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  • Effects of metals in wastewater on hydrogen gas production using electrohydrolysis
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-03-21
    Ebru Çokay; Yasin Gürler

    Hydrogen gas was produced from metal plating wastewater by electro hydrolysis. Wastewater contains chrome, copper and nickel metals which can accelerate the production of hydrogen gas. Effects of kind of metals, the voltage and reaction time on percent hydrogen gas (HGP) were investigated. After application of different DC voltages on each metallic wastewater, percent hydrogen gas (HGP), cumulative hydrogen gas volume (CHGV), hydrogen gas formation rate (HFR) and total organic carbon (TOC) removal were also evaluated. Hydrogen gas percent was obtained as %99 at 4 V for chrome plating wastewater while percent hydrogen gas was achieved as 50% H2 gas at 4 V for copper and nickel metal plating wastewater. Maximum CHGV achieved with 4 V DC voltage for all metal plating wastewater. Maximum CHGV (4000 mL), HFR (985 mL H2 d−1) and percent hydrogen gas (99%) was observed with chrome plating wastewater at 4 V DC voltage. Hydrogen gas produced from chrome metal plating wastewater using electro hydrolysis method can be efficiently used for fuel cells as a source due to nearly pure hydrogen gas.

    更新日期:2020-01-17
  • The potential role of hydrogen as a sustainable transportation fuel to combat global warming
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2018-11-23
    Canan Acar; Ibrahim Dincer

    Hydrogen is recognized as a key source of the sustainable energy solutions. The transportation sector is known as one of the largest fuel consumers of the global energy market. Hydrogen can become a promising fuel for sustainable transportation by providing clean, reliable, safe, convenient, customer friendly, and affordable energy. In this study, the possibility of hydrogen as the major fuel for transportation systems is investigated comprehensively based on the recent data published in the literature. Due to its several characteristic advantages, such as energy density, abundance, ease of transportation, a wide variety of production methods from clean and renewable fuels with zero or minimal emissions; hydrogen appears to be a great chemical fuel which can potentially replace fossil fuel use in internal combustion engines. In order to take advantage of hydrogen as an internal combustion engine fuel, existing engines should be redesigned to avoid abnormal combustion. Hydrogen use in internal combustion engines could enhance system efficiencies, offer higher power outputs per vehicle, and emit lower amounts of greenhouse gases. Even though hydrogen-powered fuel cells have lower emissions than internal combustion engines, they require additional space and weight and they are generally more expensive. Therefore, the scope of this study is hydrogen-fueled internal combustion engines. It is also highlighted that in order to become a truly sustainable and clean fuel, hydrogen should be produced from renewable energy and material resources with zero or minimal emissions at high efficiencies. In addition, in this study, conventional, hybrid, electric, biofuel, fuel cell, and hydrogen fueled ICE vehicles are comparatively assessed based on their CO2 and SO2 emissions, social cost of carbon, energy and exergy efficiencies, fuel consumption, fuel price, and driving range. The results show that when all of these criteria are taken into account, fuel cell vehicles have the highest average performance ranking (4.97/10), followed by hydrogen fueled ICEs (4.81/10) and biofuel vehicles (4.71/10). On the other hand, conventional vehicles have the lowest average performance ranking (1.21/10), followed by electric vehicles (4.24/10) and hybrid vehicles (4.53/10).

    更新日期:2020-01-17
  • A review on the catalysts used for hydrogen production from ammonia borane
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-03-19
    Ceren Yüksel Alpaydın; Senem Karahan Gülbay; C. Ozgur Colpan

    Boron compounds have recently attracted attention in hydrogen production since they contain many hydrogen atoms. Among these compounds, ammonia borane, which has high hydrogen density (in weight basis), can be used to produce hydrogen through a hydrolysis reaction. However, since the ammonia borane solution is highly resistant to hydrolysis under ambient conditions, there is a need for active and stable catalysts to accelerate the reaction. In this review paper, unsupported and carbon-based supported metal catalysts used for hydrogen production through the hydrolysis of ammonia borane are presented. Noble metal catalysts (Ru, Rh, Pd, Pt and their binary and ternary alloys) and non-noble metal catalysts (Co, Ni, Fe, Cu and their binary and ternary alloys) were examined. The activation energy of reaction and turnover frequency (TOF) values were compared for these catalysts. Among the unsupported catalysts, it was concluded that the multi-metal catalyst systems (binary, ternary and quaternary) have higher catalytic activity than a single use of the same metals. In addition, the comparison showed that the supported catalysts are more resistant to catalytic cycles and suitable for long-term use. It was observed that CNT supported Rh (TOF = 706 mol H2 mol cat−1 min−1) and graphene supported Ru (TOF = 600 mol H2 mol cat−1 min−1) catalysts are the most active catalysts for the hydrogen generation from the ammonia borane at room temperature.

    更新日期:2020-01-17
  • Effect of fuel blend composition on hydrogen yield in co-gasification of coal and non-woody biomass
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-03-15
    Busra Cabuk; Gozde Duman; Jale Yanik; Hayati Olgun

    In this study, torrefaction of sunflower seed cake and hydrogen production from torrefied sunflower seed cake via steam gasification were investigated. Torrefaction experiments were performed at 250, 300 and 350 °C for different times (10–30 min). Torrefaction at 300 °C for 30 min was selected to be optimum condition, considering the mass yield and energy densification ratio. Steam gasification of lignite, raw- and torrefied biomass, and their blends at different ratios were conducted at downdraft fixed bed reactor. For comparison, gasification experiments with pyrochar obtained at 500 °C were also performed. The maximum hydrogen yield of 100 mol/kg fuel was obtained steam gasification of pyrochar. The hydrogen yields of 84 and 75 mol/kg fuel were obtained from lignite and torrefied biomass, respectively. Remarkable synergic effect exhibited in co-gasification of lignite with raw biomass or torrefied biomass at a blending ratio of 1:1. In co-gasification, the highest hydrogen yield of 110 mol/kg fuel was obtained from torrefied biomass-lignite (1:1) blend, while a hydrogen yield from pyrochar-lignite (1:1) blend was 98 mol/kg. The overall results showed that in co-gasification of lignite with biomass, the yields of hydrogen depend on the volatiles content of raw biomass/torrefied biomass, besides alkaline earth metals (AAEMs) content.

    更新日期:2020-01-17
  • Hydrogen production via thermochemical H2O splitting using CaSO4 – CaO redox reactions
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-03-27
    Rahul R. Bhosale

    By applying the principles of the second law of thermodynamics and utilizing the HSC Chemistry software, the thermodynamic equilibrium and efficiency analysis of the CaSO4CaO water splitting cycle was performed in this investigation. The temperatures desirable and the equilibrium compositions allied with the thermal reduction of CaSO4 and the re-oxidation of CaO via water splitting reaction were estimated. The obtained results indicate that the thermal reduction temperature (TH) required to completely decompose the CaSO4 was decerased from 2220 to 1890 K due to the rise in the molar flow rate of (n˙Ar) from 1 to 50 mol/s. In addition, the consequence of the TH, n˙Ar, and the water splitting temperature (TL) on the process parameters such as total amount of solar energy needed, re-radiation losses, energy dissipated by the water splitting reactor and others associated with the CaSO4CaO water splitting cycle was scrutinized. By utilizing higher n˙Ar from 1 to 50 mol/s, the TH was decreased from 2200 to 1890 K. However, as the n˙Ar was increased from 1 to 50 mol/s, the amount of heat energy needed to heat the Ar was also upsurged from 12.5 to 625.6 kW. This rise in the Q˙Ar−heating, directly reflected into an increase in the Q˙solar−cycle from 1063.4 up to 2653.9 kW. The findings of this study further confirms that the maximum solar-to-fuel energy conversion efficiency (ηsolar−to−fuel) equal to 27.4% was realized by conducting the CaSO4CaO water splitting cycle at TH = 2220 K, n˙Ar = 1 mol/s, and TL = 1100 K. By using 50% of the recuperable heat, the ηsolar−to−fuel of the CaSO4CaO water splitting cycle can be enhanced up to 36.2%.

