462 / 2018-12-31 11:18:29

合成气添加剂对NH3-SNCR反应的影响研究/Study on Effects of Syngas Additive on NH3-SNCR Reaction

脱硝，SNCR，合成气，添加剂，流化床/Denitrification, SNCR, syngas, additive, fluidized bed

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针对流化床锅炉运行负荷变化大，选择性非催化还原脱硝技术（SNCR）受反应温度窗口限制而面临反应速率低、氨逃逸率高等问题，本文对添加煤制合成气的氨-SNCR脱硝反应进行了研究。通过实验和合成气参与的SNCR基元反应模拟计算，分别针对氨氮比、反应停留时间及添加剂种类、浓度等影响因素，研究SNCR脱硝反应特性的变化规律。结果表明，合成气的浓度因素与停留时间之间具有较弱的协同作用，与氨氮比形成较强的协同作用。随着合成气浓度的升高，氨氮比对SNCR反应的影响逐渐加强，达到相同的脱硝效率所需的氨剂可减少。虽然合成气在NOx脱除率方面无法完全替代氨还原剂，但合成气的存在可以在一定范围内加快反应速率，缩短反应停留时间，同时允许适当降低氨氮比，减少氨逃逸。

Abstract: Due to the large variation of operating load of fluidized bed boiler, the selective non-catalytic reduction denitrification technology (SNCR) faces the problems of low reaction rate and high ammonia escape rate due to the limitation of reaction temperature window. Therefore, the NH3- SNCR denitrification reaction with gasification syngas was studied in the paper. Through experiments and simulation calculation of SNCR elementary reactions with syngas, the variation of SNCR denitrification reaction characteristics was studied with varying the influencing factors such as ammonia-nitrogen ratio, reaction residence time, type and concentration of additives. The results show that there is a weak synergistic effect between the concentration of syngas and the reaction residence time, while the synergistic effect of syngas additive and ammonia-nitrogen ratio is strong. With the increase of syngas concentration, the effect of ammonia-nitrogen ratio on SNCR reaction is gradually strengthened, and the ammonia needed to achieve the same denitrification efficiency can be reduced. Therefore, although syngas cannot completely replace ammonia reductant in the removal rate of NOx, the presence of syngas can accelerate the reaction rate and shorten the reaction residence time in a certain range, while allowing appropriate reduction of ammonia-nitrogen ratio and reduction of ammonia escape.