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Evaluation of carbonized medium-density fiberboard for electrical applications
06 Electrical power supply and utilization (scientific, technical) can perform as well as and, in some circumstances, much better than conventional fuel cells. The significant innovation that Generics has introduced to this field is to combine the concept of mixed-reactant fuel cells with that of a fully porous membrane electrode assembly (MEA) structure. Passing a fuel-oxidant mixture through a stack of porous cells allows the conventional bipolar flow-field plates required m many fuel cell designs to be eliminated. In a conventional PEM stack, for example, the bipolar carbon flow-field plates may block up to half of the active cell area and account for up to 90% of the volume of the stack and of the order of one-third of the materials costs. In addition to all the advantages of mixed-reactant systems, the 'flowthrough' mode, embodied in Generics' CMR approach, significantly enhances mass-transport of reactants to the electrodes and can reduce reactant pressure drops across the stack, Redesigning fuel cells to operate in a CMR mode with selective electrodes offers the attractive prospect of much reduced stack costs and significantly higher stack power densities for all types of fuel cell. Initial modelling and proof of principle experiments using an alkaline system have confirmed the validity of the CMR approach and the potential for substantial performance improvements.
03/00597 Development of a PEM fuel cell powered portable field generator for the dismounted soldier Moore, J. M. et al. Journal of Power Sources, 2002, 106, (1-2), 16-20. The increasing use of electronic technologies by the dismounted soldier is placing a growing burden on the power sources required to operate them. Battery technology, which is close to the limit of development cannot provide for the soldiers' power needs at an acceptable weight. Air breathing proton exchange membrane (PEM) fuel cells in combination with advanced hydrogen generation technologies, are suggested as a viable alternative, providing greatly increased energy densities. An application as a portable field generator is suggested, with the fuel cell system acting as a charger coupled to rechargeable batteries.
03100598 rEiectrochemical storage of energy in carbon nanotubes and nanostructured carbons Frackowiak, E. and B~guin, F. Carbon, 2002, 40, (10), 1775 1787. Possibilities of electrochemical energy conversion using carbon nanotubes and related materials in various systems, such as lithium batteries, supercapacitors, hydrogen storage, are considered. It is shown that for these applications the electrochemical properties of multiwalled (MWNTs) and single walled (SWNTs) nanotubes are essentially dominated by their mesoporous character. During lithium insertion into nanotubular materials a high irreversible capacity Cirf (from 460 to 1080 mAh/g) has been observed after the first cycle with a tendency to further decomposition of electrolyte with cycling. Penetration of solvated lithium ions in the accessible mesopores is at the origin of this phenomenon; an almost linear dependence has been found between the mesopore volume and Cir r. Reversible capacity for lithium insertion Cr~v ranged between 220 and 780 mAh/g; however, a great divergence (hysteresis) between insertion and extraction characteristics was observed independently of the kind of nanotubes and oxygen content. Amount of lithium stored by electrostatic attraction is negligible in comparison to real redox reactions which for thermodynamic reasons present linear variation of potential, especially during deinsertion (pseudocapacitive effects). During positive polarization, i.e. removal of lithium, resistivity of the electrode also gradually increases. Due to the open network of mesopores formed by the nanotubes entanglement, and consequently an easily accessible electrode electrolyte interface, nanotubular materials are quite adapted for supercapacitor electrodes in various electrolytic solutions. High values of capacitance (80 F/g) have been obtained in 6 M KOH for materials with a surface area of only ca. 430 mZ/g. Capacitance values have been enhanced either by additional oxygenated functionalization of nanotubes (130 F/g) or by conducting polypyrrole (PPy) electrodeposition where the maximum values reached 170 F/g. The next domain of energy storage in the carbon nanostructures is the accumulation of hydrogen by the electrochemical decomposition of aqueous alkaline medium on a negatively polarized carbon electrode in ambient conditions. For SWNTs only moderate values (below 0.5 wt% of H2) have been found, while for activated carbons with highly developed surface area of 1500 m2/g, the amount of reversibly sorbed hydrogen was ca. 2 wt%, noticeably larger than under dihydrogen pressure (only 0.4 wt% for the same material at 70 bar and 273 K). The enhancement observed for the activated carbon is interpreted by the formation of nascent hydrogen during water reduction which penetrates easily in the available carbon nanopores. The values obtained by this method are comparable to those of metallic alloys, such as LaNi5 for example.
