首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
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   

2.
Reed TB  Lerner RM 《Science (New York, N.Y.)》1973,182(4119):1299-1304
We believe that methanol is the most versatile synthetic fuel available and its use could stretch or eventually substitute for, the disappearing reserves of low-cost petroleum resources. Methanol could be used now as a means for marketing economically the natural gas that is otherwise going to waste in remote locations. If methanol were used as an additive to gasoline at a rate of 5 to 15 percent, for use in internal combustion engines, there would be an immediate reduction in atmospheric pollution, there would be less need for lead in fuel, and automobile performance would be improved. With increasing production of fuel-grade methanol from coal and other sources, we foresee the increasing use of methanol for electrical power plants, for heating, and for other fuel applications. We hope that a practical methanol fuel cell will be commercially available by the time that methanol becomes plentiful for fuel purposes. Methanol offers a particularly attractive form of solar-energy conservation, since agricultural and forest waste products can be used as the starting material. Indeed, at 1 percent conversion efficiency the forest lands could supply the entire present energy requirements of the United States.  相似文献   

3.
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   

4.
Waste biomass is a cheap and relatively abundant source of electrons for microbes capable of producing electrical current outside the cell. Rapidly developing microbial electrochemical technologies, such as microbial fuel cells, are part of a diverse platform of future sustainable energy and chemical production technologies. We review the key advances that will enable the use of exoelectrogenic microorganisms to generate biofuels, hydrogen gas, methane, and other valuable inorganic and organic chemicals. Moreover, we examine the key challenges for implementing these systems and compare them to similar renewable energy technologies. Although commercial development is already underway in several different applications, ranging from wastewater treatment to industrial chemical production, further research is needed regarding efficiency, scalability, system lifetimes, and reliability.  相似文献   

5.
对比了燃煤与燃油的燃烧值与其当前的市场价格,以及运煤车辆的耗油和大修的相关标准参数。从燃油与燃煤产生的能耗与需要投入的风险、运输、折旧及培训等费用成本两方面进行了综合分析。对此分析结果表明,当运煤距离超过300km时,燃油的综合效益高于燃煤,并有利于环保,避免资源重复利用,有效提高了资源的利用效益。  相似文献   

6.
A review of research on low heat rejection engines, on cooperative efforts in the United States and abroad to incorporate ceramics in intermittent combustion engines, and on the use of ceramics in these engines is presented. The reduction of heat loss from the combustion chamber of diesel engines improves fuel efficiency only 3 or 4 percent. Some other gains may be possible from a smaller cooling system, recovery of exhaust energy, and improvements in aerodynamics. It is judged that designs of low heat rejection engines will have the greatest initial impact on armored combat vehicles. Organization, coordination, planning, and cooperation on R&D for the use of ceramics in intermittent combustion engines appear to be greater abroad than in the United States.  相似文献   

7.
运用两阶段关联网络DEA模型,对我国新能源汽车产业上市公司的债权融资效率及各子阶段对应效率进行了测算。研究结果表明:新能源汽车产业上市公司债权融资效率水平偏低,而债权筹资效率相对低下是其主要原因;随着时间推移,大部分新能源汽车产业上市公司两阶段效率逐渐趋向双重高效。  相似文献   

8.
不同替代能源密集烤房烟叶烘烤效能对比研究   总被引:3,自引:0,他引:3  
[目的]探索烟叶烘烤燃煤的替代能源。[方法]对生物质压块、生物质颗粒和醇基3类燃料与常规燃料(褐煤)的烟叶烘烤效能进行对比研究。[结果]3种替代能源在燃烧烟气中主要污染物的排放明显低于常规燃料,烘烤过程中升温速度、稳温性能明显提高(除生物质压块外),整个烘烤工艺时间可缩短6~14 h,对初烤烟叶外观质量无明显影响;醇基燃料成本较高,烘烤综合成本约是褐煤成本的2.4倍,经济效益较差。[结论]生物质颗粒燃料可作为常规燃料(褐煤)的替代能源应用于烟叶实际烘烤工艺中。  相似文献   

9.
A solid electrolyte fuel cell operating on ammonia fuel has been constructed and tested. The yield of nitric oxide can exceed 60 percent with simultaneous electric energy production. Two dimensionless numbers have been identified which govern the product selectivity and power output of this fuel cell. The cell appears to be a promising candidate for nitric acid and electric energy cogeneration.  相似文献   

10.
本文研究了秀优杂交稻和富士光两个水稻品种的光谱特性。实验结果表明,这两个不同产量水平的水稻品种,其光谱特性具有明显差别。在含等量叶绿素的情况下,高产的秀优杂交稻比低产的富士光对光的吸收能力更大,前者的叶片具有更高的潜在光合作用量子转化效率;叶绿体的PSⅡ潜在活性和PSⅡ原初光能转化效率也高。与富士光相比,Mg~(2+)不仅能较大幅度地提高秀优杂交稻叶绿体上述两个光合作用参数,而且对它两个光系统之间的激发能分配也有较大的调节能力。  相似文献   

