Methanol is regarded as an important liquid fuel for hydrogen storage, transportation, and in-situ generation due to its convenient conveyance, high energy density, and low conversion temperature. In this work, an ove...Methanol is regarded as an important liquid fuel for hydrogen storage, transportation, and in-situ generation due to its convenient conveyance, high energy density, and low conversion temperature. In this work, an overview of state-of-the-art investigations on methanol reforming is critically summarized, including the detailed introduction of methanol conversion pathways from the perspective of fuel cell applications, various advanced materials design for catalytic methanol conversion, as well as the development of steam methanol reformers. For the section of utilization pathways, reactions such as steam reforming of methanol, partial oxidation of methanol, oxidative steam reforming of methanol, and sorption-enhanced steam methanol reforming were elaborated;For the catalyst section, the strategies to enhance the catalytic activity and other comprehensive performances were summarized;For the reactor section, the newly designed steam methanol reformers were thoroughly described. This review will benefit researchers from both fundamental research and fuel cell applications in the field of catalyzing methanol to hydrogen.展开更多
A laboratory-scale intermediate-temperature H2S fuel cell with a configuration of H2S, (metal sulfide-based composite anode)/Li2SO4+Al2O3/(NiO-based composite cathode), air was developed and studied for production of ...A laboratory-scale intermediate-temperature H2S fuel cell with a configuration of H2S, (metal sulfide-based composite anode)/Li2SO4+Al2O3/(NiO-based composite cathode), air was developed and studied for production of power and for desulfurization of a fuel gas process stream. The cell was run at typical temperature (600—650℃) and ambient pressure, but its electrochemical performance may be limited by electrolyte membrane thickness. The membrane and its performance in cell have been characterized using scanning electron microscope (SEM) and electrochemical impedance spectrum (EIS) techniques. Composite anodes based on metal sulfides, Ag powder and electrolyte behaved well and stably in H2S stream, and composite cathodes based mainly on nickel oxide, Ag powder and electrolyte had superior per-formance to Pt catalyst. The maximum power density of up to 70mW?cm-2 and current density of as high as 250mA?cm-2 were obtained at 650℃. However, the long-term cell stability remains to be investigated.展开更多
Borohydrides present interesting options for the electrochemical power generation acting either as hydrogen source or anodic fuel for direct borohydride fuel cells(DBFC).In this work,Mg-Ni composite synthesized by mec...Borohydrides present interesting options for the electrochemical power generation acting either as hydrogen source or anodic fuel for direct borohydride fuel cells(DBFC).In this work,Mg-Ni composite synthesized by mechanically alloying method,used as the catalyst for the hydrolysis of borohydride,has been investigated.Co-doping treatment has been carried out for the purpose of improving the hydrolysis rate further.The as-prepared and Co-doped Mg-Ni composites with low cost showed high catalytic activity to the hydrolysis of borohydride for hydrogen generation.After Co-doping,the hydrogen generation rate was around 280 ml·g-1·min-1.Borohydride would be a promising hydrogen source for fuel cells.展开更多
Hydrogen fuel cell cars are now available for lease and for sale. Renewable hydrogen fuel can be produced from water via electrolysis, or from biomass via gasification. Electrolysis is power-hungry with high demand fr...Hydrogen fuel cell cars are now available for lease and for sale. Renewable hydrogen fuel can be produced from water via electrolysis, or from biomass via gasification. Electrolysis is power-hungry with high demand from solar or wind power. Gasification, however, can be energy self-sufficient using a recently-patented thermochemical conversion technology known as I-HPG (indirectly-heated pyrolytic gasification). I-HPG produces a tar-free syngas from non-food woody biomass. This means the balance of plant can be small, so the overall system is economical at modest sizes. This makes it possible to produce renewable hydrogen from local agricultural residues; sufficient to create distributed refueling stations wherever there is feedstock. This work describes the specifics of a novel bio-hydrogen refueling station whereby the syngas produced has much of the hydrogen extracted with the remainder powering a generator to provide the electric power to the I-HPG system. Thus the system runs continuously. When paired with another new technology, moderate-pressure storage of hydrogen in porous silicon, there is the potential to also power the refueling operation. Such systems can be operated independently. It is even possible to design an energy self-sufficient farm where all electric power, heat, and hydrogen fuel is produced from the non-food residues of agricultural operations. No water is required, and the carbon footprint is negative, or at least neutral.展开更多
Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing...Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing of large capital investment towards research and development of sustainable alternative energy sources. One of the most promising and abundant of these sources is hydrogen. Firstly, the use of current fossil fuels is. discussed focusing on the emissions and economic sides to emphasize the need for a new, cleaner and renewable fuel with particular reference to hydrogen as a suitable possible alternative. Hydrogen properties, production and storage methods are then reviewed along with its suitability from the economical point of view. Finally, a cost analysis for the use of hydrogen in internal combustion engines is carried out to illustrate the benefits of its use as a replacement for diesel. The outcome of this cost analysis shows that 98% of the capital expenditure is consumed by the equipment, and 68.3% of the total cost of the equipment is spent on the solar photovoltaic cells. The hydrogen plant is classified as a large investment project because of its high initial cost which is about 1 billion US$; but this is justified because hydrogen is produced in a totally green way. When hydrogen is used as a fuel, no harmful emissions are obtained.展开更多
The article reviews a brief literature on the modeling of hydrogen storage device for fuel cell. Different dimensional approaches in modeling hydrogen absorption/desorption in a metal hydride reactor for use in fuel c...The article reviews a brief literature on the modeling of hydrogen storage device for fuel cell. Different dimensional approaches in modeling hydrogen absorption/desorption in a metal hydride reactor for use in fuel cell are summarized. Mathematical modeling equations involved are also stated. The effect of various operating parameters such as temperature, concentration, viscosity, thermal conductivity and time on the gas is also verified. The importance of various simulation software with reference to their major functions is also identified. The review concludes on the opportunities and challenges with the use of hydrogen as an alternative renewable energy.展开更多
Three types of low-carbon vehicle technologies in China are reviewed. Potential effects are listed for those integrated energy-saving technologies for conventional vehicles. Low carbon transitions, including alternati...Three types of low-carbon vehicle technologies in China are reviewed. Potential effects are listed for those integrated energy-saving technologies for conventional vehicles. Low carbon transitions, including alternative vehicle power train systems and fuels, are discussed on their development status and trends, including life cycle primary fossil energy use and greenhouse gas emissions of each pathway. To further support the low-carbon vehicle technologies development, integrated policies should seek to: (1) employ those integrated energy-saving technologies, (2) apply hybrid electric technology, (3) commercialize electric vehicles through battery technology innovation, (4) support fuel cell vehicles and hydrogen technology R&D for future potential applications, (5) boost the R&D of second generation biofuel technology, and (6) conduct further research on applying low-carbon technologies including CO2 capture and storage technology to coal-based transportation solutions.展开更多
Anion exchange membrane(AEM)fuel cells have gained great attention partially due to the advantage of using non-precious metal as catalysts.However,the reaction kinetics of hydrogen oxidation reaction(HOR)is two orders...Anion exchange membrane(AEM)fuel cells have gained great attention partially due to the advantage of using non-precious metal as catalysts.However,the reaction kinetics of hydrogen oxidation reaction(HOR)is two orders of magnitude slower in alkaline systems than in acid.To understand the slower kinetics of HOR in base,two major theories have been proposed,such as(1)pH dependent hydrogen binding energy as a major descriptor for HOR;and(2)bifunctional theory based on the contributions of both hydrogen and hydroxide adsorption for HOR in alkaline electrolyte.Here,we discuss the possible HOR mechanisms in alkaline electrolytes with the corresponding change in their Tafel behavior.Apart from the traditional Tafel-Volmer and Heyrovsky-Volmer HOR mechanisms,the recently proposed hydroxide adsorption step is also discussed to illustrate the difference in HOR mechanisms in acid and base.We further summarize the representative works of alkaline HOR catalyst design(e.g.,precious metals,alloy,intermetallic materials,Ni-based alloys,carbides,nitrides,etc.),and briefly describe their fundamental HOR reaction mechanism to emphasize the difference in elementary reaction steps in alkaline medium.The strategy of strengthening local interaction that facilitates both H2 desorption and Hads+OHads recombination is finally proposed for future HOR catalyst design in alkaline environment.展开更多