03/00599 Encouraging distributed generation of power that improves air quality: can we have our cake and eat it too? Allison, J. E. and Lents, J. Energy Policy, 2002, 30, (9), 737 752.
82
Fuel and Energy Abstracts
March 2003
The goal of electric power deregulation in the USA is to lower electricity costs through market competition and greater consumer choice. This goal raises important questions: exactly what kinds of distributed generation (DG) should energy and environmental policy favour? What level of government is best suited and/or most capable of governing DG? And what is the range of regulations that would most easily facilitate the competitive success of DG? In response, this article provides a comparative analysis of the electricity generation process with heat recovery created to assess the level of polluting emissions associated with a range of technologies and fuel types. Given the results of this analysis, the governance structure responsible for regulating energy and environmental policy in the USA is evaluated, and a regulatory approach outlined that would ensure the use of the DG technologies and fuel sources that would be most beneficial to the environment and public health. The analysis suggests that only the lowest emitting DG with significant waste heat recovery is even marginally competitive with combined cycle power production when air pollution issues are considered. Thus, technology-forcing in the specific form of manufacturer-based regulation is advocated, which would require, over time, the reduction of emissions from DG units at the point of manufacture as a means of ensuring greater air quality.
03/00600 Evaluation of carbonized medium-density fiberboard for electrical applications Kercher, A. K. and Nagte, D, C. Carbon, 2002, 40, (8), 1321-1330. The conversion of wood-based fibreboard materials into crack-free, monolithic, porous hard carbons is of significant interest due to their ability to perform in a muhifunctional capacity. Three varieties of carbonized medium-density fibreboard (c-MDF) were studied for electrical, mechanical, and structural properties. X-ray diffraction data suggested that the volume fraction of large turbostratic crystallites increased with carbonization temperature (Tcarb). The volume fraction of large turbostratic crystallites had a positive correlation with elastic modulus and electrical conductivity. The c-MDF materials were approximately isotropic with respect to elastic modulus and exhibited increasing stiffness with increasing Tc~rb (up to 4.5 GPa). Between 600 and 1400°C, the electrical resistivity of c-MDF varied by seven orders of magnitude. The electrical resistivity of the hard carbon material in cMDF 1400°C was found to be within about an order of magnitude of polycrystalline graphite.
03•00601 Feasibility study of the co-generation system with direct internal reforming-molten carbonate fuel cell (DIRMCFC) for residential use Sugiura, K. and Naruse, I. Journal q/Power Sources, 2002, 106, (1 2), 51 59. The possibility of introducing a co-generation system with a direct internal reforming-molten carbonate fuel cell (DIR-MCFC) for residential use is examined by a feasibility study. First, the structure of a system, which can maintain the cell temperature (650°C) without the heat supply, is constructed by calculating heat and material balances among the system components. Secondly, a model family, which might use the co-generation system with a DIR-MCFC, is constructed from the results of a questionnaire on room layout, number of family members, and the number of electric appliances and consumption of electric power in Osaka. Thirdly, calculating the electric power and hot-water demand supply balance optimizes the scale of the co-generation system with a DIR-MCFC for residential use. Finally, the running costs of this optimum system using city gas or propane gas are considered. As a result, the optimum scale of a cogeneration system with DIR-MCFC and using city gas is 3 kW, while it is 6 kW for the case using propane gas. The co-generation system using city gas is suitable for a house. On the other hand, the system using propane gas is suitable for an apartment.
03/00602 Fuel cell operation Kendall, K. and Saunders, G, J. Brit. UK Pat. Appl. GB 2,366,070 (CI. H01M8/04), 27 Feb 2002, Appl. 2000/20,478, 10 Aug 2000.25. A method of operating a fuel cell comprises supplying oxygen to a cathode of the fuel cell and supplying a gaseous or vapour mixture of spent anode gas and replacement fuel to an anode of the fuel cell. The mixture comprises at least substantially 70 volume% of spent anode gas, the fuel being capable of reacting with oxygen ions and providing electrons to create electrical current, forming the gaseous or vapour mixture comprising the fuel and spent anode gas. The fuel cell provides spent anode gas as gaseous exhaust from the anode, and the spent anode gas comprises CO2.
