Ma Zi-zhen, Li Zhen, Jiang Jing-kun, Ye Zhi-xiang, Deng Jian-guo, Duan Lei
Huan Jing Ke Xue. 2015 Jul;36(7):2361-6.
To characterize the primary PM2.5 emission from coal-fired power plants in China, and to quantitatively evaluate the effects of flue gas denitrification and desulfurization on PM2.5 emission, a pulverized coal fired (PC) power plant and a circulating fluidized bed (CFB) plant were selected for measuring the mass concentration and water-soluble ion composition of PM2.5 in flue gas. The results showed that the mass concentration of PM2.5 generated from the CFB was much higher than that from the PC, while the mass concentrations of PM2.5 emitted from these two plants were very similar, because the CFB was equipped with an electrostatic-bag precipitator (EBP) with higher PM2.5 removal efficiency than the common electrostatic precipitator (ESP). Although the total concentration of water-soluble ions in PM2.5 generated from the PC was lower than that from the CFB, the total concentration of water-soluble ions in PM2.5 emitted from the PC was much higher than that from the CFB, which implied that PM2.5 emission from the PC was greatly affected by the flue gas treatment installations. For example, the flue gas denitrification system produced H2SO4 mist, part of which reacted with the excessive NH3 in the flue gas to form NH4HSO4 in PM2.5 and to increase the acidity of PM2.5. In addition, the escaping of desulfurization solution during the flue gas desulfurization process could also introduce NH4+ and SO2- into PM2.5. Therefore, although the main water-soluble ions in PM2.5 generated from both of the plants were Ca2+ and SO(4)2-, the major cation was changed to NH4+ when emitted from PC.
为了表征中国燃煤电厂一次细颗粒物（PM2.5）排放特征，并定量评估烟气脱硝和脱硫对PM2.5排放的影响，选取了一座煤粉炉（PC）电厂和一座循环流化床（CFB）电厂，对烟气中PM2.5的质量浓度和水溶性离子组成进行测量。结果表明，CFB产生的PM2.5质量浓度远高于PC产生的，而这两座电厂排放的PM2.5质量浓度非常相似，这是因为CFB配备了比普通静电除尘器（ESP）具有更高PM2.5去除效率的静电布袋除尘器（EBP）。虽然PC产生的PM2.5中水溶性离子的总浓度低于CFB产生的，但PC排放的PM2.5中水溶性离子的总浓度远高于CFB排放的，这意味着PC的PM2.5排放受烟气处理装置的影响很大。例如，烟气脱硝系统产生硫酸雾，其中一部分与烟气中过量的氨反应，在PM2.5中形成硫酸氢铵并增加PM2.5的酸度。此外，烟气脱硫过程中脱硫溶液的逸出也会将铵根离子和硫酸根离子引入PM2.5。因此，虽然两座电厂产生的PM2.5中主要的水溶性离子都是钙离子和硫酸根离子，但PC排放时主要阳离子变为铵根离子。
