共查询到19条相似文献,搜索用时 93 毫秒
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本文针对配备三通道蛇形阳极流场的液态进料直接甲醇燃料电池阳极两相流及电池性能开展了实验研究.液态进料的直接甲醇燃料电池阳极流床内会形成二氧化碳气泡与甲醇溶液构成的两相流系统,其两相流特性受到电池流道设计、运行工况和工作角度的影响,并同时影响燃料电池的性能.本文设计了三通道蛇形流场,通过可视化实验得到直接甲醇燃料电池三通道蛇形阳极流场内的两相流特性随电流密度变化的规律,并研究了燃料电池在不同旋转角度下的两相流特性和电池性能.实验结果表明:在不同的旋转角度下,电池都体现出较好的工作性能. 相似文献
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动态特性是理解质子交换膜燃料电池性能的重要参数之一.运用燃料电池测试系统、恒电流/恒电压多通道测试仪和燃料电池电流密度分布测试装置,试验测量了质子交换膜燃料电池在不同加湿温度、电池温度和压力下的电流分布动态响应和动态特性.研究发现:不同区域的局部电流达到新的平衡所需的时间不同;加湿温度变化时,不同区域的局部电流的变化趋... 相似文献
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New advanced ceramic type fuel cells using natural salt and fluoride-based electrolytes have been demonstrated. Compared with
conventional fuel cells, the natural salt and fluoride-based electrolyte fuel cells have shown a technical opportunity to
develop intermediate temperature fuel cells for commercialisation in the near future.
Paper presented at the 6th Euroconference on Solid State Ionics, Cetraro, Calabria, Italy, Sept. 12–19, 1999 相似文献
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This paper discusses hydrogen energy and the methods for production of hydrogen. It also provides a review of various materials
which are hydrogen permeable. Previous studies on the proton-conducting ceramics and their properties are summarized. The
principle of proton-conducting solid state fuel cell for conversing the energy of hydrogen containing fuel is described with
a discussion of the advantages of proton-conducting ceramic fuel cells as compared to oxygen-ionic conducting fuel cells.
The paper is concluded with a discussion of the major materials related technical challenges in the development of the proton-conducting
ceramic fuel cells.
Paper presented at the 97th Xiangshan Science Conference on New Solid State Fuel Cells, Xiangshan, Beijing, China, June 14–17,
1998. 相似文献
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Proton exchange membrane fuel cells [PEMFC] have become highly attractive for stationary as well as mobile energy applications due to their good efficiency compact cell design and zero emissions. PEM fuel cells mainly consist of anode and cathode containing platinum/platinum alloy electrocatalysts and Nafion membrane as the electrolyte. They operate on hydrogen fuel, which is generally produced by reforming of hydrocarbons, alcohols such as methanol and may contain large amounts of impurities such as methanol, carbon dioxide, trace amounts of carbon monoxide, etc. The studies on the effect of methanol impurity in hydrogen on fuel cell performance and methods of mitigation of poisoning are very important for the commercialization of fuel cells and are described in a limited number of papers only. In this paper, we present the studies on the influence of methanol impurity in hydrogen for the PEM fuel cells. The effect of various parameters such as methanol concentration, cell voltage, current density, exposure time, reversibility, operating temperature, etc. on the cell performances was investigated using pure hydrogen. Various methods of methanol poisoning mitigation were also investigated. 相似文献
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Polymer electrolyte membrane (PEM) fuel cells are susceptible to degradation due to the catalyst poisoning caused by CO present
in the fuel above certain limits. Although the amount of CO in the fuel may be within the permissible limit, the fuel composition
(% CO2, CH4, CO and H2O) and the operating conditions of the cell (level of gas humidification, cell temperature and pressure) can be such that
the equilibrium CO content inside the cell may exceed the permissible limit leading to a degradation of the fuel cell performance.
In this study, 50 cm2 active area PEM fuel cells were operated at 55–60 °C for periods up to 250 hours to study the effect of methane, carbon dioxide
and water in the hydrogen fuel mix on the cell performance (stability of voltage and power output). Furthermore, the stability
of fuel cells was also studied during operation of cells in a cyclic dead end / flow through configuration, both with and
without the presence of carbon dioxide in the hydrogen stream. The presence of methane up to 10% in the hydrogen stream showed
a negligible degradation in the cell performance. The presence of carbon dioxide in the hydrogen stream even at 1–2% level
was found to degrade the cell performance. However, this degradation was found to disappear by bleeding only about 0.2% oxygen
into the fuel stream. 相似文献
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Polymer electrolyte membrane (PEM) fuel cells are considered to have the highest power density of all the fuel cells. They operate on hydrogen fuel, which is generally produced by reforming of hydrocarbons, and may contain large amounts of impurities such as carbon dioxide, nitrogen, and trace amounts of carbon monoxide. We studied the effect of dilution of hydrogen gas with carbon dioxide on PEM fuel cells by polarization studies. The polarization curves were different when hydrogen gas was diluted with same quantities of carbon dioxide and with nitrogen. It may be due to carbon monoxide formation by reverse shift reaction and poisoning of anode platinum catalyst. Use of Pt–Ru alloy catalyst was found to suppress the poisoning. The effects of hydrogen gas composition, temperature, current density, and anode catalyst on fuel cell performances were examined in this study. 相似文献
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The performance and durability of low-temperature fuel cells seriously depend on catalyst support materials. Catalysts supported on high surface area carbons are widely used in low temperature fuel cells. However, the corrosion of carbonaceous catalyst-support materials such as carbon black has been recognized as one of the causes of performance degradation of low-temperature fuel cells, in particular under repeated start-stop cycles or high-potential conditions. To improve the stability of the carbon support, materials with a higher graphitic character such as carbon nanotubes and carbon nanofibers have been tested in fuel cell conditions. These nanostructured carbons show a several-fold lower intrinsic corrosion rate, however, do not prevent carbon oxidation, but rather simply decrease the rate. Due their high stability in fuel cell environment, ceramic materials (oxides and carbides) have been investigated as carbon-substitute supports for fuel cell catalysts. Moreover, the higher specific electrocatalytic activity of some ceramic supported metals than unsupported and carbon supported ones, suggests the possibility of a synergistic effect by supporting metal catalyst on ceramic supports. This paper presents an overview of ceramic materials tested as a support for fuel cell catalysts, with particular attention addressed to the electrochemical activity and stability of the supported catalysts. 相似文献
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A direct carbon fuel cell offers a high efficiency alternative to traditional coal fired electrical power plants. In this paper, the electrochemical performance of electrolyte supported button cells with Gd2O3-doped CeO2 (CGO) electrolyte is reported over the temperature range 600 to 800 °C with solid carbon as a fuel and He/CO2 as the purge gases in the fuel chamber. The electrochemical characterisation of the cells was carried out by the Galvanostatic Current Interruption (GCI) technique and measuring V-I and P-I curves. Power densities over 50 mWcm-2 have been demonstrated using carbon black as the fuel. Results indicate that at low temperatures around 600 °C, the direct electrochemical oxidation of carbon takes place. However, at higher temperatures (800 °C) both direct electrochemical oxidation and the reverse Boudouard reaction take place leading to some loss in fuel cell thermodynamic efficiency and reduced fuel utilisation due to the in-situ production of CO. In order to avoid reverse Boudouard reaction whilst maximising performance, an operating temperature of around 700 °C appears optimal. Further, the electrochemical performance of fuel cells has been compared for graphite and carbon black fuels. It was found that graphitic carbon fuel is electrochemically less reactive than relatively amorphous carbon black fuel in the DCFC when tested under similar conditions. 相似文献