污泥再燃脱硝特性试验研究
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摘要
为分析再燃区温度、污泥含水率、过量空气系数和停留时间对污泥再燃脱硝特性的影响,对污泥再燃脱硝特性进行试验研究。采用配气法模拟流化床锅炉燃烧产生的烟气,使用污泥颗粒作为再燃燃料,通过立式管式炉进行再燃试验。结果表明:在再燃区温度为850～950℃时,随着再燃区温度升高,NO和N_2O的还原率均升高;水分对NO和N_2O的还原机理影响不同,含水率为10%～15%时,NO_x的还原率较高;在过量空气系数为0. 7～1. 0时,随过量空气系数升高,NO和N_2O的还原率减小;在停留时间为0. 45～0. 7 s时,随停留时间增大,NO和N_2O的还原率增大。
Sludge reburning and denitration characteristics are investigated in this paper. This investigation mainly aims at studying the influence of factors such as reburning zone temperature,sludge moisture content,excess air coefficient and residence time on the sludge reburning denitration. Gas distribution method is adopted to simulate the flue gas from fluidized bed boiler. Sludge particles are used as reburning fuel. The reburning test is conducted in a vertical tube furnace. The experimental results show with the increasing of the reburning zone temperature from 850 ℃ to 950 ℃,the NO and N_2O reduction rates are both improved. The effect of moisture on the reduction mechanism of NO and N_2O is different. When the water content is between 10% and 15%,the reduction rate of NOxis higher. Within the range of excess air coefficient 0. 7 to 1. 0,the NO and N_2O reduction rates decrease with the excess air coefficient. NO and N_2O reduction rates increase with the residence time from 0. 45 s to 0. 7s.
Sludge reburning and denitration characteristics are investigated in this paper. This investigation mainly aims at studying the influence of factors such as reburning zone temperature,sludge moisture content,excess air coefficient and residence time on the sludge reburning denitration. Gas distribution method is adopted to simulate the flue gas from fluidized bed boiler. Sludge particles are used as reburning fuel. The reburning test is conducted in a vertical tube furnace. The experimental results show with the increasing of the reburning zone temperature from 850 ℃ to 950 ℃,the NO and N_2O reduction rates are both improved. The effect of moisture on the reduction mechanism of NO and N_2O is different. When the water content is between 10% and 15%,the reduction rate of NOxis higher. Within the range of excess air coefficient 0. 7 to 1. 0,the NO and N_2O reduction rates decrease with the excess air coefficient. NO and N_2O reduction rates increase with the residence time from 0. 45 s to 0. 7s.
引文
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[14]苏胜,宁星,李亮国,等.再燃条件下生物燃料及其焦还原NO特性研究[J].太阳能学报,2013,34(3):388-394.SU Sheng,NING Xing,LI Liang-guo,et al.Study on characteristics of NO reduction by biofuels and biochars under reburning conditions[J].Acta Energiae Solaris Sinica,2013,34(3):388-394.
[2]杨冬,徐鸿,陈海平.燃煤循环流化床锅炉N2O排放影响因素分析[J].洁净煤技术,2010,16(1):63-67,102.YANG Dong,XU Hong,CHEN Hai-ping.Analysis of influence factors of N2O emission of coal-circulating fluidized bed boiler[J].Clean Coal Technology,2010,16(1):63-67,102.
[3]MAHMOUDI S,BAEYENS J,SEVILLE J P K.NOxformation and selective non-catalytic reduction(SNCR)in a fluidized bed combustor of biomass[J].Biomass and Bioenergy,2010,34(6),1393-1409.
[4]SHIM S H,JEONG S H,LEE S.Reduction in nitrogen oxides emissions by MILD combustion of dried sludge[J].Renewable Energy,2014,65:29-35.
[5]王志强,田华,邹金生.干化污泥再燃降低NOx排放技术的应用分析[J].电站系统工程,2010,26(4):30-32.WANG Zhi-qiang,TIAN Hua,ZOU Jin-sheng.The application of dry sludge reburning to reduce NOxemission technology[J].Power System Engineering,2010,26(4):30-32.
[6]文军,王春昌,王月明,等.采用再燃技术降低锅炉NOx排放的工程实践[J].中国电力,2005(10):68-71.WEN Jun,WANG Chun-chang,WANG Yue-ming,et al.Research and application of reburning technology to reduce NOxemission of coal-fired boiler[J].Electric Power,2005(10):68-71.
[7]金晶.超细煤粉分级燃烧NOx还原过程的研究[D].上海:上海理工大学,2005.JIN Jing.The study on superfine pulverized coal reburning for NOx reduction[D].Shanghai:University of Shanghai for Science and Technology,2005.
[8]GULYRTLU I,ESPARTEIRO H,CABRITA I.N2O formation during fluidized bed coal combustion of chars[J].Fuel,1994,73(7):1098-1102.
[9]JOHNSON.Formation and reduction of nitrogen oxide in fluidized bed combustion[J].Fuel,1994,90:1398-1415.
[10]徐向乾.生物质掺煤混烧氮析出规律及再燃脱硝特性试验研究[D].济南:山东大学,2008.XU Xiang-qian.Experimental study on the regularity of nitrogen precipitation and the characteristics of reburning denitration of biomass mixed with coal[D].Jinan:Shandong University,2008.
[11]苟湘.直流煤粉低NOx燃烧和再燃技术的实验、理论与数值模拟研究[D].杭州:浙江大学,2007.GOU Xiang.Experimental,theoretical and numerical simulation research on direct flow pulverized coal low NOxcombustion and reburning technology[D].Hangzhou:Zhejiang University,2007.
[12]侯祥松.循环流化床锅炉NO和N2O脱除的实验研究[D].北京:清华大学,2007.HOU Xiang-song.Experimental study on NO and N2O removal in CFB boiler[D].Beijing:Tsinghua University,2007.
[13]胡笑颖.生物质气再燃脱除燃煤流化床烟气中N2O的机理研究[D].北京:华北电力大学,2011.HU Xiao-ying.Mechanism of N2O emission reduction with biomass gas reburning in a coal fired fluidized bed[D].Beijing:North China Electric Power University,2011.
[14]苏胜,宁星,李亮国,等.再燃条件下生物燃料及其焦还原NO特性研究[J].太阳能学报,2013,34(3):388-394.SU Sheng,NING Xing,LI Liang-guo,et al.Study on characteristics of NO reduction by biofuels and biochars under reburning conditions[J].Acta Energiae Solaris Sinica,2013,34(3):388-394.