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在煤粉锅炉运行中,煤粉混合器的堵塞及气流不畅,一直困扰着锅炉的安全经济运行。本文叙述了利用管路低压、炉膛高负压的方法对煤粉混顺进行节能改造设计 。 相似文献
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基于气、固两相流理论,考虑了风煤合流过程中的压力损失影响,运用能量法提出了一种测量一次风管中风-粉混合后煤粉浓度的方法,并且介绍了对一次风管中煤粉浓度,风速实现在线、实时监测的过程和方法。实验证明,在应用此系统后,煤粉浓度的在线监测与控制有利于煤粉充分燃烧,并取得了很好的节能效果。 相似文献
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实践经验表明,实现高浓度煤粉燃烧不仅对低挥发份煤种的稳燃、降低飞灰可燃物、防止结焦卓有成效,还可以成倍降低氮氧化合物的含量,保护人类生存的环境。按照组织煤粉燃烧的基本原则和湍流混合的基本原理,对煤粉气流着火存在最佳煤粉浓度进行了分析,研究了不同煤种一次风温与煤粉浓度之间的关系,为提高煤粉燃烧的工程设计和应用提供了必要的实践依据。 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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煤粉气流着火稳定性的最佳煤粉浓度分析 总被引:1,自引:0,他引:1
本文按照组织煤粉燃烧的基本原则和湍流混合的基本原理 ,对煤粉气流着火存在最佳煤粉浓度进行了分析 ,研究了不同煤种一次风温与煤粉浓度之间的关系 ,得到了三种煤种在四种一次风温下对应的最佳煤粉浓度值 ,为提高煤粉燃烧的工程设计和应用提供了必要的实践依据。 相似文献
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The paper provides an overview of current studies on the behaviour of coal during devolatilization, especially the experimental studies and modelling efforts on the formation of char structure of bituminous coals in the open literature. Coal is the most abundant fossil fuel in the world. It dominates the energy supply in the future and plays an increasing role particularly in the developing countries. Coal utilization processes such as combustion or gasification generally involve several steps: i.e., the devolatilization of organic materials, homogeneous reactions of volatile matter with the reactant gases and heterogeneous reactions of chars with the reactant gases. The devolatilization process exerts its influence throughout the life of the solid particles from the injection to the burnout, therefore is the most important step which needs to be understood. When volatile matter is generated, the physical structure of a char changes significantly during the devolatilization, some accompanying a particle's swelling. The complexity of a char's structure lies in the facts that the structure of a char itself is highly heterogenous inside an individual particle and between different particles and the chemistry of a char is strongly dependent on the raw coal properties. A char's structure is strongly dependent on the heating conditions such as temperature, heating rate and pressure. Understanding the swelling of coal and the formation of char's pore structure during the devolatilization of pulverized coal is essential to the development of advanced coal utilization technologies. During combustion and gasification of pulverized coal, the behaviour of individual particles differs markedly due to the variation of their maceral composition. Particles with different maceral constituents generate different types of char structure. The structure of a char has a significant impact on its subsequent heterogeneous reactions and ash formation. The review also covers the most recent studies carried out by the authors, including the experimental observations of the thermoplastic behaviour of individual coal particles from the density fractions using a single-particle reactor, the experimental analysis on chars prepared in a drop tube furnace using the density-separated coal samples, the development of a mathematical model for the formation of char's pore structure based on a simplified multi-bubble mechanism and the investigation on the effect of pressure on char formation in a pressurized entrained-flow reactor. 相似文献
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The production rates of furnace bottom ash in a pulverized coal-fired power plant were monitored for a two-year period and its variations with respect to coal properties were analyzed. The power plant was originally designed to fire the coal sludge generated from a washing process; however, the coal sludge and its mixture with low-rank bituminous coal have been started to be used as the main fuel with time. The results of the hardgrove grindability measurements have shown that the grinding properties of sludge or its mixtures could not be predicted based on proximate analysis (moisture, ash, carbon and volatile contents); it could only be determined by experiments. The production rate of bottom ash in this particular power plant remained relatively insensitive to the high ash and moisture contents and could be estimated almost only by knowing the calorific value of the source coal. The evaluated dependency was linear. 相似文献
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蔗糠燃料特性与煤粉混烧技术的研究 总被引:3,自引:0,他引:3
由实验得到了蔗糠的工业分析及其热解失重特性,并由此分析了蔗糠与煤粉混烧时应注意的问题。同时考虑了蔗糠与煤粉混烧的实例,由此对粉末状生物质在煤粉炉中的强化燃烧进行了探讨。 相似文献
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锅炉低NOx排放煤粉分级燃烧的优化 总被引:1,自引:0,他引:1
燃料分级燃烧是目前广泛采用的降低NOx排放的有效方法之一。本文通过数值计算对优化煤粉分级燃烧进行了研究,以保证锅炉NOx低水平的排放,并确定了煤粉4级燃烧的组织原则。 相似文献