共查询到19条相似文献,搜索用时 203 毫秒
1.
本文首次提出一种新型的高效、清洁煤燃烧方法,即粉煤流化床(PCF-FBC)燃烧技术,并在0.3MW的试验台上系统研究了其燃烧特性。该项技术全部燃用煤粉,且同时具有煤粉炉和流化床锅炉的特点。研究结果表明:煤粉能在PCF-FBC中温度为850 ̄880℃的流化床区(FBCZ)稳定着火,释放出57.7% ̄84.2%的挥发份,并完成部分炭及部分挥发份的燃烧(约70%左右);PCF-FBC的炉内最高烟温为11 相似文献
2.
在一座0.3MW热输入的PC-FBC试验台上进行了试验研究,获得了不同操作PC-FB燃烧效率的试验数据,详细讨论了这些参数对PC-FB燃烧效率的影响规律。研究结果表明,粉煤流化床的燃烧效率最高达98%-99%,可与煤粉炉相媲美。本试验研究亦首次,提出,只要燃烧温度、颗粒停留时间、火焰湍流度(3T)及炉内氧浓度、颗粒浓度(2C)合理匹配,就能够实现煤粉的低温度高效燃烧。 相似文献
3.
4.
采用热天平研究煤粉燃烧特性时的零维燃烧模型 总被引:4,自引:2,他引:2
探讨了采用热天平研究煤粉燃烧特性时试样量对试验结果的影响,得到当试样层厚度δm与煤粉粒径dp比δm/dp≤1.3-1.5×10^-4时,煤粉燃烧特性试验结果与试亲量无关,即可认为试样层为内氧浓度分布均匀及反应表面积有交利用率相同。提出了适合于采用热天平研究煤粉特性进的零维煤烧模型。 相似文献
5.
6.
煤粉气流着火存在最佳煤粉浓度的试验研究 总被引:13,自引:0,他引:13
在小型煤粉燃烧试验台上,在冷风(常温)、热风(300℃左右)和各种不同煤粉浓度(0.2-0.3kg煤粉/kg空气)条件下,对5种曲型煤种的煤粉气流着火特性进行了燃烧试验及实测分析,获得了阳佳煤粉浓度与煤质特性和热风温度之间的关系,其结果具有重要的实际意义和一定的参考价值。图2表5参5 相似文献
7.
8.
为了研究分析陕西主要煤种的燃烧特性,采用德国NETZSCH STA-409PC型热重分析仪分析了样品质量、升温速率、粒径对煤粉燃烧特性的影响。实验结果表明,随着粒径的减小,神木烟煤的燃烧性能先增强后变弱,粒径75~90μm左右燃烧特性最好。升温速率、样品质量对煤粉的燃烧特性也有影响。随着升温速率的提高,煤粉的着火温度升高,最大失重速率增大,最大失重速率对应的温度升高;随着质量的增加,煤粉的着火温度略有降低,燃尽温度却逐渐增大,最大失重速率明显增大,放热效应的最大温度点逐渐增大,并且煤粉挥发分燃烧低温放热与固定碳燃烧高温放热有一定的分期。 相似文献
9.
利用热重分析技术对微富氧条件下煤粉的燃烧特性进行了研究,并与富氧条件下煤粉的燃烧特性进行了对比,利用固定床测定了燃煤NO的生成规律,分析了反应气氛和煤种的影响.结果表明:随着氧体积分数增加,微富氧条件下煤粉的燃烧向低温区移动,综合燃烧特性指数S逐渐增大;在相同的氧体积分数下,由于N2和CO2的物性差异,煤粉的微富氧燃烧特性优于富氧燃烧特性,但当氧体积分数升高到40%时,两种气氛的燃烧特性差别不大;反应气氛和煤种均对燃料氮的转化率影响显著;氧体积分数升高或N2的参与会使反应温度上升,影响燃料氮的转化率;煤的挥发分和元素氮的质量分数也会影响燃料氮的转化率. 相似文献
10.