Rising fuel prices, increasing emission levels and impending environmental regulations made shipping industry to find an alternate for internal combustion engine in 21st century. Fuel cell is a sustainable, emerging t...Rising fuel prices, increasing emission levels and impending environmental regulations made shipping industry to find an alternate for internal combustion engine in 21st century. Fuel cell is a sustainable, emerging technology with negligible pollution. More significantly for a research ship, emission levels need to be substantially low to have quality measurements. A feasibility study is carried-out First time in the world, to drive an ice class multi-disciplinary ORV (Oceanography Research Vessel) Sagarnidbi, using hydrogen powered fuel cell. Sagamidhi is equipped with special equipments viz., Deep Sea winch, specially designed cranes for Launching and retrieval of ROV (Remotely Operable Vehicle), DSMC (Deep Sea Mining Crawler), Tsunami systems, manned/unmanned submersible and ACS (Autonomous Coring System) and other facilities that support research in Indian, International and Antarctic waters. Beside this, the propulsion system along with DP (Dynamic Positioning), centralized air conditioning and special equipments require enormous electrical power. The combustion of diesel oil in an engine, that coupled with an alternator generates electrical power required, along with NOx (Nitrous Oxides), SOx (Sulphur Oxides) and PM (Particulate Matter) emissions. Shipping industry is the fourth largest contributor to air pollution and carbon emissions, particularly in coastal areas, and the growth rate makes the problem even more critical. Stringent international air pollution regulation and increasing fuel price paves the way for an alternative "green emission technology". Various fuel cells were analyzed with different combination of fuel, electrolyte and electrodes. From the analysis, it has been found that SOFC (Solid Oxide Fuel Cell) is most suitable for the present scenario. A fuel cell designed with hydrogen as fuel, zirconium oxides stabilized with yttrium oxide as electrolyte and zirconium electrodes is used for 1.5 MW power output and 0.5 MW through regenerator. Volume required for storage of hydrogen is in line with volume of fuel and a high standard safety measures were taken using sensors. The present system saves 3000 MT/annum of diesel oil costing 3,000,000 USD approximately.展开更多
The current basic energy plan of Japan was authorized in the Cabinet in June 2010, in which ambitious energy and environmental targets and policies giving nuclear power a pivotal role toward 2030 were described. At pr...The current basic energy plan of Japan was authorized in the Cabinet in June 2010, in which ambitious energy and environmental targets and policies giving nuclear power a pivotal role toward 2030 were described. At present, the Japanese government has been forced to review the basic energy plan in the wake of the great east Japan earthquake occurred on March 11, 2011 followed by the severe accident at the nuclear power plants in Fukushima. Before the disaster, the IAE (institute of applied energy) had realized that it was not clear how CO2-free hydrogen would contribute to solving various energy and environmental issues, or that prospects were not clear for large demand of CQ-free hydrogen other than FCVs (fuel cell vehicles). In this connection, the authors organized a voluntary "Concept Study Group (in short)" in March 2011 and held four meetings until the end of March 2012. Through the quantitative studies using IAE's simulation model (GRAPE), the common recognition was built in the concept study group that hydrogen could contribute to energy security and increase in zero-emissions electric power ratio in Japan. It was also estimated that global CO2-free hydrogen supply chains could be realized by degrees after 2020. Based on these results, the authors made a proposal that hydrogen should be added in the primary energy constitution for new basic energy plan to the Japanese government because imported hydrogen could be considered as a pseudo-primary energy like LNG (liquefied natural gas). Now, the succeeding "Action Plan Study Group (in short)" has been held focusing on hydrogen demand in various applications, future pictures of CO2-free hydrogen chains and road maps. Activity results of the "Concept Study Group" are shown here.展开更多