    更新日期:2020-01-17
  • Design and analysis of a combined floating photovoltaic system for electricity and hydrogen production
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-01-30
    Mert Temiz; Nader Javani

    The current study deals with a potential solution for the replacement of fossil fuel based energy resources with a sustainable solar energy resource. Electrical energy demand of a small community is investigated where a floating photovoltaic system and integrated hydrogen production unit are employed. Data are taken from Mumcular Dam located in Aegean Region of Turkey. PvSyst software is used for the simulation purposes. Furthermore, the obtained results are analyzed in the HOMER Pro Software. Photovoltaic (PV) electricity provides the required load and excess electricity to be used in the electrolyzer and to produce hydrogen. Saving lands by preventing their usage in conventional PV farms, saving the water due to reducing evaporation, and compensating the intermittent availability of solar energy are among the obtained results of the study for the considered scenario. Stored hydrogen is used to compensate the electric load through generating electricity by fuel cell. Floating PV (FPV) system decreases the water evaporation of water resources due to 3010 m2 shading area. FPV and Hydrogen Systems provides %99.43 of the electricity demand without any grid connection or fossil fuel usage, where 60.30 MWh/year of 211.94 MWh/year produced electricity is consumed by electric load at $0.6124/kWh levelized cost of electricity (LCOE).

    更新日期:2020-01-17
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  • Biohydrogen production from acid hydrolyzed wastewater treatment sludge by dark fermentation
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-04-17
    Karapinar Ilgi; Balcan Onur

    Waste generation, waste management, sustainable energy production, and global warming are interrelated environmental issues to be considered together. Wastewater treatment sludge is an organic substance rich waste which causes significant environmental problems. However, these wastes can be used as raw material in biofuel generation. This study was designed to investigate the possible utilization of waste sludge in biohydrogen production by taking these facts into consideration. For this purpose, the sludge was first pre-treated with acid and then, the solid (sludge) and liquid (filtrate) phases of acid pre-treated sludge were used as the substrates for biohydrogen generation dark fermentation. Two-factor factorial experimental design method was used in acid hydrolysis of sludge to determine the effect of pH (pH = 2–6) and reaction period (time, min) elution of chemical oxygen demand (COD), total organic carbon (TOC) and total sugar (TS), NH4N and PO4P. Statistical evaluation of the results indicated that pH significantly affects the elution of organic carbon and nutrient content of sludge while the reaction time is significant for only organic carbon content. The optimum pretreatment conditions for maximum organic and nutrient elution were determined as pH = 2 and t = 1440 min. The pretreated products, named as filtrate sludge and sludge, conducted to dark fermentation under mesophilic conditions for biohydrogen generation showed that pretreatment of waste sludge at pH = 6 is the best condition giving the maximum yields (YH2) as YH2 = 24 mmol g−1 Total Sugar consumed and YH2 = 41 mmol g−1 Total sugar consumed, for filtrate and sludge, respectively.

    更新日期:2020-01-17
  • Application of aspen plus to renewable hydrogen production from glycerol by steam reforming
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-03-09
    Derya Unlu; Nilufer Durmaz Hilmioglu

    Steam reforming is the most favored method for the production of hydrogen. Hydrogen is mostly manufactured by using steam reforming of natural gas. Due to the negative environmental impact and energy politics, alternative hydrogen production methods are being explored. Glycerol is one of the bio-based alternative feedstock for hydrogen production. This study is aimed to simulate hydrogen production from glycerol by using Aspen Plus. First of all, the convenient reactor type was determined. RPlug reactor exhibited the highest performance for the hydrogen production. A thermodynamic model was determined according to the formation of byproduct. The reaction temperature, water/glycerol molar feed ratio as reaction parameters and reactor pressure were investigated on the conversion of glycerol and yield of hydrogen. Optimum reaction parameters are determined as 500 °C of reaction temperature, 9:1 of water to glycerol ratio and 1 atm of pressure. Reactor design was also examined. Optimum reactor diameter and reactor length values were determined as 5 m and 50 m, respectively. Hydrogen purification was studied and 99.9% purity of H2was obtained at 25 bar and 40 °C. The obtained results were shown that Aspen Plus has been successfully applied to investigate the effects of reaction parameters and reactor sizing for hydrogen production from glycerol steam reforming.

    更新日期:2020-01-17
  • Microarray analysis of high light intensity stress on hydrogen production metabolism of Rhodobacter capsulatus
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-01-22
    Muazzez Gürgan; Harun Koku; Inci Eroglu; Meral Yücel

    Biohydrogen obtained from purple non sulfur bacteria (PNSB) is an environmentally friendly alternative for hydrogen production. PNSB can be employed in large scale outdoor photobioreactors to produce hydrogen by photofermentation with sunlight as the light source. In external environmental conditions, however, bacteria can experience stress due to high light intensities, which can inhibit or slow down hydrogen production. Previous studies with other PNSB showed varying responses to light intensities (above 4000 lux), in some cases improving, and in others adversely affecting hydrogen production. In this study, Rhodobacter capsulatus, a PNSB species that produce hydrogen efficiently from dark fermenter effluents containing acetate, was used to investigate the effects of high light intensity stress on the hydrogen production metabolism at the gene expression level. A microarray analysis was carried out using a custom-design Affymetrix GeneChip TR_RCH2a520699F. R. capsulatus DSM1710 was grown under a cyclic illumination of 2000 and 7000 lux (12 h light/12 h dark) in a hydrogen production medium having 30 mM acetate and 2 mM glutamate, and was exposed to a high light intensity (10,000 lux) for 1 h in the middle of a light period. The results reveal that photosynthetic reaction center genes were down-regulated in order to protect the photosynthetic membrane from damage. On the other hand, the expression of nitrogenase and electron transport system genes were enhanced by high light intensity. These results show that a high light intensity stress drives R. capsulatus to direct gene expression towards hydrogen production, which supports the hypothesis that hydrogen production is a way for the disposal of excess reducing equivalents to maintain the internal redox balance.

    更新日期:2020-01-17
  • The effect of hydraulic retention time on thermophilic dark fermentative biohydrogen production in the continuously operated packed bed bioreactor
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-01-23
    Ilgi Karapinar; Pelin Gokfiliz Yildiz; Recep Tugcan Pamuk; Firuze Karaosmanoglu Gorgec
    更新日期:2020-01-17
  • Enhanced hydrogen purification by graphene - Poly(Dimethyl siloxane) membrane
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-01-29
    Filiz Ugur Nigiz; Nilufer Durmaz Hilmioglu

    In this study, a nanocomposite graphene oxide (GO) incorporated poly (dimethyl siloxane) (PDMS) membrane was produced and used for the purification of hydrogen (H2) by separating the (CO2). The produced membrane was characterized and the single-gas permeability test was performed. Effects of GO addition, trans-membrane pressure and membrane thickness on the gas separation performance of membrane were evaluated as a function of permeability and CO2/H2 selectivity. GO addition increased the CO2/H2 selectivity and H2 purification performance. The highest CO2 permeability of 3670 Barrer and CO2/H2 selectivity of 11.7 were obtained when the GO loading was 0.5 wt% when the trans-membrane pressure was 0.2 Mpa.

