低挥发分煤高效低NOx燃烧试验及模拟研究-热能工程专业论文.docxVIP

华中科技 大学硕士 学 华 中 科 技 大 学 硕 士 学 位 论 文 II II Abstract Energy and environment are very important topics for human’s development, especially for China—a country with great coal resource. Currently, practical applications suffer commonly from the problems of low combustion efficiency, the excess emission of pollutants, especially NOx. The combustion of the pulverized coal in utility boiler is a complex physical and chemical process. In order to achieve its efficient and clean combustion especially low NOx emission, it bases on having fully grasped the coal combustion characteristics, the appropriate methods of combustion. Following this line of thought, the researches about the efficient and low NOx combustion technologies of low-volatile coal are conducted on these aspects of the combustion characteristics of pulverized coal, the combustion experiments and numerical simulation of deep air staging, including the attempt to simulate secondary air system of W-shape boiler, with view to obtaining the valuable research results for industrial applications. By using TGA, the coal fineness influence on the physical and chemical characteristics of pulverized coal combustion is researched with generally considering the characteristics of ignition, burn-out, pyrolysis, void and so on. The results show that the refining of pulverized coal could improve its combustion characteristics and is propitious to enhance the combustion efficiency and restrain NOx emission. It is an effective approach to efficient and low NOx for the combustion of low-volatile coal, which offers solid theoretical basis. Based on the study on the coal fineness, one kind of lean coal is chose for combustion experiment of air staging with different coal fineness. In the experiment, the influence law of NOx emission and Cfh is also studied by CFD. The results show that deep air staging combustion could decrease the level of NOx emission significantly, and combined with the refining of pulverized coal it could also