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1.
The discovery of a large accumulation of natural hydrogen in Mali has triggered the opportunity to search for hydrogen accumulations in other countries. The generation of hydrogen in Mali is linked to the presence of very old iron-rich basement rocks. Solid-liquid redox reactions between iron-rich minerals and groundwater are a possible source of H2 in deep basement rocks. The hypothesis is that hydrogen degassing may result in the surface circular shallow depressions. The Archean iron-rich Yilgarn and Pilbara cratons that cover a vast area of Western Australia contain abundant iron-rich mafic-ultramafic rocks. The craton reveals many surficial circular depressions visible through satellite images. The area has abundant fault systems and is blanketed with Eocene sedimentary rocks containing high-quality reservoir rocks. All these characteristics appear to provide most of the required elements, such as a hydrogen source, migration pathway, and reservoir rock for a complete “Hydrogen System” to be developed in the area.  相似文献   

2.
Natural hydrogen seeps called fairy circles have been identified in Mali, Brazil, Russia, and United-States. Natural hydrogen is produced from a field in Mali for 7 years. The natural hydrogen system is still poorly understood and needs to be studied in new geological contexts as to streamline hypotheses on the system dynamics and elements into concepts. In Australia, numerous circular surface features, commonly called salt lakes or swaps, are visible from the sky but no existing work shows nor quantifies any hydrogen content in those features. In this study, we reviewed the existing literature on fairy circles as to determine and directly test with soil-gas measurements if hydrogen surface-emitting features are present in Australia. We determined best candidates to test with a multi-disciplinary approach linking geology, multi-physical imaging, and seismic interpretation. Soil-gas measurements showed persistent hydrogen concentration localized in the external ring of circular depressions aligned along the Darling Fault, a major crustal boundary between the granitic, mafic and ultramafic rocks of the Yilgarn Craton from the sedimentary rocks of the Perth Basin. This work is the proof that fairy circles, in the meaning of H2 emitting structures, are present in Australia and opens the door to new prospectivity pathways by evaluating original hypotheses on natural hydrogen generation, migration pathways and entrapment. This geological setting promotes deep serpentinization of ultramafic rocks as well as oxidation of iron-rich Archean rocks and mafic dikes as potential hydrogen sources that are both of massive potential economic value. This hydrogen can circulate and be entrapped as aqueous hydrogen in low-salinity aquifers or migrate in gaseous phase in fault zones up to intermediate structural reservoir or to the surface.  相似文献   

3.
Hydrogen escaping from sedimentary basins has already been described in various parts of the world. Some of these leakages have been identified by superficial circular depressions, also called “fairy circles”. Gas detection measurements, randomly repeated after a few months have shown that the amount of hydrogen present in soils is not constant neither versus time nor versus position in a given structure. Permanent monitoring gas analyzers were installed in the ground to estimate hydrogen flow outgassing from a topographical circular depression located in Brazil. Data show that a hydrogen flux occurs during the hottest moment of the day, as shown with permanent sensors set at a regular spacing. The process may look like a soil evaporation. In that same structure, other detectors show much higher and irregular gas output which present an unclear correlation as a function of ambient temperature and atmospheric pressure. The relationship with temperature suggests a role of water saturation driving the overall hydrogen fluxes. The reported geochemical data imply that (1) one measurement taken at a given hour on a structure cannot be considered as quantitative, as it varies too much with time and is also probably related to the soil perturbation induced by the shallow drilling, (2) hydrogen released through the soils of the studied structure is recharged daily, (3) hydrogen flux is high enough to reach the surface without being buffered by water or bacterial activity within the soil and (4) soil cannot be solely considered as a hydrogen sink but also, at least in some areas, as a hydrogen emitter. This appears to highlight that the subsurface may be considered in this site as a source of natural hydrogen, clearly differentiated from a biochemical system of atmospheric H2 consumed by bacteria.  相似文献   

4.
On September 22, 2021, 5 experts from Brazil and 5 from Italy discussed the future of research-to-business (R2B) cooperation between Italy and Brazil on green hydrogen (H2) and related technologies. The workshop discussed some priorities of the Brazilian policies and elucidated the strengths and the weaknesses of the biggest economy among the Latin American countries. Because of its territorial and underground resources its social and economic activities, Brazil offers an excellent basin for supporting an H2-based economy. A well-established connection between Brazilian Universities and EU research organisations already exists in up-to-date research activities and frameworks for grants programmes. Nevertheless, Brazil has some difficulties creating new economies through the industrialisation of research achievements. On the other hand, Italy has a long tradition of creating and exporting technologies because its enterprises are generally prone to creating new business.In this communication, we reported the argued discussions between Brazilian and Italian players on green hydrogen that discussed how to improve the technological interaction between the two countries. This meeting discussed the entire value chain for green hydrogen, from the production to the end-user, and included distribution and commercialisation of green H2 and related technologies.  相似文献   