    更新日期:2020-01-17
  • Numerical modeling of a downdraft plasma coal gasifier with plasma reactions
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-01-24
    Beycan Ibrahimoglu; M. Zeki Yilmazoglu

    In this paper, a 3D numerical simulation of a downdraft plasma gasifier with plasma reactions is conducted. The effects of the equivalence ratio (ER) on the syngas properties in the presence of the plasma reactions are investigated. The boundary conditions for the air plasma inlet of the gasifier are obtained from the outlet of a 10 kW microwave plasma generator. A conventional gasification analysis is carried out to validate the model. In the second part of the study, plasma reactions are added to conventional gasification equations. Mole fractions of the constituents of the syngas and temperature contours are obtained for different ER values. According to the results, with the increase of ER from 0.20 to 0.45 the lower heating value of the produced syngas decreased from 1536.6 kcal/m3 to 751.8 kcal/m3.

    更新日期:2020-01-17
  • Optimum energy evaluation and life cycle cost assessment of a hydrogen liquefaction system assisted by geothermal energy
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-04-15
    Ceyhun Yilmaz

    In this study, analyses of the thermodynamic performance and life cycle cost of a geothermal energy-assisted hydrogen liquefaction system were performed in a computer environment. Geothermal water at a temperature of 200 °C and a flow rate of 100 kg/s was used to produce electricity. The produced electricity was used as a work input to liquefy the hydrogen in the advanced liquefaction cycle. The net work requirement for the liquefaction cycle was calculated as 8.6 kWh/kg LH2. The geothermal power plant was considered as the work input in the liquefaction cycle. The hydrogen could be liquefied at a mass flow rate of 0.2334 kg/s as the produced electricity was used directly to produce liquid hydrogen in the liquefaction cycle. The unit costs of electricity and liquefied hydrogen were calculated as 0.012 $/kWh and 1.44 $/kg LH2. As a result of the life cycle cost analysis of the system, the net present value (NPV) and levelized annual cost (LAC) were calculated as 123,100,000 and 14,450,000 $/yr. The simple payback period (Nspp) and discount payback period (Ndpp) of the system were calculated as 2.9 and 3.6 years, respectively.

    更新日期:2020-01-17
  • Bimetallic palladium-cobalt nanomaterials as highly efficient catalysts for dehydrocoupling of dimethylamine borane
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-02-15
    Betül Şen; Ayşenur Aygün; Aysun Şavk; Mehmet Harbi Çalımlı; Senem Karahan Gülbay; Fatih Şen

    In this work, we report the synthesis, characterization and application of graphene oxide stabilized PdCo nanoparticles ([email protected]) for the dehydrocoupling of dimethylamine borane (DMAB) as a model reaction. Bimetallic graphene oxide stabilized PdCo nanoparticles were readily synthesized using an ultrasonic reduction technique, in which both metals of Pd and Co were reduced with GO. The dispersion of PdCo nanoparticles on the surface of GO was enhanced with the help of the ultrasonic reduction method which result in the enhancing of dispersion of both metals without any agglomeration problem. The characterization studies revealed that graphene oxide stabilized PdCo nanoparticles have a uniform, homogeneous distribution on graphene oxide and an average particle size of 3.48 ± 0.22 nm. After fully characterization of graphene oxide stabilized PdCo nanoparticles, they have been tried in model reaction as a catalyst and exhibited a high catalytic performance compared the previous catalysts in literature with a TOF value of 226.80 h−1. The investigation of kinetic parameters showed that graphene oxide stabilized PdCo nanoparticles have very high negative entropy (ΔS: −170.85 J mol−1 K−1) value and a low activation energy value (Ea: 17.53 ± 2 kJ mol−1) for the model reaction.

    更新日期:2020-01-17
  • Modeling and analysis of a model solid oxide fuel cell running on low calorific value coal gases
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-02-23
    Mustafa İlbaş; Berre Kümük

    Solid oxide fuel cell (SOFC) is a device that produces electricity directly from oxidizing a fuel. Some of the advantages are operating at high temperatures and converting various hydrocarbon fuels directly into electricity. This study investigates the parameters that influence the cell characteristics of a cathode-supported SOFC (CSSOFC) model. Numerical modeling has been performed utilizing low calorific value coal gases, generator gas, and water gas by deriving an SOFC model based on finite element method (FEM). The effects of fuel compositions, temperature, pressure, and porosity on the performance of the developed SOFC have been examined using COMSOL software. These effects are presented by polarization and power curves. A mathematical model has been developed to determine the performance of a CSSOFC with low calorific value coal gases that were obtained from Turkey/Turk coal. It is predicted that the performance of CSSOFC is higher than that of the electrolyte-supported SOFC (ES-SOFC) for all studied fuels. Besides this, the cost of the cathode supporting materials for high-performance CSSOFC is low. The performance of SOFC using water gas is higher than that of the generator gas. This being maybe the hydrogen content of the water gas is higher compared with the generator gas. Therefore, the result confirmed that low calorific value coal gases could be used in SOFCs as a source of fuel. Moreover, the power of the CSSOFC increases as the pressure, temperature, and hydrogen content increase.

    更新日期:2020-01-17
  • Energy and exergy performance assessments of a high temperature-proton exchange membrane fuel cell based integrated cogeneration system
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-02-22
    Yagmur Nalbant; C. Ozgur Colpan; Yilser Devrim

    High-temperature proton exchange membrane fuel cell (HT-PEMFC), which operates between 160 °C and 200 °C, is considered to be a promising technology, especially for cogeneration applications. In this study, a mathematical model of a natural gas fed integrated energy system based on HT-PEMFC is first developed using the principles of electrochemistry and thermodynamics (including energy and exergy analyses). The effects of some key operating parameters (e.g., steam-to-carbon ratio, HT-PEMFC operating temperature, and anode stoichiometric ratio) on the system performance (electrical, cogeneration, and exergetic efficiencies) are examined. The exergy destruction rates of each component in the integrated system are found for different values of these parameters. The results show that the most influential parameter which affects the performance of the integrated system is the anode stoichiometric ratio. For the baseline conditions, when the anode stoichiometric ratio increases from 1.2 to 2, the electrical, cogeneration, and exergetic efficiencies decrease by 42.04%, 33.15%, and 37.39%, respectively. The highest electrical power output of the system is obtained when the SCR, operating temperature, and anode stoichiometric ratio are taken as 2, 160 °C, and 1.2, respectively. For this case, the electrical, cogeneration, and exergetic efficiencies are found as 26.20%, 70.34%, and 26.74%, respectively.

    更新日期:2020-01-17
  • The effects of driving patterns and PEM fuel cell degradation on the lifecycle assessment of hydrogen fuel cell vehicles
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-02-13
    Pouria Ahmadi; Seyed Hosein Torabi; Hadi Afsaneh; Yousef Sadegheih; Hadi Ganjehsarabi; Mehdi Ashjaee

    This research paper mainly deals with the realistic simulation of hydrogen fuel cell vehicles and the development of a lifecycle assessment (LCA) tool to calculate and compare the environmental impacts of hydrogen fuel cell passenger vehicles with conventional vehicles. Since fuel cell vehicles are equipped with regenerative braking, they have strong potential to recover an ample portion of the energy being wasted in the braking system. Thus, the driving cycle can significantly affect the performance of fuel cell vehicles. In order to investigate the effect of driving patterns, several driving patterns are considered, and both vehicle fuel economy and lifecycle emissions are calculated and compared. Fuel cell degradation, on the other hand, is another major problem fuel cell vehicles face. This is mainly caused by the starts/stops, acceleration/deceleration, membrane humidity variation and a high load of the engine. When the vehicle operates on various driving patterns, the fuel cell will degrade which eventually affects the fuel economy. The effect of fuel cell degradation is also investigated for these driving patterns, and the results are compared. The results showed that the highway driving cycle has the lowest total lifecycle emission compared to New York city driving cycle, the city of Surrey (CoS) driving cycle, and the UDDS driving cycles. The results also indicate that fuel cell degradation undesirably affected the average fuel economy of the vehicle for about 23%.

