內黑 Abstract: The effects of gas composit可文ions on NOx reduction and NH3 slip by selective non-cataly銀高tic reduction (SNCR) w女裡ith NH3 were investigated in a simulated玩很 cement precalciner atmosphere. The re錢裡sults show that the pres光小ence of H2O improves NOx reduc場上tion and widens the reduction te音器mperature window significantly. O2 is indispensable for reducing NOx木數. The optimum reduction temperature de這廠creases and the temperature win爸舞dow widens to a lower tempera金光ture with the increase of O2 content. In addition, the increase of O市問2 content also results in a de離刀crease of the maximum NOx redu雨校ction efficiency. The effect of SO2 on NOx reduction is negligib雜中le in the simulated precalcin間黃er atmosphere. To increase CO 了公concentration makes NO reduct體師ion take place at relatively low 草電temperatures. However, NH3 will tend to be oxidized 林著into NO instead of reduci匠草ng NO after entering什議 the stream containi什遠ng O2 at high temperatures i有嗎f it is initially blended with腦廠 a high concentration of CO in an 哥唱oxygen-free environment. 店老The increase of H2O, O2, SO2 or CO concentration is hel綠風pful to reduce NH3 slip in the temperature 歌銀region below 900 °C.影媽 These effects are resulted from 議拿the fact that the generation and在煙 consumption of O and OH 醫女radicals which are crucial 劇習to NO reduction and formation 快哥can be influenced by the fou章朋r gas compositions. In industrial opera那費tion of SNCR for cement precalc匠購iner, these effects should be ta來那ken into account to increas算湖e NOx reduction efficiency 唱劇and avoid NH3 slip.
