臭氧脱硝过程中硝酸盐气溶胶的生成机理及控制Formation mechanism and control of nitrate aerosol during ozone deNOx process
黄元凯,朱燕群,邵嘉铭,唐海荣,何勇,王智化
HUANG Yuankai,ZHU Yanqun,SHAO Jiaming,TANG Hairong,HE Yong,WANG Zhihua
摘要(Abstract):
在工程项目中,大多采用湿法喷淋对烟气进行洗涤以实现污染物高效脱除。但研究发现该过程会产生较多气溶胶,使尾部烟气无法达标排放。目前,相关研究集中在SO_3酸雾和硫酸盐气溶胶的生成机理及相应控制手段,鲜见部分臭氧脱硝技术应用中出现的硝酸盐气溶胶现象。因此,通过建立臭氧脱硝试验系统,利用Gasmet烟气分析仪测定烟气组分及浓度,采用气溶胶粒度分布采样器和离子色谱对生成的硝酸盐气溶胶浓度进行测量,以开展硝酸盐生成机理及控制研究。结果表明,硝酸盐气溶胶浓度与烟气中初始NO浓度呈正相关,烟气中NO浓度从200×10~(-6)升高至400×10~(-6)时,硝酸盐气溶胶的浓度从7.06 mg/m~3升高至18.66 mg/m~3;在O_3/NO摩尔比为1的条件下,浆液中存在的NH_4~+导致气溶胶浓度升高,虽然NH_4~+浓度从2 g/L升高至4 g/L时,气溶胶浓度基本保持在约8 mg/m~3不变,但气溶胶平均粒径有所增大;浆液中无NH_4~+时,气溶胶浓度随着O_3/NO摩尔比的升高而降低;但浆液中存在2 g/L的NH_4~+时,随着O_3/NO摩尔比从1.0升高至1.6,气溶胶浓度从7.06 mg/m~3升高至161.94 mg/m~3,上升明显;浆液中还原型添加剂X的添加可明显抑制气溶胶的产生,气溶胶抑制效率可达到47.7%,该方法可以作为一种臭氧脱硝过程中硝酸盐气溶胶生成的抑制技术。
Most of flue gas is washed by wet spraying to achieve efficient removal of pollutants in engineering projects. However,it is found that there is a large amount of aerosol produced during this process,which makes the tail gas unable to meet emission standards. Up to now,the relevant researches focus on the formation mechanism and corresponding control methods of SO_3 acid mist and sulfate aerosol,and there is no report or research focuses on the phenomenon of nitrate aerosol in some applications of ozone deNO_x technology. Therefore,through the establishment of ozone deNO_x system,the Gasmet flue gas analyzer was used to measure the gas components and concentration,the aerosol particle size distribution sampler and ion chromatography were used to measure the concentration of the nitrate aerosol. An experimental study on the formation mechanism and control of nitrate aerosol was carried out. The results show that the nitrate aerosol concentration is positively correlated with the initial NO concentration,which increases from 7.06 mg/m~3 to 18.66 mg/m~3 as the NO concentration increases from 200×10~(-6) to 400× 10~(-6). When O_3/NO molar ratio is 1.0,the presence of NH_4~+ in the slurry causes the nitrate aerosol concentration to increase. When the N_H4~+ concentration increases from 2 g/L to 4 g/L,the nitrate aerosol concentration remains at 8 mg/m~3,but the average particle size increases. Additionally,the aerosol concentration decreases with the increase of O_3/NO molar ratio without NH_4~+ addition. However,when 2 g/L NH_4~+ was added into the slurry,the aerosol concentration increases dramatically from 7.06 mg/m~3 to 161.94 mg/m~3 as the O_3/NO raises from 1.0 to 1.6. The addition of reducing additives X in the slurry significantly reduces the aerosol concentration with the maximum aerosol suppression efficiency of 47.7%. This method has a certain industrial application prospect as a nitrate aerosol suppression technology in the ozone deNO_x process.
关键词(KeyWords):
臭氧脱硝;气溶胶;NH_4~+;还原型添加剂;生成机理
ozone deNO_x;aerosol;NH_4~+;reducing additive;formation mechanism
基金项目(Foundation): 国家重点研发计划资助项目(2018YFB0605200)
作者(Author):
黄元凯,朱燕群,邵嘉铭,唐海荣,何勇,王智化
HUANG Yuankai,ZHU Yanqun,SHAO Jiaming,TANG Hairong,HE Yong,WANG Zhihua
DOI: 10.13226/j.issn.1006-6772.IF20070901
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