part in the hydroheterogeneous process of formation of minor hydrogen amounts. The potential for hydrogen formation in such a way needs to be taken into account during long-term operation of nuclear reactors, and during accidents and incidents at NPPs

High-Purity, CO2-Free Hydrogen Generation from Crude Oils in Crushed Rocks Using Microwave Heating

2021 ◽  
Author(s):  
Qingwang Yuan ◽  
Xiangyu Jie ◽  
Bo Ren
Keyword(s):  
Microwave Heating ◽  
Environmental Impacts ◽  
High Purity ◽  
Oil And Gas ◽  
Hydrogen Generation ◽  
Petroleum Industry ◽  
Petroleum Reservoirs ◽  
Crude Oils ◽  
Hydrogen Yield ◽  
Free Hydrogen

Abstract While the demand for hydrocarbon resources has been continuously increasing in the past 150 years, the industry is, however, criticized for carbon dioxide (CO2) emissions and concomitant global warming concerns. The oil and gas industry also face growing pressures in the ongoing energy transition. Generating and producing hydrogen (H2) directly from petroleum reservoirs has the potential to mitigate environmental impacts while revolutionizing the traditional petroleum industry and enabling it to become a clean hydrogen industry. This paper proposes a novel approach to generate high-purity, CO2-free hydrogen from the abundant oil and gas resources in petroleum reservoirs using microwave heating. In this work, laboratory experiments were conducted to validate this scientific proof-of-concept and examine the roles of crushed rocks, catalysts, and water/oil ratio in hydrogen generation from crude oils in a reactor. A maximum of 63% ultimate hydrogen content is obtained in the generated gas mixtures, while the original CO2content in all experiments is negligible (<1%). Catalysts can promote hydrogen generation by accelerating rate and locally enhancing microwave (MW) absorption to create ‘super-hot spots'. Water also participates in reactions, and additional hydrogen is generated through water-gas shift reactions. The water-oil ratio in porous rocks affects the ultimate hydrogen yield. Overall, this research demonstrates the great potential of using MW heating to generate high-purity, CO2-free hydrogen from in situ petroleum reservoirs. Further research and wide application of this technology would potentially transform petroleum reservoirs to hydrogen generators, thus mitigating the environmental impacts of traditional petroleum industry while meeting the increasing demand for clean hydrogen energy. This technology would also benefit the safe transition towards a decarbonized society.

scholarly journals Research on hydrogen generation from rapid hydrolysis of aluminum in sodium fluoride solution

2019 ◽  
Vol 118 ◽  
pp. 03048
Author(s):  
Changchun Li ◽  
Yuxin Wu
Keyword(s):  
Hydrogen Production ◽  
Kinetic Model ◽  
Sodium Fluoride ◽  
Hydrogen Generation ◽  
Hydrogen Yield ◽  
Shrinking Core Model ◽  
Fluoride Solution ◽  
Shrinking Core ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of

Hydrogen generation from rapid hydrolysis of aluminum in sodium fluoride solution was investigated through a hydrolysis experiment. Rapid and instant hydrogen yield were observed using sodium fluoride as additive. The experimental results demonstrate that the increase of temperature and the amount of additives in a certain range will boost the hydrogen production. The amount of additives outside the range only has an effect on the rapid hydrolysis of the aluminum during the initial stage, but the total amount of hydrogen produced doesn’t increased significantly. Theoretical analysis of the effects of the mixing ratio and the temperature on the hydrogen production rates were performed using the shrinking core model and the kinetic model. The shrinking core model parameter a and k indicate the film change degree of porosity and thickness and the effect of time on the diffusion coefficient. the kinetic model is verified and the activation energy confirming hydrogen yield control by a molecular diffusion process. Correspondingly, mechanisms of Al corrosion in NaF solutions under low and high alkalinity were proposed, respectively.

scholarly journals Study of Hydrogen Generation of Aluminum-Containing Compositions with Boric Acid

