过硫酸钠工艺同时氧化吸收燃煤烟气中NO和SO_2的研究

Initial study on simultaneous absorption and oxidation of NO and SO_2 from coal-fired flue gas by aqueous solutions of sodium persulfate

在半间歇式鼓泡床反应器中进行了过硫酸钠工艺同时氧化吸收燃煤烟气中NO和SO2的研究。研究了过硫酸钠浓度、溶液温度、NO初始浓度、SO2初始浓度对体系NO脱除的影响。结果表明,随着Na2S2O8溶液浓度的增加,NO脱除率呈现先增加后变化不大的趋势,0.2 mol/L均为单独脱硝和同时脱硫脱硝的最佳浓度。随着溶液温度的提高、NO初始浓度的降低,NO脱除率显著增加。在所有实验条件下,SO2脱除率均在95%以上。SO2对NO的脱除具有双重作用,一定浓度的SO2,在较低温度范围内,对NO的脱除表现为增强效应,随着温度的升高,增强效应逐渐减弱,在较高温度范围内,转为抑制作用。SO4·-和OH·活性自由基与液相中NO和SO2的相对比例变化是引起NO脱除率变化的根本原因,实验条件的变化直接或间接的改变了这一比例,导致NO脱除率发生变化。

The initial study on simultaneous absorption and oxidation of NO and SO2 from coal-fired flue gas by aqueous solutions of sodium persulfate（ Na2S2O8 ） has been studied in a bubble column reactor op- erated in semibatch mode. The effects of Na2S2O8 concentration, temperature, the NO concentration, SO2 concentration on NO removal has been investigated. The result showed that along with the increasing of the Na2S2O8 concentration, the NO conversion increased first and then smooth after Na2S2O8 concentration turns to 0.2 mol/L and 0.2 mol/L is also the best concentration for aqueous NO removal, both in the presence and absence of SO2. As temperature raising and decreasing of the NO concentration, the conver- sion of NO has dramatically growth. SO2 can be almost removed entirely in each conditions. With presence of the SO2, NO conversion can shows different performance. When temperature within a low area, NO con- version can be strengthen by the presence of the SOs, however, when temperature goes high, two conditions begin to be the same and finally shows the opposite result. The changing proportion of the existence of SO4 ^＋- , OH^- and SO2, NO in liquid are the mainly reason of the NO converting variation and the different condition of the experiment directly or indirectly change the proportion and then cause the difference of the NO conversion ultimately.