5.
Geothermal power plants emit high amount of hydrogen sulfide (H2S). The presence of H2S in the air, water, soils and vegetation is one of the main environmental concerns for geothermal fields. There is an increasing interest in developing suitable methods and technologies to produce hydrogen from H2S as promising alternative solution for energy requirements. In the present study, the AMIS technology is the invention of a proprietary technology (AMIS® - acronym for “Abatement of Mercury and Hydrogen Sulfide” in Italian language) for the abatement of hydrogen sulphide and mercury emission, is primarily employed to produce hydrogen from H2S. A proton exchange membrane (PEM) electrolyzer operates at 150 °C with gaseous H2S sulfur dimer in the anode compartment and hydrogen gas in the cathode compartment. Thermodynamic calculations of electrolysis process are made and parametric studies are undertaken by changing several parameters of the process. Also, energy and exergy efficiencies of the process are calculated as % 27.8 and % 57.1 at 150 °C inlet temperature of H2S, respectively.  相似文献   

6.
This work analysed the permeation of binary and ternary H2-containing mixtures through a SAPO-34 membrane, aiming at investigating how hydrogen influences and its permeation is influenced by the presence of the other gaseous species, such as CO2 and CH4. We considered the behaviour of various gas mixtures in terms of permeability and selectivity at various temperatures (25–300 °C), feed pressures (400–1000 kPa) and compositions by means of an already validated mass transport model, which is based on surface and gas translation diffusion. We found that the presence of CO2 and CH4 in the H2-containing mixtures influences in a similar way the H2 permeation, reducing its permeability of about 80% compared to the single-gas value because of their stronger adsorption. On the other hand, H2 promotes the permeation of CO2 and CH4, causing an increment of their permeability with respect to those as single gases. These combined effects reflected in interesting selectivity values in binary mixture (e.g., CO2/H2 about 11 at 25 °C, H2/CH4 about 9 at 180 °C), which showed the potential of SAPO-34 membranes in treating of H2-containing mixtures.  相似文献   

7.
Subsurface geological reservoirs of natural hydrogen gas (H2), a clean fuel and energy vector, are currently a target for energy resource exploration. Such reservoirs can be revealed by the presence of H2 within soil, analogous to hydrocarbon seepage in petroleum systems. Nevertheless, defining the level of soil H2 that can indicate a potentially economic resource is currently impossible, and identifying geological H2 within soil-gas is challenging because H2 concentrations and the isotopic composition (δ2H) may overlap with the in-situ biological signature. In spite of these limitations, analogies to conventional hydrocarbon systems suggest that the presence of surface advective gas flows can reveal (unlike diffusion) a subsoil source and even pressurised gas accumulations of H2. Here, a massive release of H2 is reported from a CH4–H2 rich seep in Turkey, known as Chimaera, an emblematic example of H2 advection. The site represents the first case where a closed-chamber flux method was applied for H2 seepage. H2 advection at the site was clearly indicated by numerous gas vents and flames, and by the heterogeneous spatial distribution of pervasive, invisible exhalation (miniseepage), inducing rapid H2 concentration build-up within the chamber. H2 emission (~10 ± 3 kg day?1, with the highest H2 emission factor reported, thus far, of ~5000 kg km?2 day?1) is continuous and long lasting (flames have been documented for millennia) and, using an analogy for hydrocarbon seeps, may stem from pressurised accumulations. The Chimaera case is illustrative of how detecting soil H2 advection may help unravel surface (biological) vs. subsoil (geological) gas origins in cases where, in the absence of significant gas seepage, soil H2 concentrations are within the range of biological production (100-103 ppmv, e.g., as for “fairy circles” observed in several countries). Interpretations must, however, be supported by additional geochemical data and evaluations of potential biological H2 production within the surface ecosystem.  相似文献   