Metal/Air batteries are considered to be promising electricity storage devices given their compactness, environmental benignity and affordability. As a commonly available metal, aluminum has received great attention s...Metal/Air batteries are considered to be promising electricity storage devices given their compactness, environmental benignity and affordability. As a commonly available metal, aluminum has received great attention since its first use as an anode in a battery. Its high specific energy (even better volumetric energy density than lithium) makes it ideal for many primary battery applications. However, the development of A1/Air cell with alkaline electrolyte has been lagged behind mainly due to the unfavorable parasitic hydrogen generation. Herein, we designed and constructed a novel A1/H_2/Air tandem fuel cell to turn the adverse parasitic reaction into a useful process. The system consists of two anodes, namely, aluminum and hydrogen, and one common air-breathing cathode. The aluminum acts as both the anode for the A1/Air sub-cell and the source to generate hydrogen for the hydrogen/air sub-cell. The aluminum/air sub-cell has an open circuit voltage of 1.45 V and the H_2/Air sub-cell of 0.95 V. We demonstrated that the maximum power output of aluminum as a fuel was largely enhanced by 31% after incorporating the H_2/Air sub-cell with the tandem concept. In addition, a passive design was utilized in our tandem system to eliminate the dependence on auxiliary pumping sub-systems so that the whole system remained neat and eliminated the dependence of energy consuming pumps or heaters which were typically applied in micro fuel cells.展开更多
The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen e...The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen electrolytic cell equipped with an electrostatic-induction potential-superposed water electrolytic cell that provides a stoichiometric H2-O2 fuel mixture during operation of the vehicle. This generator functions with zero power input, zero matter input and zero emission due to the so-called "zero power input" electrostatic-to-chemical energy conversion occurring in the electrolytic cell. Here, theoretical simulations were performed to verify the target performance of such generators, assuming a pair of FC (fuel cell) and electrolytic cell stacks, both of which are commercially available.展开更多
The hydrogen leakage detection and alarm processing system is established for the fuel cell (FC) power train lab to meet the hydrogen safety demand of the FC performance test and examination for the project named "...The hydrogen leakage detection and alarm processing system is established for the fuel cell (FC) power train lab to meet the hydrogen safety demand of the FC performance test and examination for the project named "Research and Development of the Vehicular Technology for the Fuel Cell City Bus" by Tsinghua University. The established hydrogen safety system includes the hydrogen supply system, hydrogen leakage detection system, alarm processing system, ventilation system, measures against electrostatic, thunder-arresting and explosion-protection, and the strict hydrogen operation rules. In this safety system, the explosion proof catalytic combustion sensors are used to detect the hydrogen leakage and the electrical control system is designed to process the alarm automatically. The hydrogen safety system plays an important role in the performance, examination of the FC and the assuring the personnel' s safety of the fuel cell power train lab.展开更多
One of the main challenges of biogas and syngas use as fuel in hybrid solid oxide fuel cell (SOFC) cycles is the variable nature of their composition, which may cause significant changes in plant performance. On the...One of the main challenges of biogas and syngas use as fuel in hybrid solid oxide fuel cell (SOFC) cycles is the variable nature of their composition, which may cause significant changes in plant performance. On the other hand, hydrogen is one of the main components in some types of gasified biomass and syngas. Therefore, it is vital to investigate the influences of hydrogen fraction in inlet fuel on the cycle performance. In this work, a steady-state simulation of a hybrid tubular SOFC-gas turbine (GT) cycle is first presented with two configurations: system with and without anode exhaust recirculation. Then, the results of the model when fueled by syngas, biofuel, and gasified biomass are analyzed, and significant dependency of system operational parameters on the inlet fuel composition are investigated. The analysis of impacts of hydrogen concentration in the inlet fuel on the performance of a hybrid tubular SOFC and gas turbine cycle was carried out. The simulation results were considered when the system was fueled by pure methane as a reference case. Then, the performance of the hybrid SOFC-GT system when methane was partially replaced by H2 from a concentration of 0% to 95% with an increment of 5% at each step was investigated. The system performance was monitored by investigating parameters like temperature and flow rate of streams in different locations of the cycle; SOFC and system thermal efficiency; SOFC, GT, and cycle net and specific work; air to fuel ratio; as well as air and fuel mass flow rate. The results of the sensitivity analysis demonstrate that hydrogen concentration has significant effects on the system operational parameters, such as efficiency and specific work.展开更多
