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研究热风管中不同结构的氧煤枪出口下游冷态两相流场。提出高炉炼铁大功率氧煤燃烧器新型结构。用流场显示,热球风速仪,三孔探针和取样探针给出其中时均速度场、回流区大小、位置及颗粒浓度分布。冷态试验结果表明:大口径同轴射流渐扩式大功率氧煤燃烧器在加强氧煤混合,增长煤粉停留时间,强化枪体冷却。延长使用寿命上会有好的效果。为实现提高大喷煤量气化率的热态试验和结构优选提供了依据。 相似文献
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Reactions of pulverized coal injection (PCI) in a blast furnace were simulated using a drop tube furnace (DTF) to investigate the burnout behavior of a number of coals and coal blends. For the coals with the fuel ratio ranging from 1.36 to 6.22, the experimental results indicated that the burnout increased with decreasing the fuel ratio, except for certain coals departing from the general trend. One of the coals with the fuel ratio of 6.22 has shown its merit in combustion, implying that the blending ratio of the coal in PCI operation can be raised for a higher coke replacement ratio. The experiments also suggested that increasing blast temperature was an efficient countermeasure for promoting the combustibility of the injected coals. Higher fuel burnout could be achieved when the particle size of coal was reduced from 60–100 to 100–200 mesh. However, once the size of the tested coals was in the range of 200 and 325 mesh, the burnout could not be improved further, resulting from the agglomeration of fine particles. Considering coal blend reactions, the blending ratio of coals in PCI may be adjusted by the individual coal burnout rather than by the fuel ratio. 相似文献
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为了准确计算炉内煤粉的燃尽率,从研究煤粉粒子的燃烧机理入手,以炉膛内最复杂的燃烧器区域的煤粉燃烧过程为研究对象,通过合理简化煤粉中挥发分和焦炭的燃烧过程,建立了炉内煤粉燃烧沿高度方向上的一维宏观模型,在模型中考虑了煤粉燃烧过程中氧含量的变化,以单个煤粉颗粒燃烧的等密度模型为基础,通过多种煤粉粒径的燃烧过程反映煤粉燃烧的整体过程,推导出计算炉内煤粉燃尽率的显示公式,满足了实时仿真计算的要求。计算结果与实测数据和现有的文献相符,并对结果进行了分析。 相似文献
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The main aim of rationalizing the energy management of a blast-furnace plant is to save coke. In general practice coke is replaced by injecting cheaper auxiliary fuels (among others hydrocarbon plastic wastes). The paper gives a short account about such attempts carried out so far in some countries. The energy effects of injecting plastic wastes into the blast furnace have been analyzed and compared with the injection of pulverized coal, natural gas and coke-oven gas. 相似文献
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The efficiency of coal combustion is important for the blast furnace process. Incomplete combustion of coal does not reduce coke consumption as can be expected and decreases burden permeability which results in improper gas flow and temperature distribution. Consequently, this reduces the throughput of the blast furnace.
