摘要
选择性非催化还原(SNCR)脱硝技术是燃煤工业锅炉领域重要的脱硝技术之一,目前电站锅炉SNCR脱硝效率普遍偏低,且工业锅炉SNCR应用研究较少。针对一台20 t/h气流床煤粉工业锅炉测量了炉膛温度以及不同喷枪位置和气液压力下炉膛出口的NO_(x)排放浓度,研究了气流床煤粉工业锅炉中SNCR的脱硝性能。结果表明,采用尿素进行脱硝反应的最佳温度窗口为790~850℃,最佳温度窗口位于炉膛中心截面附近,喷枪设置在炉膛侧壁中心优于炉膛顶部,喷枪插入深度和角度对脱硝效率的影响较小,喷枪位于最优位置时,脱硝效率可达87.2%,出口NO_(x)质量浓度为38 mg/m^(3),满足超低排放。喷枪流量随液压升高和气压降低而增大,气压大于液压时,喷枪雾化较好,整个扇面液滴分布较均匀,2.38≤氨氮物质的量比≤3.00时,液压越低,脱硝效率越高,0.30 MPa≤液压≤0.35 MPa,0.29 MPa≤气压≤0.40 MPa时,SNCR脱硝效率较高,且氨逃逸较少。喷枪液滴雾化情况对脱硝效率的影响高于扇面角度。
Selective Non Catalytic Reduction(SNCR)denitrification technology is one of the most important technology for denitration from coal-fired industrial boilers.The NO_(x) removal efficiency of SNCR in the utility boiler is generally low.And few work has been done to study on the SNCR from industrial boilers.In the study,the temperature inside the chamber of the furnace and the NO_(x) emission concentration with different spray gun positions,the hydraulic pressure and the gas pressure were measured for a 20 t/h entrained-flow boiler,and the denitrification performance of SNCR in an entrained flow bed coal powder industrial boiler was studied.The results show that the temperature window of SNCR using urea is range of 790-850℃,which is located around the central region of the furnace.The better NO_(x) removal efficiency can be achieved with the spray gun on the centre of the side wall in comparison with that on the top of the furnace.The depth and angel of the spray gun inside the furnace have less influence on the NO_(x) removal efficiency.When the spray gun is located the best position,the NO_(x) emission concentrion is 38 mg/m^(3) with NO_(x) removal efficiency of 87.2%,satisfying the ultra-low emission standard.The flow rate of the spray gun increases with the increase of the hydraulic pressure or the decrease of the gas pressure.When the hydraulic pressure is larger than the gas pressure,the excellent atomization can be obtained and the small liquid droplet can be uniform distributed like a fan.When the ammonia-nitrogen molar ratio is larger than 2.38 and less than 3.00,the lower the hydraulic pressure is,the higher the denitrification efficiency is.The SNCR denitrification efficiency is higher and ammonia escape is less with hydraulic pressure larger than 0.30 MPa and less than 0.35 MPa,as well as gas pressure greater than 0.29 MPa and lower than 0.40 MPa.The homogeneous droplet size distribution and the uniform spatial distribution have more important impact on the NO_(x) removal efficiency than that of the sector angle.
作者
段璐
崔豫泓
孟长方
李慧
张朝
DUAN Lu;CUI Yuhong;MENG Changfang;LI Hui;ZHANG Chao(Beijing Tiandi Rongchuang Technology Co.,Ltd.,Beijing 100013,China)
出处
《洁净煤技术》
CAS
CSCD
北大核心
2023年第6期128-134,共7页
Clean Coal Technology
基金
煤科院节能技术有限公司科技发展基金资助项目(2022JNSJ-01)。
关键词
SNCR
脱硝效率
温度窗口
尿素
氨氮比
煤粉工业锅炉
SNCR
NO_(x)removal efficiency
temperature window
urea
ammonia-nitrogen molar ratio
industrial pulverized coal-fired boiler
