Abstract: Humidified activation of fly ashes from circulating fluidized bed (CFB) boilers was conducted. Samples of the fly ash were characterized by desulfurization in the suspended fluidized bed and scanning electron microscopy (SEM). The desulfurization of humidified fly ashes was conducted at low temperature. The results indicated that with increase of reaction temperature, the calcium utilization increased when water/CaO ratio was 1. The utilization increased continuously and then decreased with temperature when the ratio was 3 or 5. The rate decreased when the ratio was 10. It was shown that the calcium utilization of humidified fly ashes in a suspended fluidized bed could be increased from 41% to 60%. The optimal reaction temperature was between 60℃ and 80℃. The results from SEM showed that treatment of humidified activation promoted an increase in ash porosity, while the porosity contributed to further desulfurization in suspended fluidized beds.

Key words: desulfurization, fly ash, low temperature, humidification, activation, circulating fluidized bed

摘要： 以循环流化床锅炉飞灰作为实验对象，研究增湿活化飞灰在低温悬浮反应器中的脱硫特性。实验结果表明：增湿低温悬浮脱硫过程中，当水钙比能保证反应器中增湿灰的悬浮流化状态时，反应温度对钙利用率存在促进与抑制作用。水钙比为1时，钙利用率随反应温度的升高而增大；水钙比为3、5时，钙利用率随反应温度升高先升高后降低；水钙比为10时，钙利用率随反应温度的升高而降低；当水钙比为10，飞灰增湿低温悬浮脱硫可将循环流化床锅炉飞灰初始钙利用率由41%提高至60%左右，最佳反应温度在60～80℃之间。扫描电镜表明，飞灰增湿活化后，飞灰颗粒表面空隙增多、产生裂缝，有利于进一步在悬浮反应器中脱硫。

关键词: 脱硫, 飞灰, 低温, 增湿, 活化, 循环流化床