A suitable channel structure can lead to efficient gas distribution and significantly improve the power density of fuel cells.In this study,the influence of two channel design parameters is investigated,namely,the rat...A suitable channel structure can lead to efficient gas distribution and significantly improve the power density of fuel cells.In this study,the influence of two channel design parameters is investigated,namely,the ratio of the channel width to the bipolar plate ridge width(i.e.,the channel ridge ratio)and the channel depth.The impact of these parameters is evaluated with respect to the flow pattern,the gas composition distribution,the temperature field and the fuel cell output capability.The results show that a decrease in the channel ridge ratio and an increase in the channel depth can effectively make the distributions of velocity,temperature and concentration more uniform in each channel and improve the output capability of the fuel cell.An increase in the channel ridge ratio and depth obviously reduces the flow resistance and improves the flow characteristics.展开更多
A novel design of plate-type microchannel reactor has been developed for fuel cell-grade hydrogen production.Commercial Cu/Zn/Al2O3 was used as catalyst for the reforming reaction,and its effectiveness was evaluated o...A novel design of plate-type microchannel reactor has been developed for fuel cell-grade hydrogen production.Commercial Cu/Zn/Al2O3 was used as catalyst for the reforming reaction,and its effectiveness was evaluated on the mole fraction of products,methanol conversion,hydrogen yield and the amount of carbon monoxide under various operating conditions.Subsequently,0.5 wt% Ru/Al2O3 as methanation catalyst was prepared by impregnation method and coupled with MSR step to evaluate the capability of methanol processor for CO reduction.Based on the experimental results,the optimum conditions were obtained as feed flow rate of 5mL/h and temperature of 250℃,leading to a low CO selectivity and high H2 yield.The designed reformer with catalyst coated layer was compared with the conventional packed bed reformer at the same operating conditions.The constructed fuel processor had a good performance and excellent capability for on-board hydrogen production.展开更多
Fuel cells are considered to be one of the ideal alternatives to traditional fossil energy conversion devices.Membrane electrodes are the core components in the hydrogen fuel cells.Our work reported the synthesis of t...Fuel cells are considered to be one of the ideal alternatives to traditional fossil energy conversion devices.Membrane electrodes are the core components in the hydrogen fuel cells.Our work reported the synthesis of the Pt/C catalysts with different Pt loading,and by changing the Nafion content,hot pressing temperature and hot pressing pressure,the catalyst coated membrane(CCM)spraying process was optimized.Moreover,the three-dimensional structure model of the single battery membrane electrode was studied quantitatively,and the porous membrane electrode with gradient distribution was fabricated under optimized processing conditions,with excellent electrical performance.展开更多
The synergistic effect of H_3PMo_(12)O_(40) or H_3PW_(12)O_(40) polyoxometalate solution(POM) and TiO_2 to catalyze formic acid oxidation was investigated. Under UV irradiation, hole and electron were photogenerated b...The synergistic effect of H_3PMo_(12)O_(40) or H_3PW_(12)O_(40) polyoxometalate solution(POM) and TiO_2 to catalyze formic acid oxidation was investigated. Under UV irradiation, hole and electron were photogenerated by TiO_2. Formic acid was oxided by the photogenerated hole and photogenerated electron was transferred to reduce polyoxometalate. With this design, formic acid can be converted into electricity in the fuel cell and hydrogen can be generated in the electrolysis cell without noble metal catalyst. Unlike other noble metal catalysts applied in the fuel cells and electrolysis cell, POM and TiO_2 are stable and low cost. The maximum output power density of liquid formic acid fuel cell after 12 h UV irradiation is 5.21 mW/cm^2 for phosphmolybdic acid and 22.81 m W/cm^2 for phosphotungstic acid respectively. The applied potential for the hydrogen evolution is as low as 0.8 V for phosphmolybdic acid and 0.6 V for phosphotungstic acid.展开更多
