共查询到18条相似文献,搜索用时 187 毫秒
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高燃烧效率、低N0x排放、着火稳定性好和运行安全是设计与布置切圆燃烧系统的首要考虑。基于此,提出了一种改进型切圆燃烧系统——一次风双向切圆布置燃烧系统,并在2台300MW锅炉上进行试验和应用研究。与传统的切圆燃烧系统相比,水平浓淡燃烧器和同层一次风双向切圆布置是该系统的主要改进之处。锅炉试验和运行结果显示:该型燃烧系统在燃用高硫份、高灰份、难着火与燃尽、具有中等结渣程度倾向的煤种时可有效防范炉内结渣和水冷壁高温剧蚀,过热器和再热器运行安全,额定负荷下锅炉固体未完全燃烧热损失小于2%,可实现35%~100%额定负荷范围内不投油稳燃,NOx排放浓度低。该燃烧系统是一种先进的高燃烧效率、低NOx排放和低负荷稳燃能力强的切圆燃烧系统。图4表4参3。 相似文献
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1000MW超超临界锅炉水冷壁壁温计算 总被引:1,自引:0,他引:1
采用分区计算简化大容量高参数超超临界锅炉炉内辐射、对流传热模型,研究炉膛水冷壁热负荷及壁温的空间分布情况,并与试验数据进行了对比,计算结果与试验值之间的偏差较小,最大为5.72%.该模型与算法可给出不同锅炉负荷条件下,水冷壁壁面热负荷与壁温沿炉膛宽度方向的分布规律.结果表明,水冷壁热负荷与壁温均呈现出中间高两端低的弧形分布.四角切圆燃烧锅炉火焰位置对炉内传热有很大影响.模拟计算可为超超临界锅炉的运行提供参考,预测了在材料允许温度范围内,火焰中心偏斜最大不超过2 m. 相似文献
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600 MW偏转二次风系统锅炉炉内结渣特性的数值模拟 总被引:1,自引:1,他引:1
偏转二次风系统已广泛应用于大型四角切圆燃烧锅炉,用以报制炉内结渣,防止水冷壁高温腐蚀等。为降低炉膛出口扭转残余,通常采和下部二次风大角度正切、上部二次风和OFA风反切的布置方式。本文对某台采用偏转二次风系统的600MW燃煤四角切圆燃烧锅炉的炉内结渣过程进行模拟,对炉内气固相流动、温度场、气固相燃烧、固相向水冷的输运过程和灰粒在水冷壁上的附生长过程进行了数值模拟,结果表明,偏转二次风系统具有较强的防结渣性能,这一点也被锅炉的实际运行所证实。 相似文献
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对某电厂600 MW切圆燃烧锅炉进行了O2/CO2气氛下炉内流动、传热和燃烧过程的数值研究。结果表明:在O2/CO2气氛下,随着氧气摩尔浓度的增加,炉内温度升高,高温区变大,对煤粉的着火燃烧有利;但考虑到燃烧器安全和水冷壁结渣,氧气摩尔浓度不能太高,对燃用文中煤质的锅炉其极限摩尔浓度在40%至45%之间。O2/CO2气氛对现有切圆燃烧锅炉的上层燃烧器煤粉的燃烧影响较小,对下层燃烧器煤粉的燃烧影响较大。与空气气氛煤粉燃烧相比,炉内火焰中心上移,且在氧气摩尔浓度不太高时,炉内温度分布特性有利于防止水冷壁的结渣。 相似文献
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四角切圆燃烧锅炉中各角一、二次风风速均衡是提高锅炉燃烧效率 ,防止炉内火焰中心偏移、炉膛结渣的重要因素。但大容量锅炉多采用直吹式制粉系统 ,且送粉管道阻力不均 ,燃烧器数量众多 ,易发生配风不均。采用数值模拟方法对采用同心反切二次风系统的某 3 0 0MW四角切圆燃烧锅炉四角配风不均对炉内多相流动特性进行了多工况模拟。获得了配风不均对炉内切圆中心、颗粒运动轨迹、贴壁风速等的影响。同时就配风不均对采用同心反切二次风系统和不采用二次风反切技术的四角燃烧系统的影响进行了比较 ,结果表明 ,采用同心反切系统的四角燃烧锅炉对配风偏差更为敏感 ,应引起设计和运行人员的注意 相似文献
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目前,燃煤锅炉三维CFD数值模拟中对炉膛水冷壁传热分布的预测大都基于给定的壁面温度边界条件。然而,此方法无法体现锅炉运行状态对壁面传热与壁温分布的影响。提出了一种基于锅炉烟气侧放热与汽水侧吸热间热平衡关系的壁面传热计算方法,并重点讨论了壁面传热系数的物理意义及取值方法。研究发现,壁面传热系数基本由壁面结渣状态决定,因此可根据壁面渣层的传热系数确定。本文方法将影响壁面传热的关键因素合理地体现在计算过程中,同时在模型复杂性与工程适用性之间保持了合理的平衡。采用此方法对一台320 MW锅炉的燃烧与传热分布进行了数值模拟,水冷壁吸热量的预测结果与锅炉运行数据吻合良好。 相似文献
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在1台670t/h电站锅炉上安装了1套三维温度场可视化监测系统,该系统由炉膛火焰图像探测器、视频分割器及工控机等组成。通过对炉膛火焰辐射图像的处理,采用正则化方法实现了炉膛内三维温度场(沿锅炉高度方向划分为12层横截面)的在线监测。检测结果表明,由于该锅炉掺烧高炉煤气。在沿炉膛高度方向上形成了两个燃烧高温区;炉内平均温度与机组负荷和主汽压力的相关性较好;通过对一次锅炉灭火事件的分析,表明该系统在燃烧诊断方面具有重要作用。 相似文献
