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Extensive efforts to develop a solid-oxide fuel cell for transportation, the bottoming cycle of a power plant, and distributed generation of electric energy are motivated by a need for greater fuel efficiency and reduced air pollution. Barriers to the introduction of hydrogen as the fuel have stimulated interest in developing an anode material that can be used with natural gas under operating temperatures 650 degrees C < T < 1000 degrees C. Here we report identification of the double perovskites Sr2Mg(1-x)MnxMoO(6-delta) that meet the requirements for long-term stability with tolerance to sulfur and show a superior single-cell performance in hydrogen and methane. 相似文献
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《农业科学与工程前沿(英文版)》2015,(1)
The major source of energy comes from fossil fuels.The current situation in the fi eld of fuel and energy is becoming more problematic as world population continues to grow because of the limitation of fossil fuels reserve and its pressure on environment.This review aims to fi nd economic,reliable,renewable and non-polluting energy sources to reduce high energy tariffs in Russian Federation.Biofuel is fuel derived directly from plants,or indirectly from agricultural,commercial,domestic,and/or industrial wastes.Other alternative energy sources including solar energy and electric power generation are also discussed.Over 100 Mt of biomass available for energy purposes is produced every year in Russian.One of the downsides of biomass energy is its potential threatens to food security and forage industries.An innovative approach proved that multicomponent fuel(80%diesel oil content for motor and 64%for in stove fuel)can remarkably reduce the costs.This paper proposed that the most promising energy model for future is based on direct solar energy conversion and transcontinental terawatt power transmission with the use of resonant wave-guide technology. 相似文献
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通过对热媒炉助燃风机调速控制方案改造的实例，证明选用变频调速方案可实现热媒炉燃烧过程的优化控制，提高效率，节约电能和燃油。变频调速可抑制启动电流、上击地进行加减速运行、频繁地进行启动与停机实现合理控制。介绍了变频调速的节能原理及系统组成。 相似文献
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We compare the energy efficiency of hybrid and fuel cell vehicles as well as conventional internal combustion engines. Our analysis indicates that fuel cell vehicles using hydrogen from fossil fuels offer no significant energy efficiency advantage over hybrid vehicles operating in an urban drive cycle. We conclude that priority should be placed on hybrid vehicles by industry and government. 相似文献
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In examining the potential role of hydrogen in the energy economy of the future, we take an optimistic view. All the technology required for implementation is feasible but a great deal of development and refinement is necessary. A pessimistic approach would obviously discourage further thinking about an important and perhaps the most reasonable alternative for the future. We have considered a limited number of alternative energy systems involving hydrogen and have shown that hydrogen could be a viable secondary source of energy derived from nuclear power; for the immediate future, hydrogen could be derived from coal. A hydrogen supply system could have greater flexibility and be competitive with a more conventional all-electric delivery system. Technological improvements could make hydrogen as an energy source an economic reality. The systems examined in this article show how hydrogen can serve as a general-purpose fuel for residential and automotive applications. Aside from being a source of heat and motive power, hydrogen could also supply the electrical needs of the household via fuel cells (19), turbines, or conventional "total energy systems." The total cost of energy to a residence supplied with hydrogen fuel depends on the ratio of the requirements for direct fuel use to the requirements for electrical use. A greater direct use of hydrogen as a fuel without conversion to electricity reduces the overall cost of energy supplied to the household because of the greater expense of electrical transmission and distribution. Hydrogen fuel is especially attractive for use in domestic residential applications where the bulk of the energy requirement is for thermal energy. Although a considerable amount of research is required before any hydrogen energy delivery system can be implemented, the necessary developments are within the capability of present-day technology and the system could be made attractive economically .Techniques for producing hydrogen from water by electrolysis, from coal, and directly from thermal energy could be found that are less expensive than those now available; inexpensive fuel cells could be developed, and high-temperature turbines could be used for the efficient conversion of hydrogen (and oxygen) to electricity. The use of hydrogen as an automotive fuel would be a key factor in the development of a hydrogen energy economy, and safe storage techniques for carrying sufficient quantities of hydrogen in automotive systems can certainly be developed. The use of hydrogen in automobiles would significantly reduce urban pollution because the dispersed fossil fuel emissions would be replaced by radioactive wastes generated at large central stations. The conversion of internal or external combustion engines for combustion of hydrogen fuel would probably have less economic impact on the automotive industry than the