共查询到19条相似文献,搜索用时 390 毫秒
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实际工程表明,采用飞灰复燃技术对锅炉进行改造,可以减少飞灰所带走的燃料损失,提高锅炉效率,但飞灰回收复燃给壁面颗粒沉积状况也带来了影响.采用FLUENT模拟了SZL15-1.25-AⅡ型双筒链条蒸汽锅炉炉内燃烧,对比分析了采用飞灰复燃技术前后炉内壁面颗粒沉积状况.模拟结果表明,飞灰复燃对锅炉顶墙、前墙及后墙的颗粒沉积速率影响较大,其中飞灰复燃提高了顶墙和前墙的颗粒沉积速率,降低了后墙颗粒沉积速率,而对锅炉前后拱的影响很小可以忽略.减小飞灰入射质量流量或调整飞灰入射角度为水平偏下,均可以降低颗粒在水冷壁的沉积速率,有利于炉膛与水冷壁间的传热. 相似文献
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《动力工程学报》2016,(12):945-950
当炉内燃烧温度为950℃、1 150℃和1 350℃时,改变炉膛出口氧体积分数,分别设置为2.0%~2.5%、4.0%~4.5%和6.5%~7.0%,在准东煤沾污结焦实验台上进行实验,并收集沾污段的飞灰进行可燃物化验、电子扫描电镜扫描和X射线荧光光谱仪检验等分析.结果表明:炉内燃烧温度升高会使煤粉表面烧结性更强,阻碍了氧气向煤粉内部的扩散,导致飞灰可燃物质量分数增大;钠元素在950~1 150℃存在某种形式的快速释放,而钾元素则不会;炉内燃烧温度越低,煤灰熔融温度越低,结渣性越强,但这不是引起炉内沾污积灰的主要原因;炉膛出口氧体积分数的变化对飞灰成分和碱金属析出的影响较小. 相似文献
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建立了与气固两相流动燃烧模型相耦合的飞灰沉积模型,对一台660 MW超临界锅炉燃用准东五彩湾煤时的飞灰沉积特性进行了数值模拟,并且讨论了烟气流速和灰颗粒粒径对飞灰沉积速率的影响规律.结果表明:在BMCR工况下,炉膛辐射受热面上的飞灰颗粒沉积分布主要集中在高度为30~45 m处的区域,且各墙的沉积分布规律呈现出相似性;烟气流速为9.5~12.5 m/s时,辐射受热面上的飞灰沉积速率与烟气流速成正比;烟气流速大于12.5 m/s时,辐射受热面上的飞灰沉积速率与烟气流速成反比;辐射受热面上飞灰颗粒的沉积速率的整体变化趋势是随灰颗粒粒径的增大而增大的. 相似文献
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中小型燃煤锅炉,特别是链条炉,尾部受热面易产生积灰,由于煤质及锅炉运行工况的不同,会对受热面产生污染,堵塞作用,有时又可以产生磨损问题,现提供一种简单、高效率应用在燃煤锅炉尾部受热面的飞灰回收装置。 相似文献
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煤中FeS2和含铁粘土矿物在锅炉结渣过程中的作用 总被引:3,自引:0,他引:3
采用 57Fe Mossbauer谱学方法并辅以 X 射线衍射分析和灰成分分析等方法 ,对取自一台 2 2 0t h锅炉的平朔煤煤粉、飞灰和结渣沉积物中的含铁成分进行了分析、测定 ,以探讨煤中 Fe S2 和含铁粘土矿物在炉内的变化和在结渣形成过程中的作用。通过煤粉和飞灰中不同成分的含铁份额的比较 ,表明在炉内 Fe S2 最终转变成氧化物 ,而含铁粘土矿物最终转变成玻璃体。对内层沉积物成分的研究表明 ,Fe S2 的炉内产物在水冷壁上的选择性沉积是初始结渣形成的主要原因 ,而含铁硅酸盐矿物的产物对初始结渣的贡献极小 ,虽然平朔煤中上述两种成分的含铁份额相差无几。 相似文献
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本文针对稠油热力开发在用23t/h工业注汽锅炉燃烧渣油过程中出现的炉管结渣和积灰严重、导致热效率下降的状况,通过技术调研,根据弱爆炸吹灰原理,经过优化设计,首次在稠油油田注蒸汽锅炉上应用弱爆吹灰技术,确保注汽锅炉的高效运行,有明显的节能效果。 相似文献
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利用热天平实验研究了飞灰碳厦其入炉煤的反应性,从理论上分析了飞灰回燃对CFB锅炉燃烧效率的影响,并通过工业试验测试了回燃飞灰量对锅炉返料器运行温度、飞灰的粒度分布及其含碳量、锅炉燃烧效率及其它运行参数的影响。研究表明,燃烧福建无烟煤CFB锅炉飞灰碳的反应性高于其对应入炉煤。回燃飞灰的含碳量、回燃飞灰量与入炉煤量的比值等参数对锅炉燃烧效率有重要影响。采取飞灰回燃技术有利于降低飞灰含碳、降低返料器运行温度和提高锅炉燃烧效率,但当回燃飞灰量较大时会影响锅炉的稳定运行。 相似文献
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《Progress in Energy and Combustion Science》1998,25(2):117-132
A predictive scheme based on CCSEM flyash data and computational fluid dynamics (CFD) was developed to study the slagging propensity of coals. The model was applied to predict the deposition potential of three UK coals; Bentinck, Daw Mill and Silverdale, in a pilot scale single burner ash deposition test facility. The project is part of a collaborative research programme sponsored by the UK Department of Trade and Industry and involved various industrial organizations and universities. The objective is to understand the fundamental aspects of slagging in pulverized coal-fired combustion systems. The present model predicts the relative slagging propensity of the three coals successfully, and the predicted deposition patterns are also consistent with the observations. The results from the model indicate a preferential deposition of iron during the initial stage of ash deposition. The average compositions of the deposits become closer to that of the bulk ash when the accumulation of ash deposits is taken into account. 相似文献
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《能源学会志》2020,93(6):2399-2408
Phosphorus effect on ash fouling deposition produced during combustion process of sewage sludge solid fuel is a very important factor. Previous studies have only focused on decrease of the ash melting temperature and increase of slagging and sintering by phosphorus content. Therefore, research regarding combustion fouling formation and its effect on temperature reduction of deposit surface by phosphorus content is insufficient. Ash fouling is an important factor, because ash in the combustion boiler process deposits on the surface of heat exchanger and interferes with heat exchange efficiency. In particular, temperature reduction of heat exchanger surface via fouling should be considered together with fouling deposition, because this is related to the heat exchanger efficiency. Synthetic ash, phosphorus vaporization, and drop tube furnace experiments were performed to investigate effect of phosphorus on ash fouling formation and temperature reduction of deposit surface under combustion condition. Phosphorus was highly reactive and reacted with ash minerals to produce mineral phosphate, which promoted ash fouling deposition during the combustion experiments. In contrast, the occurrence of sintering on deposited fouling resulted in formation of a large hollow structure, which alleviated the temperature reduction on the deposit surface. Phosphorus content had a substantial correlation with fouling deposition behavior and influenced reduction in the surface temperature of the heat exchanger, because it led to generating low temperature mineral phases. 相似文献