高温主燃区还原性氛围下喷氨脱硝的试验研究
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摘要
为研究煤粉燃烧过程中高温主燃区NH_3对NO_x还原效果的影响,采用尿素溶液为氨基还原剂,利用一维管式电加热沉降炉分析了氨剂对NO_x在不同反应条件下的还原特性。实验结果表明:主燃区温度为1 573 K时,在过量空气系数α≤0.95条件下,尿素溶液可有效的将主燃区烟气中NO_x还原为N_2,且脱硝效率都随氨氮比n增大而快速升高,当n>1.75时,脱硝效率升高速度变缓;在还原性氛围中,相同n时,温度越高,脱硝效率越高,且高挥发分烟煤的脱硝效率大于低挥发分无烟煤所对应脱硝效率;试验条件下,神华烟煤的整体脱硝效率最高可达95%;单独喷水可降低NO_x浓度,但与喷氨工况相比,其降低幅度不明显。
In order to study the effect of NH_3 on the NO_x reduction in high temperature main combustion zone during pulverized coal combustion,the NO_x reduction characteristics of ammonia under different reaction conditions were studied by using urea solution as amino reductant and one-dimensional tube electric heating settling furnace.The experimental results showed that when the temperature of the main combustion zone is 1 573 K and the Stoichiometric Ratio α is less than 0.95,the urea solution can effectively reduce NO_x to N_2 in the flue gas of the main combustion zone,and the denitrification efficiency increases rapidly with the increase of the ratio of Nitrgen Stoichiometric Ratio(NSR).With n>1.75,the rate of denitrification increases slowly.In the reduction atmosphere,the higher the temperature,the better the reduction effect of NO_x with the same n.The denitrification efficiency of the high volatile bituminous coal is greater than that of the low volatile anthracite. The overall denitrification efficiency of Shenhua bituminous coal can reach up to 95%,and the concentration of NO_x can be reduced by water injection alone,but it is not evident compared with the ammonia injection condition.
In order to study the effect of NH_3 on the NO_x reduction in high temperature main combustion zone during pulverized coal combustion,the NO_x reduction characteristics of ammonia under different reaction conditions were studied by using urea solution as amino reductant and one-dimensional tube electric heating settling furnace.The experimental results showed that when the temperature of the main combustion zone is 1 573 K and the Stoichiometric Ratio α is less than 0.95,the urea solution can effectively reduce NO_x to N_2 in the flue gas of the main combustion zone,and the denitrification efficiency increases rapidly with the increase of the ratio of Nitrgen Stoichiometric Ratio(NSR).With n>1.75,the rate of denitrification increases slowly.In the reduction atmosphere,the higher the temperature,the better the reduction effect of NO_x with the same n.The denitrification efficiency of the high volatile bituminous coal is greater than that of the low volatile anthracite. The overall denitrification efficiency of Shenhua bituminous coal can reach up to 95%,and the concentration of NO_x can be reduced by water injection alone,but it is not evident compared with the ammonia injection condition.
引文
[1] 徐青,郑章靖,凌长明,等.氮氧化物污染现状和控制措施[J].安徽农业科学,2010,38(29):16388-16391.XU Qing,ZHENG Zhang-jing,LING Chang-ming,et al.Status and control measures of Nitrogen oxide pollution[J].Anhui Agricultural Science.2010,38(29):16388-16391.
[2] GB13223-2011,火电厂大气污染物排放标准[S].GB13223-2011,Emission standard of air pollutants for thermal power plants[S].
[3] HILL S C,SMOOT L D.Modeling of nitrogen oxides formation and destruction in combustion systems[J].Progress in Energy & Combustion Science,2000,26(4):417-458.
[4] ZHANG J,ITO T,OKADA T,et al.Improvement of NOx,formation model for pulverized coal combustion by increasing oxidation rate of HCN[J].Fuel,2013,113(2):697-706.
[5] BECIDAN M,?YVIND S.NOx and N2O precursors (NH3 and HCN) in pyrolysis of biomass residues[J].Energy & Fuels,2007,21(2):1173-1180.
[6] 朱全利.大型锅炉NOx生成机理及燃烧器火焰脱硝数值模拟的研究[D].武汉:华中科技大学,2001.ZHU Quan-li.Formation mechanism of NOx in large boiler and numerical simulation of flame denitrification in burner [D].Wuhan:Huazhong University of Science and Technology,2001.
[7] FENIMORE C P.Formation of nitric oxide from fuel nitrogen in ethylene flames[J].Combustion & Flame,1972,19(2):289-296.
[8] 张永春.O2 / CO2气氛下燃煤NOx生成与还原机理研究[D].南京:东南大学,2011.ZHANG Yong-chun.Mechanism of formation and reduction of NOx in O2/CO2 atmosphere [D].Nanjing:Southeast University,2011.