mass introduction of electric automobiles. However, this is a subject that requires more detailed study. All of the safety aspects of hydrogen utilization will have to be examined, especially the problems of safety in the domestic use and the long distance transport of hydrogen in pipelines at high pressures. It is our opinion that the various energy planning agencies should now begin to outline the mode of implementing hydrogen energy delivery systems in the energy economy. The initial transition to hydrogen energy derived from available fossil fuels such as coal should be considered together with the long range view of all the hydrogen being derived eventually from nuclear energy. By the year 1985 when petroleum imports may be in excess of the domestic supply, these plans could set the stage for the transition period from fossil to a predominantly nuclear energy economy able to supply abundant synthetic fuels such as hydrogen. Synthetic fuels will obviously be more expensive than fuels now derived from petroleum; however, there may be no other viable choice. Thus, it is essential that the analysis and technological feasibility of a hydrogen energy system be considered now. It is of vital importance to the nation to develop some general-purpose fuel that can be Produced from a variety of domestic energy sources and reduce our dependence on imported oil. 相似文献
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Fuel cells are uniquely capable of overcoming combustion efficiency limitations (e.g., the Carnot cycle). However, the linking of fuel cells (an energy conversion device) and hydrogen (an energy carrier) has emphasized investment in proton-exchange membrane fuel cells as part of a larger hydrogen economy and thus relegated fuel cells to a future technology. In contrast, solid oxide fuel cells are capable of operating on conventional fuels (as well as hydrogen) today. The main issue for solid oxide fuel cells is high operating temperature (about 800°C) and the resulting materials and cost limitations and operating complexities (e.g., thermal cycling). Recent solid oxide fuel cells results have demonstrated extremely high power densities of about 2 watts per square centimeter at 650°C along with flexible fueling, thus enabling higher efficiency within the current fuel infrastructure. Newly developed, high-conductivity electrolytes and nanostructured electrode designs provide a path for further performance improvement at much lower temperatures, down to ~350°C, thus providing opportunity to transform the way we convert and store energy. 相似文献
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Morris SC Moskowitz PD Sevian WA Silberstein S Hamilton LD 《Science (New York, N.Y.)》1979,206(4419):654-662
Several technologies to convert coal to liquid and gaseous fuels are being developed in the United States, some with support from the Department of Energy. Substitution of these technologies for those currently being used will produce different health and environmental hazards. In this article, selected health and environmental effects of four coal conversion and four existing technologies are compared. For each technology, the emission estimates for complete fuel cycles, including all steps in fuel use from extraction to the end use of space and water heating by electricity or direct combustion, were prepared by means of the Brookhaven Energy System Network Simulator model. Quantitative occupational health and safety estimates are presented for the extraction, transportation, distribution, processing, and conversion activities associated with each technology; also included are some public health damage estimates arising from fuel transportation and air pollution impacts. Qualitative estimates of health damage due to polycyclic organic matter and reduced sulfur are discussed. In general, energy inefficiencies, environmental residuals, and hence implied environmental effects and health damage increase in the order: (i) direct combustion of natural gas and oil, (ii) direct combustion of synthetic gas and oil, (iii) central-station electric power produced from synthetic gas, (iv) central-station electric power produced from coal, and (v) central-station electric power produced by the combustion of synthetic liquid fuels. The compliance and conflict of these technologies with the amendments of the Clean Air Act and other legislation are discussed. 相似文献
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From an analysis of the long-run electric generating requirements of several representative utilities, it is concluded that the energy supplied by solar photovoltaic power devices will displace primarily base-load, and to a lesser extent intermediate, generating plants, even at relatively modest penetrations corresponding to several percent of the utility peak load. Attaching photovoltaic devices to the utility grid will not yield significant fuel oil savings over the long run, in which utilities approach the economic optimum generating mix, and will increase peak plant requirements. Utility capacity and fuel savings of photovoltaic devices are reported both for the case without storage and for the case in which the utility has access to load-leveling storage. 相似文献
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Rose DJ 《Science (New York, N.Y.)》1974,184(4134):351-359