8.
The subject of this study is the analysis of influence of capillary threshold pressure and injection well location on the dynamic CO2 and H2 storage capacity for the Lower Jurassic reservoir of the Sierpc structure from central Poland. The results of injection modeling allowed us to compare the amount of CO2 and H2 that the considered structure can store safely over a given time interval. The modeling was performed using a single well for 30 different locations, considering that the minimum capillary pressure of the cap rock and the fracturing pressure should not be exceeded for each gas separately.Other values of capillary threshold pressure for CO2 and H2 significantly affect the amount of a given gas that can be injected into the reservoir. The structure under consideration can store approximately 1 Mt CO2 in 31 years, while in the case of H2 it is slightly above 4000 tons. The determined CO2 storage capacity is limited; the structure seems to be more prospective for underground H2 storage. The CO2 and H2 dynamic storage capacity maps are an important element of the analysis of the use of gas storage structures. A much higher fingering effect was observed for H2 than for CO2, which may affect the withdrawal of hydrogen. It is recommended to determine the optimum storage depth, particularly for hydrogen. The presented results, important for the assessment of the capacity of geological structures, also relate to the safety of use of CO2 and H2 underground storage space.  相似文献   

9.
We have applied ab initio random structure searching to study the structure, stability and hydrogen storage properties of monolayer TiS2 coated with Li and small Li2O clusters. For the low Li covered system we found a complex adsorption mechanism: some hydrogen molecules were adsorbed due to polarization with Li, others due to polarization with S near the surface of TiS2. The peculiarities of the interaction of the H2 molecules with each other and the preferred adsorption sites allowed us to formulate a series of recommendations that can be useful when selecting the material for the most effective support. Moreover, the findings also show that the storage capacity of this system can reach up to 9.63 wt%, presenting a good potential as hydrogen storage material. As for the Li2O clusters supported on TiS2, we found that the polarization of the Li–O bond increases upon the adsorption of the Li2O nanocluster. Moreover, the polarized Li–S bonds appear in addition to the already existing Li–O bonds. All this is possible due to the extraction of 1.46 electrons from the S atom of the substrate by O atom of the cluster, and should contribute to an increase in both the adsorption energy and the maximum capacity. The adsorption energies of H2 for the systems studied here are within 0.11–0.16 eV/H2 which is a recommended range for reversible hydrogen physisorption under standard test conditions. This study may stimulate experimental efforts to check the claims of high-capacity, stable and reversible hydrogen adsorption reported here.  相似文献   

10.
Wind and solar photovoltaic electricity production have already reached very low levels of levelized cost of energy (LCOE). Electrolyzers have already reached high efficiencies which are further improving, while costs are dramatically reducing. They are commercial products. Green hydrogen (H2) is the product of excess wind and solar electricity, specifically electricity that will be otherwise wasted, without the huge energy storage needed presently almost completely missing. By growing the installed capacity of wind and solar power plants, there will be a non-dispatchable production by wind and solar more often in excess, but sometimes also in defect, of the grid demand, in presence of limited energy storage. H2 is one of the key energy storage technologies needed to ensure grid stability. Production of H2 above what is needed to stabilize the grid significantly helps in applications such as land, and sea but especially air transport where the storage of energy onboard in a fuel is preferable to the storage of energy as electricity into a battery. The engineered diagenesis for H2 is unlikely better than green hH2. Apart from being a nice idea to be proven workable, with a technology readiness level (TRL) presently of zero, and thus impossible to be objectively compared with commercial products, the engineered diagenesis for H2, even if possible, also does not help with non-dispatchable renewable energy production. The concept may also have negative environmental aspects similar to fracking which have not been considered yet, and also bear huge economic costs in addition to environmental. Here we review the pros and cons of this novel technology, which once proven workable, which is not the case yet, should be considered as a possible way to complement rather than replace green H2 production.  相似文献   

11.
Binding of group 8B transition metals (TMs) on Si2BN nanotubes and the adsorption of H2 molecules on TM-decorated Si2BN nanotubes are investigated in the framework of first principles-based density functional theory (DFT). Our results show the adsorption energy of H2 molecule on TM-decorated Si2BN nanotube (−2.57 eV) to be greater than those of the other reported adsorbents. The enhancement of the adsorption property is attributed to the structural deformation and the induced charge transfer between TM–decorated Si2BN nanotube and the hydrogen molecule. Our findings reveal the TM–decorated Si2BN nanotubes to be highly sensitive to the presence of H2 molecules. Additionally, we also investigated the adsorption process of multiple H2 molecules on TM-decorated Si2BN nanotubes. Our observations lead us to surmise that the maximum storage number of H2 molecules adsorbed over the TM-decorated Si2BN nanotubes is four. These results suggest useful potential for the TM-decorated Si2BN nanotube to be considered as an appropriate medium for hydrogen storage.  相似文献   