    更新日期:2020-01-17
  • Investigation of the effect of graphitized carbon nanotube catalyst support for high temperature PEM fuel cells
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-02-06
    Yılser Devrim; Elif Damla Arıca

    In this study, it is aimed to investigate the graphitization effect on the performance of the multi walled carbon nanotube catalyst support for high temperature proton exchange membrane fuel cell (HT-PEMFC) application. Microwave synthesis method was selected to load Pt nanoparticles on both CNT materials. Prepared catalyst was analyzed thermal analysis (TGA), Transmission Electron Microscopy (TEM) and corrosion tests. TEM analysis proved that a distribution of Pt nanoparticles with a size range of 2.8–3.1 nm was loaded on the Pt/CNT and Pt/GCNT catalysts. Gas diffusion electrodes (GDE) were manufactured by an ultrasonic spray method with synthesized catalyst. Polybenzimidazole (PBI) membrane based Membrane Electrode Assembly (MEA) was prepared for observe the performance of the prepared catalysts. The synthesized catalysts were also tested in a HT-PEMFC environment with a 5 cm2 active area at 160 °C without humidification. This study demonstrates the feasibility of using the microwave synthesis method as a fast and effective method for preparing high performance Pt/CNT and Pt/GCNT catalyst for HT-PEMFC. The HT-PEMFC performance evaluation shows current densities of 0.36 A/cm20.30 A/cm2 and 0.20 A/cm2 for the MEAs prepared with Pt/GCNT, Pt/CNT and Pt/C catalysts @ 0.6 V operating voltage, respectively. AST (Accelerated Stress Test) analyzes of MEAs prepared with Pt/GCNT and Pt/CNT catalysts were also performed and compared with Pt/C catalyst. According to current density @ 0.6 V after 10,000 potential cycles, Pt/GCNT, Pt/CNT and Pt/C catalysts can retain 61%, 67% and 60% of their performance, respectively.

    更新日期:2020-01-17
  • Degradations in porous components of a proton exchange membrane fuel cell under freeze-thaw cycles: Morphology and microstructure effects
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2018-11-22
    Adnan Ozden; Samaneh Shahgaldi; Jian Zhao; Xianguo Li; Feridun Hamdullahpur

    In this study, porous components of a proton exchange membrane (PEM) fuel cell, i.e., single-layer gas diffusion layer (GDL, carbon paper), double-layer GDL (microporous layer (MPL) deposited carbon papers), and catalyzed electrodes, are subjected to 60 repetitive freeze-thaw cycles between −40 °C and 30 °C under water-submerged conditions; and their morphological and microstructural characteristics are investigated at each 15 cycles and compared with those of virgin materials. The results indicate that consecutive cycling of temperature causes different degradation patterns in different components. The single-layer GDL shows a unique degradation mechanism, in which macro-scale pores volumetrically expand, and relatively small-scale hollows and cracks form on the polymeric binder and carbon fiber interfaces, respectively. For the double-layer GDL, large-scale surface cracks form on the MPL surface after 15 cycles, and the morphology and microstructure degradation gains momentum with the formation of these cracks, and upon completion of 30 cycles, large-scale carbon/hydrophobic agent flakes start to detach from the surface. For the catalyzed electrodes, due to their inherently cracked surface, the catalyst layers (CLs) degrade first through expansion of the cracks in the in- and through-plane directions, and then through swelling and agglomeration of the ionomer; and combination of these two patterns triggers detachment of large CL flakes from the surface, negatively affecting the microstructure.

    更新日期:2020-01-17
  • Assessment of NOx emissions of the Scimitar engine at Mach 5 based on a thermodynamic cycle analysis
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-03-14
    Tayfun Tanbay; Muhammed Bişar Uca; Ahmet Durmayaz

    The Scimitar engine is a new advanced propulsion system designed to propel the aircraft A2 of the LAPCAT project. It is a hybrid system that utilizes the features of turbofan, ramjet and air-turborocket. Hydrogen and air are used as the fuel and oxidant, respectively, while helium is used to transfer heat from the hot incoming air to the hydrogen in the engine. In this study, we present a thermodynamic cycle analysis of the Scimitar engine for the assessment of NOx emissions. The combustion of fuel is studied in detail with an equilibrium model taking into account various dissociation and formation reactions since high levels of temperatures are achieved in its combustion chamber. The NOx emissions of the engine at Mach 5 and the effects of fuel and air flow rates, cruise speed and altitude on these emissions are presented by solving a nonlinear system of equations formed through our novel thermodynamic model. The results show that the NO emissions of the engine can be diminished significantly by decreasing air flow rate, cruise speed and altitude and by increasing the fuel flow rate. The variations of NO2 emissions with these parameters are similar except the variation with altitude which has an inverse effect as compared to the variation of NO.

    更新日期:2020-01-17
  • Application of distributed combustion technique to hydrogen-rich coal gases: A numerical investigation
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-03-04
    Serhat Karyeyen; Mustafa Ilbas

    Distributed combustion has been a promising combustion technique, for enabling a more uniform thermal field, resulting in ultra-low pollutant emissions, reduced combustion noise, and enhanced combustion efficiency. This work examines combustion of hydrogen-rich coal gases derived from Turkish coal under distributed combustion conditions. Focus here is on obtaining a broadened flame and reducing pollutant emissions. Numerical modelling was carried out using a commercial code in order to predict the thermal field and pollutant emissions of the hydrogen-rich coal gases under distributed combustion conditions. A gas mixture (90% N2 and 10% CO2) was utilized to simulate controlled entrainment of hot reactive product gases into the fresh mixture prior to ignition in order to seek distributed combustion. The results showed that distributed combustion provided far more uniform thermal field that resulted in greatly reduced NOx emissions. The results also showed that the temperature difference between the maximum and exit temperature was reduced to approximately 200 K under distributed conditions. In addition, the NOx pollutant emissions predicted for each gas were reduced to near zero levels under high intensity distributed combustion conditions supporting the available experimental data. It has been concluded that enhanced thermal field uniformity and significantly reduced NOx emissions were achieved for hydrogen-rich coal gases under distributed conditions.

    更新日期:2020-01-17
  • Analysis of the effect of H2O content on combustion behaviours of a biogas fuel
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-02-27
    Murat Sahin; Mustafa Ilbas

    The present work deals with the biogas in a combustor with regard to its combustion features under differing conditions of H20 content and H2S. The content of water (H2O) vapour has been changed from 0% to 10% and a CFD code has been employed while implementing numerical investigations. In modelling, a combustion model (the PDF/Mixture Fraction) along with a turbulence model (the k-Ɛ standard turbulence model) has been utilised. This study also deals with the combustion performances of the biogas by the addition of a different quantity of H2O into the biogas. The Emissions and the flame temperature of the biogas through the combustor apparently seem to be strikingly affected by the changes in H2O contents. It is interesting to note that the flame temperature zones change their positions and advance to the burner's downstream. The rise in flame temperatures of the biogas can be attributed to the change in H2O content caused by a better fuel-air mixture. It is also observed that adding H2O into the biogas lowers the axial temperature levels.

    更新日期:2020-01-17
  • The changing role of diesel oil-gasoil-LPG and hydrogen based fuels in human health risk: A numerical investigation in ferry ship operations
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2019-04-03
    Ender Yalcin; Munir Suner

    The ships and on-road vehicles are two main emission sources in transportation. In the special form of the ships such as ferry ship, the passengers face with both of two sources because the passengers and vehicles could be proceeding simultaneously. Hence, the exposed emission value in g/m³ by passengers has rapidly increased in the ferries. In this study, the authors found that the vehicles produced emission average 1515 g/s. The calculated value of CO2, SO2, NO2, NO forms respectively, 153.6, 1.37, 0.138, 0.12 g/s. The impatient passengers could be exposed to these emissions more than the reference dose limits within a certain time period. Among these forms, we revealed SO2, NO2 and NO have health risk with HQ value within the 1-year period. The expected symptoms could be summarized respiratory paralysis, damage to liver, lung, spleen, and blood, respiratory and CNS involvement, cancer in long-term.

