共查询到15条相似文献,搜索用时 421 毫秒
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船形体煤粉燃烧器NO_x生成特性的研究 总被引:1,自引:0,他引:1
船形体煤粉燃烧器NO_x生成特性的研究钟北京,徐旭常(清华大学煤的高效低污染燃烧国家重点实验室北京100084)关键词煤粉燃烧器,“三高区”原理,NO_x1前言我国电力工业的发展主要依赖于以煤为主要燃料,采用粉状燃烧方式的火力发电。1992年我国年产煤... 相似文献
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1引言预燃室燃烧技术是近十多年来开发研究的一种高燃烧效率低NO。的燃烧技术门.它是一种分级燃烧技术。燃料在预燃室内只是部分地燃烧,在贫氧的一次火焰区内脱挥发分,从而减少了NO。的形成。自1982年以来,我国开发研究了很多种类的预燃室,如旋流、大速差l‘]、偏置射流预燃室等。工程热物理研究所研究开发了逆向复式射流预燃室燃烧器l‘,‘]。经实验室和工业实验证明,该预燃室有极优良的火焰稳定性能和煤种适应性,能够实现较低的NOx排放。本文针对逆向射流预燃室内这一独特的流场结构,利用数值模拟来预报煤粉颗粒在其内的运… 相似文献
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应用预蒸发技术燃烧液体燃料 总被引:3,自引:1,他引:2
本文介绍了一种燃烧液体燃料的新技术-预蒸发燃烧技术:通过分离液体燃料的蒸发过程和燃烧过程,实现液体燃料的“气体化”燃烧;重点介绍利用液体燃料着火前存在的冷焰燃烧现象实现燃料预蒸发的技术原理。与传统的燃烧技术相比,液体燃料的预蒸发燃烧具有高效率、低噪音、低有害污染物特别是NOx排放、和易调节等优点。 相似文献
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Ekenechukwu C. Okafor K.D. Kunkuma A. Somarathne Akihiro Hayakawa Taku Kudo Osamu Kurata Norihiko Iki Hideaki Kobayashi 《Proceedings of the Combustion Institute》2019,37(4):4597-4606
Recent studies have demonstrated stable generation of power from pure ammonia combustion in a micro gas turbine (MGT) with a high combustion efficiency, thus overcoming some of the challenges that discouraged such applications of ammonia in the past. However, achievement of low NOx emission from ammonia combustors remains an important challenge. In this study, combustion techniques and combustor design for efficient combustion and low NOx emission from an ammonia MGT swirl combustor are proposed. The effects of fuel injection angle, combustor inlet temperature, equivalence ratio, and ambient pressure on flame stabilization and emissions were investigated in a laboratory high pressure combustion chamber. An FTIR gas analyser was employed in analysing the exhaust gases. Numerical modeling using OpenFOAM was done to better understand the dependence of NO emissions on the equivalence ratio. The result show that inclined fuel injection as opposed to vertical injection along the combustor central axis resulted to improved flame stability, and lower NH3 and NOx emissions. Numerical and experimental results showed that a control of the equivalence ratio upstream of the combustor is critical for low NOx emission in a rich-lean ammonia combustor. NO emission had a minimum value at an upstream equivalence ratio of 1.10 in the experiments. Furthermore, NO emission was found to decrease with ambient pressure, especially for premixed combustion. For the rich-lean combustion strategy employed in this study, lower NOx emission was recorded in premixed combustion than in non-premixed combustion indicating the importance of mixture uniformity for low NOx emission from ammonia combustion. A prototype liner developed to enhance the control and uniformity of the equivalence ratio upstream of the combustor further improved ammonia combustion. With the proposed liner design, NOx emission of 42?ppmv and ammonia combustion efficiency of 99.5% were achieved at 0.3?MPa for fuel input power of 31.44?kW. 相似文献
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《Proceedings of the Combustion Institute》2023,39(4):4881-4888
Fuel reforming technology using a low temperature oxidation reaction was applied to improvement of NOx reduction efficiency of hydrocarbons selective catalytic reduction (HC-SCR) system, which does not require urea. The low temperature oxidation reaction of hydrocarbons produces oxygenated hydrocarbons which has high NOx reduction ability such as aldehydes. A pre-evaporation and premixing-type fuel reformer was developed in order to generate uniform fuel/air premixed gas. To prevent from hot-flame ignition, the reaction chamber of the fuel reformer has a high surface/volume ratio and the wall temperature of the reaction chamber was controlled. As a fundamental study, NOx reduction experiments and elementary reaction calculation were carried out to investigate the suitable fuel reformer temperature and reforming equivalence ratio for the promotion of NOx reduction on the surface of the catalyst. It was found that the reforming fuel gas has a higher NOx reduction efficiency than the fuel vapor in the catalyst temperature range from 473 to 773 K. The NOx reduction efficiency was highest at the reforming temperature of 673 K. The NOx reduction efficiency at the catalyst temperature of 723 K increases with the increase in the reforming equivalence ratio. It was suggested that alcohols predominantly affect NOx reduction reaction at low catalyst temperatures, and aldehydes at high catalyst temperatures. 相似文献
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高温空气燃烧NOx排放特性的试验研究 总被引:2,自引:0,他引:2
通过两种结构烧嘴的热态燃烧试验对比,研究了烧嘴结构、燃气射流速度、过量空气系数对高温空气燃烧过程氮氧化物排放的影响特性。研究结果认为:在燃气喷口两侧布置两个矩形空气喷口的烧嘴,氮氧化物排放量低于圆形空气喷口烧嘴;随着燃气射流速度的提高,高温空气燃烧过程排放的氮氧化物逐渐减少。与普通燃烧过程不同的是,随着过量空气系数的提高,在一定范围内高温空气燃烧的氮氧化物排放量不断增加。分析认为,高温空气燃烧氮氧化物排放量与火焰体积、炉内氧气与燃气混合过程以及燃气射流和空气射流对炉内烟气的卷吸量有关。 相似文献
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《Proceedings of the Combustion Institute》2023,39(4):4791-4799
Prior studies about liquid fuel combustion in a vitiated air environment have shown increased combustion efficiency with reduced NOx, CO, and soot emissions. The concept of lean azimuthal flame (LEAF), which can be associated to the latter combustion mode, is based on opposed injections of air and liquid fuel sprays in an axisymmetric chamber with a central outlet, which can result in a highly turbulent toroidal reaction zone. The mixture of fresh air and hot combustion products of each spray provides a vitiated cross-flow configuration to the next spray distributed along the chamber circumference, leading to ignition and sequential combustion of the sprays by the others. The present paper deals with a LEAF combustor with air-assisted spray atomization, which has not been investigated so far. The combustor is fueled with Jet A-1 and operated from 15 to 25 kW with variations in the atomization-air to liquid mass flow ratio (ALR). This study focuses on the flame topology transitions as a function of atomizer ALR. Experimental results based on flame chemiluminescence and OH planar laser-induced fluorescence show two flame topologies: tubular and LEAF topology for ratio of 2 and 4, respectively (denoted ALR2 and ALR4). The spray Mie scattering indicates a significant presence of unburnt droplets for ALR2, whereas quick evaporation is observed for ALR4 cases. In this paper, we propose and validate a basic model based on the spray droplet size distribution, and the evaporation and convection timescales, which are the prominent factors governing the flame topology. Indeed, for ALR2, the evaporation timescale is longer than the convective timescale, which causes incomplete spray evaporation and insufficient vitiated environment, leading to a tubular flame topology and preventing a LEAF to develop. In contrast, for ALR4, the spray evaporation timescales are smaller than the convective timescales, which aids the LEAF topology. 相似文献