Catalyst using CeO2/MWNT(multi-walled carbon nanotube) was prepared by chemical deposition method and was applied to prepare the cathode of fuel cell for hydrogen peroxide synthesis.Effect of catalyst loading, flow ...Catalyst using CeO2/MWNT(multi-walled carbon nanotube) was prepared by chemical deposition method and was applied to prepare the cathode of fuel cell for hydrogen peroxide synthesis.Effect of catalyst loading, flow rate of aqueous solution, and KOH concentration on hydrogen peroxide synthesis were investigated.Experimental results indicated that hydrogen peroxide concentration approached 275 mmol/L given 25% of CeO2/MWNT, 18 ml/h of aqueous solution, and 5 mol/L of KOH concentration.Moreover, the reaction mechanism was further discussed.The results indicated that MWNT and cerium oxide were the synergism to produce hydrogen peroxide.Increase of KOH concentration not only reduced the apparent cell resistance but also increased the open-circuit voltage.展开更多
For a 120 kW hydrogen fuel cell system,a centrifugal air compressor with fixed power of 22 kW fuel cell is designed.Firstly,the theoretical calculation is carried out for the aerodynamic characteristics of a ultra-hig...For a 120 kW hydrogen fuel cell system,a centrifugal air compressor with fixed power of 22 kW fuel cell is designed.Firstly,the theoretical calculation is carried out for the aerodynamic characteristics of a ultra-high-speed permanent magnet synchronous motor,an air compressor,and an aerodynamic foil bearing.Then,a prototype is trial-produced and a related test bench is built for test verification.Finally,both the simulation and test results indicate that the designed centrifugal air compressor meets the overall requirements of the hydrogen fuel cell system,and the relevant conclusions provide both theoretical and experimental references for the subsequent series development and design of the centrifugal air compressor.展开更多
In order to improve the design of PSA system for fuel cell hydrogen production,a non-isothermal model of eight-bed PSA hydrogen process with five-component(H_(2)/N_(2)/CH_(4)/CO/CO_(2)=74.59%/0.01%/4.2%/2.5%/18.7%(vol...In order to improve the design of PSA system for fuel cell hydrogen production,a non-isothermal model of eight-bed PSA hydrogen process with five-component(H_(2)/N_(2)/CH_(4)/CO/CO_(2)=74.59%/0.01%/4.2%/2.5%/18.7%(vol))four-stage pressure equalization was developed in this article.The model adopts a composite adsorption bed of activated carbon and zeolite 5 A.In this article,pressure variation,temperature field and separation performance are stimulated,and also effect of providing purge(PP)differential pressure and the ratio of activated carbon to zeolite 5 A on separation performance in the process of producing industrial hydrogen(CO content in hydrogen is 10μl·L^(-1))and fuel cell hydrogen(CO content is 0.2μl·L^(-1))are compared.The results show that Run 3,when the CO content in hydrogen is 10μl·L^(-1),the hydrogen recovery is 89.8%,and the average flow rate of feed gas is 0.529 mol·s^(-1);When the CO content in hydrogen is 0.2μl·L^(-1),the hydrogen recovery is 85.2%,and the average flow rate of feed gas is 0.43 mol·s^(-1).With the increase of PP differential pressure,hydrogen recovery first increases and then decreases,reaching the maximum when PP differential pressure is 0.263 MPa;With the decrease of the ratio of activated carbon to zeolite 5 A,the hydrogen recovery increases gradually.When the CO content in hydrogen is 0.2μl·L^(-1) the hydrogen recovery increases more obviously,from 83.96%to 86.37%,until the ratio of activated carbon to zeolite 5 A decreases to 1.At the end of PP step,no large amount of CO_(2) in gas or solid phase enters the zeolite 5 A adsorption bed,while when the CO content in hydrogen is 10μl·L^(-1),and the ratio of carbon to zeolite 5 A is less than 1.4,more CO_(2) will enter the zeolite 5 A bed.展开更多
In this study,an amine-coordinated cobalt phthalocyanine(CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen peroxide fuel cells(HPFCs) and enzymatic biofuel cells(EBC...In this study,an amine-coordinated cobalt phthalocyanine(CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen peroxide fuel cells(HPFCs) and enzymatic biofuel cells(EBCs).For this purpose,polyethyleneimine(PEI) was added onto the reduced graphene oxide and CoPc composite(RGO/CoPc) to create abundant NH2 axial ligand groups,for anchoring the Co core within the CoPc.Owing to the PEI addition,the onset potential of the hydrogen peroxide oxidation reaction was shifted by 0.13 V in the negative direction(0.02 V) and the current density was improved by 1.92 times(1.297 mA cm^(-2)),compared to those for RGO/CoPc(0.15 V and 0.676 mA cm^(-2),respectively),due to the formation of donor-acceptor dyads and the prevention of CoPc from leaching out.The biocatalyst using glucose oxidase(GOx)([RGO/CoPc]/PEI/GOx) showed a better onset potential and catalytic activity(0.15 V and 318.7 μA cm^(-2)) than comparable structures,as well as significantly improved operational durability and long-term stability.This is also attributed to PEI,which created a favorable microenvironment for the enzyme.The maximum power densities(MPDs) and open-circuit voltages(OCVs) obtained for HPFCs and EBCs using the suggested catalyst were 105.2±1.3 μW cm^(-2)(0.317±0.003 V) and 25.4±0.9 μW cm^(-2)(0.283±0.007 V),respectively.This shows that the amine axial ligand effectively improves the performance of the actual driving HPFCs and EBCs.展开更多
