共查询到19条相似文献,搜索用时 78 毫秒
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本研究的目的是揭示富氧燃烧过程中的氮氧化物生成机理,针对富氧火焰特性探讨NOx抑制机制机理。文中以对向流扩散火焰为对象,利用详细的基元反应动力学模型研究了燃料稀释对富氧空气/甲烷扩散火焰中氮氧化物生成的影响,稀释剂为N2或CO2。结果表明,随着燃料中稀释组分浓度的变化,火焰结构和NO生成的决定机理显著变化;同时发现,随稀释剂CO2浓度增大,NO的排放指数EINO(Emission Index of NO)单调减少,随稀释刺N2稀释时EINO存在最大值。 相似文献
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煤和石油焦混合燃料的热解特性及其动力学参数 总被引:1,自引:0,他引:1
介绍了在热重分析仪上进行石油焦及其煤和石油焦混合燃料的热解试验,研究了样品种类、升温速率、掺混比等因素对石油焦及其煤和石油焦混合燃料的影响规律,同时对石油焦和烟煤进行了比较,并进一步研究了其热解的动力学参数。试验结果对利用石油焦作为锅炉替代燃料具有参考价值。 相似文献
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实验条件对煤热解特性影响的分析 总被引:9,自引:0,他引:9
采用TG-FTIR联机实验方法.对不同煤样进行了热重分析.同时对煤样的析出产物进行红外光谱实时跟踪检测;研究不同升温速率和试样用量对煤热解过程TG、DTG曲线以及实时跟踪红外光谱分析的影响.为掌握煤的热解特性、提高煤的有效利用提供依据。 相似文献
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富氧燃烧对柴油机排放特性的影响 总被引:3,自引:0,他引:3
柴油机因其废气中的碳烟排放高而被排除在清洁发动机之外。减少碳烟排放的一种方法是增加缸内空气的氧含量,使燃烧更彻底充分进行。本文介绍了在S195柴油机上进行富氧燃烧试验。对其排放特性进行比较与分析,通过试验研究,找到在富氧条件下同时降低碳烟和NOx排放的方法。 相似文献
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在固定床反应器上考察了高温下不同氧浓度气氛下NO-煤焦还原反应的还原效果,并采用XPS分析了不同氧浓度预处理后的煤焦表面的含氧官能团.研究结果表明,高温下氧气对于NO-煤焦还原反应依然有显著的促进作用,也同样存在临界氧浓度(0.25%)的现象,比低温下临界氧浓度(1%)有所提前.由XPS分析结果发现,高温下氧气对煤焦表面的影响是产生促进NO还原的表面含氧官能团(C(O)),适量的氧气浓度能形成饱和的C(O)活性位,使得还原效果达到最佳.随着温度的升高,C(O)的总量略有减少.有可能是温度过高致使煤焦表面的C(O)极易达到饱和,多余的氧气以O的形式排出. 相似文献
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添加剂对燃煤NO排放的影响 总被引:4,自引:0,他引:4
利用DTA-TG-DTG设备,实验研究了CaO对抚顺烟煤NO排放特性的影响以及由CaO分别与TiO,和Na2CO3组成的混合添加剂对抚顺烟煤NO排放特性的影响.结果表明,CaO能够增加抚顺煤在燃烧过程中的NO排放浓度和排放量,CaO对燃煤NO排放的影响与CaO在煤中的含量有关,钙氮比(Ca/N)增加,煤的NO排放量增大.但是,向抚顺煤中同时加入CaO和TiO2或CaO和Na2CO3后,煤的NO的排放浓度和排放量比只添加CaO一种成分时低,即添加剂TiO2和Na2CO3能够减弱CaO对抚顺煤NO排放特性的影响.增加TiO2或Na2CO3在混合添加剂中的份额后,NO排放量进一步下降,但在实验范围内,含混合添加剂的煤,NO排放浓度和排放量仍比原煤高。 相似文献
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Effects of fluorine doping on the structural properties of the CdO films deposited by ultrasonic spray pyrolysis 总被引:1,自引:0,他引:1
Metin Kul Ahmet Senol Aybek Evren Turan Muhsin Zor Sinan Irmak 《Solar Energy Materials & Solar Cells》2007,91(20):1927-1933
The fluorine doped cadmium oxide samples have been deposited at 250 °C by ultrasonic spray pyrolysis method. X-ray diffraction patterns of the CdO:F samples have revealed that the samples are polycrystalline with cubic sodium chloride structure. The texture coefficients calculated for various planes at different fluorine concentrations indicate that the samples have exhibited (1 1 1) and (2 0 0) preferential orientations. The lattice parameters for cubic structure of each diffraction plane have been calculated. The crystallite size of the samples being nearly constant until 4% of fluorine doping showed reasonable decrease above this concentration value. The macro strain and dislocation density vary with fluorine concentrations. 相似文献
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The cathodic discharge of hydrogen on the surface of massive specimens of NiZr intermetallic compound readily forms the trihydride NiZrH3 which exhibits the same crystallographic parameters as the trihydride obtained by gas phase charging. Moreover microstructural studies of the first stage of the hydriding process during cathodic charging of massive samples allow to follow the influence of the microstructure of NiZr on the germination of cracks and on the first stage of the decrepitation associated with H absorption. These results show that the NiZr microstructure could strongly affect both the hydriding kinetic, the hydride stability and further the amount of hydrogen stored in the intermetallic compound. 相似文献
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Paul S. Gentile 《Journal of power sources》2011,196(10):4545-4554
Aluminosilicate represents a potential low cost alternative to alumina for solid oxide fuel cell (SOFC) refractory applications. The objectives of this investigation are to study: (1) changes of aluminosilicate chemistry and morphology under SOFC conditions, (2) deposition of aluminosilicate vapors on yttria stabilized zirconia (YSZ) and nickel, and (3) effects of aluminosilicate vapors on SOFC electrochemical performance. Thermal treatment of aluminosilicate under high temperature SOFC conditions is shown to result in increased mullite concentrations at the surface due to diffusion of silicon from the bulk. Water vapor accelerates the rate of surface diffusion resulting in a more uniform distribution of silicon. The high temperature condensation of volatile gases released from aluminosilicate preferentially deposit on YSZ rather than nickel. Silicon vapor deposited on YSZ consists primarily of aluminum rich clusters enclosed in an amorphous siliceous layer. Increased concentrations of silicon are observed in enlarged grain boundaries indicating separation of YSZ grains by insulating glassy phase. The presence of aluminosilicate powder in the hot zone of a fuel line supplying humidified hydrogen to an SOFC anode impeded peak performance and accelerated degradation. Energy dispersive X-ray spectroscopy detected concentrations of silicon at the interface between the electrolyte and anode interlayer above impurity levels. 相似文献