    更新日期:2020-01-17
  • 更新日期:2020-01-17
  • Interfaces engineering of MoNi-based sulfides electrocatalysts for hydrogen evolution reaction in both acid and alkaline media
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-17
    Yan Xie; Yuanwei Liu; Zhongnian Yang

    Searching for efficiently noble-metal-free hydrogen evolution catalysts is critical to the development of hydrogen energy. In this work, we report an in-situ growing defect-rich heterointerfaces structure MoNi-based sulfides on carbon cloth via a facile and controllable hydrothermal process. The interface structure in [email protected]/CC can not only provide suffcient channel for transportation of electrolyte, but also release of produced gases in the catalytic process, thence enhance the sluggish hydrogen evolution efficiency. Furthermore, the defects in [email protected]/CC have significant impacts on hydrogen evolution behavior. Therefore, the as-synthesied [email protected]/CC shows a low overpotential of 33 mV to deliver a current density of 10 mAcm−2 and a small tafel slope of 80 mVdec−1, and also exhibits an excellent long-term stability in 0.5 M H2SO4. Additionaly, the [email protected]/CC offers outstanding hydrogen evolution reaction performances in 1 M KOH.

    更新日期:2020-01-17
  • Hybrid niobium and titanium nitride nanotube arrays implanted with nanosized amorphous rhenium–nickel: An advanced catalyst electrode for hydrogen evolution reactions
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-17
    Huibin Zhang; Xuanhan Chen; Zhimao Lin; Liqiang Zhang; Huazhen Cao; Linping Yu; Guoqu Zheng
    更新日期:2020-01-17
  • Effect of non-solvent from the phase inversion method on the morphology and performance of the anode supported microtubular solid oxide fuel cells
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-17
    Cong Ren; Yanxiang Zhang; Qi Xu; Tian Tian; Fanglin Chen

    The microstructure of the anode in anode-supported solid oxide fuel cells has significant influence on the cell performance. In this work, microtubular Ni-yttria stabilized zircona (Zr0.8 Y0.2O2, YSZ) anode support has been prepared by the phase inversion method. Different compositions of non-solvent have been used for the fabrication of the Ni-YSZ anode support, and the correlation between non-solvent composition and characteristics of the microstructure of the anode support has been investigated. The presence of ethanol or isopropanol in the non-solvent can inhibit the growth of the finger-like pores in the anode support. With the increase of the concentration of ethanol or isopropanol in the non-solvent, a thin dense layer can be observed on the top of the prepared tubular anode support. In addition, the mechanism of pore formation is explained based on the inter-diffusivity between the solvent and the non-solvent. The prepared microtubular solid oxide fuel cells (MT-SOFCs) have been tested, and the influence of the anode microstructure on the cell electrochemical performance is analyzed based on a polarization model.

    更新日期:2020-01-17
  • 更新日期:2020-01-17
  • Sequential dark and photo-fermentative hydrogen gas production from agar embedded molasses
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-17
    Muhammet Enes Mıynat; İkbal Ören; Ebru Özkan; Hidayet Argun

    In this study, molasses and dark fermentation effluent were solidified using agar and used for H2 production by dark and photo-fermentation. During dark fermentation, the solid jelly form of molasses enabled a slow release of the substrate to the liquid broth hindering fast pH decreases. The initial total sugar concentration, H2 yield, H2 rate and lag phase in dark fermentation were 36.2 g/L, 226.24 mL H2/g TS, 29.85 mL H2/h and 4.37 h, respectively. Photo-fermentation of 5.77 g TVFA/L embedded dark fermentation effluent did not lead to efficient H2 production. The best performance in photo-fermentation was obtained with 1.55 g TVFA/L containing diluted dark fermentation effluent. The H2 yield, H2 rate and lag phase in photo-fermentation were 870.26 mL H2/g TVFA, 0.913 mL H2/h and 54.07 h, respectively. Embedding concentrated substrate using agar can enhance H2 production performance but only if the release of the substrate does not exceed inhibitory levels and if the rate of diffusion is tolerable for microbial activity.

    更新日期:2020-01-17
  • High-performance solid oxide fuel cells with fiber-based cathodes for low-temperature operation
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-17
    Joseph Parbey; Qin Wang; Jialong Lei; Mayken Espinoza-Andaluz; Feng Hao; Yong Xiang; Tingshuai Li; Martin Andersson

    Low-temperature operation of solid oxide fuel cells (SOFCs) results in deterioration in electrochemical performance due to sluggish oxygen reduction reaction (ORR) at the cathode. To enhance the reaction pathway for ORR, La0.8Sr0.2MnO3 (LSM) nanofibers were fabricated by electrospinning and used for low-temperature solid oxide fuel cells operated at 600–700 °C. The morphological and structural characteristics show that the electrospun LSM nanofiber has a highly crystallized perovskite structure with a uniform elemental distribution. The average diameter of the LSM nanofiber after sintering is 380 nm. A symmetric cell of nanofiber-based LSM cathode on scandia-stabilized zirconia (SSZ) electrolyte pellet exhibits much lower area specific resistances compared to commercial LSM powder-based cathode. A single cell based on the nanofiber LSM cathode on yttrium-doped barium cerate-zirconia (BCZY) electrolyte exhibits a power density of 0.35 Wcm−2 at 600 °C, which increases to 0.85 Wcm−2 at 700 °C. The cell has an area specific resistance (ASR) of 0.46 Ωcm2 at 600 °C, which decreases to 0.07 Ωcm2 at 700 °C. The results indicate that the LSM electrode fabricated by the electrospinning process produces a nanostructured porous electrode which optimizes the microstructure and significantly enhances the ORR at the cathode of SOFCs.

    更新日期:2020-01-17
  • Methods for measuring the effective thermal conductivity of metal hydride beds: A review
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-17
    Wenli Zhao; Yi Yang; Zewei Bao; Dong Yan; Zezhi Zhu

    The effective thermal conductivity of metal hydride beds is a crucial parameter for metal hydride reactor design. In this review, methods and principles for the measurement of the effective thermal conductivity of metal hydride beds are discussed, including steady-state techniques (the radial heat flow, comparative cut bar, guarded heat flow meter, and guarded hot plate methods) and transient techniques (the hot-wire, thermal probe, transient plane source, and laser flash methods). Reports of effective thermal conductivity measurements for characterizing metal hydride beds have been reviewed, including the measurement methods, material composition, measurement results, temperature, and gas pressure. The advantages, disadvantages, and applications of each measurement method have been presented, and an assessment regarding different techniques of measurement has been conducted. Laser flash and transient plane source are found to be the most frequently used methods, and have been increasingly applied in recent years. Finally, a brief discussion of recommended future development of effective thermal conductivity measurement is presented.

    更新日期:2020-01-17
  • Effect of retrograde condensation on the production performance of organic hydrogen compounds energy
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-17
    Yue Peng; Tao Bu; Zhenyun Shi; Qing Tian; Wanjing Luo

    The gas-condensate reservoirs are typical organic fossil reservoirs of hydrogen compounds energy. With the development of gas-condensate reservoirs, a part of condensate liquid of hydrogen compounds will appear under the influence of retrograde condensation mechanism. However, the effects of retrograde condensation on the production performance of organic hydrogen compound energy with different well types are still not clear. In this study, a series of numerical simulation models were established to investigate the law of retrograde condensation with different well types and reservoir permeabilities. Furthermore, the effects of retrograde condensation on gas well productivity were analyzed by the comparison between the compositional modeling and black oil modeling results. Results show that the condensate oil for the fractured wells is mainly distributed around the fracture tips instead of the perforation intervals for the unfractured wells. The maximum oil saturation and condensate area of two fractures at ends are much larger than those of middle fractures. The retrograde condensation exhibits a negligible impact on the production of multiple fractured horizontal wells with a cumulative gas production reduction 0.87%–1.57%. Hydraulic fracturing, multiple fractures and high reservoir permeability are conducive to lower the impact of retrograde condensation on the production of organic hydrogen compounds energy.

