China, People’s Republic
Paths to Low-cost Hydrogen Energy at a Scale for Transportation Applications in the USA and China via Liquid-hydrogen Distribution Networks
Dec 2019
Publication
The cost of delivered H2 using the liquid-distribution pathway will approach $4.3–8.0/kg in the USA and 26–52 RMB/kg in China by around 2030 assuming large-scale adoption. Historically hydrogen as an industrial gas and a chemical feedstock has enjoyed a long and successful history. However it has been slow to take off as an energy carrier for transportation despite its benefits in energy diversity security and environmental stewardship. A key reason for this lack of progress is that the cost is currently too high to displace petroleum-based fuels. This paper reviews the prospects for hydrogen as an energy carrier for transportation clarifies the current drivers for cost in the USA and China and shows the potential for a liquid-hydrogen supply chain to reduce the costs of delivered H2. Technical and economic trade-offs between individual steps in the supply chain (viz. production transportation refuelling) are examined and used to show that liquid-H2 (LH2) distribution approaches offer a path to reducing the delivery cost of H2 to the point at which it could be competitive with gasoline and diesel fuel.
Two-Stage Energy Management Strategies of Sustainable Wind-PV-Hydrogen-Storage Microgrid Based on Receding Horizon Optimization
Apr 2022
Publication
Hydrogen and renewable electricity-based microgrid is considered to be a promising way to reduce carbon emissions promote the consumption of renewable energies and improve the sustainability of the energy system. In view of the fact that the existing day-ahead optimal operation model ignores the uncertainties and fluctuations of renewable energies and loads a two-stage energy management model is proposed for the sustainable wind-PV-hydrogen-storage microgrid based on receding horizon optimization to eliminate the adverse effects of their uncertainties and fluctuations. In the first stage the day-ahead optimization is performed based on the predicted outpower of WT and PV the predicted demands of power and hydrogen loads. In the second stage the intra-day optimization is performed based on the actual data to trace the day-ahead operation schemes. Since the intra-day optimization can update the operation scheme based on the latest data of renewable energies and loads the proposed two-stage management model is effective in eliminating the uncertain factors and maintaining the stability of the whole system. Simulations show that the proposed two-stage energy management model is robust and effective in coordinating the operation of the wind-PV-hydrogen-storage microgrid and eliminating the uncertainties and fluctuations of WT PV and loads. In addition the battery storage can reduce the operation cost alleviate the fluctuations of the exchanged power with the power grid and improve the performance of the energy management model.
Optimized Operation Plan for Hydrogen Refueling Station with On-Site Electrolytic Production
Dec 2022
Publication
The cost reduction of hydrogen refueling stations (HRSs) is very important for the popularization of hydrogen vehicles. This paper proposes an optimized operation algorithm based on hydrogen energy demand estimation for on-site hydrogen refueling stations. Firstly the user’s hydrogen demand was estimated based on the simulation of their hydrogenation behavior. Secondly mixed integer linear programming method was used to optimize the operation of the hydrogen refueling station to minimize the unit hydrogen energy cost by using the peak–valley difference of the electricity price. We then used three typical scenario cases to evaluate the optimized operation method. The results show that the optimized operation method proposed in this paper can effectively reduce the rated configuration of electrolyzer and storage tank for HRS and can significantly reduce the unit hydrogen energy cost considering the construction cost compared with the traditional method. Therefore the optimization operation method of a local hydrogen production and hydrogen refueling station proposed in this paper can reduce the cost of a hydrogen refueling station and accelerate the popularization of hydrogen energy vehicles. Finally the scope of application of the proposed optimization method and the influence of the variation of the electricity price curve and the unit cost of the electrolyzer are discussed.
Digital Navigation of Energy–structure–function Maps for Hydrogen-bonded Porous Molecular Crystals
Feb 2021
Publication
Energy–structure–function (ESF) maps can aid the targeted discovery of porous molecular crystals by predicting the stable crystalline arrangements along with their functions of interest. Here we compute ESF maps for a series of rigid molecules that comprise either a triptycene or a spiro-biphenyl core functionalized with six different hydrogen-bonding moieties. We show that the positioning of the hydrogen-bonding sites as well as their number has a profound influence on the shape of the resulting ESF maps revealing promising structure–function spaces for future experiments. We also demonstrate a simple and general approach to representing and inspecting the high-dimensional data of an ESF map enabling an efficient navigation of the ESF data to identify ‘landmark’ structures that are energetically favourable or functionally interesting. This is a step toward the automated analysis of ESF maps an important goal for closed-loop autonomous searches for molecular crystals with useful functions.
