摘要
热天平(TGA)是最常用的研究煤粉炉内燃烧特性的设备,但由于设备本身需要逐步升温的局限性,不能得到特定温度下煤粉的燃烧动力学。利用自制恒温热重实验台,对几种典型煤种进行恒定高温情况下的燃烧失重实验,研究了温度、煤种等因素对煤粉燃烧特性的影响。结果表明:煤粉突然置于恒定高温条件下燃烧,随温度的升高,失重速率逐渐增大,燃尽时间缩短,同时失重速率峰值升高,而且后移,使反应初期更多的挥发分析出,燃烧更加剧烈。提高温度可以改善煤粉着火与燃尽特性。煤种的煤化程度越低,挥发分含量越高,燃烧初期速率高,着火特性越好。挥发分析出燃烧和焦炭的燃烧存在时间上的重叠。利用一维均相反应模型模拟计算恒定高温下的煤粉燃烧过程,判定系数高达0.96,结果较精确,可为实际锅炉设计与运行提供一定的参考价值。
Thermogravimetric analyzer is the most common equipment to investigate characteristics of pulverized- coal furnace. Because of limitations of gradually heating, TGA cannot get combustion dynamics at particular tem- perature. The effects of temperature and coal types on the combustion characteristics of pulverized coal at constant high temperature were investigated using a customized thermogravimetrie analysis system. The results showed that with the increase of temperature, the coal combustion speeded up and the burnout time of coal reduced, when coal was suddenly injected into the furnace. At the same time, the rate of weight loss would rise and backward, indica- ting that more volatiles released at the initial stage of combustion. It also demonstrates that the characteristics of ig- nition and burnout would be greatly improved by increasing temperature. The volatile contents and the combustion rate at the initial stage were higher for lower quality coal, which means the characteristics of ignition were improved. And the combustion process of volatile and char overlaps. In addition, one-dimensional homogeneous reaction model was used to simulate the combustion process of coal at constant high temperature. The results show that the determination coefficient was more than 0. 96 and the simulated profiles and experimental profiles could be fitted well, which could provide certain reference values for boiler design and operation.
出处
《电力科学与工程》
2015年第9期1-6,共6页
Electric Power Science and Engineering
基金
河北省自然科学基金(E2013502292)
关键词
高温
煤粉
燃烧特性
动力学模型
high temperature
pulverized coal
combustion characteristics
dynamic model
