为研究煤粉燃烧过程中高温主燃区NH3对NOx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NOx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NOx还原为N2,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NOx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 NH3 on the NOx reduction in high temperature main combustion zone during pulverized coal combustion,the NOx 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 NOx to N2 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 NOx 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 NOx can be reduced by water injection alone,but it is not evident compared with the ammonia injection condition.
Journal of Engineering for Thermal Energy and Power
main combustion zone
nitrogen stoichiometric ratio