Recently ammonia has been investigated as a fuel for SOFCs (solid oxide fuel cells). Ammonia is widely produced and transported globally, and stores hydrogen in its bonds making it an excellent fuel for fuel cells. ...Recently ammonia has been investigated as a fuel for SOFCs (solid oxide fuel cells). Ammonia is widely produced and transported globally, and stores hydrogen in its bonds making it an excellent fuel for fuel cells. The high temperature of SOFCs allows for internal decomposition of ammonia. Previous models of ammonia-fed SOFCs treat ammonia decomposition as having first order dependence on ammonia partial pressure, and ignore the effect of hydrogen inhibition. However, research has shown that at low temperatures (≤ 600 ℃) and low ammonia partial pressures, the rate of ammonia decomposition is inhibited by the presence of hydrogen. This hydrogen inhibition effect was studied and implemented in a model of an ammonia decomposition reactor. Results showed that it may significantly decrease the rate of hydrogen generation. This work sets the foundation for more accurate modelling of intermediate temperature ammonia-fed SOFCs.展开更多
基金Project(51876224)supported by the National Natural Science Foundation of ChinaProject(2020CX008)supported by the Innovation-Driven Project of Central South University,China。
文摘Methanol is regarded as an important liquid fuel for hydrogen storage, transportation, and in-situ generation due to its convenient conveyance, high energy density, and low conversion temperature. In this work, an overview of state-of-the-art investigations on methanol reforming is critically summarized, including the detailed introduction of methanol conversion pathways from the perspective of fuel cell applications, various advanced materials design for catalytic methanol conversion, as well as the development of steam methanol reformers. For the section of utilization pathways, reactions such as steam reforming of methanol, partial oxidation of methanol, oxidative steam reforming of methanol, and sorption-enhanced steam methanol reforming were elaborated;For the catalyst section, the strategies to enhance the catalytic activity and other comprehensive performances were summarized;For the reactor section, the newly designed steam methanol reformers were thoroughly described. This review will benefit researchers from both fundamental research and fuel cell applications in the field of catalyzing methanol to hydrogen.
基金Supported by the Natural Science Foundation of Guangdong Province (No. 05006552).
文摘A laboratory-scale intermediate-temperature H2S fuel cell with a configuration of H2S, (metal sulfide-based composite anode)/Li2SO4+Al2O3/(NiO-based composite cathode), air was developed and studied for production of power and for desulfurization of a fuel gas process stream. The cell was run at typical temperature (600—650℃) and ambient pressure, but its electrochemical performance may be limited by electrolyte membrane thickness. The membrane and its performance in cell have been characterized using scanning electron microscope (SEM) and electrochemical impedance spectrum (EIS) techniques. Composite anodes based on metal sulfides, Ag powder and electrolyte behaved well and stably in H2S stream, and composite cathodes based mainly on nickel oxide, Ag powder and electrolyte had superior per-formance to Pt catalyst. The maximum power density of up to 70mW?cm-2 and current density of as high as 250mA?cm-2 were obtained at 650℃. However, the long-term cell stability remains to be investigated.
基金Supported by the Natural Science Foundation of Zhejiang Province (Y405496) the State Key Development Program for Basic Research of China (2007CB216409)
文摘Borohydrides present interesting options for the electrochemical power generation acting either as hydrogen source or anodic fuel for direct borohydride fuel cells(DBFC).In this work,Mg-Ni composite synthesized by mechanically alloying method,used as the catalyst for the hydrolysis of borohydride,has been investigated.Co-doping treatment has been carried out for the purpose of improving the hydrolysis rate further.The as-prepared and Co-doped Mg-Ni composites with low cost showed high catalytic activity to the hydrolysis of borohydride for hydrogen generation.After Co-doping,the hydrogen generation rate was around 280 ml·g-1·min-1.Borohydride would be a promising hydrogen source for fuel cells.
