【作者】 李金平； 王启民； 李红； 吕俊复； 张海； 刘青； 岳光溪；

【Author】 Li Jinping1,Wang Qimin1, Li Hong2, Lu Junfu1, Zhang Hai1, Liu Qing1, Yue Guangxi1 (1.Department of Thermal Engineering, Tsinghua University, Beijing 100084) (2. Hongguang Grate Plant, Harbin City, 150050)

【机构】 清华大学热能工程系； 红光炉排厂；

【摘要】 随着煤粉燃烧产物――氮氧化物NOX环境污染危害性的被广泛认识,人们越来越关心其排放问题,特别是火电厂煤粉炉的NOX排放问题,本文以NO为例,分析了不同煤种煤粉燃烧时NOX的主要生成途径。根据低挥发份煤粉的结构特性,作者认为低挥发份煤粉燃烧过程中,NO主要集中在焦炭燃烧过程中形成。利用快速热解挥发份产量较高、改善了热解之后焦炭的物理结构的特点,充分利用瞬时释放的挥发份较多及其对焦炭燃烧产生NO的还原作用,是减小低挥发份煤粉燃烧NO排放高的有效措施。为此作者提出用‘煤粉偏富燃料预热燃烧、空气分级长宽火焰’的燃烧方法来实现低挥发份煤粉快速热解,使一次风煤粉气流在着火点之前利用炉膛高温烟气气流快速预热达到较高的温度,使较多的挥发份瞬时释放并在着火点后焦炭的燃烧中还原其燃烧生成的NO,实现低NO排放的高效燃烧。实践表明,在一次风温为130oC燃用干燥无灰基为5.4%、N含量大于2%的无烟煤时,其低负荷稳燃能力为47%以下,而NO排放可以控制在260mg/Nm3(6%O2)以下,完全满足严格的NOX环保排放要求。更多还原

【Abstract】 People have paid more attention on NOx discharge, especially on the power plant’s pulverized coal combustion when they have fully realized the atmosphere pollution of NOx. Taking example of NO in this paper, the formation path of NOX is discussed for different kinds of coal. Based on the structure characteristics, the authors believe that NO are mainly formatted during the char combustion in low volatile matter content pulverized coal (LMC), which is quit different from the traditional opinion that it is mainly during volatile matter combustion. And rapid pyrolysis of LMC could increase the volatile matter yield and enlarge the hole structure of char, which will reduce the NO formed during char combustion. This is the effective way for low NO combustion of LMC. Thus a pulverized coal particles slanting richened and pre-heat combustion manner is suggested for LMC combustion, where the coal particle is rapidly heating and the primary air reaches the high temperature before entering the furnace, which decreases the NO emission as well as the flame stability load rate. Now this has been confirmed by practices. Burning anthracite coal with 5.4% volatile matter as dry and ash free base, N bigger than 2% and the primary air temperature of 130oC, the load reaches 45% with stable flame and the NOX emission is less than 260mg/Nm3(6%O2).更多还原