2018 ◽  
Vol 3 (3) ◽  
pp. 230
Author(s):  
Salakhova A.A. ◽  
Suvorov V.A. ◽  
Firsova A. I. ◽  
Belozerov V.I. ◽  
Milinchuk V.K.
Keyword(s):  
Boric Acid ◽  
Hydrogen Generation ◽  
Sodium Metasilicate ◽  
Chemical Processes ◽  
System Management ◽  
Control Rod ◽  
Radiation Fields ◽  
Fuel Elements ◽  
And Control ◽  
Kinetics Of

The results of investigations of the kinetics of hydrogen generation compositions with aluminum, chemical activators (hydrated sodium metasilicate, oxide and calcium hydroxide) boric acid. Aluminium and its alloys used for the manufacture of protective sheaths of fuel elements and control rod protection system management, pipelines, tanks, and various support structures in the active zone of atomic reactors RBMK, research water-cooled reactors. The aluminum is protected from direct contact with water and steam surface layer of metal oxide having a high corrosion resistance at high temperatures in powerful radiation fields. However, after removal or when the discontinuity of the oxide layer of activated metal efficiently decompose water to hydrogen. It is established that the hydrogen aluminum-containing compositions is dependent on the concentration of boric acid. The discovery of the involvement of boric acid in these reactions expands the ideas about regularities of chemical processes of formation of hydrogen flowing in the water coolant of VVER reactors with the participation of the corrective additives and impurities.

scholarly journals Co-digestion of Oil Palm Trunk Hydrolysate and Slaughterhouse Wastewater for Biohydrogen Production in a Fixed Bed Reactor by Immobilized Thermoanaerobacterium thermosaccharolyticum KKU19 on Expanded Clay

2021 ◽  
Vol 9 ◽  
Author(s):  
Sontaya Khamtib ◽  
Sureewan Sittijunda ◽  
Tsuyoshi Imai ◽  
Alissara Reungsang
Keyword(s):  
Oil Palm ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Hydrogen Yield ◽  
Support Material ◽  
Slaughterhouse Wastewater ◽  
Term Operation ◽  
Oil Palm Trunk ◽  
Thermoanaerobacterium Thermosaccharolyticum

The goal of this study was to evaluate the use of expanded clay as a support material for Thermoanaerobacterium thermosaccharolyticum KKU19 to produce hydrogen from oil palm trunk hydrolysate (OPT) and slaughterhouse wastewater (SHW) in a fixed-bed reactor (FBR) under non-sterile conditions. The effects of hydraulic retention time (HRT) on the performance of the FBR were also investigated. The FBR was operated at an OPT hydrolysate to SHW ratio of 2.55:1 (v:v), 60°C, initial pH 6.5, and 1.2 mg (as total volatile solids/g expanded clay) of T. thermosaccharolyticum KKU19 immobilized on expanded clay. A maximum hydrogen production rate (HPR) and hydrogen yield (HY) of 7.15 ± 0.22 L/L day and 234.45 ± 5.14 mL H2/g-COD, respectively, were obtained at an HRT of 6 h. Long-term operation of FBR at 6 h HRT indicated that expanded clay efficiently immobilizes T. thermosaccharolyticum KKU19, for which an HPR of 6.82 ± 0.56 L H2/L day, and an HY of 231.99 ± 19.59 mL H2/g-COD were obtained. Furthermore, the COD removal efficiency of 30% obtained under long-term operation was comparable to that under short-term operation at an HRT of 6 days. Butyric and acetic acids were the main soluble metabolite products, thereby indicating a butyrate–acetate type fermentation. Our findings indicate that expanded clay is an effective support material that contributes to the protection of microbial cells and can be used for long-term operation.

scholarly journals Continuous Volatile Fatty Acid Production From Acid Brewery Spent Grain Leachate in Expanded Granular Sludge Bed Reactors

2021 ◽  
Vol 5 ◽  
Author(s):  
Juan Castilla-Archilla ◽  
Jonas Heiberger ◽  
Simon Mills ◽  
Julia Hilbig ◽  
Gavin Collins ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Total Concentration ◽  
Granular Sludge ◽  
Organic Loading Rate ◽  
Hydrogen Yield ◽  
Fatty Acid Production ◽  
Spent Grain ◽  
Total Carbohydrates ◽  
Ph Shock ◽  
Hydrolysis Of