文摘Hydrogen fuel cell cars are now available for lease and for sale. Renewable hydrogen fuel can be produced from water via electrolysis, or from biomass via gasification. Electrolysis is power-hungry with high demand from solar or wind power. Gasification, however, can be energy self-sufficient using a recently-patented thermochemical conversion technology known as I-HPG (indirectly-heated pyrolytic gasification). I-HPG produces a tar-free syngas from non-food woody biomass. This means the balance of plant can be small, so the overall system is economical at modest sizes. This makes it possible to produce renewable hydrogen from local agricultural residues; sufficient to create distributed refueling stations wherever there is feedstock. This work describes the specifics of a novel bio-hydrogen refueling station whereby the syngas produced has much of the hydrogen extracted with the remainder powering a generator to provide the electric power to the I-HPG system. Thus the system runs continuously. When paired with another new technology, moderate-pressure storage of hydrogen in porous silicon, there is the potential to also power the refueling operation. Such systems can be operated independently. It is even possible to design an energy self-sufficient farm where all electric power, heat, and hydrogen fuel is produced from the non-food residues of agricultural operations. No water is required, and the carbon footprint is negative, or at least neutral.
文摘Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing of large capital investment towards research and development of sustainable alternative energy sources. One of the most promising and abundant of these sources is hydrogen. Firstly, the use of current fossil fuels is. discussed focusing on the emissions and economic sides to emphasize the need for a new, cleaner and renewable fuel with particular reference to hydrogen as a suitable possible alternative. Hydrogen properties, production and storage methods are then reviewed along with its suitability from the economical point of view. Finally, a cost analysis for the use of hydrogen in internal combustion engines is carried out to illustrate the benefits of its use as a replacement for diesel. The outcome of this cost analysis shows that 98% of the capital expenditure is consumed by the equipment, and 68.3% of the total cost of the equipment is spent on the solar photovoltaic cells. The hydrogen plant is classified as a large investment project because of its high initial cost which is about 1 billion US$; but this is justified because hydrogen is produced in a totally green way. When hydrogen is used as a fuel, no harmful emissions are obtained.
文摘The article reviews a brief literature on the modeling of hydrogen storage device for fuel cell. Different dimensional approaches in modeling hydrogen absorption/desorption in a metal hydride reactor for use in fuel cell are summarized. Mathematical modeling equations involved are also stated. The effect of various operating parameters such as temperature, concentration, viscosity, thermal conductivity and time on the gas is also verified. The importance of various simulation software with reference to their major functions is also identified. The review concludes on the opportunities and challenges with the use of hydrogen as an alternative renewable energy.
基金co-supported by the China National Social Science Foundation(09&ZD029)MOE Project of Key Research Institute of Humanities and Social Sciences at Universities in China (2009JJD790029)+1 种基金Doctoral Thesis Fund of Beijing Municipal Science and Technology Commission (zz200923)the CAERC program(Tsinghua/ GM/SAIC-China)
文摘Three types of low-carbon vehicle technologies in China are reviewed. Potential effects are listed for those integrated energy-saving technologies for conventional vehicles. Low carbon transitions, including alternative vehicle power train systems and fuels, are discussed on their development status and trends, including life cycle primary fossil energy use and greenhouse gas emissions of each pathway. To further support the low-carbon vehicle technologies development, integrated policies should seek to: (1) employ those integrated energy-saving technologies, (2) apply hybrid electric technology, (3) commercialize electric vehicles through battery technology innovation, (4) support fuel cell vehicles and hydrogen technology R&D for future potential applications, (5) boost the R&D of second generation biofuel technology, and (6) conduct further research on applying low-carbon technologies including CO2 capture and storage technology to coal-based transportation solutions.
文摘Anion exchange membrane(AEM)fuel cells have gained great attention partially due to the advantage of using non-precious metal as catalysts.However,the reaction kinetics of hydrogen oxidation reaction(HOR)is two orders of magnitude slower in alkaline systems than in acid.To understand the slower kinetics of HOR in base,two major theories have been proposed,such as(1)pH dependent hydrogen binding energy as a major descriptor for HOR;and(2)bifunctional theory based on the contributions of both hydrogen and hydroxide adsorption for HOR in alkaline electrolyte.Here,we discuss the possible HOR mechanisms in alkaline electrolytes with the corresponding change in their Tafel behavior.Apart from the traditional Tafel-Volmer and Heyrovsky-Volmer HOR mechanisms,the recently proposed hydroxide adsorption step is also discussed to illustrate the difference in HOR mechanisms in acid and base.We further summarize the representative works of alkaline HOR catalyst design(e.g.,precious metals,alloy,intermetallic materials,Ni-based alloys,carbides,nitrides,etc.),and briefly describe their fundamental HOR reaction mechanism to emphasize the difference in elementary reaction steps in alkaline medium.The strategy of strengthening local interaction that facilitates both H2 desorption and Hads+OHads recombination is finally proposed for future HOR catalyst design in alkaline environment.