Synthesis of organic fuels from carbon dioxide and hydrogen is analysed,in terms of energy recovery efficiency,and the required energy input for electrolysis of water.This electrical energy is related to the thermal e...Synthesis of organic fuels from carbon dioxide and hydrogen is analysed,in terms of energy recovery efficiency,and the required energy input for electrolysis of water.This electrical energy is related to the thermal energy required in a power station.A method is described to recover heat from energy-producing reactions in the fuel synthesis process,which can then be used to reduce the electrical energy requirement for electrolysis.By co-locating the fuel synthesis plant with a thermal power station,primary(thermal) energy can be used to produce high temperature steam,with a lower electrical requirement for electrolytic production of hydrogen.This can make more efficient use of the primary energy than a thermodynamic engine.Comparison is made with alternative fuels,in terms of energy budget,sustainability,carbon dioxide emissions,etc.The energy security benefits of advanced fuel synthesis are also identified.展开更多
The hydrogen production from methane for proton exchange membrane fuel cell (PEMFC) was studied experimentally. The conversion rate of methane under different steam carbon ratios, the effect of the different excess ai...The hydrogen production from methane for proton exchange membrane fuel cell (PEMFC) was studied experimentally. The conversion rate of methane under different steam carbon ratios, the effect of the different excess air ratios on the constituents of the gas produced, the permeability of hydrogen under different pressure differences, and the effect of different system pressure on the reaction enthalpy of hydrogen were obtained. The results lay the basis for the production of hydrogen applicable to PEMFC, moreover, provide a new way for the comprehensive utilization of the coal bed methane.展开更多
Fuel cell using borohydride as the fuel has received much attention. AB5-type hydrogen storage alloy used as the anodic material instead of noble metals has been investigated. In order to restrain the generation of hy...Fuel cell using borohydride as the fuel has received much attention. AB5-type hydrogen storage alloy used as the anodic material instead of noble metals has been investigated. In order to restrain the generation of hydrogen and enhance the utilization of borohydride, Ti/Zr metal powders has been added into the parent LmNi4.78Mn0.22 (where Lm is La-richened mischmetal) alloy (LNM) by ball milling and heat treatment methods. It is found that the addition of Ti/Zr metal powders lowers the electrochemical catalytic activity of the electrodes, at the same time, restrains the generation of hydrogen and enhances the utilization of the fuel. All the results show that the hydrogen generation rate or the utilization of the fuel is directly relative to the electrochemical catalytic activity or the discharge capability of the electrodes. The utilization of the fuel increases with discharge current density. It is very important to find a balance between the discharge capability and the utilization of the fuel.展开更多
Gamma uranium-molybdenum alloys have been considered as the fuel phase in plate type fuel elements for material and test reactors (MTR), due to their acceptable performance under irradiation. Regarding their usage as ...Gamma uranium-molybdenum alloys have been considered as the fuel phase in plate type fuel elements for material and test reactors (MTR), due to their acceptable performance under irradiation. Regarding their usage as a dispersion phase in aluminum matrix, it is necessary to convert the as cast structure into powder, and one of the techniques considered for this purpose is the hydration-dehydration (HDH). This paper shows that, under specific conditions of heating and cooling, γ-UMo fragmentation occurs in a non-reactive predominant mechanism, as shown by the curves of hydrogen absorption/desorption as a function of time and temperature. Our focus was on the experimental results presented by the addition of 8% weight molybdenum. Following the production by induction melting, samples of the alloys were thermally treated under a constant flow of hydrogen for temperatures varying from 500°C to 600°C and for times of 0.5 to 4 h. It was observed that, even without a massive hydration-dehydration process, the alloys fragmented under specific conditions of thermal treatment during the thermal shock phase of the experiments. Also, it was observed that there was a relation between absorption and the rate of gamma decomposition or the gamma phase stability of the alloy.展开更多