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Interfacial oxidation of Nb and Si at 650 °C on Laves phase forming Ti–Nb stabilized ferritic stainless steel (Fe–19Cr–0.9Si–0.2Nb–0.1Ti (at.%), grade EN 1.4509) was studied by electrochemical impedance spectroscopy and photoelectron spectroscopy. It was found that excess Nb efficiently hinders the formation of electrically resistive SiO2 layer at the oxide–metal interface. The beneficial role of Nb was attributed to its high segregation rate and the formation of conductive oxides at the interface. However, the oxidation was strongly influenced by age-precipitation of the Laves (FeNbSi)-type intermetallic phase, which removed free Nb from the alloy solution and thus allowed SiO2 layer to form more easily. These results can be applied to optimize the oxide scale composition by Nb alloying of the ferritic stainless steel to maintain high performance under various operation conditions, particularly in solid oxide fuel cell applications. 相似文献
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Inayat Ali Khan Amin Badshah Muhammad Amtiaz Nadeem Naghma Haider Muhammad Arif Nadeem 《International Journal of Hydrogen Energy》2014
The article describes the conversion of MOF-199 to Cu–Cu2O–CuO/C 700 (1) and Cu–Cu2O–CuO/C 800 (2) nanostructures by simple pyrolysis at 700 and 800 °C under inert atmosphere. The X-ray photoelectron spectroscopy analysis reveals that the nanostructures Cu–Cu2O–CuO/C consist of graphitic carbon functionalized with carboxylic, carbonyl and hydroxyl functional groups with copper/copper oxide particles on surfaces. The electrochemical properties of 1 and 2 are evaluated as electrode material for supercapacitors using cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The results for the capacitive performance from cyclic voltammetry and galvanostatic charge/discharge reveal that both the samples have gravimetric capacitance greater than 750 F g−1 at a scan rate of 2 mV s−1 and current density of 2 mA cm−2. The samples retain about 43% of their initial capacitance even at high scan rate of 75 mV s−1. The cycling performance of the nanostructures illustrate that there is 5.5% capacitance loss after 3000 cycles. The sample 1 and 2 are washed with 1 mol L−1 HCl solution to obtain copper oxide free materials Cu/C 700 (3) and Cu/C 800 (4). Samples 3 and 4 are tested as electrocatalysts for glucose sensing and the cyclic voltammetry measurement shows enhanced current densities compared to the literature values. 相似文献
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This study synthesized platinum (Pt) nanoparticles supported on carbon nanotubes (CNTs) using a microwave-assisted polyol method. The oxidation treatment of CNTs introduced primarily -OH and -COOH groups to the CNTs, thereby enhancing the reduction of Pt ionic species, resulting in smaller Pt particles with improved dispersion and attachment properties. The Pt particles supported on oxidized CNTs displayed superior durability to those on pristine CNTs or commercially available Pt/C. These improvements are most likely associated with the percentage of metallic Pt in the particles. After 400 cycles, the losses of electrochemical surface area in Pt nanoparticle supported on oxidized CNTs and pristine CNTs catalysts were 66 and 84%, respectively, of that associated with commercial Pt/C. A single proton exchange membrane fuel cell using Pt supported on oxidized CNTs at the cathode with a total catalytic loading of 0.6 Pt mg cm−2 exhibited the highest power density of 890 mW cm−2 and displayed a lower mass transfer loss, compared to Pt/C. 相似文献
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催化改性活性碳纤维降低NO的实验研究 总被引:1,自引:0,他引:1
在微型反应器中对负载离子聚丙烯腈基活性碳纤维(ACF)进行了脱除NO的实际效果对比,定量测定在不同温度下它们与NO的反应产物,通过程序升温脱附(TPD)、热重(TG)及扫描电镜(SEM)的研究,为反应机理探索和催化剂筛选提供了依据。结果显示,金属离子的引入可大大提高催化活性。考察了所选负载铜离子ACF在不同气氛下的变化规律,并进行了化学动力学计算。实验结果表明,以聚丙烯腈基活性碳纤维为载体负载铜离子的ACF具有较高催化还原活性。活性碳纤维既作载体又作还原剂,它本身的性质十分重要。 相似文献