NO REMOVAL AND NITROGEN CONVERSION PERFORMANCE BY O3 OXIDATION COMBINED WITH WET ABSORPTION
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摘要: 气相臭氧氧化协同湿法吸收脱硝技术具有脱除效率高、设备简单、投资低、运行易控等优点,适用于钢铁烧结、焦炉和陶瓷等较低温度(<150℃)和较低NOx浓度(<400 mg/m3)烟气的深度净化。从理论上分析了臭氧氧化协同湿法吸收脱硝反应过程物理化学行为,并采用傅里叶红外光谱和离子色谱等方法,分别考察了气相臭氧氧化NO和气相臭氧氧化协同湿法吸收脱硝的氮产物分布,计算氮转化率。结果表明:n(O3):n(NO)和水溶性是影响NO氧化程度和氧化产物吸收脱除效率的关键因素。当n(O3):n(NO)>1.5时,NO的氧化产物是与SO2水溶性相当的N2O5和HNO3,均可实现在传统脱硫吸收塔中同步高效脱除,而且产物为稳定性良好的NO3-。氮平衡分析结果表明,氮转化率接近99%,而不可检测的氮组分可以忽略不计或者不存在。Abstract: The denitrification technology using ozone oxidation combined with wet absorption can be used in the purification of flue gas with relatively low temperature (<150℃) and NOx concentration (<400 mg/m3), such as the flue gas from steel sintering, coke oven and ceramics industries. The technology has the advantages of higher SO2 and NOx removal efficiency, simpler equipment, relatively lower construction and operation cost. The physicochemical behaviors of ozone oxidation combined with the liquid phase absorption denitrification process was firstly analyzed. The distribution of nitrogen products from both gas-phase NO oxidation and gas-phase oxidation combined with wet absorption were investigated by Fourier infrared spectroscopy and ion chromatography, and the nitrogen conversion was calculated. The results showed that the O3/NO molar ratio and water solubility were the key factors affecting the degree of NO oxidation and NOx removal efficiency. When the O3/NO molar ratio was higher than 1.5, NO oxidation products were mainly N2O5 and HNO3, and their water solubility was equivalent to SO2. Thus, NOx could be effectively removed in the traditional desulfurization absorber, and the product was NO3- with good stability. The nitrogen conversion rate was close to 99%, and the undetectable nitrogen components could be ignored or never exist.
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Key words:
- ozone oxidation /
- absorption /
- denitrification /
- molecular diffusion /
- water solubility /
- nitrogen conversion
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