12.
The present study develops a new solar and geothermal based integrated system, comprising absorption cooling system, organic Rankine cycle (ORC), a solar-driven system and hydrogen production units. The system is designed to generate six outputs namely, power, cooling, heating, drying air, hydrogen and domestic hot water. Geothermal power plants emit high amount of hydrogen sulfide (H2S). The presence of H2S in the air, water, soils and vegetation is one of the main environmental concerns for geothermal fields. In this paper, AMIS(AMIS® - acronym for “Abatement of Mercury and Hydrogen Sulphide” in Italian language) technology is used for abatement of mercury and producing of hydrogen from H2S. The present system is assessed both energetically and exergetically. In addition, the energetic and exergetic efficiencies and exergy destruction rates for the whole system and its parts are defined. The highest overall energy and exergy efficiencies are calculated to be 78.37% and 58.40% in the storing period, respectively. Furthermore, the effects of changing various system parameters on the energy and exergy efficiencies of the overall system and its subsystems are examined accordingly.  相似文献   

13.
The high production of sugarcane in Brazil and its application of ethanol and sugar production results in a higher generation of vinasse and bagasse. The treatment of these residues can be carried out using anaerobic co-digestion procedures. Besides promoting waste treatment, it enables energy exploration through biogas and hydrogen generation. Bioenergy use can also generate steam in sugar and alcohol plants by burning, sugarcane milling, fueling vehicles for the transport of products, among others. These energy applications allow total and efficient, energetic exploring of sugarcane. Hence, this study estimated the production of methane, hydrogen, thermal and electrical energy generated from vinasse and bagasse in the autonomous and annexed Brazilian ethanol and sugar plants. Three scenarios present the use of biogas generated: Scenario 1: energy use of all methane from biogas; Scenario 2: hydrogen production from the remaining methane, after considering the energy autonomy of the ethanol plants; Scenario 3: hydrogen production from all the methane generated. All the scenarios which considered the use of methane led to energy self-sufficiency in the sector. However, only annexed plants present economic feasibility for implementing the project. Scenario 2 is highlighted in this study, once beyond the sector's energetic self-sufficiency, the operational conditions enabled the storage of 9.26E+07 Nm3.d?1 of hydrogen, equal 3.04E+08 ton per year. CH4 and H2 production seen in a global scenario of circular economy and energy security have high benefits, contributing to the gradual transformation of an economy dependent on non-renewable resources into a circular and renewable economy.  相似文献   

14.
In this study, we studied defect-engineering and lithium decoration of 2D phosphorene for effective hydrogen storage using density functional theory. Contrary to graphene, it is found that the presence of point-defects is not preferable for anchoring of H2 molecules over defective phosphorene. According to previous research, strategies such as defect engineering, metal decoration, and doping enhance the hydrogen storage capacity of several 2D materials. Our DFT simulations show that point defects in phosphorene do not improve the hydrogen storage capacity compared to pristine phosphorene. However, selective lithium decoration over the defective site significantly improves the hydrogen adsorption capacity yielding a binding energy of as high as ?0.48 eV/H2 in Li-decorated single vacancy phosphorene. Differential charge densities and projected density of states have been computed to understand the interactions and charge transfer among the constituent atoms. Strong polarization of the H2 molecule is evidenced by the charge accumulation and depletion. The PDOS shows that the presence of Li leads to enhanced charge transfer. The maximum gravimetric density was investigated by sequentially adding H2 molecules to the Li-decorated single vacancy defective phosphorene. The Li-decorated single vacancy phosphorene is found to possess a gravimetric density of around 5.3% for hydrogen storage.  相似文献   

15.
The most troublesome problems in making blue hydrogen are fugitive emissions of methane in extraction, transportation, and in converting methane to hydrogen by the SMR-WGS-PSA that needs burning methane to provide endothermic heat. The solution is to generate blue hydrogen on the extraction site and use a part of the hydrogen to make electricity on site by a hydrogen fuel cell that also provides steam and heat and eliminates H2 burning. CO2 emissions are sequestered by pushing the gas into geological formations from which fossil gas was extracted. Another alternative is to use a half of the produced H2 to make ammonia on-site by the Haber- Bosh process along with the electricity by the hydrogen fuel cell that also provides concentrated nitrogen from air used to oxidize hydrogen. Turquoise hydrogen conversion wherein high heat or plasma converts methane to COx free hydrogen is promising and produces valuable solid carbon and graphene byproducts.  相似文献   