03/00603
Fuel cell power plant
Ukai, K. et al. Jpn. Kokai Tokkyo Koho JP 2002 216,831 (CI. H01M8/ 06), 2 Aug 2002, Appl. 2001/151,379, 24 Jan 2001. 6. (In Japanese) The power plant has a device removing CO from a H containing water gas, produced by reacting coal with water, and a fuel cell; where H is supplied to the fuel cell via the CO removing device. The CO removing
03/00597 Development of a PEM fuel cell powered portable field generator for the dismounted soldier Moore, J. M. et al. Journal of Power Sources, 2002, 106, (1-2), 16-20. The increasing use of electronic technologies by the dismounted soldier is placing a growing burden on the power sources required to operate them. Battery technology, which is close to the limit of development cannot provide for the soldiers' power needs at an acceptable weight. Air breathing proton exchange membrane (PEM) fuel cells in combination with advanced hydrogen generation technologies, are suggested as a viable alternative, providing greatly increased energy densities. An application as a portable field generator is suggested, with the fuel cell system acting as a charger coupled to rechargeable batteries.
03100598 rEiectrochemical storage of energy in carbon nanotubes and nanostructured carbons Frackowiak, E. and B~guin, F. Carbon, 2002, 40, (10), 1775 1787. Possibilities of electrochemical energy conversion using carbon nanotubes and related materials in various systems, such as lithium batteries, supercapacitors, hydrogen storage, are considered. It is shown that for these applications the electrochemical properties of multiwalled (MWNTs) and single walled (SWNTs) nanotubes are essentially dominated by their mesoporous character. During lithium insertion into nanotubular materials a high irreversible capacity Cirf (from 460 to 1080 mAh/g) has been observed after the first cycle with a tendency to further decomposition of electrolyte with cycling. Penetration of solvated lithium ions in the accessible mesopores is at the origin of this phenomenon; an almost linear dependence has been found between the mesopore volume and Cir r. Reversible capacity for lithium insertion Cr~v ranged between 220 and 780 mAh/g; however, a great divergence (hysteresis) between insertion and extraction characteristics was observed independently of the kind of nanotubes and oxygen content. Amount of lithium stored by electrostatic attraction is negligible in comparison to real redox reactions which for thermodynamic reasons present linear variation of potential, especially during deinsertion (pseudocapacitive effects). During positive polarization, i.e. removal of lithium, resistivity of the electrode also gradually increases. Due to the open network of mesopores formed by the nanotubes entanglement, and consequently an easily accessible electrode electrolyte interface, nanotubular materials are quite adapted for supercapacitor electrodes in various electrolytic solutions. High values of capacitance (80 F/g) have been obtained in 6 M KOH for materials with a surface area of only ca. 430 mZ/g. Capacitance values have been enhanced either by additional oxygenated functionalization of nanotubes (130 F/g) or by conducting polypyrrole (PPy) electrodeposition where the maximum values reached 170 F/g. The next domain of energy storage in the carbon nanostructures is the accumulation of hydrogen by the electrochemical decomposition of aqueous alkaline medium on a negatively polarized carbon electrode in ambient conditions. For SWNTs only moderate values (below 0.5 wt% of H2) have been found, while for activated carbons with highly developed surface area of 1500 m2/g, the amount of reversibly sorbed hydrogen was ca. 2 wt%, noticeably larger than under dihydrogen pressure (only 0.4 wt% for the same material at 70 bar and 273 K). The enhancement observed for the activated carbon is interpreted by the formation of nascent hydrogen during water reduction which penetrates easily in the available carbon nanopores. The values obtained by this method are comparable to those of metallic alloys, such as LaNi5 for example.
03/00599 Encouraging distributed generation of power that improves air quality: can we have our cake and eat it too? Allison, J. E. and Lents, J. Energy Policy, 2002, 30, (9), 737 752.