    更新日期:2020-01-17
  • Intensifying vehicular proton exchange membrane fuel cells for safer and durable, design and operation
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-17
    Nilesh Ade; Benjamin Wilhite; Henry Goyette; M. Sam Mannan

    The explosion in a proton exchange membrane fuel cell (PEMFC) powered forklift in Louisiana, USA in May 2018 and the resulting fatality highlights the need for the improved safety of this technology. Apart from the safety concerns, PEMFC durability has been an important issue towards its further commercialization. Both the safety and durability concerns associated with this technology can be attributed to the temporal degradation of its components. In this study, we have developed a mathematical model that relates the microscale PEMFC degradation to the probability of a macroscale explosion in a Fuel Cell Electric Vehicle (FCEV). Using the model and the inherent safety principle of intensification, it was observed that increasing the operating temperature of the PEMFC system can significantly improve both its safety and durability while intensifying membrane design parameters i.e. membrane thickness and membrane conductivity do not provide any significant improvements. A key inference from this study is that the durability (expressed in voltage loss) and safety (expressed in explosion probability) of a PEMFC system are not perfectly correlated.

    更新日期:2020-01-17
  • Multi-objective optimization for efficient modeling and improvement of the high temperature PEM fuel cell based Micro-CHP system
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-17
    Yu Yang; Hao Zhang; Ping Yan; Kittisak Jermsittiparsert

    Fuel cells due to different useful features such as high efficiency, low pollution, noiselessness, lack of moving parts, variety of fuels used and wide range of capacity of these sources can be the main reasons for their tendency to use them in different applications. In this study, the application of a high temperature proton exchange membrane fuel cell (HT-PEMFC) in a combined heat and power (CHP) plant has been analyzed. This study presents a multi-objective optimization method to provide an optimal design parameters for the HT-PEMFC based micro-CHP during a 14,000 h lifetime by considering the effect of degradation. The purpose is to optimize the net electrical efficiency and the electrical power generation. For the optimization process, different design parameters including auxiliary to process fuel ratio, anodic stoichiometric ratio, steam to carbon ratio, and fuel partialization level have been employed. For optimization, A new technique based on Tent mapping and Lévy flight mechanism, called improved collective animal behavior (ICAB) algorithm has been employed to solve the algorithm premature convergence shortcoming. Experimental results of the proposed method has been applied to the data of a practical plant (Sidera30) for analyzing the efficiency of the proposed ICAB based system, it is compared with normal condition and another genetic algorithm based method for this purpose. Final results showed that the difference between the maximum electrical power production under normal condition and ICAB based condition changes from 2.5 kW when it starts and reaches to its maximum value, 3.0 kW, after 14,000 h lifetime. It is also concluded that the cumulative average for the normal and the ICAB based algorithm are 24.01 kW and 27.04 kW, respectively which showed about 3.03 kW cumulative differences.

    更新日期:2020-01-17
  • 更新日期:2020-01-17
  • Highly efficient methanol oxidation on durable PtxIr/MWCNT catalysts for direct methanol fuel cell applications
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-17
    Narayanamoorthy Bhuvanendran; Sabarinathan Ravichandran; Weiqi Zhang; Qiang Ma; Qian Xu; Lindiwe Khotseng; Huaneng Su
    更新日期:2020-01-17
  • The role of oxygen vacancies in the CO2 methanation employing Ni/ZrO2 doped with Ca
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-16
    Oliver E. Everett; Priscila C. Zonetti; Odivaldo C. Alves; Roberto R. de Avillez; Lucia G. Appel

    The Ni/ZrO2 catalyst doped with Ca and Ni/ZrO2 were employed in the CO2 methanation, a reaction which will possibly be used for storing intermittent energy in the future. The catalysts were characterized by X-ray photoelectron spectroscopy (XPS, reduction in situ), X-ray diffraction (XRD, reduction in situ and Rietveld refinement), electron paramagnetic resonance (EPR), temperature-programmed surface reaction, cyclohexane dehydrogenation model reaction, temperature-programmed desorption of CO2 and chemical analysis. The catalytic behavior of these catalysts in the CO2 methanation was analyzed employing a conventional catalytic test. Adding Ca to Ni/ZrO2, the metallic surface area did not change whereas the CO2 consumption rate almost tripled. The XRD, XPS and EPR analyses showed that Ca+2 but also some Ni2+ are on the ZrO2 surface lattice of the Ni/CaZrO2 catalyst. These cations form pairs which are composed of oxygen vacancies and coordinatively unsaturated sites (cus). By increasing the number of these pairs, the CO2 methanation rate increases. Moreover, the number of active sites of the CO2 methanation rate limiting step (CO and/or formate species decomposition, rls) is enhanced as well, showing that the rls occurs on the vacancies-cus sites pairs.

    更新日期:2020-01-17
  • Synthesis and characterization of Nanocrystalline Ba0·6Sr0·4Co0·8Fe0·2O3 for application as an efficient anode in solid oxide electrolyser cell
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-16
    Shoroshi Dey; Jayanta Mukhopadhyay; Raja Kishora Lenka; Pankaj Kumar Patro; Abhijit Das Sharma; Tarasankar Mahata; Rajendra N. Basu

    Nanocrystalline Ba0·6Sr0·4Co0·8Fe0·2O3 (BSCF-6482) powder is synthesized by combustion synthesis technique. Powder calcined at 1000 °C reveals phase pure cubic perovskite. Transmission electron microscopic (TEM) analysis exhibits soft agglomerates of average size ∼50 nm wherein interplanar spacing for (110) and (221) resembles to the cubic lattice. While DC electrical conductivity of 23 S cm−1@800 °C is observed, interfacial polarization measured by electrochemical impedance spectroscopy is found to be the least @850 °C (0.18 Ω cm2). Cell performance has been compared among BSCF-6482, BSCF-5582 and LSCF-6482 mixed ionic and electronic conducting (MIEC) and conventional electrode (LSM). Higher performance (1.37 A/cm2@1.3 V,800 °C) with high hydrogen generation rate (0.57 Nl/cm2/h) is found during steam electrolysis with cell fabricated using BSCF-6482 having minimal area specific resistance 0.33 Ω cm2. Under similar operating condition, BSCF-5582, LSCF-6482 and LSM exhibit hydrogen generation rate of 0.35, 0.28 and 0.23 Nl/cm2/h respectively. Cell microstructure is clinically correlated with the higher reactivity of BSCF-6482 air electrode in steam electrolysis.

