摘要
加快推进燃煤工业锅炉环保改造,有效降低煤粉工业锅炉大气污染物排放量,特别是降低NO x排放迫在眉睫。空气分级燃烧技术是一种减排效果显著,改造成本较低的低氮燃烧技术,已在电站锅炉得到成功应用。为考察空气分级燃烧技术在煤粉工业锅炉上应用效果,以煤科院某58 MW煤粉工业锅炉空气分级改造项目为研究对象,通过在侧墙上布置6个火上风喷口,实现空气分级燃烧。通过工程试验,采用特制水冷取样枪以及耐高温烟气分析仪,测量了该锅炉原工况(不采用火上风)与分级燃烧(采用火上风)工况下,炉内3个不同截面(每个截面10个取样点)以及双锥燃烧器内6个测点处烟气温度及烟气组分。结果表明,分级燃烧工况下,双锥燃烧器内在x=0.3 m测点后形成了高温、强还原性气氛,有效抑制了燃烧初始阶段NO x的生成。这是因为分级工况下双锥燃烧器内氧气被迅速消耗,焦炭燃烧反应速率显著下降,焦炭气化反应明显增强,故形成了较强的还原性,有效遏制了NO x的生成。炉内不同截面烟气温度及组成变化规律表明,原工况烟气温度分布整体呈现燃烧器射流中心高、外侧低的趋势,氧含量分布与温度分布趋势相反,而分级工况受双锥燃烧强还原性高速火焰以及火上风喷射的影响,截面温度波动较大,中间截面呈现燃烧器射流中心偏低的现象。分级工况在炉内形成明显的还原区,且表现为燃烧器射流中心CO浓度高、外侧低的现象,有效降低了炉内NO x生成。58 MW煤粉工业锅炉火上风空气分级低氮改造,在双锥燃烧器及炉内创造了合理的贫氧还原区,具有良好的低氮效果。
It is urgent to speed up the environmental protection transformation of coal-fired industrial boilers and effectively reduce the emission of air pollutants,especially the emission of nitrogen oxides.Air staged combustion technology is a low nitrogen combustion technology with significant emission reduction effect and low transformation cost,which has been successfully applied in a large number of utility boilers.In order to investigate the application effect of air staged combustion technology in pulverized coal industrial boiler,a 58 MW pulverized coal industrial boiler air staged transformation project of Coal Research Institute was studied and six nozzles were arranged on the side wall to realize air staged combustion.Through engineering test,the flue gas temperature and flue gas composition at three different sections(10 sampling points for each section)and six measuring points in the double cone burnerwere measured by using special water-cooled sampling gun and high temperature resistant flue gas analyzer under the original working condition and staged combustion working condition.The results show that a high temperature and strong reducing atmosphere is formed after x=0.3 m measuring point in the burner under the condition of air-staged combustion,which effectively inhibits the formation of NO x in the initial stage of combustion.This is because the oxygen in the burner is consumed rapidly under the air-staged condition,the combustion reaction rate of char is significantly reduced,the gasifications are significantly enhanced,and a strong reducibility is formed which effectively curbs the generation of NOx.The variation law of flue gas temperature and composition in different sections of the furnace shows that the temperature distribution of flue gas in the original working condition is generally high in the center and low in the outside,and the distribution trend of oxygen content is just opposite to that of temperature distribution.However,the air-staged combustion is affected by the strong reductive high-speed flame of burner and the air injection on the fire,the section temperature fluctuates greatly,and the jet center of the burner is lower in the middle section in the middle section.In the air-staged combustion,there is an obvious reduction zone in the furnace,which is characterized by high CO concentration in the center and low CO concentration on the outside,effectively reducing NO x generation in the furnace.The air-staged retrofit of 58 MW pulverized coal industrial boiler has created a reasonable oxygen deficient reduction zone in the burner and furnace,which has a good effect of low nitrogen.
作者
牛芳
NIU Fang(China Coal Research Institute Company of Energy Conservation,Beijing 100013,China;State Key Laboratory of High Efficient Mining and Clean Utilization of Coal Resources,Beijing 100013,China;National Energy Technology&Equipment Laboratory of Coal Utilization and Emission Control,Beijing 100013,China)
出处
《洁净煤技术》
CAS
2020年第4期127-133,共7页
Clean Coal Technology
基金
煤科院节能技术有限公司技术创新项目(11014-zc)。
关键词
空气分级燃烧
煤粉
工业锅炉
热态
air-staged combustion
pulverized coal
industrial boiler
heat state
