臭氧氧化结合硫代硫酸钠溶液喷淋同时脱硫脱硝

Simultaneous removal of SO_2 and NO_x by combination of ozone oxidation and Na_2S_2O_3 solution spray

采用臭氧氧化结合湿法喷淋硫代硫酸钠溶液的方法开展模拟烟气同时脱硫脱硝实验研究。结果表明,采用臭氧氧化结合Na2S2O3-Na OH溶液湿法喷淋可以实现NOx和SO_2协同脱除:在O_3/NO摩尔比为1.1~1.2时,溶液中Na2S2O3浓度的增加会提高系统的NO_x脱除效率,烟气中SO2的存在会促进NOx的脱除,当SO2浓度为1030mg·m^(-3)、2.0%Na_2S_2O_3溶液作为喷淋液时可实现较高的SO_2脱除效率,同时NO_x脱除效率可达70%以上;喷淋液p H在2.5~9范围内变化时提高浆液p H有利于NOx的脱除,当p H=9时脱硝效率可达75%。180 min连续同时脱硫脱硝实验结果表明,硫代硫酸钠可有效促进NOx的脱除,并实现SO2较高的脱除效率,同时可实现系统同时脱硫脱硝连续稳定运行,喷淋吸收后烟气中NO_x的主要转化产物为NO^-_2,该方法作为一种有效的同时脱硫脱硝技术,具有一定的工业应用推广前景。

Ozone oxidation and Na2S2O3 solution spray was combined to remove SO2 and NOx simultaneously. This coupling was studied experimentally. The results show that： SO2 and NOx can be eliminated simultaneously; at O3/NO mole ratio 1.1—1.2, the NOx removal efficiency increases with increasing concentration of Na2S2O3; existence of SO2 can facilitate removal of NOx; the NOx removal efficiency reaches 70% with low emission of SO2 at Na2S2O3 concentration 2.0% and at SO2 gas concentration 1030 mg·m^-3. Furthermore, the NOx removal efficiency is enhanced with the p H of solution from 2.5 to 9, and reaches 75% at p H 9. The result of 3 hours running experiment indicates that NOx and SO2 can be removed efficiently and simultaneously and the stable and continuous operation is possible, because sodium thiosulfate can facilitate removal of NOx and the NOx is dominantly converted into NO2^-. This process could be an efficient approach for eliminating SO2 and NOx simultaneously and could have potential industrial application.