烟气脱汞过程中活性炭喷射量的影响因素

Factors affecting amount of activated carbon injection for flue gas mercury control

在模拟燃煤烟气流动反应试验台上,对喷射吸附脱汞过程中影响活性炭喷射量的汞浓度、停留时间、温度、除尘设备等因素进行了试验研究.结果表明获得相同脱汞效率,在较低烟气汞浓度下活性炭的喷射量较大.停留时间对活性炭喷射量的影响最大,在较长停留时间下活性炭能够进行充分的吸附,相应的活性炭喷射量较少;在较短停留时间下受动力学限制,过多的活性炭喷射量不会引起脱汞效率相应增加.随着温度升高,活性炭的喷射量也随之增加;通过化学改性能提高活性炭在较高烟气温度下的吸附能力,从而减少喷射量.布袋除尘设备的使用能在较大程度上降低活性炭的喷射量.

The influences of mercury concentration, residence time, flue gas temperature and particulate control device on the amount of activated carbon injection were investigated through the pilot-scale tests. The results showed that a greater amount of active carbon injection for mercury removal was needed at lower Hg concentration. Residence time was one of the critical factors affecting mercury removal. A longer residence time would increase the availability of activated carbon. On the other hand, increased injection of activated carbon would not result in the corresponding increase of mercury removal efficiency at a short residence time. Flue gas temperature had a negative influence on activated carbon mercury removal. However, activated carbon treated with chemical agents had a good performance at a high temperature. The fabric filter would be very helpful for activated carbon mercury removal and could decrease the amount of activated carbon injection.