Safety System Design for Mitigating Risks of Intended Hydrogen Releases from Thermally Activated Pressure Relief Device of Onboard Storage
Sep 2019
Publication
All vehicular high-pressure hydrogen tanks are equipped with thermally-activated pressure relief devices (TPRDs) required by Global Technical Regulation. This safety device significantly reduces the risk of tank catastrophic rupture by venting the hydrogen pressure outside. However the released flammable hydrogen raises additional safety problems. Japan Automobile Research Institute has demonstrated that in the vehicle fire event once the TPRD opens the hydrogen fires will engulf the whole vehicle making it difficult for the drivers and passenger to evacuate from the vehicle. This paper designs a new safety system to solve the evacuation problem. The safety system includes a rotatable pressure relief device with a motor a sensory system that consists of infrared sensors ultrasonic radar and temperature sensors a central control unit and an alarm device. The new design of the pressure relief device allows the system actively adjusting the release direction towards void open space outside the vehicle to minimize the risks of hydrogen fires. The infrared sensors located at the roof of the vehicles collect info inside the vehicle and the ultrasonic radar detect the region outside the vehicle. Temperature sensors tell when to trigger the alarm and set the motor in standby mode and the central control unit determines where to rotate based on the info from the infrared sensors and ultrasonic radars. A control strategy is also proposed to operate the safety system in an appropriate way. The cost-benefit analysis show that the new safety system can significantly reduce the risks of intended hydrogen releases from onboard pressure relief devices with total cost increases by less than 1% of the vehicle cost making it a good cost-effective engineering solution.
Catalytic Effect of MoS2 on Hydrogen Storage Thermodynamics and Kinetics of an As-milled YMg11Ni Alloy
Jul 2017
Publication
In this study YMg11Ni and YMg11Ni + 5 wt% MoS2 (named YMg11Ni–MoS2) alloys were prepared by mechanical milling to examine the effect of adding MoS2 on the hydrogen storage performance of a Y–Mg–Ni-based alloy. The as-cast and milled alloys were tested to identify their structures by X-ray diffraction and transmission electron microscopy. The isothermal hydrogen storage thermodynamics and dynamics were identified through an automatic Sieverts apparatus and the non-isothermal dehydrogenation performance was investigated by thermogravimetry and differential scanning calorimetry. The dehydrogenation activation energy was calculated by both Arrhenius and Kissinger methods. Results revealed that adding MoS2produces a very slight effect on hydrogen storage thermodynamics but causes an obvious reduction in the hydrogen sorption and desorption capacities because of the deadweight of MoS2. The addition of MoS2significantly enhances the dehydrogenation performance of the alloy such as lowering dehydrogenation temperature and enhancing dehydrogenation rate. Specifically the initial desorption temperature of the alloy hydride lowers from 549.8 K to 525.8 K. The time required to desorb hydrogen at 3 wt% H2 is 1106 456 363 and 180 s corresponding to hydrogen desorption temperatures at 593 613 633 and 653 K for the YMg11Ni alloy and 507 208 125 and 86 s at identical conditions for the YMg11Ni–5MoS2 alloy. The dehydrogenation activation energy (Ea) values with and without added MoS2are 85.32 and 98.01 kJ mol−1. Thus a decrease in Ea value by 12.69 kJ mol−1 occurs and is responsible for the amelioration of the hydrogen desorption dynamics by adding a MoS2 catalyst.