The production of volatile fatty acids (VFAs) in expanded granular sludge bed (EGSB) reactors using leachate from thermal diluted acid hydrolysis of brewery spent grain was evaluated. Partial inhibition of the anaerobic digestion process to induce VFA accumulation was achieved by applying a high organic loading rate [from 15.3 to 46.0 gCOD/(L·day)], and using a feed with an inlet concentration of 15 g/L total carbohydrates. Two EGSB reactors were operated under identical conditions, both inoculated with the same granular sludge. However, granular sludge in one reactor (R1) was subsequently disaggregated to flocculent sludge by a pH shock, whereas granules remained intact in the other reactor (R2). The hydraulic retention time (HRT) of both reactors was decreased from 36 to 24, 18 and 12 h. The main fermented compounds were acetic acid, butyric acid, propionic acid and ethanol. Despite fluctuations between these products, their total concentration was quite stable throughout the trial at about 134.2 (±27.8) and 141.1 (±21.7) mmol/L, respectively, for R1 and R2. Methane was detected at the beginning of the trial, and following some periods of instability in the granular sludge reactor (R2). The hydrogen yield increased as the HRT decreased. The highest VFA production was achieved in the granular sludge reactor at a 24 h HRT, corresponding to 120.4 (±15.0) mmol/L of VFAs. This corresponded to an acidification level of 83.4 (±5.9) g COD of VFA per 100 gram of soluble COD.

Facile synthesis of hollow carbon microspheres embedded with molybdenum carbide nanoparticles as an efficient electrocatalyst for hydrogen generation

RSC Advances ◽  
2016 ◽  
Vol 6 (79) ◽  
pp. 75870-75874 ◽  
Author(s):  
Cuncai Lv ◽  
Jie Wang ◽  
Qingli Huang ◽  
Qianpeng Yang ◽  
Zhipeng Huang ◽  
...  
Keyword(s):  
Molybdenum Carbide ◽  
Hydrogen Generation ◽  
Ultrasonic Spray Pyrolysis ◽  
Basic Solution ◽  
Carbon Microspheres ◽  
Term Operation ◽  
Ultrasonic Spray ◽  
Hollow Carbon ◽  
Hollow Carbon Microspheres

Hollow carbon microspheres embedded with molybdenum carbide nanoparticles are prepared via ultrasonic spray pyrolysis. The product exhibits an enhanced HER activity and good stability in the long-term operation both in acidic and basic solution.

Hydrogen Generation From Acetic Acid Catalyzed Magnesium Hydride Using an On-Demand Hydrogen Reactor

2016 ◽  
Author(s):  
Tien-Chien Jen ◽  
Joshua Adeniran ◽  
Esther Akinlabi ◽  
Chung-Hsing Chao ◽  
Yen-Hsi Ho ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Organic Acid ◽  
Hydrogen Generation ◽  
Magnesium Hydride ◽  
Hydrolysis Reaction ◽  
Hydrogen Yield ◽  
Acetic Acid Concentration ◽  
External Temperature ◽  
On Demand ◽  
Acid Catalyzed

This study reports an acetic acid catalyzed hydrolysis reaction for hydrogen generation from magnesium hydride (MgH2) using an on-demand hydrogen reactor. Acetic acid, a weak and benign organic acid, has been reported as a single catalyst in hydrolysis reaction for hydrogen generation using other substrates, but this is the first study where acetic acid has been employed as a catalyst in a magnesium hydride hydrolysis reaction for hydrogen generation. In this study, the effects of MgH2 weight, acetic acid concentration and external temperature on hydrogen generation from MgH2 were examined. The results of the hydrolysis reaction indicated that the weight of MgH2 was the major factor influencing hydrogen generation, followed by the concentration of acetic acid while the effect of external temperature was insignificant. Similarly, hydrogen yield was proportional to the weight of MgH2 with a reported maximum hydrogen yield at each weight been: 0.4g (∼ 0.07 L); 0.8 g (∼ 0.125 L) and 1.2 g (∼1.285 L). The successful use of acetic acid in the study reinforced the versatility of the on-demand hydrogen reactor and as a scalable technology for hydrogen generation.

scholarly journals Investigation of the K-Mg-Ca Sulfate System as Part of Monitoring Problematic Phase Formations in Renewable-Energy Power Plants