    更新日期:2020-01-17
  • One-step synthesis of self-standing porous palladium-ruthenium nanosheet array on Ni foam for ambient electrosynthesis of ammonia
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-16
    Yinghao Li; Hongjie Yu; Ziqiang Wang; Songliang Liu; You Xu; Xiaonian Li; Liang Wang; Hongjing Wang
    更新日期:2020-01-16
  • Tuning morphology and structure of Fe–N–C catalyst for ultra-high oxygen reduction reaction activity
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-15
    Yanping Huang; Weifang Liu; Shuting Kan; Penggao Liu; Rui Hao; Hang Hu; Jian Zhang; Hongtao Liu; Min Liu; Kaiyu Liu
    更新日期:2020-01-15
  • Electric field effects on hydrogen/methane oxidation: A reactive force field based molecular dynamics study
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-14
    Fuzhong Sun; Weilin Zeng

    In the study, molecular dynamics simulations associated with reactive force fields are performed to examine the effect of an imposed electric field at different strengths upon the reactive systems of hydrogen/methane mixture oxidation. Temporal evolution results regarding the initial species evidence the distinct alteration of external electric effects to the consumption rates and the reaction-starting time of the reactants in hydrogen/methane oxidation systems. Significantly, hydrogen molecules play contrasting roles under electric and electric-free reactions. The discoveries about the various categories of intermediate radicals and the differences in the temporal progress reveal that the introduction of an electric field to the reactive system modifies the diversities and generation trends of intermediate radicals and alters the reaction rates by affecting the reaction pathways. Different unique species are formed under electric fields of different strength. The current findings prove and support that molecular dynamics simulation associated with reactive force field is a feasible and promising technique for detailed investigation into combustion/oxidation reaction kinetics, involving high temperature and pressure.

    更新日期:2020-01-15
  • Counter-rotating dual-stage swirling combustion characteristics of hydrogen and carbon monoxide at constant fuel flow rate
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-14
    Qinghua Zeng; Dong Zheng; Yixiang Yuan

    In this paper, experimental and numerical methods were used to study the combustion characteristics of a counter-rotating double-stage swirling syngas combustor at constant fuel flow rate, and the effect on it of hydrogen content of syngas. In the experiment, the speed and temperature in the combustor were respectively obtained with PIV and temperature rake, while Reynolds stress equation model and the detailed chemical reaction mechanism of syngas were adopted in the numerical method. The calculation results were in good agreement with the experimental data. Research results indicated that in the working conditions of different hydrogen contents, the flow field structures in the combustor are almost the same, and the maximum temperatures at the outlet remain almost the same. However, as hydrogen content in the fuel increases, the axial velocity in the central area of flow field is increasing, and the outlet temperature distribution coefficient decreases first and then increases. In addition, it was also found in the study that the distribution structure of temperature on the central section of the combustor is almost impervious to the changes in hydrogen content, but with numerical differences, i.e. the higher hydrogen content in the fuel, the farther the stabilization position of flames in the central area is away from the head. It was also indicated in the study that the conventional combustor is no longer applicable to the combustion of syngas, especially the hydrogen-rich fuel. And the work provided the improvement scheme of hydrogen-containing fuel for gas turbine combustor.

    更新日期:2020-01-15
  • 更新日期:2020-01-15
  • Experimental and numerical study on the high-pressure hydrogen jet and explosion induced by sudden released into the air through tubes
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-14
    Zhilei Wang; Han Zhang; Xuhai Pan; Yiming Jiang; Qingyuan Wang; Jianjun Xiao; Thomas Jordan; Juncheng Jiang
    更新日期:2020-01-15
  • Effect of ball milling in presence of additives (Graphite, AlCl3, MgCl2 and NaCl) on the hydrolysis performances of Mg17Al12
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-14
    S. Al Bacha; M. Zakhour; M. Nakhl; J.-L. Bobet

    In most of the Mg–Al alloys, Al forms with Mg the intermetallic compound Mg17Al12. In order to understand the hydrogen production from the Mg–Al alloys waste by the hydrolysis reaction in “model” seawater (i.e. 3.5 wt % NaCl), hydrolysis with Mg17Al12 was investigated. The effect of ball milling time, the nature of the additives (graphite, NaCl, MgCl2 and AlCl3) and the synergetic effects of both graphite and AlCl3 were investigated. It has been established that increasing ball milling time up to 5 h is necessary to activate the intermetallic and to decrease sufficiently its crystallites and particles size. On one hand, the presence of AlCl3 provides the best hydrolysis performance (14% of the theoretical hydrogen volume in 1 h). On the other hand, the mixture obtained by simultaneous addition of graphite and AlCl3 shows the best hydrolysis performances with 16% of the theoretical H2 volume reached in 1 h.

    更新日期:2020-01-15
  • Platinum-rhodium alloyed dendritic nanoassemblies: An all-pH efficient and stable electrocatalyst for hydrogen evolution reaction
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-14
    Zhu Han; Ru-Lan Zhang; Jiao-Jiao Duan; Ai-Jun Wang; Qian-Li Zhang; Hong Huang; Jiu-Ju Feng
    更新日期:2020-01-15
  • 更新日期:2020-01-15
  • Enhanced H2 evolution and the interfacial electron transfer mechanism of titanate nanotube sensitized with CdS quantum dots and graphene quantum dots
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-14
    Jiayan Xue; Lizhen Long; Lin Zhang; Hongtian Luo; Li Yang; Fuchi Liu; Fengzhen Lv; Wenjie Kong; Jun Liu

    Synergistic the modulation of photon absorption capability and interfacial charge transfer of the photocatalyst are highly required for developing high-performance heterojunction photocatalysts. The ternary CdS-graphene quantum dots-titanate nanotubes (CdS-GQDs-TNTs) nanocomposite have been prepared by an in situ growth method. The physicochemical characterization reveals that the GQDs are firmly decorated on both inner and outer surface of TNT through the formation of Ti–O–C chemical bonding, and CdS QDs are loaded on the outer surface of TNTs through strong interfacial interaction. The intimate integrated CdS-GQDs-TNTs nanocomposite exhibits much superior photocatalytic performance toward H2 production compared with binary GQDs-TNTs and pure TNTs photocatalyst, which can be attributed to the combined interaction of the stronger visible light harvesting, the longer lifetime of photogenerated electron−hole pairs, faster interfacial charge transfer rate, fast and long-distance electron transport pass. The interfacial charge transfer mechanism of CdS-GQDs-TNTs ternary composite are proposed based on photoelectrochemical measurements.

    更新日期:2020-01-15
  • Gliding arc plasma reforming of toluene for on-board hydrogen production
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-14
    Wang Baowei; Liu Shize; Peng Yeping; Wang Chengyu
    更新日期:2020-01-15
  • Prediction of liquid hydrogen flow boiling critical heat flux condition under microgravity based on the wall heat flux partition model
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-14
    Yao Zheng; Huawei Chang; Yinan Qiu; Chen Duan; Jianye Chen; Hong Chen; Shuiming Shu

    Critical heat flux (CHF) of liquid hydrogen (LH2) flow boiling under microgravity is vital for designing space cryogenic propellant conveying pipe since the excursion of wall temperature may cause system failure. In this study, a two-dimensional axisymmetric model based on the wall heat flux partition (WHFP) model was proposed to predict the CHF condition under microgravity including the wall temperature and the CHF location. The proposed numerical model was validated to demonstrate a good agreement between the simulated and experimentally reported results. Then, the wall temperature distribution and the CHF location under different gravity conditions were compared. In addition, the WHFP and vapor-liquid distribution along the wall under microgravity were predicted and its difference with terrestrial gravity condition was also analysed and reported. Finally, the effects of flow velocity and inlet sub-cooling on the wall temperature distributions were analysed under microgravity and terrestrial gravity conditions, respectively. The results indicate that the CHF location moves upstream about 5.25 m from 1g to 10−4g since the void fraction near the wall reaches the breakpoint of CHF condition much earlier under the microgravity condition. Furthermore, the increase of the velocity and decrease of the sub-cooling have smaller effects on the CHF location during LH2 flow boiling under microgravity.

