摘要
基于带有预燃室的煤粉燃烧系统而开发的深度空气分级低氮燃烧技术,可实现低氮氧化物(NOx)初始排放效果。阐述了中心逆喷强旋流煤粉预燃系统的技术原理以及燃烧系统的配风策略优化,并从分级配风对比未分级配风、三次风比例对NOx的影响、不同配风位置对NOx的影响、炉膛出口氧含量等方面分析7MWth热态燃烧台架实验结果。结果表明,深度空气分级有利于降低NOx初始排放,当三次风配风比例不超过40%时,三次风占比越高,NOx初始排放值越低,最优工况NOx初始排放值约200 mg/Nm^3(@9%O2),配风比超过40%时NOx初始排放有增高趋势;采用炉膛侧墙对冲的三次风配风方式,配风控制精准,混合效果好,炉膛温度分布更均匀,炉膛出口断面氧量分布差异小,延长了煤粉在还原区的停留时间,利于降低NOx初始排放。
Based on the pulverized coal combustion system with pre-combustion chamber,the deep air staged low-nitrogen combustion technology was developed to achieve low NOx initial emissions.The technical principle of the central counter-injection strong swirl pulverized coal pre-combustion system and the optimization of the air distribution strategy of the combustion system were expounded,from aspects such as comparison of graded air distribution and ungraded air distribution,effect of tertiary air ratio on NOx,effect of different air distribution positions on NOx,and furnace outlet oxygen content,the experimental results of 7MWth hot combustion bench were analyzed.The results show that deep air classification is beneficial to reduce the initial NOx emissions.When the proportion of tertiary air distribution does not exceed 40%,the higher the proportion of tertiary air,the lower the initial NOx emission value,the optimal NOx initial emission value is about 200 mg/Nm^3(@9%O2).The initial NOx emission tends to increase when it exceeds 40%;when adopting the three-way air distribution method of side wall of the furnace,the air distribution is controlled accurately,the mixing effect is good,the temperature distribution of the furnace is more uniform,oxygen content of cross section of furnace exit has small distribution difference.Therefore,this air distribution method can prolong the residence time of the coal powder in the reduction zone,it is beneficial to reduce the initial NOx emissions.
作者
张鑫
ZHANG Xin(China Coal Research Institute Company of Energy Conservation,Beijing 100013,China;State Key Laboratory of Coal Mining and Clean Utilization,Beijing 100013,China;National Energy Technology & Equipment Laboratory of Coal Utilization and Emission Control,Beijing 100013,China)
出处
《煤质技术》
2020年第4期25-31,共7页
Coal Quality Technology
基金
中国煤炭科工集团科技创新创业资金专项资助项目(2018-TD-ZD001)。
关键词
煤粉
低氮燃烧
预燃室
深度空气分级
氮氧化物
配风
初始排放值
pulverized coal
low nitrogen combustion
pre-combustion chamber
deep air stage
nitrogen oxides
combustion air distribution
initeal emission value