11.
渔业节能减排和保护环境对促进国家海洋经济发展将起到重要作用。与传统的船舶动力系统相比,混合动力推进系统的电力推进具有调速范围广、驱动力大、易于正反转、体积小、布局灵活、安装方便、便于维修、振动和噪音小等优点。金枪鱼延绳钓船在作业时间内,主机处于低转速低负荷运行状态,燃油消耗率升高,出现积炭,导致增压器背压增加,可能引起喘振;主机受最低稳定转速限制,易造成航速忽快忽慢,不利于生产作业。根据金枪鱼延绳钓船作业方式和特点,提出分段驱动并联结构机电混合动力推进系统应用于金枪鱼延绳钓船,形成机电混合推进系统,降低了金枪鱼延绳钓船在航行及作业工况下对主机的依赖性,提高船舶推进系统冗余度,提高船舶放钓、收钓作业工况下的操纵灵活性,大幅度提高船舶操纵性和综合推进效率。通过经济适用性和环境保护性指标体系分析,与常规金枪鱼延绳钓船相比较,在放钓、巡钓和收钓作业等相同工况下,综合耗油量降低20%,系统可靠性,安全性和综合推进效率有一定提高。  相似文献   

12.
New applications such as hybrid electric vehicles and power backup require rechargeable batteries that combine high energy density with high charge and discharge rate capability. Using ab initio computational modeling, we identified useful strategies to design higher rate battery electrodes and tested them on lithium nickel manganese oxide [Li(Ni(0.5)Mn(0.5))O2], a safe, inexpensive material that has been thought to have poor intrinsic rate capability. By modifying its crystal structure, we obtained unexpectedly high rate-capability, considerably better than lithium cobalt oxide (LiCoO2), the current battery electrode material of choice.  相似文献   

13.
陈江波 《油气储运》1999,18(6):51-53
对热炉燃烧油预热流温度的控制是热炉炉提高炉效、稳定运行的关键,也有降耗的有效途径。以东管于黄岛输油管道中东营、寿光、昌邑这三个砂站采用的CE-NATCO热煤炉为例,分析和计算了采用胜利原油和青岛渣 作了为热炉燃料时发控制的温度范围,并根据实际运行的经验,对的燃料油系统进行了改进。  相似文献   

14.
There are substantial barriers to the introduction of hydrogen fuel cells for transportation, including the high cost of fuel-cell systems, the current lack of a hydrogen infrastructure, and the relatively low fuel efficiency when using hydrogen produced from hydrocarbons. Here, we describe a solid oxide fuel cell that combines a catalyst layer with a conventional anode, allowing internal reforming of iso-octane without coking and yielding stable power densities of 0.3 to 0.6 watts per square centimeter. This approach is potentially the basis of a simple low-cost system that can provide substantially higher fuel efficiency by using excess fuel-cell heat for the endothermic reforming reaction.  相似文献   

15.
热油管道的能耗费用主要包括输油泵的动力费用和加热炉的燃料费用。对于我国东西部地区的热油管道,输油泵大多为电动离心泵,加热炉大多以所输原油为燃料,因而相应的能耗费用包括电费和燃料费两部分,以此费用之和最小为目标函数,建立长输热油管道运行效率优化模型,并采用自适应模拟退火算法进行了求解。  相似文献   

16.
Ross M 《Science (New York, N.Y.)》1989,244(4902):311-317
Largely in response to the energy shocks of the 1970s, U.S. manufacturers reduced their real fossil fuel intensity (the weighted-average ratio of energy use to production in each subsector) by 50% and achieved zero growth in real electricity intensity. In the future, adoption of new technologies for increasing the efficiency of electricity use is likely to continue to be as important as new modes of electrification, implying that the real electricity intensity will be stable; but the outcome depends on electricity pricing and other policies, public and private.  相似文献   

17.
With high rates of food and nonrenewable fossil fuel consumption worldwide, we are facing great challenges in ensuring food and energy security to satisfy the world population. Intercropping, as an important and sustainable cropping practice in agroecosystems, has been widely practiced around the world. Many studies have shown that some plants can deliver high yields when intercropped with other plants. Here, we review the biological mechanisms in improving resource utilization efficiency and illustrate the practical application of intercropping in ensuring food and energy security through improving production. Identifying suitable energy plants for marginal land, land not suitable for food crops growth, is an effective strategy to acquire high production of bioenergy, thus removing competition between the use of land for food and energy. The effective application of intercropping provides a potential pathway for production of food crops and energy plants by improving resource use efficiency and resistance to environmental stress.  相似文献   

18.
[目的]探讨高产杂交水稻的高光效特性。[方法]以高产水稻组合K优52和对照品种汕优63为材料,围绕剑叶光合速率、光能的转化及碳同化等特性,比较2种水稻抽穗后的叶色值(SPAD)及净光合速率(Pn)的差异。[结果]K优52的光合速率在剑叶抽出之初略低于对照,展开后7~14d与对照相当,全展开14d后超过对照,尤其在21~35d显著高于对照;随着水稻灌浆、结实至成熟,2种水稻的叶片也随之衰老,净光合速率下降,但K优52下降速率缓慢,其剑叶净光合速率高值持续期能维持在25d左右,而对照维持在21d左右,与对照相比具有优势;2种水稻的叶片叶绿素含量的变化与光合速率变化类似。[结论]K优52灌浆结实期的净光合速率优势可能是其高产形成的主要原因。  相似文献   

19.
Among the potential non-food energy crops,the sugar-rich C_4 grass sweet sorghum and the biomass-rich Miscanthus are increasingly considered as two leading candidates.Here,we outline the biological traits of these energy crops for largescale production in China.We also review recent progress on understanding of plant cell wall composition and wall polymer features of both plant species from large populations that affect both biomass enzymatic digestibility and ethanol conversion rates under various pretreatment conditions.We finally propose genetic approaches to enhance biomass production,enzymatic digestibility and sugar-ethanol conversion efficiency of the energy crops.  相似文献   

20.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号