82
Fuel and Energy Abstracts
March 2003
The goal of electric power deregulation in the USA is to lower electricity costs through market competition and greater consumer choice. This goal raises important questions: exactly what kinds of distributed generation (DG) should energy and environmental policy favour? What level of government is best suited and/or most capable of governing DG? And what is the range of regulations that would most easily facilitate the competitive success of DG? In response, this article provides a comparative analysis of the electricity generation process with heat recovery created to assess the level of polluting emissions associated with a range of technologies and fuel types. Given the results of this analysis, the governance structure responsible for regulating energy and environmental policy in the USA is evaluated, and a regulatory approach outlined that would ensure the use of the DG technologies and fuel sources that would be most beneficial to the environment and public health. The analysis suggests that only the lowest emitting DG with significant waste heat recovery is even marginally competitive with combined cycle power production when air pollution issues are considered. Thus, technology-forcing in the specific form of manufacturer-based regulation is advocated, which would require, over time, the reduction of emissions from DG units at the point of manufacture as a means of ensuring greater air quality.
03/00600 Evaluation of carbonized medium-density fiberboard for electrical applications Kercher, A. K. and Nagte, D, C. Carbon, 2002, 40, (8), 1321-1330. The conversion of wood-based fibreboard materials into crack-free, monolithic, porous hard carbons is of significant interest due to their ability to perform in a muhifunctional capacity. Three varieties of carbonized medium-density fibreboard (c-MDF) were studied for electrical, mechanical, and structural properties. X-ray diffraction data suggested that the volume fraction of large turbostratic crystallites increased with carbonization temperature (Tcarb). The volume fraction of large turbostratic crystallites had a positive correlation with elastic modulus and electrical conductivity. The c-MDF materials were approximately isotropic with respect to elastic modulus and exhibited increasing stiffness with increasing Tc~rb (up to 4.5 GPa). Between 600 and 1400°C, the electrical resistivity of c-MDF varied by seven orders of magnitude. The electrical resistivity of the hard carbon material in cMDF 1400°C was found to be within about an order of magnitude of polycrystalline graphite.
03•00601 Feasibility study of the co-generation system with direct internal reforming-molten carbonate fuel cell (DIRMCFC) for residential use Sugiura, K. and Naruse, I. Journal q/Power Sources, 2002, 106, (1 2), 51 59. The possibility of introducing a co-generation system with a direct internal reforming-molten carbonate fuel cell (DIR-MCFC) for residential use is examined by a feasibility study. First, the structure of a system, which can maintain the cell temperature (650°C) without the heat supply, is constructed by calculating heat and material balances among the system components. Secondly, a model family, which might use the co-generation system with a DIR-MCFC, is constructed from the results of a questionnaire on room layout, number of family members, and the number of electric appliances and consumption of electric power in Osaka. Thirdly, calculating the electric power and hot-water demand supply balance optimizes the scale of the co-generation system with a DIR-MCFC for residential use. Finally, the running costs of this optimum system using city gas or propane gas are considered. As a result, the optimum scale of a cogeneration system with DIR-MCFC and using city gas is 3 kW, while it is 6 kW for the case using propane gas. The co-generation system using city gas is suitable for a house. On the other hand, the system using propane gas is suitable for an apartment.
03/00602 Fuel cell operation Kendall, K. and Saunders, G, J. Brit. UK Pat. Appl. GB 2,366,070 (CI. H01M8/04), 27 Feb 2002, Appl. 2000/20,478, 10 Aug 2000.25. A method of operating a fuel cell comprises supplying oxygen to a cathode of the fuel cell and supplying a gaseous or vapour mixture of spent anode gas and replacement fuel to an anode of the fuel cell. The mixture comprises at least substantially 70 volume% of spent anode gas, the fuel being capable of reacting with oxygen ions and providing electrons to create electrical current, forming the gaseous or vapour mixture comprising the fuel and spent anode gas. The fuel cell provides spent anode gas as gaseous exhaust from the anode, and the spent anode gas comprises CO2.
03/00603
Fuel cell power plant
Ukai, K. et al. Jpn. Kokai Tokkyo Koho JP 2002 216,831 (CI. H01M8/ 06), 2 Aug 2002, Appl. 2001/151,379, 24 Jan 2001. 6. (In Japanese) The power plant has a device removing CO from a H containing water gas, produced by reacting coal with water, and a fuel cell; where H is supplied to the fuel cell via the CO removing device. The CO removing