A sinter-locked three-dimensional network of microfibrous nickel catalyst has been fabricated based on wet layup papermaking and sintering processes and this novel approach permits the production of -11 W fuel cell po...A sinter-locked three-dimensional network of microfibrous nickel catalyst has been fabricated based on wet layup papermaking and sintering processes and this novel approach permits the production of -11 W fuel cell power H2 via NH3 decomposition with a conversion of 97% at 750 ℃ in a bed of 0.6 cm^3.展开更多
As the practicability of a hydrogen-fueled economy emerges, intermediate technologies would be necessary for the transition between hydrocarbon fueled internal combustion engines and hydrogen powered fuel cells. In th...As the practicability of a hydrogen-fueled economy emerges, intermediate technologies would be necessary for the transition between hydrocarbon fueled internal combustion engines and hydrogen powered fuel cells. In the present study, the hydrogen engine efficiency and the load control are the two main parameters that will be improved by using the combined operation of in-cylinder direct fuel injection (DI) and port fuel injection (PFI) strategies to obtain maximum engine power outputs with acceptable efficiency equivalent to gasoline engines. Wide open throttle (WOT) operation has been used to take advantage of the associated increase in engine efficiency, in which the loads have been regulated with mixture richness (qualitative control) instead of volumetric efficiency (quantitative control). The capabilities of a 3D-CFD code have been developed and employed to simulate the whole engine physicochemical process which includes the hydrogen injection through the intake manifold (PFI) and/or the hydrogen DI in the engine compression stroke. Conditions with simulated PFI, PFI + DI and DI have been analyzed to study the effects of mixture preparation behaviors on the hydrogen ignition and its flame propagation inside the engine combustion chamber. Numerically, the CFD code has been intensively validated against experimental engine data which provided remarkable agreement in terms of in-cylinder pressure history evaluation.展开更多
This paper presents the concept of a passive electrochemical hydrogen recombiner(PEHR).The reaction energy of the recombination of hydrogen and oxygen is used as a source of electrical energy according to the operatin...This paper presents the concept of a passive electrochemical hydrogen recombiner(PEHR).The reaction energy of the recombination of hydrogen and oxygen is used as a source of electrical energy according to the operating principle for hydrogen fuel cells to establish forced circulation of the hydrogen mixture as an alternative to natural circulation(as is not utilized in conventional passive autocatalytic hydrogen recombiners currently used in nuclear power plants(NPPs)).The proposed concept of applying the physical operation principles of a PEHR based on a fuel cell simultaneously increases both productivity in terms of recombined hydrogen and the concentration threshold of flameless operation(the‘ignition’limit).Thus,it is possible to reliably ensure the hydrogen explosion safety of NPPs under all conditions,including beyond-design accidents.An experimental setup was assembled to test a laboratory sample of a membrane electrode assembly(MEA)at various hydrogen concentrations near the catalytic surfaces of the electrodes,and the corresponding current–voltage characteristics were recorded.The simplest MEA based on the Advent P1100W PBI membrane demonstrated stable performance(delivery of electrical power)over a wide range of hydrogen concentrations.展开更多
In the last decade, increasing applications of information technology (IT) within power industry has become a significant reality. As distributed power networks are gaining importance and renewables are getting a bigg...In the last decade, increasing applications of information technology (IT) within power industry has become a significant reality. As distributed power networks are gaining importance and renewables are getting a bigger ratio within energy production, Smart Grid applications have become essential, especially due to the intermittent nature of renewable energy resources. Smart Grid is a sustainable energy system that measures, checks, and controls the generation, transmission, and consumption of electrical energy in grids on all voltage levels. Smart Grid experts are driving forward the