文摘Rising fuel prices, increasing emission levels and impending environmental regulations made shipping industry to find an alternate for internal combustion engine in 21st century. Fuel cell is a sustainable, emerging technology with negligible pollution. More significantly for a research ship, emission levels need to be substantially low to have quality measurements. A feasibility study is carried-out First time in the world, to drive an ice class multi-disciplinary ORV (Oceanography Research Vessel) Sagarnidbi, using hydrogen powered fuel cell. Sagamidhi is equipped with special equipments viz., Deep Sea winch, specially designed cranes for Launching and retrieval of ROV (Remotely Operable Vehicle), DSMC (Deep Sea Mining Crawler), Tsunami systems, manned/unmanned submersible and ACS (Autonomous Coring System) and other facilities that support research in Indian, International and Antarctic waters. Beside this, the propulsion system along with DP (Dynamic Positioning), centralized air conditioning and special equipments require enormous electrical power. The combustion of diesel oil in an engine, that coupled with an alternator generates electrical power required, along with NOx (Nitrous Oxides), SOx (Sulphur Oxides) and PM (Particulate Matter) emissions. Shipping industry is the fourth largest contributor to air pollution and carbon emissions, particularly in coastal areas, and the growth rate makes the problem even more critical. Stringent international air pollution regulation and increasing fuel price paves the way for an alternative "green emission technology". Various fuel cells were analyzed with different combination of fuel, electrolyte and electrodes. From the analysis, it has been found that SOFC (Solid Oxide Fuel Cell) is most suitable for the present scenario. A fuel cell designed with hydrogen as fuel, zirconium oxides stabilized with yttrium oxide as electrolyte and zirconium electrodes is used for 1.5 MW power output and 0.5 MW through regenerator. Volume required for storage of hydrogen is in line with volume of fuel and a high standard safety measures were taken using sensors. The present system saves 3000 MT/annum of diesel oil costing 3,000,000 USD approximately.
文摘The current basic energy plan of Japan was authorized in the Cabinet in June 2010, in which ambitious energy and environmental targets and policies giving nuclear power a pivotal role toward 2030 were described. At present, the Japanese government has been forced to review the basic energy plan in the wake of the great east Japan earthquake occurred on March 11, 2011 followed by the severe accident at the nuclear power plants in Fukushima. Before the disaster, the IAE (institute of applied energy) had realized that it was not clear how CO2-free hydrogen would contribute to solving various energy and environmental issues, or that prospects were not clear for large demand of CQ-free hydrogen other than FCVs (fuel cell vehicles). In this connection, the authors organized a voluntary "Concept Study Group (in short)" in March 2011 and held four meetings until the end of March 2012. Through the quantitative studies using IAE's simulation model (GRAPE), the common recognition was built in the concept study group that hydrogen could contribute to energy security and increase in zero-emissions electric power ratio in Japan. It was also estimated that global CO2-free hydrogen supply chains could be realized by degrees after 2020. Based on these results, the authors made a proposal that hydrogen should be added in the primary energy constitution for new basic energy plan to the Japanese government because imported hydrogen could be considered as a pseudo-primary energy like LNG (liquefied natural gas). Now, the succeeding "Action Plan Study Group (in short)" has been held focusing on hydrogen demand in various applications, future pictures of CO2-free hydrogen chains and road maps. Activity results of the "Concept Study Group" are shown here.