Hydrolysis Hydrogen Production Mechanism of Mg10Ni10Ce Alloy Surface Modified by SnO2 Nanotubes in Different Aqueous Systems
May 2020
Publication
(Mg-10wt.%Ni)-10wt.%Ce (Mg10Ni10Ce) was ball-milled with SnO2 nanotubes and Mg10Ni10Ce-xSnO2 (x=0 5 10 and 15wt.%) composites have been prepared. The phase compositions microstructures morphologies and hydrolysis H2 generation performance in different aqueous systems (distilled water tap water and simulated seawater) have been investigated and the corresponding hydrolysis mechanism of Mg10Ni10Ce and Mg10Ni10Ce-SnO2 has been proposed. Adding a small amount of SnO2 nanotubes can significantly enhance the hydrolysis reaction of Mg10Ni10Ce especially the initial hydrolysis kinetics and the final H2 generation yield. Unfortunately the Mg10Ni10Ce-xSnO2 hardly react with distilled water at room temperature. The hydrolysis reaction rate of Mg10Ni10Ce-5SnO2 composite in tap water is still very slow with only 17.3% generation yield after 1 hour at 303 K. Fortunately in simulated seawater (3.5wt.% NaCl solution) the hydrolytic H2 generation behavior of the Mg10Ni10Ce-5SnO2 composite has been greatly improved which can release as high as 468.6 mL/g H2 with about 60.9% generation yield within 30 s at 303 K. The Cl- destroys the passivation layer on Mg-Ni-Ce alloy surface and the added SnO2 nanotubes accelerate the hydrolysis reaction rate and enhance the H2 generation yield. The Mg10Ni10Ce-5SnO2 composite can rapidly generate a large amount of H2 in simulate seawater in a short time which is expected to be applied on portable H2 generators in the future.
Integrated Ni-P-S Nanosheets Array as Superior Electrocatalysts for Hydrogen Generation
Jan 2017
Publication
Searching for efficient and robust non-noble electrocatalysts for hydrogen generation is extremely desirable for future green energy systems. Here we present the synthesis of integrated Ni-P-S nanosheets array including Ni2P and NiS on nickel foam by a simple simultaneous phosphorization and sulfurization strategy. The resultant sample with optimal composition exhibits superior electrocatalytic performance for hydrogen evolution reaction (HER) in a wide pH range. In alkaline media it can generate current densities of 10 20 and 100 mA cm−2 at low overpotentials of only −101.9 −142.0 and −207.8 mV with robust durability. It still exhibits high electrocatalytic activities even in acid or neutral media. Such superior electrocatalytic performances can be mainly attributed to the synergistic enhancement of the hybrid Ni-P-S nanosheets array with integration microstructure. The kind of catalyst gives a new insight on achieving efficient and robust hydrogen generation.
Numerical Simulation of The Laminar Hydrogen Flame In The Presence of a Quenching Mesh
Sep 2009
Publication
Recent studies of J.H. Song et al. and S.Y. Yang et al. have been concentrated on mitigation measures against hydrogen risk. The authors have proposed installation of quenching meshes between compartments or around the essential equipment in order to contain hydrogen flames. Preliminary tests were conducted which demonstrated the possibility of flame extinction using metallic meshes of specific size.<br/>Considerable amount of numerical and theoretical work on flame quenching phenomenon has been performed in the second half of the last century and several techniques and models have been proposed to predict the quenching phenomenon of the laminar flame system. Most of these models appreciated the importance of heat loss to the surroundings as a primary cause of extinguishment in particular the heat transfer by conduction to the containing wall. The supporting simulations predict flame-quenching structure either between parallel plates (quenching distance) or inside a tube of a certain diameter (quenching diameter).<br/>In the present study the flame quenching is investigated assuming the laminar hydrogen flame propagating towards a quenching mesh using two-dimensional configuration and the earlier developed models. It is shown that due to a heat loss to a metallic grid the flame can be quenched numerically.
Review of the Current Status of Ammonia-Blended Hydrogen Fuel Engine Development
Jan 2022
Publication
As fossil fuels continue to be extracted and used issues such as environmental pollution and energy scarcity are surfacing. For the transportation industry the best way to achieve the goal of “carbon neutrality” is to research efficient power systems and develop new alternative fuels. As the world’s largest product of chemicals ammonia is a new renewable fuel with good combustion energy. It can be used as an alternative fuel to reduce carbon emissions because of its proven production process low production and transportation costs safe storage the absence of carbon-containing compounds in its emissions and its future recyclability. This paper firstly introduces the characteristics of ammonia fuel engine and its problems; then it summarizes the effects of various ammonia-blended fuels on the combustion and emission characteristics of the engine from the combustion problem of ammonia-blended engine; then the fuel storage of ammonia-blended hydrogen is discussed the feasibility of hydrogen production instead of hydrogen storage is introduced.