development of effective communication and information technologies for the build-up of intelligent power supply networks. Examples of these are control systems for the realization of virtual power plants, intelligent consumer data acquisition systems, and smart distribution management systems. Fuel cell-based hydrogen electricity, in comparison to other renewable energy sources, is more stable and predictable. Yet hydrogen power and smart-grids have many application points, mainly as means of energy storage. This study claims that hydrogen energy and smart-grids could also engage through an appliance of IT managed metering of hydrogen power production. Smart metering and management of hydrogen fuel cells would enable advanced planning of short-to-mid-term power productions and thus foster use of hydrogen power within distributed networks, as local community or industrial applications.展开更多
基金This work was sponsored by the National Key R&D Program of China[Grant Number 2020YFB0106603]the Key R&D Program of Shandong Province[Grant Number 2020CXGC010404]the Undergraduate School of Shandong University,China[Grant Number 2022Y155].
文摘A suitable channel structure can lead to efficient gas distribution and significantly improve the power density of fuel cells.In this study,the influence of two channel design parameters is investigated,namely,the ratio of the channel width to the bipolar plate ridge width(i.e.,the channel ridge ratio)and the channel depth.The impact of these parameters is evaluated with respect to the flow pattern,the gas composition distribution,the temperature field and the fuel cell output capability.The results show that a decrease in the channel ridge ratio and an increase in the channel depth can effectively make the distributions of velocity,temperature and concentration more uniform in each channel and improve the output capability of the fuel cell.An increase in the channel ridge ratio and depth obviously reduces the flow resistance and improves the flow characteristics.
基金supported by the Iran National Science Foundation (INSF)
文摘A novel design of plate-type microchannel reactor has been developed for fuel cell-grade hydrogen production.Commercial Cu/Zn/Al2O3 was used as catalyst for the reforming reaction,and its effectiveness was evaluated on the mole fraction of products,methanol conversion,hydrogen yield and the amount of carbon monoxide under various operating conditions.Subsequently,0.5 wt% Ru/Al2O3 as methanation catalyst was prepared by impregnation method and coupled with MSR step to evaluate the capability of methanol processor for CO reduction.Based on the experimental results,the optimum conditions were obtained as feed flow rate of 5mL/h and temperature of 250℃,leading to a low CO selectivity and high H2 yield.The designed reformer with catalyst coated layer was compared with the conventional packed bed reformer at the same operating conditions.The constructed fuel processor had a good performance and excellent capability for on-board hydrogen production.
基金This work was financially supported by China Petrochemical Corporation(ST 20006-1,ST 20006-2).
文摘Fuel cells are considered to be one of the ideal alternatives to traditional fossil energy conversion devices.Membrane electrodes are the core components in the hydrogen fuel cells.Our work reported the synthesis of the Pt/C catalysts with different Pt loading,and by changing the Nafion content,hot pressing temperature and hot pressing pressure,the catalyst coated membrane(CCM)spraying process was optimized.Moreover,the three-dimensional structure model of the single battery membrane electrode was studied quantitatively,and the porous membrane electrode with gradient distribution was fabricated under optimized processing conditions,with excellent electrical performance.
文摘The synergistic effect of H_3PMo_(12)O_(40) or H_3PW_(12)O_(40) polyoxometalate solution(POM) and TiO_2 to catalyze formic acid oxidation was investigated. Under UV irradiation, hole and electron were photogenerated by TiO_2. Formic acid was oxided by the photogenerated hole and photogenerated electron was transferred to reduce polyoxometalate. With this design, formic acid can be converted into electricity in the fuel cell and hydrogen can be generated in the electrolysis cell without noble metal catalyst. Unlike other noble metal catalysts applied in the fuel cells and electrolysis cell, POM and TiO_2 are stable and low cost. The maximum output power density of liquid formic acid fuel cell after 12 h UV irradiation is 5.21 mW/cm^2 for phosphmolybdic acid and 22.81 m W/cm^2 for phosphotungstic acid respectively. The applied potential for the hydrogen evolution is as low as 0.8 V for phosphmolybdic acid and 0.6 V for phosphotungstic acid.