This paper describes combustion conditions and mechanisms of coal combustion in the blast furnace, and discusses factors affecting coal combustion such as injector location, coal type, injection rate, maceral composition, and air blast parameters. Also, mathematical models of coal and coal/coke combustion in the blast furnace are considered. 相似文献
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中心大速差射流浓缩煤粉方法的研究 总被引:3,自引:2,他引:3
本文提出了一种新的煤粉浓缩方法-位于一次风出口处的中心大速差射流方法,并对中心大速差射流的冷态工况进行了实验研究和数值模拟,实验和计算表明,该方法有明显的浓缩煤粉的效果,因此它不仅可以改善煤粉锅炉的燃烧稳定性及降低NOx,而且有可能解决当前煤粉浓缩燃烧技术难以解决的煤粉浓度难以控制,后期混合不好,煤粉管易堵塞和磨损以及引发炉内结焦等一系列问题。 相似文献
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乏气送粉锅炉煤粉浓度软测量技术及其仿真研究 总被引:18,自引:4,他引:14
锅炉燃烧过程中,喷燃器出口煤粉浓度不均将会导致炉膛火焰中心偏斜,从而引起炉膛气流冲刷后墙及右墙,高温过热器,高温再热器出现局部超温,结焦的现象。因此准确测量各风管中的煤粉浓度并指导调节对锅炉的安全,经济运行非常重要,为此,必须寻找一种简单,高效,实用而且适合工程应用的煤粉浓度测量的方法。对于热风送粉锅炉的煤粉浓度测量,国内外做了大量的研究,并得到了工程应用。本文提出了一种乏气送粉方式下基于气固两相流理论,根据风粉混合前后压力差大小计算粉煤浓度的新方法,并在理论推导的基础上进行了仿真研究,结果表明,煤粉浓度计算值与混合压差呈很好的对应, 说明能量法理论计算公式是适用的。 相似文献
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This paper reports the development effort of using coconut shell-based fuel slurries in an oil-fired foundry furnace. Solid fuel fines were dispersed in a liquid medium and the resultant fuel slurry was burnt like a liquid fuel. Light disel oil, furnace oil and water served as the liquid media. The solid fuels burnt were pulverized coal and pulverized coconut shell. The solid fuel was directly mixed with the liquid medium and was burnt in an oil-fired foundry furnace. No chemicals were used for the stabilization of slurries. Pulverized coal was found to settle down and was often blocking the fuel atomizer. But no such problems were encountered when pulverized coconut shell - light diesel oil and pulverized coconut shell-water slurries were burnt. Among the various slurries burnt, the pulverized coconut shell-water slurry was found to be the most appropriate slurry to be used in the oil-fired foundry furnace without any modifications to the existing furnace hardware. Preliminary results are presented. 相似文献
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切圆燃烧锅炉炉膛传热过程综合模型及模拟计算 总被引:2,自引:0,他引:2
本文针对大容量煤粉锅炉的特点,对炉内各过程的数值模拟提出切合实际简化模型,用假想面有效辐射分析法模型计算内辐射传热,应用理想反应器的串并联网络模拟炉内宏观流动-燃烧过程,从而建立了适合于任意形状炉膛的传热计算综合模型,通过对一台670T/H锅炉进行的实例计算,对模型的准确性和实用性进行了初步验证,得到了较满意的结果。 相似文献
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在实验室的卧式煤粉炉中,对中心大速差射流是否能降低NOx排放量进行了实验研究。实验表明:中心大速差射流不仅能明显降低NOX排放量,而且可使煤粉提前着火,从而提高了煤粉燃烧的稳定性。该方法若用于煤粉锅炉的最上一层的燃烧器,则可望在降低NOX排放量的同时不影响锅炉的燃烧效率。 相似文献
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运行参数对锅炉煤粉着火燃烧和飞灰含碳量影响的数值研究 总被引:6,自引:1,他引:6
为了达到锅炉的优化运行以保证煤粉气流及时着火和充分燃尽,采用IPSA两相流动模型和煤粉燃烧综合模型,在不同的一次风率和煤粉细度的工况下,对1台350MW锅炉煤粉燃烧过程进行了数值模拟,得出了炉内燃烧器区域以及出口处烟气温度场和燃烧产物的组分浓度分布。分析了一次风率和煤粉细度对煤粉着火燃烧和飞灰含碳量的影响规律,并确定了优化的运行参数。结果表明:一次风率对煤粉气流的着火影响较大,而对出口处烟气温度、氧量以及飞灰含碳量影响较小。煤粉细度对煤粉气流的着火、燃烧以及燃尽均有较大影响。图8表2参9 相似文献
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单角试验炉煤粉射流着火可视化试验研究 总被引:2,自引:0,他引:2
本文通过一个图像采集与处理系统,将单角试验炉煤粉射流着火火焰锋面从背景中分离出来。将火焰锋面到燃烧器出口的最近距离定义为着火距离,对一种烟煤的试验研究结果表明,随着煤粉浓度的提高,其平均着火距离明显缩短。具有较高稳定性的钝体燃烧器的煤粉射流着火,倾向于在分离射流的外侧首先出现。 相似文献