鼓泡反应器中Na2S对低浓度NOx的吸收

实验研究了在鼓泡反应器中硫化钠溶液吸收低浓度NOx的吸收特性，分析了NOx、O2、Na2S和NaOH浓度对吸收过程的影响，以及被吸收NO2的形态。结果显示，Na2S浓度在15.8和47.5 mmol·L-1时，气相中NO2浓度变化对吸收率影响不明显，但在0.30~3.25 mmol·L-1时，NO2浓度变化对吸收率有较大影响。气相中的O2会加速吸收反应，但同时也引起吸收剂的额外消耗。当Na2S溶液中加入NaOH，浓度达到0.1%时，可强化NO2的吸收。NOx中NO含量增加会导致吸收率下降，即使有NaOH的条件下，也未观察到NOx氧化度为0.5时NO与NO2的协同吸收效应。Na2S溶液将被吸收的NO2一部分还原为N2，一部分还原为NO2-。

Absorption of nitrogen dioxides with sodium sulfide solutions in bubbling reactor

Effects of NO2, O2, Na2S, and alkalinity on the absorption of low-concentration NOx by sodium sulfide solution in a bubbling reactor were empirically evaluated; the speciation of the absorbed NO2 was also discussed. The results showed that when the Na2S concentration was in the range of 15.8 to 47.5 mmol·L-1, the effect of the NO2 concentration on the absorption efficiency was poor; however, the effect was pronounced when the concentration of Na2S solution was 0.30 to 3.25 mmol·L-1. Oxygen in the simulated flue gas did not decrease the NO2 absorption efficiency, but led to extra consumption of Na2S. The NO2 absorption efficiency could be augmented by 0.1% NaOH in the Na2S solution. When the NO content in NOx increased, the efficiency of NOx absorption declined. Even in the presence of NaOH, no synergistic effect of NO and NO2 on the absorption was observed at a NOx oxidation degree of 0.5. The absorbed NO2 was converted into N2 and NO2- by Na2S solution.