O3-NH3协同活性焦脱硫脱硝的均相预反应特性研究

为进一步提高活性焦脱硫脱硝性能，提出臭氧（O₃）预氧化协同喷氨（NH₃）的工艺优化思路.通过在固定床上开展相关均相反应实验，研究外部引入的O₃、NH₃对NO_x、SO₂的反应特性.结果表明，O₃对NO的氧化反应为逐级过程，随着O₃/NO物质的量比增大，O₃将NO依次氧化为NO₂和N₂O₅.O₃对SO₂的均相氧化作用十分有限，O₃/SO₂=1时SO₂氧化率低于5.0%.在O₃预氧化条件下喷入NH₃后，O₃/NH₃=1时约有6.7%的O₃消耗量；当O₃/NO=1时，预氧化产物NO₂含量显著下降，同时NO排放浓度小幅上升；当O₃/NO=1.5时，NO_x排放水平与未喷入NH₃条件时相当.在O₃和NH₃协同作用下，SO₂的氧化率显著提高，推测此时脱硫反应产物为更加稳定的NH₄HSO₄或（NH₄）₂SO₄.O₃-NH₃协同脱硫脱硝反应中，O₃/NO不超过1时，NH₃-NO₂和NH₃-SO₂反应同时发生，提高NH₃引入量能够同时提高脱硫率和脱硝率.O₃/NO > 1时，NH₃-N₂O₅反应优先级最高，N₂O₅对NH₃的消耗抑制了NH₃-SO₂脱硫反应发生.仅运用O₃预氧化和NH₃协同作用方式的脱硫脱硝效率较为有限，但对烧结烟气中氮、硫污染物的形态的改变产生重要影响.

Characteristics of simultaneous removal of NOx and SO2 by O3-NH3 synergy

A technology of O₃ pre-oxidation combined with NH₃ injection had been proposed to improve the performance of desulfurization and denitrification for sintering flue gas. The characteristics of the homogeneous reaction among the introduced O₃ and NH₃, and the NO_x and SO₂ from the sintering flue gas had been studied in a fixed-bed reactor. Results show that the oxidation of NO by O₃ proceeds in a step-by-step manner. With the increase of the mole ratio of O₃/NO in the gas mixture with only O₃ and NO, O₃ had firstly oxidized NO into NO₂, while subsequently to N₂O₅. However, the oxidation of SO₂ by O₃ in the gas mixture with only SO₂ and O₃ was very limited. When O₃/SO₂=1in the gas mixture of O₃ and NO, the oxidation efficiency of SO₂ was less than 5.0%. After NH₃ had been introduced into the pre-reacted gas mixture of O₃ and NO, about 6.7% of O₃ was consumed. In this gas mixture, when O₃/NO=1, the pre-oxidation product NO₂ decreased significantly from 278×10^-6to 144×10^-6, while the NO concentration at reactor outlet increased slightly from 16×10^-6 to 35×10^-6. When O₃/NO=1.5, the NO_x concentration at reactor outlet was equal to that without NH₃ introduction. With the simultaneous introduction of O₃ and NH₃, the oxidation rate of SO₂ increased significantly from 24.0% to 41.1%. It had been speculated that the desulfurization products was the compound of NH₄HSO₄ or (NH₄)₂SO₄, which was stable in the reaction condition. During the reaction among SO₂, NO_x and the simultaneously introduced O₃ and NH₃, the reactions of NH₃-NO₂ and NH₃-SO₂ took place at the same time when the ratio of O₃/NO <1. Therefore, the increasing amount of NH₃ could improve both the desulfurization and denitrification efficiencies. When O₃/NO >1, the reaction between NH₃ and N₂O₅ showed the highest priority, and the consumption of NH₃ by N₂O₅ inhibited the desulfurization reaction of between NH₃ and SO₂. The simultaneous introduction of O₃ and NH₃ had limited impact on desulfurization and denitrification efficiencies, but it had an obvious impact on changing the form of N- and S-containing pollutants in the sintering flue gas.