基金supported by the National High-Tech Development Plan (2006AA02Z211) Jiangsu Province Pollution Prevention Fundament Research (2006-1-W-19)
文摘Catalyst using CeO2/MWNT(multi-walled carbon nanotube) was prepared by chemical deposition method and was applied to prepare the cathode of fuel cell for hydrogen peroxide synthesis.Effect of catalyst loading, flow rate of aqueous solution, and KOH concentration on hydrogen peroxide synthesis were investigated.Experimental results indicated that hydrogen peroxide concentration approached 275 mmol/L given 25% of CeO2/MWNT, 18 ml/h of aqueous solution, and 5 mol/L of KOH concentration.Moreover, the reaction mechanism was further discussed.The results indicated that MWNT and cerium oxide were the synergism to produce hydrogen peroxide.Increase of KOH concentration not only reduced the apparent cell resistance but also increased the open-circuit voltage.
基金supported in part by the Key R&D projects in Hebei Province under Grant 20312202D。
文摘For a 120 kW hydrogen fuel cell system,a centrifugal air compressor with fixed power of 22 kW fuel cell is designed.Firstly,the theoretical calculation is carried out for the aerodynamic characteristics of a ultra-high-speed permanent magnet synchronous motor,an air compressor,and an aerodynamic foil bearing.Then,a prototype is trial-produced and a related test bench is built for test verification.Finally,both the simulation and test results indicate that the designed centrifugal air compressor meets the overall requirements of the hydrogen fuel cell system,and the relevant conclusions provide both theoretical and experimental references for the subsequent series development and design of the centrifugal air compressor.
文摘In order to improve the design of PSA system for fuel cell hydrogen production,a non-isothermal model of eight-bed PSA hydrogen process with five-component(H_(2)/N_(2)/CH_(4)/CO/CO_(2)=74.59%/0.01%/4.2%/2.5%/18.7%(vol))four-stage pressure equalization was developed in this article.The model adopts a composite adsorption bed of activated carbon and zeolite 5 A.In this article,pressure variation,temperature field and separation performance are stimulated,and also effect of providing purge(PP)differential pressure and the ratio of activated carbon to zeolite 5 A on separation performance in the process of producing industrial hydrogen(CO content in hydrogen is 10μl·L^(-1))and fuel cell hydrogen(CO content is 0.2μl·L^(-1))are compared.The results show that Run 3,when the CO content in hydrogen is 10μl·L^(-1),the hydrogen recovery is 89.8%,and the average flow rate of feed gas is 0.529 mol·s^(-1);When the CO content in hydrogen is 0.2μl·L^(-1),the hydrogen recovery is 85.2%,and the average flow rate of feed gas is 0.43 mol·s^(-1).With the increase of PP differential pressure,hydrogen recovery first increases and then decreases,reaching the maximum when PP differential pressure is 0.263 MPa;With the decrease of the ratio of activated carbon to zeolite 5 A,the hydrogen recovery increases gradually.When the CO content in hydrogen is 0.2μl·L^(-1) the hydrogen recovery increases more obviously,from 83.96%to 86.37%,until the ratio of activated carbon to zeolite 5 A decreases to 1.At the end of PP step,no large amount of CO_(2) in gas or solid phase enters the zeolite 5 A adsorption bed,while when the CO content in hydrogen is 10μl·L^(-1),and the ratio of carbon to zeolite 5 A is less than 1.4,more CO_(2) will enter the zeolite 5 A bed.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(Nos.2017R1D1A1B03032033 and 2020R1C1C1010386)“Leaders in INdustry-university Cooperation+”project supported by the Ministry of Education and National Research Foundation of Korea。
文摘In this study,an amine-coordinated cobalt phthalocyanine(CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen peroxide fuel cells(HPFCs) and enzymatic biofuel cells(EBCs).For this purpose,polyethyleneimine(PEI) was added onto the reduced graphene oxide and CoPc composite(RGO/CoPc) to create abundant NH2 axial ligand groups,for anchoring the Co core within the CoPc.Owing to the PEI addition,the onset potential of the hydrogen peroxide oxidation reaction was shifted by 0.13 V in the negative direction(0.02 V) and the current density was improved by 1.92 times(1.297 mA cm^(-2)),compared to those for RGO/CoPc(0.15 V and 0.676 mA cm^(-2),respectively),due to the formation of donor-acceptor dyads and the prevention of CoPc from leaching out.The biocatalyst using glucose oxidase(GOx)([RGO/CoPc]/PEI/GOx) showed a better onset potential and catalytic activity(0.15 V and 318.7 μA cm^(-2)) than comparable structures,as well as significantly improved operational durability and long-term stability.This is also attributed to PEI,which created a favorable microenvironment for the enzyme.The maximum power densities(MPDs) and open-circuit voltages(OCVs) obtained for HPFCs and EBCs using the suggested catalyst were 105.2±1.3 μW cm^(-2)(0.317±0.003 V) and 25.4±0.9 μW cm^(-2)(0.283±0.007 V),respectively.This shows that the amine axial ligand effectively improves the performance of the actual driving HPFCs and EBCs.
