共查询到18条相似文献,搜索用时 109 毫秒
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径向浓淡旋流煤粉燃烧器的工业性试验研究 总被引:10,自引:1,他引:9
该文对径向浓淡旋流煤粉燃烧器设计中的一些问题进行了探讨,并在燃用贫煤的670t/h锅炉及燃用烟煤的410t/h锅炉上进行了冷态及热态试验。结果表明:新型燃烧器是同时具有高效,稳燃,低污染,防结渣及防高温腐蚀性能的新一代旋流煤粉燃烧器。 相似文献
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煤粉浓度连续可调型浓淡燃烧器及其气固两相流动特性 总被引:2,自引:0,他引:2
针对电站锅炉燃用煤种多变和负荷多变的问题,提出了一种新型的浓淡偏差燃烧技术,即利用组合叶片的导向作用对煤粉气流进行分离浓缩的煤粉浓度连续可调型浓淡燃烧器。应用激光粒子动态分析仪对这种燃烧器进行的两相流动特性测量表明,在一定的组合叶片角度范围内,可以实现煤粉浓度的连续调节,且由于叶片的扰动作用,气相和颗粒相的湍动都能有所提高,不同粒径颗粒的分布也发生了变化。 相似文献
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Lingyan Zeng Zhengqi Li Guangbo Zhao Jing Li Fucheng Zhang Shanping Shen Lizhe Chen 《Energy》2011,36(10):6184-6194
Improvements were made to a low-NOx axial swirl burner (LNASB), aimed at mitigating slagging in a 600-MWe boiler burning bituminous coal. The new design is referred to as improved low-NOx axial swirl burner (ILNASB). This paper describes investigations of the influence of swirl burner structure on the gas/particle flow characteristics using a three-dimensional particle-dynamics anemometer. In comparing results from both ILNASB and LNASB, a central recirculation zone is seen to form in the region x/d = 0.1–0.3 within the ILNASB. This zone had shifted from the region between primary and secondary air in LNASB to a region between inner and outer secondary air. In the vicinity of the burner outlet, particle volume flux is reduced significantly in the central recirculation zone. In contrast, this flux is high near the central axis in ILNASB, thus concentrating a great fraction of pulverized coal near the central axis. Form the study, the gas/particle flow characteristics of the ILNASB show that the improved burner has the ability to ease slagging and reduce NOx emissions. 相似文献
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Low NOx burner and air staged combustion are widely applied to control NOx emission in coal-fired power plants. The gas-solid two-phase flow, pulverized coal combustion and NOx emission characteristics of a single low NOx swirl burner in an existing coal-fired boiler was numerically simulated to analyze the mechanisms of flame stability and in-flame NOx reduction. And the detailed NOx formation and reduction model under fuel rich conditions was employed to optimize NOx emissions for the low NOx burner with air staged combustion of different burner stoichiometric ratios. The results show that the specially-designed swirl burner structures including the pulverized coal concentrator, flame stabilizing ring and baffle plate create an ignition region of high gas temperature, proper oxygen concentration and high pulverized coal concentration near the annular recirculation zone at the burner outlet for flame stability. At the same time, the annular recirculation zone is generated between the primary and secondary air jets to promote the rapid ignition and combustion of pulverized coal particles to consume oxygen, and then a reducing region is formed as fuel-rich environment to contribute to in-flame NOX reduction. Moreover, the NOx concentration at the outlet of the combustion chamber is greatly reduced when the deep air staged combustion with the burner stoichiometric ratio of 0.75 is adopted, and the CO concentration at the outlet of the combustion chamber can be maintained simultaneously at a low level through the over-fired air injection of high velocity to enhance the mixing of the fresh air with the flue gas, which can provide the optimal solution for lower NOx emission in the existing coal-fired boilers. 相似文献
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Nicholas Syred Mohammed AbdulsadaAnthony Griffiths Tim O’DohertyPhil Bowen 《Applied Energy》2012,89(1):106-110
Lean premixed swirl combustion is widely used in gas turbines and many other combustion Processes due to the benefits of good flame stability and blow off limits coupled with low NOx emissions. Although flashback is not generally a problem with natural gas combustion, there are some reports of flashback damage with existing gas turbines, whilst hydrogen enriched fuel blends, especially those derived from gasification of coal and/or biomass/industrial processes such as steel making, cause concerns in this area. Thus, this paper describes a practical experimental approach to study and reduce the effect of flashback in a compact design of generic swirl burner representative of many systems. A range of different fuel blends are investigated for flashback and blow off limits; these fuel mixes include methane, methane/hydrogen blends, pure hydrogen and coke oven gas. Swirl number effects are investigated by varying the number of inlets or the configuration of the inlets. The well known Lewis and von Elbe critical boundary velocity gradient expression is used to characterise flashback and enable comparison to be made with other available data.Two flashback phenomena are encountered here. The first one at lower swirl numbers involves flashback through the outer wall boundary layer where the crucial parameter is the critical boundary velocity gradient, Gf. Values of Gf are of similar magnitude to those reported by Lewis and von Elbe for laminar flow conditions, and it is recognised that under the turbulent flow conditions pertaining here actual gradients in the thin swirl flow boundary layer are much higher than occur under laminar flow conditions. At higher swirl numbers the central recirculation zone (CRZ) becomes enlarged and extends backwards over the fuel injector to the burner baseplate and causes flashback to occur earlier at higher velocities. This extension of the CRZ is complex, being governed by swirl number, equivalence ratio and Reynolds Number. Under these conditions flashback occurs when the cylindrical flame front surrounding the CRZ rapidly accelerates outwards to the tangential inlets and beyond, especially with hydrogen containing fuel mixes. Conversely at lower swirl numbers with a modified exhaust geometry, hence restricted CRZ, flashback occurs through the outer thin boundary layer at much lower flow rates when the hydrogen content of the fuel mix does not exceed 30%. The work demonstrates that it is possible to run premixed swirl burners with a wide range of hydrogen fuel blends so as to substantially minimise flashback behaviour, thus permitting wider used of the technology to reduce NOx emissions. 相似文献
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采用旋流拱顶燃烧器的W型锅炉炉内流动特性 总被引:1,自引:0,他引:1
采用旋流燃烧器,可以强化燃烧器出口煤粉气流的着火,配合采用燃烧器内部分级燃烧方式后,也有利于降低污染气体的排放。但采用旋流燃烧器后,由于W型锅炉燃烧的特殊性,给锅炉的设计和运行带来了新的情况,如对旋流燃烧器在W型锅炉拱顶采用旋流燃烧器后炉内的空气动力特性不能很好得到掌握,不但得不到旋流燃烧器所带来的优点,还会引起很多问题。本文对采用旋流燃烧器的W型锅炉的炉内多相流动特性进行分析,并与相应的采用直流燃烧器的W型锅炉进行对比,指出在采用直流燃烧器的W型锅炉设计中常采用的参数在采用旋流燃烧器时可能会出现的问题,并提出了改进的方法。 相似文献