为了研究煤粉燃烧过程中挥发分释放与焦炭燃烧之间存在竞争/协同关系,基于煤粉颗粒物理模型,结合能量守恒与质量守恒方程,在利用随机孔模型处理煤粉燃烧的同时,采用化学反应模型计算挥发分释放与焦炭燃烧过程,联立NO生成与还原模型,并考虑各模型之间的相互耦合作用,建立一个集成多种模型优势的煤粉恒温燃烧数值模型,实现煤粉恒温燃烧过程中NO生成特性的准确预测。结果表明:计算结果与实验结果误差较小,拟合R~2接近于1,相同自由度下,计算F值小于查表F值;多模型耦合预测方法能够有效、准确地预测煤粉恒温燃烧过程中NO的释放特性,且泛化能力强。 相似文献
11.
流化床-煤粉复合燃烧锅炉的炉膛传热计算方法 总被引:2,自引:2,他引:0
针对流化床-煤粉复合燃烧锅炉的特点,在综合考虑流化床、火焰和受热面之间换热的基础上,推导了流化床-煤粉复合燃烧锅炉炉膛传热计算的基本方程,得到了复合燃烧锅炉炉膛传热计算的零维模型半径验法。以某75t/h树皮流化床-煤粉复合燃烧锅炉为例,进行了炉膛传热计算。图1表6参5 相似文献
12.
13.
14.
15.
16.
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
17.
Combustion behavior in air of single particles from three different coal ranks and from sugarcane bagasse 总被引:1,自引:0,他引:1
Yiannis A. Levendis Kulbhushan Joshi Reza Khatami Adel F. Sarofim 《Combustion and Flame》2011,158(3):452-465
Comparative combustion studies were performed on particles of pulverized coal samples from three different ranks: a high-volatile bituminous coal, a sub-bituminous coal, and two lignite coals. The study was augmented to include observations on burning pulverized woody biomass residues, in the form of sugarcane bagasse. Fuel particles, in the range of 75–90 μm, were injected in a bench-scale, transparent drop-tube furnace, electrically-heated to 1400 K, where they experienced high-heating rates, ignited and burned. The combustion of individual particles in air was observed with three-color pyrometry and high-speed high-resolution cinematography to obtain temperature–time–size histories. Based on combined observations from these techniques, in conjunction to morphological examinations of particles, a comprehensive understanding of the combustion behaviors of these fuels was developed. Observed differences among the coals have been striking. Upon pyrolysis, the bituminous coal chars experienced the phenomena of softening, melting, swelling and formation of large blowholes through which volatile matter escaped. Combustion of the volatile matter was sooty and very luminous with large co-tails forming in the wake of the particle trajectories. Only after the volatile matter flames extinguished, the char combustion commenced and was also very luminous. In contrast, upon pyrolysis, lignite coals became fragile and experienced extensive fragmentation, immediately followed by ignition of the char fragments (numbering in the order of 10–100, depending on the origin of the lignite coal) spread apart into a relatively large volume. As no separate volatile matter combustion period was evident, it is likely that volatiles burned on the surface of the chars. The combustion of the sub-bituminous coal was also different. Most particles experienced limited fragmentation, upon pyrolysis, to several char fragments, with or without the presence of brief and low-luminosity volatile flames; other particles did not fragment and directly proceeded to char combustion. Finally combustion of bagasse was once again very distinctive. Upon pyrolysis, long-lasting, low-luminosity, nearly-transparent spherical flames formed around slowly-settling devolatilizing particles. They were followed by bright, short-lived combustion of the chars. Both volatiles and chars experienced shrinking core mode of burning. For all fuels, flame and char temperature profiles were deduced from pyrometric data and burnout times were measured. Combustion rates were calculated from luminous carbon disappearance measurements, and were compared with predictions based on published kinetic expressions. 相似文献
18.