16.
17.
The effects of CO and H2S as catalyst inhibitors on the rate of toluene hydrogenation were studied as a means of hydrogen storage using low-grade hydrogen. Pd/SiO2 suffered serious negative effects from catalyst inhibitors; however, Pd/TiO2–SiO2 exhibited high CO and H2S tolerance because the acidic support decreased the electron density of the Pd metal particles, which, in turn, decreased the interaction between the Pd surface and CO (or H2S). The TiO2–SiO2-supported Pd catalyst exhibited activity greater than that of the TiO2–SiO2-supported Pt catalyst in the presence of CO; however, it exhibited lower activity in presence of H2S. Catalyst characterization after sulfidation with H2S revealed that Pd particles were fully sulfided, whereas Pt particles were sulfided only on their surface. We concluded that Pd catalysts supported on acidic oxides exhibit excellent activity toward toluene hydrogenation in the presence of CO and that Pt catalysts exhibit excellent activity in the presence of H2S.  相似文献   

18.
Biohydrogen production is a cheap and clean way to obtain hydrogen gas. In subtropical countries such as Brazil the average temperatures of 27 °C can favor the hydrogen producing bacteria growth. A mixed culture was obtained from a subtropical sludge treating brewery wastewater and anaerobic batch reactors were fed with glucose, sucrose, fructose and xylose in low concentrations (2.0, 5.0 and 10.0 g L−1) at 37 °C, initial pH 5.5 and headspace with N2 (99%) to maintain the anaerobic conditions. The inoculum was a subtropical granulated sludge from UASB (Upflow Anaerobic Sludge Blanket) reactor treating brewery wastewater. The higher H2 yields were obtained in reactors operated with 2 and 5 g L−1 of fructose and they were 1.5 mol H2 mol−1 of fructose and 1.3 mol H2 mol−1 of sucrose, respectively. The volatile fatty acids (VFA) generated at the end of operation were, predominantly, butyric and acetic acid, indicating the favoring of the metabolic route of hydrogen generation by the consortium of anaerobic bacteria from the brewery wastewater. Biomolecular analyses revealed the predominance of hydrogen producing bacteria from Firmicutes phylum distributed in the families Streptococcaceae, Veillonellaceae and uncultured bacteria. These results confirm future applications of subtropical sludges with agroindustrial wastewaters containing low concentrations of sugars on hydrogen generation.  相似文献   

19.
Energy security is an issue at stake in governments all over the world, and also in Brazil. Although the country's energetic matrix is largely based on hydropower sources, the need for diversification is increasingly needed. The possibility of hybrids between hydropower and wind power for hydrogen production emerges as a clean alternative source for energy security. In high-throughput seasons, excess energy could be used to produce hydrogen, which could supply shortages of energy. This study shows the potential for producing hydrogen in Brazil, using excess energy from hydroelectric and wind farms. Taking into account one hour per day of surplus energy production, it would be possible to generate 6.50E+09 Nm³.y−1 of H2. On the other hand, considering two and three hours, the H2 generation would be equal to 1.30E+10 Nm³.y−1 and 2.00E+10 Nm³.y−1, respectively. This study calculated the economic viability for hydrogen production, at a cost of 0.303 USD.kWh−1, a higher cost if compared to that of the wind and hydroelectric plants.  相似文献   

20.
Owing to its high energy density and environmentally friendly nature, hydrogen has already been regarded as the ultimate energy of the 21st century and gained significant attention from the worldwide researchers. Meanwhile, there are increasing concerns about its safe use, storage and transport as, despite being colorless and odorless, after certain concentration level it becomes flammable and explosive in air. Therefore, it is imperative to develop H2 sensors for real-time monitoring of the H2 leakage for an early warning. This paper firstly introduces the general hydrogen gas sensing mechanism of TiO2-based hydrogen sensors. Then we summarize and comment on the current hydrogen gas sensor based on various TiO2 materials, which include pristine TiO2, metal-assisted TiO2, organic-TiO2 composites, carbon-TiO2 composites, MOX-TiO2 composites and novel sensor concept with effective top-bottom electrode configuration. Finally, we briefly discuss the obstacles that TiO2-based H2 sensors have to overcome in the progress of the systematically practical application, possible solutions, and future research perspectives that can be focused in this area.  相似文献   

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