【作者】 李永波；

【导师】 陈刚；

【作者基本信息】 华中科技大学 ， 热能工程， 2009， 硕士

【摘要】 燃煤电站中,如何保证锅炉有较高的热效率一直是各个发电企业共同关心的问题。影响锅炉热效率的主要因素有两个:排烟损失和机械不完全燃烧损失。但是,排烟损失的降低受到尾部受热面传热温差小和烟气露点温度等条件的限制,只能在一定程度上提高锅炉热效率。因此,如何使机械不完全燃烧损失降低成为提高锅炉效率的主要途径。在实际电站运行中,机械不完全燃烧损失的降低就是提高煤粉的燃尽特性。它与锅炉的安全、经济、环保运行密切相关。本文根据广东某电厂来煤的实际情况,实验煤种由煤1、煤2、煤3、煤4四种单煤组成。本文研究目的是确定它们之间有代表性的16个配比以及它们各自四个不同粒径煤样对燃尽特性的影响。本文首先通过常规煤质分析(工业分析、元素分析、热值分析等)对样品进行燃尽特性好坏的初步判断,并利用由煤质分析数据拟合得到的燃尽指数进行初步判定,进而利用热重分析仪进行试验,求出与燃尽特性相关的指数和反应动力学参数活化能。在此基础上,利用煤燃烧国家重点实验室的沉降炉试验台架对样品进一步分析。配比对燃尽特性的影响和粒径对燃尽特性的影响都是通过这种实验方法来研究的。同时,通过建立简化的炭粒燃烧模型求解粒径对燃尽时间的影响。本文采用了多种实验方法及理论分析,最后得出煤1:煤3=3:2时燃尽特性最优,煤2:煤4=1:4时燃尽特性最差,而煤2的燃尽特性对粒径不敏感。更多还原

【Abstract】 How to ensure a higher boiler thermal efficiency in a coal-fired power plant have been issues of common concern. In the power plant operation, there are two main factors impact the boiler thermal efficiency. The one is as the form of smoke heat loss, the other one is as the form of mechanical loss of incomplete combustion. However, to reduce the smoke heat loss is confined by the small temperature difference in the tail heating surface and the flue gas dew-point temperature. In this case, how to reduce the mechanical loss of incomplete combustion is the main way to improve the boiler thermal efficiency. In the power plant operation, the way to improve the thermal efficiency is to improve the burnout characteristics of pulverized coal. It is bound up with the safety、economic & environment protected run of a utility boiler .In this paper, the laboratory samples are from a power plant in Guangdong province, they are Coal 1, Coal 2, Coal 3, Coal 4. The samples of the study consisted of 16 different ratio blended coals and different particle size coals.First of all, we took the conventional analysis with the samples, such as proximate analysis, ultimate analysis, heating value analysis and so on. Furthermore, we took the thermo-gravimetric analysis. From this analysis, we can get some index of burnout characteristic and activation energy for these samples. Then we do some experiment in the drop tube furnace which is a model of a utility boiler in the SKLCC. Meanwhile, we establish a simplified mathematical modeling of empirical formula to get the burnout time of pure carbon.The conclusion of this thesis is that the coal 1 and coal 3 in the ratio of 3:2 is the best, the coal 2 and coal 4 in the ratio of 1:4 is the worst and the coal 2 is not so sensitive to the particle size than others.更多还原