文摘Synthesis of organic fuels from carbon dioxide and hydrogen is analysed,in terms of energy recovery efficiency,and the required energy input for electrolysis of water.This electrical energy is related to the thermal energy required in a power station.A method is described to recover heat from energy-producing reactions in the fuel synthesis process,which can then be used to reduce the electrical energy requirement for electrolysis.By co-locating the fuel synthesis plant with a thermal power station,primary(thermal) energy can be used to produce high temperature steam,with a lower electrical requirement for electrolytic production of hydrogen.This can make more efficient use of the primary energy than a thermodynamic engine.Comparison is made with alternative fuels,in terms of energy budget,sustainability,carbon dioxide emissions,etc.The energy security benefits of advanced fuel synthesis are also identified.
文摘The hydrogen production from methane for proton exchange membrane fuel cell (PEMFC) was studied experimentally. The conversion rate of methane under different steam carbon ratios, the effect of the different excess air ratios on the constituents of the gas produced, the permeability of hydrogen under different pressure differences, and the effect of different system pressure on the reaction enthalpy of hydrogen were obtained. The results lay the basis for the production of hydrogen applicable to PEMFC, moreover, provide a new way for the comprehensive utilization of the coal bed methane.
文摘Fuel cell using borohydride as the fuel has received much attention. AB5-type hydrogen storage alloy used as the anodic material instead of noble metals has been investigated. In order to restrain the generation of hydrogen and enhance the utilization of borohydride, Ti/Zr metal powders has been added into the parent LmNi4.78Mn0.22 (where Lm is La-richened mischmetal) alloy (LNM) by ball milling and heat treatment methods. It is found that the addition of Ti/Zr metal powders lowers the electrochemical catalytic activity of the electrodes, at the same time, restrains the generation of hydrogen and enhances the utilization of the fuel. All the results show that the hydrogen generation rate or the utilization of the fuel is directly relative to the electrochemical catalytic activity or the discharge capability of the electrodes. The utilization of the fuel increases with discharge current density. It is very important to find a balance between the discharge capability and the utilization of the fuel.
文摘Gamma uranium-molybdenum alloys have been considered as the fuel phase in plate type fuel elements for material and test reactors (MTR), due to their acceptable performance under irradiation. Regarding their usage as a dispersion phase in aluminum matrix, it is necessary to convert the as cast structure into powder, and one of the techniques considered for this purpose is the hydration-dehydration (HDH). This paper shows that, under specific conditions of heating and cooling, γ-UMo fragmentation occurs in a non-reactive predominant mechanism, as shown by the curves of hydrogen absorption/desorption as a function of time and temperature. Our focus was on the experimental results presented by the addition of 8% weight molybdenum. Following the production by induction melting, samples of the alloys were thermally treated under a constant flow of hydrogen for temperatures varying from 500°C to 600°C and for times of 0.5 to 4 h. It was observed that, even without a massive hydration-dehydration process, the alloys fragmented under specific conditions of thermal treatment during the thermal shock phase of the experiments. Also, it was observed that there was a relation between absorption and the rate of gamma decomposition or the gamma phase stability of the alloy.