Direct Ammonia Low-temperature Symmetrical Solid Oxide Fuel Cells with Composite Semiconductor Electrolyte
Jan 2022
Publication
In this work a low-temperature symmetrical solid oxide fuel cell with Ni-NCAL|SDC/NCAL|Ni-NCAL (70 SDC:30 NCAL) configuration was successfully constructed by a simple dry press method. At 500 and 550 ◦C the peak power densities of the cell in ammonia were 501 and 755 mW cm− 2 and in hydrogen were 670 and 895 mW cm− 2 respectively. EIS data showed that the Rp values of the cell in ammonia and hydrogen at 550 ◦C were 0.250 and 0.246 Ω cm− 2 respectively indicating the excellent catalytic activity of the Ni-NCAL electrode toward ammonia decomposition and hydrogen oxidation. The different cell output can be ascribed to additional ammonia decomposition steps compared to hydrogen. The noticeable reaction product on the surface of the Ni foam was detrimental to ammonia decomposition. In summary a symmetrical cell with SDC/NCAL semi-conductor electrolyte and Ni-NCAL electrodes exhibited higher electrochemical performance at low temperature than the results reported to date. Therefore higher electrochemical performance can be expected from this cell configuration with more efficient ammonia decomposition catalysts.
Hydrolysis-Based Hydrogen Generation Investigation of Aluminium System Adding Low-Melting Metals
Mar 2021
Publication
In this age of human civilization there is a need for more efficient cleaner and renewable energy as opposed to that provided by nonrenewable sources such as coal and oil. In this sense hydrogen energy has been proven to be a better choice. In this paper a portable graphite crucible metal smelting furnace was used to prepare ten multi-element aluminum alloy ingots with different components. The microstructure and phase composition of the ingots and reaction products were analyzed by X-ray diffraction (XRD) scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The reaction was carried out in a constant temperature water bath furnace at 60°C and the hydrogen production performance of the multi-element aluminum alloys in different proportions was compared by the drainage gas collection method. The experimental results show that the as-cast microstructure of Al–Ga–In–Sn aluminum alloy is composed of a solid solution of Al and part of Ga and a second phase of In3Sn. After the hydrolysis reaction the products were dried at 150°C and then analyzed by XRD. The products were mainly composed of AlOOH and In3Sn. Alloys with different compositions react at the same hydrolysis temperature and the hydrogen production performance is related to the ratio of low-melting-point metal elements. By comparing two different ratios of Ga–In–Sn (GIS) the hydrogen production capacity and production rate when the ratio is 6:3:1 are generally higher than those when the ratio is 7:2:1. The second phase content affects the hydrogen production performance.
Experimental Investigation of the Effect of Hydrogen on Fracture Toughness of 2.25Cr-1Mo-0.25V Steel and Welds after Annealing
Mar 2018
Publication
Hydrogen embrittlement (HE) is a critical issue that hinders the reliability of hydrogenation reactors. Hence it is of great significance to investigate the effect of hydrogen on fracture toughness of 2.25Cr-1Mo-0.25V steel and weld. In this work the fracture behavior of 2.25Cr-1Mo-0.25V steel and welds was studied by three-point bending tests under hydrogen-free and hydrogen-charged conditions. The immersion charging method was employed to pre-charge hydrogen inside specimen and the fracture toughness of these joints was evaluated quantitatively. The microstructure and grain size of the specimens were observed by scanning electron microscopy (SEM) and by metallurgical microscopy to investigate the HE mechanisms. It was found that fracture toughness for both the base metal (BM) and the weld zone (WZ) significantly decreased under hydrogen-charged conditions due to the coexistence of the hydrogen-enhanced decohesion (HEDE) and hydrogen-enhanced localized plasticity (HELP) mechanisms. Moreover the formation and growth of primary voids were observed in the BM leading to a superior fracture toughness. In addition the BM compared to the WZ shows superior resistance to HE because the finer grain size in the BM leads to a larger grain boundary area thus distributing more of the diffusive hydrogen trapped in the grain boundary and reducing the hydrogen content.