文摘Metal/Air batteries are considered to be promising electricity storage devices given their compactness, environmental benignity and affordability. As a commonly available metal, aluminum has received great attention since its first use as an anode in a battery. Its high specific energy (even better volumetric energy density than lithium) makes it ideal for many primary battery applications. However, the development of A1/Air cell with alkaline electrolyte has been lagged behind mainly due to the unfavorable parasitic hydrogen generation. Herein, we designed and constructed a novel A1/H_2/Air tandem fuel cell to turn the adverse parasitic reaction into a useful process. The system consists of two anodes, namely, aluminum and hydrogen, and one common air-breathing cathode. The aluminum acts as both the anode for the A1/Air sub-cell and the source to generate hydrogen for the hydrogen/air sub-cell. The aluminum/air sub-cell has an open circuit voltage of 1.45 V and the H_2/Air sub-cell of 0.95 V. We demonstrated that the maximum power output of aluminum as a fuel was largely enhanced by 31% after incorporating the H_2/Air sub-cell with the tandem concept. In addition, a passive design was utilized in our tandem system to eliminate the dependence on auxiliary pumping sub-systems so that the whole system remained neat and eliminated the dependence of energy consuming pumps or heaters which were typically applied in micro fuel cells.
文摘The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen electrolytic cell equipped with an electrostatic-induction potential-superposed water electrolytic cell that provides a stoichiometric H2-O2 fuel mixture during operation of the vehicle. This generator functions with zero power input, zero matter input and zero emission due to the so-called "zero power input" electrostatic-to-chemical energy conversion occurring in the electrolytic cell. Here, theoretical simulations were performed to verify the target performance of such generators, assuming a pair of FC (fuel cell) and electrolytic cell stacks, both of which are commercially available.
文摘The hydrogen leakage detection and alarm processing system is established for the fuel cell (FC) power train lab to meet the hydrogen safety demand of the FC performance test and examination for the project named "Research and Development of the Vehicular Technology for the Fuel Cell City Bus" by Tsinghua University. The established hydrogen safety system includes the hydrogen supply system, hydrogen leakage detection system, alarm processing system, ventilation system, measures against electrostatic, thunder-arresting and explosion-protection, and the strict hydrogen operation rules. In this safety system, the explosion proof catalytic combustion sensors are used to detect the hydrogen leakage and the electrical control system is designed to process the alarm automatically. The hydrogen safety system plays an important role in the performance, examination of the FC and the assuring the personnel' s safety of the fuel cell power train lab.
文摘One of the main challenges of biogas and syngas use as fuel in hybrid solid oxide fuel cell (SOFC) cycles is the variable nature of their composition, which may cause significant changes in plant performance. On the other hand, hydrogen is one of the main components in some types of gasified biomass and syngas. Therefore, it is vital to investigate the influences of hydrogen fraction in inlet fuel on the cycle performance. In this work, a steady-state simulation of a hybrid tubular SOFC-gas turbine (GT) cycle is first presented with two configurations: system with and without anode exhaust recirculation. Then, the results of the model when fueled by syngas, biofuel, and gasified biomass are analyzed, and significant dependency of system operational parameters on the inlet fuel composition are investigated. The analysis of impacts of hydrogen concentration in the inlet fuel on the performance of a hybrid tubular SOFC and gas turbine cycle was carried out. The simulation results were considered when the system was fueled by pure methane as a reference case. Then, the performance of the hybrid SOFC-GT system when methane was partially replaced by H2 from a concentration of 0% to 95% with an increment of 5% at each step was investigated. The system performance was monitored by investigating parameters like temperature and flow rate of streams in different locations of the cycle; SOFC and system thermal efficiency; SOFC, GT, and cycle net and specific work; air to fuel ratio; as well as air and fuel mass flow rate. The results of the sensitivity analysis demonstrate that hydrogen concentration has significant effects on the system operational parameters, such as efficiency and specific work.
文摘Recently ammonia has been investigated as a fuel for SOFCs (solid oxide fuel cells). Ammonia is widely produced and transported globally, and stores hydrogen in its bonds making it an excellent fuel for fuel cells. The high temperature of SOFCs allows for internal decomposition of ammonia. Previous models of ammonia-fed SOFCs treat ammonia decomposition as having first order dependence on ammonia partial pressure, and ignore the effect of hydrogen inhibition. However, research has shown that at low temperatures (≤ 600 ℃) and low ammonia partial pressures, the rate of ammonia decomposition is inhibited by the presence of hydrogen. This hydrogen inhibition effect was studied and implemented in a model of an ammonia decomposition reactor. Results showed that it may significantly decrease the rate of hydrogen generation. This work sets the foundation for more accurate modelling of intermediate temperature ammonia-fed SOFCs.