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5366
Author(s):  
Fiseha Tesfaye ◽  
Daniel Lindberg ◽  
Mykola Moroz ◽  
Leena Hupa
Keyword(s):  
Renewable Energy ◽  
Power Plants ◽  
Alkali Metals ◽  
Wind Farms ◽  
Biomass Combustion ◽  
Term Operation ◽  
Binary Phase Diagrams ◽  
Combustion Processes ◽  
And Control

Besides the widely applied hydropower, wind farms and solar energy, biomass and municipal and industrial waste are increasingly becoming important sources of renewable energy. Nevertheless, fouling, slagging and corrosion associated with the combustion processes of these renewable sources are costly and threaten the long-term operation of power plants. During a high-temperature biomass combustion, alkali metals in the biomass fuel and the ash fusion behavior are the two major contributors to slagging. Ash deposits on superheater tubes that reduce thermal efficiency are often composed of complex combinations of sulfates and chlorides of Ca, Mg, Na, and K. However, thermodynamic databases involving all the sulfates and chlorides that would favor a better understanding and control of the problems in combustion processes related to fouling, slagging and corrosion are not complete. In the present work, thermodynamic properties including solubility limits of some phases and phase mixtures in the K2SO4-(Mg,Ca)SO4 system were reviewed and experimentally investigated. Based on the new and revised thermochemical data, binary phase diagrams of the K2SO4-CaSO4 and K2SO4-MgSO4 systems above 400 °C, which are of interest in the combustion processes of renewable-energy power plants, were optimized.

FISSION FRAGMENT IRRADIATIONS OF HYDROCARBONS: I. YIELD AND ISOTOPIC COMPOSITION OF HYDROGEN FROM MIXTURES OF CYCLOHEXANE AND BENZENE WITH THEIR DEUTERATED ANALOGUES

1964 ◽  
Vol 42 (6) ◽  
pp. 1418-1425 ◽  
Author(s):  
A. W. Boyd ◽  
H. W. J. Connor
Keyword(s):  
Isotopic Composition ◽  
Fission Fragment ◽  
Hydrogen Yield ◽  
Transient Species ◽  
Hydrogen Formation ◽  
Fission Fragments ◽  
Gamma Radiolysis

Cyclohexane and benzene and mixtures of each of these with cyclohexane-d12 and benzene-d6 have been irradiated with fission fragments using thin sources of [Formula: see text]. The hydrogen yield G(H2) for cyclohexane is 7.73, and is only slightly reduced by the addition of benzene. G(H2) for benzene is 2.14. The isotopic composition of the hydrogen from the four mixtures indicates that most is formed in bimolecular processes.To correlate these results with those obtained in gamma radiolysis, a mechanism is proposed based on hydrogen formation by reactions between transient species in both cyclohexane and benzene.

Accelerated Hydrolysis of Solid-state NaBH4/Al System by Co2B Milled with Li for Hydrogen Generation

2016 ◽  
Vol 19 (2) ◽  
pp. 109-115
Author(s):  
Jiasong Chang ◽  
Wenlong Song ◽  
Ting Li ◽  
Jindan Chen ◽  
Hanmei Wu ◽  
...  
Keyword(s):  
Milling Time ◽  
Hydrogen Generation ◽  
Synergetic Effect ◽  
Hydrogen Yield ◽  
Preparation Process ◽  
Preparation Technology ◽  
High Hydrogen ◽  
Hydrolysis Process ◽  
Hydrolysis Of ◽  
Li Content

Co2B catalyst was milled with Al and Li to form Al-Li-Co2B composite, and the hydrogen generation performance of Al-Li-Co2B/NaBH4 system was investigated in this study. 100% hydrogen yield was reached, and high hydrogen generation rate was regulated by optimizing the composition design and preparation technology. The improvement was attributed to the synergetic effect of Co2B and Li in the preparation process, whereas a large specific surface area was obtained with the increase in Li content, Co2B, and milling time. In addition, the catalytic activity of Co2B and LiOH from Li hydrolysis was heightened for the hydrolysis of the Al/NaBH4 system because of the addition of Al(OH)3, LiAl2(OH)7.xH2O, and NaBO2 in the hydrolysis process.

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