文摘A sinter-locked three-dimensional network of microfibrous nickel catalyst has been fabricated based on wet layup papermaking and sintering processes and this novel approach permits the production of -11 W fuel cell power H2 via NH3 decomposition with a conversion of 97% at 750 ℃ in a bed of 0.6 cm^3.
文摘As the practicability of a hydrogen-fueled economy emerges, intermediate technologies would be necessary for the transition between hydrocarbon fueled internal combustion engines and hydrogen powered fuel cells. In the present study, the hydrogen engine efficiency and the load control are the two main parameters that will be improved by using the combined operation of in-cylinder direct fuel injection (DI) and port fuel injection (PFI) strategies to obtain maximum engine power outputs with acceptable efficiency equivalent to gasoline engines. Wide open throttle (WOT) operation has been used to take advantage of the associated increase in engine efficiency, in which the loads have been regulated with mixture richness (qualitative control) instead of volumetric efficiency (quantitative control). The capabilities of a 3D-CFD code have been developed and employed to simulate the whole engine physicochemical process which includes the hydrogen injection through the intake manifold (PFI) and/or the hydrogen DI in the engine compression stroke. Conditions with simulated PFI, PFI + DI and DI have been analyzed to study the effects of mixture preparation behaviors on the hydrogen ignition and its flame propagation inside the engine combustion chamber. Numerically, the CFD code has been intensively validated against experimental engine data which provided remarkable agreement in terms of in-cylinder pressure history evaluation.
基金Open access funding provided by North-West University
文摘This paper presents the concept of a passive electrochemical hydrogen recombiner(PEHR).The reaction energy of the recombination of hydrogen and oxygen is used as a source of electrical energy according to the operating principle for hydrogen fuel cells to establish forced circulation of the hydrogen mixture as an alternative to natural circulation(as is not utilized in conventional passive autocatalytic hydrogen recombiners currently used in nuclear power plants(NPPs)).The proposed concept of applying the physical operation principles of a PEHR based on a fuel cell simultaneously increases both productivity in terms of recombined hydrogen and the concentration threshold of flameless operation(the‘ignition’limit).Thus,it is possible to reliably ensure the hydrogen explosion safety of NPPs under all conditions,including beyond-design accidents.An experimental setup was assembled to test a laboratory sample of a membrane electrode assembly(MEA)at various hydrogen concentrations near the catalytic surfaces of the electrodes,and the corresponding current–voltage characteristics were recorded.The simplest MEA based on the Advent P1100W PBI membrane demonstrated stable performance(delivery of electrical power)over a wide range of hydrogen concentrations.
文摘In the last decade, increasing applications of information technology (IT) within power industry has become a significant reality. As distributed power networks are gaining importance and renewables are getting a bigger ratio within energy production, Smart Grid applications have become essential, especially due to the intermittent nature of renewable energy resources. Smart Grid is a sustainable energy system that measures, checks, and controls the generation, transmission, and consumption of electrical energy in grids on all voltage levels. Smart Grid experts are driving forward the development of effective communication and information technologies for the build-up of intelligent power supply networks. Examples of these are control systems for the realization of virtual power plants, intelligent consumer data acquisition systems, and smart distribution management systems. Fuel cell-based hydrogen electricity, in comparison to other renewable energy sources, is more stable and predictable. Yet hydrogen power and smart-grids have many application points, mainly as means of energy storage. This study claims that hydrogen energy and smart-grids could also engage through an appliance of IT managed metering of hydrogen power production. Smart metering and management of hydrogen fuel cells would enable advanced planning of short-to-mid-term power productions and thus foster use of hydrogen power within distributed networks, as local community or industrial applications.