Progress in Biofuel Production from Gasification
May 2017
Publication
Biofuels from biomass gasification are reviewed here and demonstrated to be an attractive option. Recent progress in gasification techniques and key generation pathways for biofuels production process design and integration and socio-environmental impacts of biofuel generation are discussed with the goal of investigating gasification-to-biofuels’ credentials as a sustainable and eco-friendly technology. The synthesis of important biofuels such as bio-methanol bio-ethanol and higher alcohols bio-dimethyl ether Fischer Tropsch fuels bio-methane bio-hydrogen and algae-based fuels is reviewed together with recent technologies catalysts and reactors. Significant thermodynamic studies for each biofuel are also examined. Syngas cleaning is demonstrated to be a critical issue for biofuel production and innovative pathways such as those employed by Choren Industrietechnik Germany and BioMCN the Netherlands are shown to allow efficient methanol generation. The conversion of syngas to FT transportation fuels such as gasoline and diesel over Co or Fe catalysts is reviewed and demonstrated to be a promising option for the future of biofuels. Bio-methane has emerged as a lucrative alternative for conventional transportation fuel with all the advantages of natural gas including a dense distribution trade and supply network. Routes to produce H2 are discussed though critical issues such as storage expensive production routes with low efficiencies remain. Algae-based fuels are in the research and development stage but are shown to have immense potential to become commercially important because of their capability to fix large amounts of CO2 to rapidly grow in many environments and versatile end uses. However suitable process configurations resulting in optimal plant designs are crucial so detailed process integration is a powerful tool to optimize current and develop new processes. LCA and ethical issues are also discussed in brief. It is clear that the use of food crops as opposed to food wastes represents an area fraught with challenges which must be resolved on a case by case basis.
Microbial Fuel Cells: Technologically Advanced Devices and Approach for Sustainable/renewable Energy Development
Dec 2021
Publication
There is a huge quantity of energy needs/demands for multiple developmental and domestic activities in the modern era. And in this context consumption of more non-renewable energy is reported and created many problems or issues (availability of fossil fuel stocks in the future period causes a huge quantity of toxic gases or particles or climatic change effects) at the global level. And only sustainable or renewable fuel development can provide alternate fuel and we report from various biological agents processes including microbial biofuel cell applications for future energy needs only. These will not cause any interference in natural resources or services. Microbial biofuel cells utilize the living cell to produce bioelectricity via bioelectrochemical system. It can drive electricity or other energy generation currents via lived cell interaction. Microbial fuel cells (MFCs) and enzymatic biofuel cells with their advancement in design can improve sustainable bio-energy production by proving an efficient conversion system compared to chemical fuels into electric power. Different types of MFCs operation are reported in wastewater treatment with biogas biohydrogen and other biofuel/energy generation. Later biogas can convert into electric power. Hybrid microbial biofuel cell utility with photochemical reaction is found for electricity generation. Recent research and development in microbial biofuel design and its application will emphasize bioenergy for the future.
Research on Carbide Characteristics and Their Influence on the Properties of Welding Joints for 2.25Cr1Mo0.25V Steel
Feb 2021
Publication
The carbide characteristics of 2.25Cr1Mo0.25V steel have an extremely important influence on the mechanical properties of welding joints. In addition hydrogen resistance behavior is crucial for steel applied in hydrogenation reactors. The carbide morphology was observed by scanning electron microscopy (SEM) and the carbide microstructure was characterized by transmission electron microscopy (TEM). Tensile and impact tests were carried out and the influence of carbides on properties was studied. A hydrogen diffusion test was carried out and the hydrogen brittleness resistance of welding metal and base metal was studied by tensile testing of hydrogenated samples to evaluate the influence of hydrogen on the mechanical properties. The research results show that the strength of the welding metal was slightly higher and the Charpy impact value was significantly lower compared to the base metal. The hydrogen embrittlement resistance of the welding metal was stronger than that of the base metal. The presence of more carbides and inclusions was the main cause of the decreased impact property and hydrogen brittleness resistance of the welding metal. These conclusions have certain reference value for designing and manufacturing hydrogenation reactors. View Full-Text
Hydrogen-Assisted Crack Growth in the Heat-Affected Zone of X80 Steels during in Situ Hydrogen Charging
Aug 2019
Publication
Herein the hydrogen embrittlement of a heat-affected zone (HAZ) was examined using slow strain rate tension in situ hydrogen charging. The influence of hydrogen on the crack path of the HAZ sample surfaces was determined using electron back scatter diffraction analysis. The hydrogen embrittlement susceptibility of the base metal and the HAZ samples increased with increasing current density. The HAZ samples have lower resistance to hydrogen embrittlement than the base metal samples in the same current density. Brittle circumferential cracks located at the HAZ sample surfaces were perpendicular to the loading direction and the crack propagation path indicated that five or more cracks may join together to form a longer crack. The fracture morphologies were found to be a mixture of intergranular and transgranular fractures. Hydrogen blisters were observed on the HAZ sample surfaces after conducting tensile tests at a current density of 40 mA/cm2 leading to a fracture in the elastic deformation stage.