    更新日期:2020-01-15
  • Catalytic dehydrogenation of formic acid-triethanolamine mixture using copper nanoparticles
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-14
    Samuel Eshorame Sanni; Teniola Abayomi Alade; Oluranti Agboola; Peter Adeniyi Alaba

    In a bid to complement the lost reserves from fossils, recent advances in research are tailored towards producing hydrogen as an alternative source of fuel which is aimed at fostering a globally sustainable and reliable energy-economy. In this work, hydrogen was produced from formic acid (FA) using a new technology that involves the use of copper nanoparticles (CuNPs) supported on triethanolamine. The CuNP-catalysts of variant concentrations (i.e. 0.6–1.2 M) were synthesized using the conventional chemical deposition method. Also, a novel approach that bothers on the application of the Differential Method of Analysis (DMA) was used in determining the kinetic parameters for the FA-dehydrogenation. Based on the results, the volume of H2 produced varied with time, pH, concentration and catalyst-size. At 6 h, the 1 M CuNPs gave the highest volume (815 mL) of hydrogen with corresponding pH, particle size and approximate conversion of 3.19, 1.5 nm and 100% respectively, whereas, over extended periods i.e. over 6 h, the approximate volume-conversions of FA increased insignificantly for all catalysts. According to the investigation, the optimum CuNP-catalyst concentration required to produce 815 mL H2 in 6 h is 1 M. The decomposition was a first-order-type with a rate constant (k-value) of 1.0041 s−1.

    更新日期:2020-01-14
  • Phosphatized pseudo-core-shell Ni@Pt/C electrocatalysts for efficient hydrazine oxidation reaction
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-14
    Yahui Wang; Xianyi Liu; Juan Han; Yumao Kang; Yajun Mi; Wei Wang
    更新日期:2020-01-14
  • Sustainability assessment and decision making of hydrogen production technologies: A novel two-stage multi-criteria decision making method
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-13
    Xusheng Ren; Weichen Li; Shimin Ding; Lichun Dong

    A novel two-stage multi-criteria decision making (MCDM) method is proposed with the aim to select the most sustainable hydrogen production technology (HPT) by considering the preference information on both attributes and alternatives. In the first stage of the method, the initial sustainability ranking of the alternative HPTs was achieved by using the FBWM (Fuzzy Best-Worst Method) to determine the weights of the criteria and the fuzzy TOPSIS (Technique for Order Performance by Similarity to Ideal Solution) method to prioritize the sustainability of alternative HPTs. While, in the second stage, a novel Preference Ranking Linear Programming Method (PRLPM) was used to acquire the final sustainability ranking according to the alternative preference information by following the principle of the outranking method. The proposed method was illustrated by a case study with 8 HTPs, demonstrating that the developed two-stage MCDM method can reflect the alternative preference of the decision-maker more accurately for selecting the most preferred alternative among various HTPs.

    更新日期:2020-01-13
  • One-step potentiostatic electrodeposition of Ni–Se–Mo film on Ni foam for alkaline hydrogen evolution reaction
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-13
    Ying Gao; Hanwei He; Wenyu Tan; Yizhi Peng; Xiaomei Dai; Yihui Wu

    Exploring efficient, abundant, low-cost and stable materials for hydrogen evolution reaction (HER) is highly desired but still a challenging task. Herein, Ni–Se–Mo electrocatalysts supported on nickel foam (NF) substrate were synthesized by a facile one-step electrodeposition method. The Ni–Se–Mo film presents high electrocatalytic activity and stability toward HER, with a low overpotential of 101 mV to afford a current density of 10 mA cm−2 in 1.0 M KOH medium. Such excellent HER performance of Ni–Se–Mo film induced by the synergistic effects from Mo-doped Ni–Se film leads to the fast electron transfer. This work provides the validity of interface engineering strategy in preparing highly efficient transition metal chalcogenides based HER electrocatalysts.

    更新日期:2020-01-13
  • Hydrogen evolution behavior of nickel coated TiO2
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-13
    Hasan Uzal; Ali Döner; Hüseyin Bayrakçeken

    Nickel modified titanium dioxide nanotubes (TiO2-NTs/Ni) and TiO2-NTs electrodes are investigated for hydrogen evolution reaction (HER). To obtain large surface area, TiO2-NTs are prepared by using anodization method at a constant voltage of 60 V for various anodization times (30 min, 1 h and 2 h). Small amount of Ni is successfully deposited over TiO2-NTs via electrodeposition method. Hydrogen evolution activities of TiO2-NTs/Ni and TiO2-NTs are investigated in 1 M KOH solution at room temperature. Characterizations of prepared nano-structured electrodes are analyzed with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and cyclic voltammetry (CV) and electrochemical-activities are determined through cathodic current-potential curves and electrochemical impedance spectroscopy (EIS). Hydrogen volumes produced from prepared electrodes are also measured under constant voltage of 3 V for 30 min. Obtained results showed that hydrogen evolution activity increased with the modification of TiO2-NTs by nickel. High current density at specific overpotentials, hydrogen volume and small polarization resistance are obtained on TiO2-NTs/Ni. High stability and durability are also obtained on this electrode. So, TiO2-NTs/Ni as an electrocatalyst is suggested to use in water electrolysis systems.

    更新日期:2020-01-13
  • Potential of thermoelectric waste heat recovery in a combined geothermal, fuel cell and organic Rankine flash cycle (thermodynamic and economic evaluation)
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-13
    Shoaib Khanmohammadi; Morteza Saadat-Targhi; Faraedoon Waly Ahmed; Masoud Afrand

    The present work aim is performance improvement of an integrated geothermal system by proposing the integration of organic Rankine flash cycle (ORFC) with the Proton exchange membrane fuel cell (PEMFC) and waste heat recovery from condensers using thermoelectric generator (TEG) modules. To achieve this goal, a novel integrated system is proposed, thermodynamically modeled, investigated, and compared with the conventional system. To assess the performance of proposed system, thermodynamic and economic evaluations are performed. The results indicate that R123 as working fluid, has the best performance for the conventional and proposed systems. The findings demonstrate that with employing TEG modules an increase of 2.7% and 2.8%, for the first and second law efficiencies can be obtained respectively. Additionally, the results of parametric analysis indicate that however the geothermal fluid temperature increment decreases the first and second law efficiencies of the system, it leads to the net output power enhancement. Also, enhancement of the flash vessel pressure ratio increases the first and second law efficiency as well. Additionally, the simple payback method showed that a payback time between 1.25 years and 25 years according to the TEG modules cost can be achieved.

    更新日期:2020-01-13
  • Low temperature and fast response hydrogen gas sensor with Pd coated SnO2 nanofiber rods
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-13
    Feipeng Wang; Kelin Hu; Hongcheng Liu; Qi Zhao; Kaizheng Wang; Yuxin Zhang
    更新日期:2020-01-13
  • Nickel centered metal-organic complex as an electro-catalyst for hydrogen evolution reaction at neutral and acidic conditions
    Int. J. Hydrogen Energy (IF 4.084) Pub Date : 2020-01-13
    Madhumitha Rajakumar; Matheswaran Manickam; Nagarajan Nagendra Gandhi; Karuppan Muthukumar

    In this study, we report the development of dihydropyrimidines substituted nickel electro-catalyst at mild conditions for hydrogen evolution reaction. The Biginelli type reaction was carried out to produce 4-(4-chlorophenyl)-3,4,5,6-tetrahydrobenzo[h]quinazoline-2(1H)-thione moiety. This was added with NiCl2.6H2O to synthesize Ni-quinazoline-2(1H)-thione catalyst. The prepared catalyst was characterized using UV–Vis, FT-IR, Mass, 1H and 13C NMR and SEM-EDX spectroscopy. It showed an excellent hydrogen evolution reaction (HER) activity. LSV polarization showed a low Tafel slope (34 mV/dec) nearly close to Pt/C (28 mV/dec) in neutral medium whereas a Tafel slope of 100 mV/dec was observed with 0.5M H2SO4 while Pt/C showed 50 mV/dec. Electrochemical impedance spectroscopy measured by applying −1.18 V in neutral medium showed two depressed semicircles whereas with 0.5M H2SO4 and -1.45 V applied voltage single half was observed.

    更新日期:2020-01-13
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