【作者】 徐璋；

【导师】 岑可法； 池作和；

【作者基本信息】 浙江大学 ， 工程热物理， 2003， 博士

【摘要】 污染物NOx的排放日益严重地影响着环境、气候和人类的健康，成为一个迫切需要解决的问题。火电厂燃煤产生的NOx是排放的主要来源。为了解决电站锅炉排放的NOx对环境的污染问题，许多控制NOx的技术应运而生。其中燃料再燃是一种很有效的方法。本文针对燃料再燃的脱氮效果、煤粉燃烬等关键问题，提出了超细煤粉再燃降低NOx排放的技术，并对此进行了一系列探索性的研究。 本文首先对超细煤粉的物理、燃烧特性进行了试验研究，通过煤粉细度的测定、孔隙结构的分析以及热重分析等试验，得到了煤粉粒径变化后煤粉特性的变化趋势，为超细煤粉再燃降低NOx排放的试验研究奠定理论基础。 本文经过大量的调研和仔细的设计、完善，建成了具有空气分级、燃料再燃等多种用途的一维热态试验系统。该系统为半工业性试验台，所取得的数据对实际工程具有指导意义。试验炉内温度可控制，可以模拟煤粉炉内NOx的生成和还原过程，为超细粉再燃的研究提供了试验基础。 利用上述的一维热态试验系统，本文进行了试验炉NOx排放特性和煤粉燃烬性能的研究。通过大量的试验，得出了煤种、煤粉细度、炉膛温度和过量空气系数等因素对NOx排放和煤粉燃烬率的影响趋势；并在此基础上研究了超细粉再燃对脱氮效果和燃烬性能的作用，试验结果表明超细煤粉再燃对降低NOx排放和飞灰含碳量具有明显的效果。 本文通过建立数学模型，对超细煤粉再燃降低NOx排放进行了数值模拟，研究了各因素对再燃效果的影响以及再燃过程中NOx浓度的沿程变化，丰富了试验结果，完善了试验过程无法得到的整体分布，为超细粉降低NOx排放的研究开拓了思路。 本文通过对镇海电厂670t/h锅炉机组的研究分析以及现场试验，提出了实现超细粉再燃的初步方案，为超细煤粉再燃的工业应用打下了基础。 本文利用半工业型的试验台架，并结合数值模拟对超细粉再燃进行了系统的研究，得出的结论为工程实际应用提供了参考和指导。更多还原

【Abstract】 Pollutant NOx emission is an increasing threat to environment and human health, which becomes an urgent problem to be solved. Coal combustion in power plant is a major source of NOx. Many control methods have emerged as the times require for solving the NOx emission problem. One of these is fuel reburning. In this paper, micronized coal powder reburning technology is brought forward and a series of exploring research work is carried out aiming at the key issues of fuel reburning such as NOx reduction efficiency and burnout rate.First research on physics and combustion characteristic of micronized coal is processed in this paper. The results of the change tendency of pulverized coal character with particle diameter are got from particle diameter determining test, hole structure analysis test and TG analysis test, which provide theory element for NOx reduction research with micronized coal reburning.After a lot of survey and careful design work, a one-dimensional test system with multi-function such as air stage and fuel reburning is built up. This system is a semi-industrial facility and can get instructive results for engineering utility. The temperature is controllable and resultant and reductive process of NOx can be simulated in furnace, which provide test element for NOx reduction research with micronized coal reburning.Using this system, research on NOx emission and burnout characters of the test facility are carried out. The results of influence on NOx emission and carbon in fly ash by coal type, coal particle diameter, furnace temperature and excess air are reached through tests. Then micronized coal reburning tests are processed, which show a remarkable effect results on NOx reduction and burnout rate.In this paper, the numerical simulations of micronized coal reburning are conducted. The influence on reburning efficiency by above-mentioned factors and NOx concentration along the furnace are studied. This simulation enriches the test results and gives out the global distribution of furnace temperature, NOx and other components, which provides a new way for the research work on NOx reduction by micronized coal reburning.In this paper, a primary scheme for micronized coal reburning is brought forward from equipment analysis and local test of a 670t/h boiler in Zhenhai Power Plant. The industrial experiments provide valuable experience for the application of the new technology.In a word, researches on micronized coal reburning are carried out with test studies at semi-industrial facility and numerical simulation in this paper. The results provide a useful reference and instruction for industrial utility.更多还原