A Fracture Analysis of Ti-10Mo-8V-1Fe-3.5Al Alloy Screws during Assembly
Oct 2016
Publication
Titanium screws have properties that make them ideal for applications that require both a high strength-to-weight ratio and corrosion resistance such as fastener applications for aviation and aerospace. The fracture behavior of Ti-10Mo-8V-1Fe-3.5Al (TB3) alloy screws during assembly was explored. Besides visual examination other experimental techniques used for the investigation are as follows: (1) fracture characteristics and damage morphology via scanning electron microscopy (SEM); (2) chemical constituents via energy dispersive spectroscopy (EDS) and hydrogen concentration testing; (3) metallographic observation; (4) stress durability embrittlement testing; and (5) torsion simulation testing. Results show that the fracture mode of the screws is brittle. There is no obvious relation to hydrogen-induced brittle. The main reason for the fracture of titanium alloy screws is internal defects around which oxygen content is high increasing brittleness. The internal defects of screws result from grain boundary cracking caused by hot forging.
Influence of Synthesis Gas Components on Hydrogen Storage Properties of Sodium Aluminium Hexahydride
Feb 2021
Publication
A systematic study of different ratios of CO CO2 N2 gas components on the hydrogen storage properties of the Na3AlH6 complex hydride with 4 mol% TiCl3 8 mol% aluminum and 8 mol% activated carbon is presented in this paper. The different concentrations of CO and CO2in H2 and CO CO2 N2 in H2 mixture were investigated. Both CO and CO2gas react with the complex hydride forming Al oxy-compounds NaOH and Na2CO3 that consequently cause serious decline in hydrogen storage capacity. These reactions lead to irreversible damage of complex hydride under the current experimental condition. Thus after 10 cycles with 0.1 vol % CO + 99.9 vol %H2 and 1 vol % CO + 99 vol %H2 the dehydrogenation storage capacity of the composite material decreased by 17.2% and 57.3% respectively. In the case of investigation of 10 cycles with 1 vol % CO2 + 99 vol % H2 gas mixture the capacity degradation was 53.5%. After 2 cycles with 10 vol % CO +90 vol % H2 full degradation was observed whereas after 6 cycles with 10 vol % CO2+ 90 vol % H2 degradation of 86.8% was measured. While testing with the gas mixture of 1.5 vol % CO + 10 vol % CO2+ 27 vol % H2 + 61.5 vol % N2 the degradation of 94% after 6 cycles was shown. According to these results it must be concluded that complex aluminum hydrides cannot be used for the absorption of hydrogen from syngas mixtures without thorough purification.
Hydrogen Station Technology Development Review Through Patent Analysis
May 2018
Publication
This study is a review of hydrogen station patents using the Derwent Innovation system and also a secondary screening. This was undertaken by the researchers to better understand and identify hydrogen station trends. The review focuses on analyzing the developing trends of patent technologies associated with a hydrogen station. The results of the review indicated that the countries with the major distribution of patents were Japan China the USA and Europe. Japan is leading the developmental trajectory of hydrogen stations. The results of the analysis found the leading developers of these patented technologies are Kobe Steel Nippon Oil Toyota and Honda. Other active patent developers analyzed include Linde Hyundai and Texaco. The review concludes with a suggestion that using a patent analysis methodology is a good starting point to identify evaluate and measure the trend in hydrogen station commercial development.
No more items...