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混煤燃烧反应动力学参数的热重研究 总被引:14,自引:1,他引:14
采用热天平,对两种标准煤的混煤燃烧反应动力学参数进行了实验研究。首先对热天平实验的重复性进行了验证,确保获得的实验参数准确、可靠。采取不同的燃烧方式分析动力学参数的变化。非等温燃烧的研究表明,以特征温度区间计算,表观活化能和频率因子均随混煤中烟煤比例的增加而降低。升温速率增加,混煤燃烧的表观活化能有所下降。等温燃烧的研究表明,模型的选择对动力学参数的研究影响很大,通过计算,认为球对称收缩核模型适合于混煤等温燃烧动力学参数的研究。表观活化能的计算结果表明高活性煤种的存在可以很好的改善混煤的着火性能,并且存在最佳掺混比例。图6表5参3 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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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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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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《International Communications in Heat and Mass Transfer》2006,33(3):327-334
The burning characteristics of pulverized coal in blowpipe and tuyere at two different injection patterns are simulated numerically, to aid improving the practical performance of blast furnace. With the condition of the same fuel and oxidant mass flow rates, the predictions indicate that the combustion efficiency of pulverized coal using double-lance can be substantially enhanced compared with that using single lance. Accordingly, the pulverized coal injection in a practical blast furnace was modified from single lance to double-lance. As a result, the practical injection rate of the pulverized coal in the blast furnace was increased from 110 to 153 kg/tHM, revealing that a profound decrease in operating cost of the blast furnace has been implemented. 相似文献
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本文介绍了分离式热管煤气、空气双预热器在上海宝钢4#高炉热风炉上的实际应用情况,通过换热器将煤气和空气预热来提高热风炉风温,从而提高高炉冶炼的经济效益。文章从技术、节能以及经济效益三方面详细分析其优越性。 相似文献
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高岭土与低钠煤可以有效抑制燃用准东煤时炉内的沾污结渣问题,但由于其价格升高,为降低电厂燃煤成本,因此提出将煤灰成分相似的煤矸石作为准东煤防结渣添加剂。分析煤矸石作为添加剂抑制炉内沾污结渣的可行性,根据入炉煤灰中折算Na2O含量低于3.0%,确定掺烧比例,并在某150 MW机组上进行实炉掺烧试验。通过掺烧试验分析可见,煤矸石掺烧比例不宜过大,否则煤粉细度变粗,入炉煤热量降低,影响锅炉带负荷能力;掺烧煤矸石锅炉能够安全稳定运行,并可有效抑制炉内结渣,同时还可节约标煤,为电厂带来一定经济效益。 相似文献
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