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Numerical simulations of gas–solid flows, heat transfer and gas–particle turbulent combustion have been conducted for a three‐dimensional, W‐shaped boiler furnace. The gas–particle flow, distributions of temperature and concentrations of gaseous constituents, distributions of the rates of heat release, burnout rates of coal particles, and formations of volatiles have been predicted. The results indicate that a steady high‐temperature zone is formed under the arch of the W‐shaped flame boiler, this zone would be of benefit to the ignition and carbon burn‐out and suggest that the W‐shaped flame boiler is suitable for burning low‐quality coals and can operate well under different operating conditions for full and partial loads. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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To investigate the aerodynamic field, cold airflow experiments were conducted under different boiler loads in a cold small-scale model of a down-fired pulverized-coal 300 MWe utility boiler. At 300 MWe and 250 MWe loads, a deflected flow field appeared in the lower furnace. In contrast, at a 150 MWe load, a U-shaped flow field appeared in regions near the left- and right-side walls in the lower furnace. Concurrently, the regions near the two wing walls adjacent to the front arch had received deflected upward airflow emanating from the region near the rear wall. Moreover, a symmetric W-shaped flow field appeared in the central regions below the front and rear arches.Industrial-sized experiments on the full-scale furnace were also performed at different loads with measurements taken of gas temperatures in the burner region and near the right-side wall, as well as heat fluxes and gas components in the near-wall region. Asymmetric combustion appeared at 300 MWe and 250 MWe loads, with large differences arising in gas temperatures, gas components, and heat fluxes between zones near the front and rear walls. At 150 MWe load, gas temperatures, gas components and heat fluxes are, in general, symmetrically distributed throughout the furnace. By decreasing the load, differences in gas temperatures, gas components, and heat fluxes near the front and rear walls decrease, as did NOx emissions. Meanwhile, the carbon content in fly ash essentially decreased, yielding an increase in boiler efficiency assisted by a drop in exhaust gas temperature. 相似文献