The uranium and thorium resources, the technology, and the social impacts all seem to presage an even sharper increase in nuclear power for electric generation than had hitherto been predicted. There are more future consequences. The "hydrogen economy." Nuclear power plants operate best at constant power and full load. Thus, a largely nuclear electric economy has the problem of utilizing substantial off-peak capacity; the additional energy generation can typically be half the normal daily demand. Thus, the option of generating hydrogen as a nonpolluting fuel receives two boosts: excess nuclear capacity to produce it, plus much higher future costs for oil and natural gas. However, the so-called "hydrogen economy" must await the excess capacity, which will not occur until the end of the century. Nonelectric uses. By analyses similar to those performed here, raw nuclear heat can be shown to be cheaper than heat from many other fuel sources, especially nonpolluting ones. This will be particularly true as domestic natural gas supplies become more scarce. Nuclear heat becomes attractive for industrial purposes, and even for urban district heating, provided (i) the temperature is high enough (this is no problem for district heating, but could be for industry; the HTGR's and breeders, with 600 degrees C or more available, have the advantage); (ii) there is a market for large quantities (a heat rate of 3800 Mw thermal, the reactor size permitted today, will heat Boston, with some to spare); and (iii) the social costs become more definitely resolved in favor of nuclear power. Capital requirements. Nuclear-electric installations are very capital-intensive. One trillion dollars for the plants, backup industry, and so forth is only 2 percent of the total gross national product (GNP) between 1974 and 2000, at a growth rate of 4 percent per year. But capital accumulation tends to run at about 10 percent of the GNP, so the nuclear requirements make a sizable perturbation. Also increasing the electric share of energy provision means increasing electric power utilization, which has a high technological content and demands yet more capital. Thus, provision of capital is a major problem ahead, especially for electric utilities. The need for people. The supply of available trained technologists, environmental engineers, and so on, especially in the architect-engineer profession, is insufficient for the task ahead, especially since the same categories of people will be in demand to build up a synthetic fuels industry and do other new things. Beyond these specific items and beyond the technological discussion, one can feel deeper currents running in this debate. Issues that started out seeming technological ended up being mainly societal: prevention of clandestine use, either by vigilance or by public spirit; a determination to maintain quality and to safeguard wastes that transcends narrow interests; a perception of social benefits and damage much more holistic than before; the need to manage programs more openly and better than before. Questions and doubts become more acute, answers and methods less sure. Here is a final question. We have never before been given a virtually infinite resource of something we craved. So far, increasingly large amounts of energy have been used to turn resources into junk, from which activity we derive ephemeral benefit and pleasure; the track record is not too good. What will we do now? 相似文献
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The Particle Beam Fusion Accelerator II (PBFA II) is presently under construction and is the only existing facility with the potential of igniting thermonuclear fuel in the laboratory. The accelerator will generate up to 5 megamperes of lithium ions at 30 million electron volts and will focus them onto an inertial confinement fusion (ICF) target after beam production and focusing have been optimized. Since its inception, the light ion approach to ICF has been considered the one that combines low cost, high risk, and high payoff. The beams are of such high density that their self-generated electric and magnetic fields were thought to prohibit high focal intensities. Recent advances in beam production and focusing demonstrate that these self-forces can be controlled to the degree required for ignition, break-even, and high gain experiments. ICF has been pursued primarily for its potential military applications. However, the high efficiency and cost-effectiveness of the light ion approach enhance its potential for commercial energy application as well. 相似文献
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木质生物质能源树种生物量数量分析 总被引：1，自引：0，他引：1
由于非再生能源资源量有限,生物质能的开发和利用就具有越来越重要的意义. 该文通过对中国能源林树种的单位面积生物量与产单位标煤热值生物量所需土地的面积及生产木质燃料所需成本三者之间的关系进行分析,在三者之间建立数学模型;并通过时间序列方法预测未来煤炭的价格,将各能源林树种生产木质燃料的成本与煤炭价格进行比较分析,最终确定目前可以利用哪些能源树种生产成型木质燃料来替代煤炭,从数量上提供可行的依据. 相似文献
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刘杰成 《东北林业大学学报》1988,(2)
在静电学中提出了电场能等于带电体系的自能与互能之和,但并未对自能的总和永远大于互能作更进一步的论证。本文从特殊情况出发,论证了这个问题。这对于深刻理解电场能的本质,具有重要的意义。 相似文献
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木质纤维素类生物质转化生物乙醇预处理B2B工艺的发展研究 总被引：2，自引：0，他引：2
在能源问题日益紧张的时局下,寻求可再生的清洁能源成为目前亟待解决的关键问题,而乙醇燃料无疑是化石类能源的最佳替代能源。生物质转化为生物乙醇（简称B2B）工艺无论是从可行性、清洁性抑或是经济性来看都具有可大规模工业化应用的前景。基于木质纤维素物质来源广、成本低等特点,这类原料制备生物乙醇的研究取得了很大的进展。详细综述了木质纤维素类生物质转化生物乙醇中的预处理工艺进展和发展方向,并对各种预处理工艺的优缺点进行了论述,此外,对于双螺杆挤出爆破工艺也进行了详细阐释。 相似文献
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长白山林区主要可燃物类型地表可燃物载量分析 总被引：5，自引：0，他引：5
对长白山林区主要可燃物类型地表可燃物载量进行了对比分析和聚类分析。通过可燃物类型载量的对比分析,得出易燃的可燃物类型是云冷杉林(鱼鳞云杉103a)、落叶松林(115a)和云冷杉林(鱼鳞云杉80a),最不易燃的是岳桦林(142a)、白桦林(87a)和岳桦林(115a);释放能量最大的可燃物类型是落叶松林(115a),释放能量最小的可燃物类型是白桦林(87a)。通过各可燃物类型的1h时滞可燃物载量和地表总可燃物载量的聚类分析,可把13个可燃物类型化为6类。 相似文献