[9] GLASS J W,WENDT J O L.Mechanisms governing the destruction of nitrogeneous species during the fuel rich combustion of pulverized coal[J].Symposium on Combustion,1982,19(1):1243-1251.
[10] JAVED M T,IRFAN N,GIBBS B M.Control of combustion-generated nitrogen oxides by selective non-catalytic reduction[J].Journal of Environmental Management,2007,83(3):251-289.
[11] ?YVIND S,KILPINEN P,GLARBORG P.Ammonia chemistry below 1 400 K under fuel-rich conditions in a flow reactor[J].Combustion & Flame,2004,136(4):501-518.
[12] LI S,WEI X,GUO X.Effect of H2O vapor on NO reduction by CO:experimental and kinetic modeling study[J].Energy & Fuels,2012,26(7):4277-4283.
[13] BI D,ZHANG J,ZHANG Z,et al.Industrial trials of high-temperature SNCR injected in primary combustion zone in a 50 MW tangentially firing pulverized-coal boiler for deeper NOx reduction[J].Energy & Fuels,2016,30(12):10858-10867.
[14] 岑可法.高等燃烧学[M].杭州:浙江大学出版社,2002.CEN Ke-fa.Advanced combustion science [M].Hangzhou:Zhejiang University Press,2002.
[15] 周昊,翁安心,岑可法,等.不同煤种挥发氮析出过程的数值模拟与试验研究[J].热能动力工程,2004,19(2):127-130.ZHOU Hao,WENG An-xin,CEN Ke-fa,et al.Numerical simulation and experimental study of the separation-release process of volatile nitrogen from various sorts of coal[J].Journal of Engineering for Thermal Energy and Power,2004,19(2):127-130.
[2] GB13223-2011,火电厂大气污染物排放标准[S].GB13223-2011,Emission standard of air pollutants for thermal power plants[S].
[3] HILL S C,SMOOT L D.Modeling of nitrogen oxides formation and destruction in combustion systems[J].Progress in Energy & Combustion Science,2000,26(4):417-458.
[4] ZHANG J,ITO T,OKADA T,et al.Improvement of NOx,formation model for pulverized coal combustion by increasing oxidation rate of HCN[J].Fuel,2013,113(2):697-706.
[5] BECIDAN M,?YVIND S.NOx and N2O precursors (NH3 and HCN) in pyrolysis of biomass residues[J].Energy & Fuels,2007,21(2):1173-1180.
[6] 朱全利.大型锅炉NOx生成机理及燃烧器火焰脱硝数值模拟的研究[D].武汉:华中科技大学,2001.ZHU Quan-li.Formation mechanism of NOx in large boiler and numerical simulation of flame denitrification in burner [D].Wuhan:Huazhong University of Science and Technology,2001.
[7] FENIMORE C P.Formation of nitric oxide from fuel nitrogen in ethylene flames[J].Combustion & Flame,1972,19(2):289-296.
[8] 张永春.O2 / CO2气氛下燃煤NOx生成与还原机理研究[D].南京:东南大学,2011.ZHANG Yong-chun.Mechanism of formation and reduction of NOx in O2/CO2 atmosphere [D].Nanjing:Southeast University,2011.
[9] GLASS J W,WENDT J O L.Mechanisms governing the destruction of nitrogeneous species during the fuel rich combustion of pulverized coal[J].Symposium on Combustion,1982,19(1):1243-1251.
[10] JAVED M T,IRFAN N,GIBBS B M.Control of combustion-generated nitrogen oxides by selective non-catalytic reduction[J].Journal of Environmental Management,2007,83(3):251-289.
[11] ?YVIND S,KILPINEN P,GLARBORG P.Ammonia chemistry below 1 400 K under fuel-rich conditions in a flow reactor[J].Combustion & Flame,2004,136(4):501-518.
[12] LI S,WEI X,GUO X.Effect of H2O vapor on NO reduction by CO:experimental and kinetic modeling study[J].Energy & Fuels,2012,26(7):4277-4283.
[13] BI D,ZHANG J,ZHANG Z,et al.Industrial trials of high-temperature SNCR injected in primary combustion zone in a 50 MW tangentially firing pulverized-coal boiler for deeper NOx reduction[J].Energy & Fuels,2016,30(12):10858-10867.
[14] 岑可法.高等燃烧学[M].杭州:浙江大学出版社,2002.CEN Ke-fa.Advanced combustion science [M].Hangzhou:Zhejiang University Press,2002.
[15] 周昊,翁安心,岑可法,等.不同煤种挥发氮析出过程的数值模拟与试验研究[J].热能动力工程,2004,19(2):127-130.ZHOU Hao,WENG An-xin,CEN Ke-fa,et al.Numerical simulation and experimental study of the separation-release process of volatile nitrogen from various sorts of coal[J].Journal of Engineering for Thermal Energy and Power,2004,19(2):127-130.
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