添加剂对NO_xOUT脱硝及N_2O、CO生成的影响特性

Influence of additives on NO_xOUT denitration and formation of N_2O and CO

通过试验研究了NOx污染的NOxOUT脱除特点和温室气体N2O及CO的生成规律,结合动力学分析,探讨了添加剂的作用。结果表明:在不同氨氮比(NSR)下,最佳反应温度为950℃,最高脱硝效率可达76.33%;N2O随温度的生成曲线类似于效率曲线,在950℃左右达到最大排放量;N2O的排放随NSR和氧量的增加而升高;温度较高时,N2O的排放随停留时间的延长先增加后减少;碳酸钠、乙酸钠、谷氨酸钠及乙醇可有效提高低温侧的脱硝效率和拓宽相应的温度窗口,其中谷氨酸钠最为明显;脱硝效率随钠盐添加量的变化与温度有关,钠原子最佳添加量为60μl·L-1;上述添加剂均可明显降低中高温段的N2O、CO排放,低温端则相反;N2O、CO的排放随温度、添加剂种类及浓度的不同而呈现各自的变化趋势。

An experiment was performed to study the removal of NOx pollution and formation of greenhouse gas （N2O） and CO in NOxOUT process. Kinetic analysis was combined with the experiment results to discuss the effect of additives. The optimum reaction temperature was 950℃ and the highest denitration efficiency could reach 76.33%with different normalized stoichimetric ratios （NSR）. The formation curves of N2O with temperature were similar to the efficiency curve and N2O emission reached a peak value at the temperature around 950℃. Increasing NSR and O2 concentration made N2O emission level higher. N2O emission first increased and then decreased with increasing residence time at higher temperatures （950℃,1000℃）. Sodium carbonate, sodium acetate, sodium glutamate and ethanol could effectively improve the denitration efficiency on the low temperature side and extend corresponding temperature window, especially obviously for sodium glutamate. Denitration efficiency was related to temperature when altering the concentration of sodium salts and the optimum addition amount was 60μl·L-1 for sodium atom. Above-mentioned additives could all remarkably reduce the emission of N2O and CO at medium and high temperatures, but adversely at the end point of low temperature. N2O and CO emission presented respective variation trends with the differences of temperature, type and concentartion of additives.