华电技术 ›› 2020, Vol. 42 ›› Issue (10): 41-47.

• 重金属脱除 • 上一篇    下一篇

湿法烟气脱硫系统中 Hg0再释放特性及离子液体脱汞研究

  

  1. 1. 四川大学 水力学与山区河流开发保护国家重点实验室,水利水电学院,成都 610065;2. 诺丁汉大学 工程学院,诺丁汉 NG7 2TU
  • 出版日期:2020-10-25

Study on the characteristics of Hg0 re-emission and mercury removal by ionic liquid in WFGD systems

  1. 1.State Key Laboratory of Hydraulics and Mountain River Engineering,College of Water Resource & Hydropower,Sichuan University,Chengdu 610065,China;2.Faculty of Engineering,University of Nottingham,Nottingham NG7 2TU,UK
  • Published:2020-10-25

摘要: 为进一步提高湿法烟气脱硫(WFGD)系统中的脱汞效率,对低浓度 SO32-工况下 Hg0 再释放特性以及不同离
子液体的脱汞性能进行了研究。基于鼓泡塔反应器,在 N2 气氛下研究了 SO32- 和金属离子(Fe2+ ,Fe3+ 和 Cu2+)对
WFGD 系统中 Hg0 再释放特性的影响,同时考察了 3 种离子液体(HMIM[PF6],BMIM[PF6],BMIMCl)的脱汞性能,筛
选出表现最佳的添加剂和其最优运行工况。结果表明,当脱硫液中 SO32-浓度处于较低水平时,增加 SO32-浓度可促
进 Hg2+的还原;而当 SO32-过量时,Hg0 再释放行为将被明显抑制。Fe2+,Fe3+和 Cu2+等金属离子浓度的增加均能促进
Hg0 的再释放。上述 3 种离子液体添加剂抑制效果为 BMIMCl>BMIM[PF6]>HMIM[PF6]。对脱汞性能较好的添加
剂 BMIMCl 进行进一步试验,获得其抑制 Hg0 再释放的最佳工况,即添加质量浓度为 10 g/L、较低脱硫液 pH 值以及
50 ℃脱硫液温度。

关键词: 湿法烟气脱硫, Hg0 再释放, SO32-浓度, 金属离子, 离子液体, 脱汞

Abstract: To further improve the mercury removal efficiency of wet flue gas desulfurization(WFGD)systems,the
characteristics of Hg0 re-emission and the mercury removal performances of different ionic liquids were studied at low SO32-
concentrations. Based on a bubble reactor,the effects of SO32- and metal ions(Fe2+,Fe3+ and Cu2+)on the characteristics of
Hg0 re-emission in WFGD systems were investigated under N2 atmosphere. The mercury removal performances of three
ionic liquid additives(HMIM[PF6],BMIM[PF6]and BMIMCl)were also studied,and the optimal operating conditions
for the best-performing additives were obtained. The results indicate that increasing SO32- concentration at a relatively low
level can intensify the reduction of Hg2+ ,whereas Hg0 re-emission is significantly inhibited with excess concentration of
SO32- . It is also found that Fe2+ ,Fe3+and Cu2+can facilitate Hg0 re-emission. The three ionic liquid additives above show
effective inhibitions on Hg0 re-emission in the order of BMIMCl>BMIM[PF6]>HMIM[PF6]. Further experiments were
carried out on BMIMCl to obtain its optimal condition for inhibiting Hg0 re-emission. The optimal condition for BMIMCl is
at a mass concentration of 10 g/L,a lower pH value and a desulfurization liquid temperature at 50 ℃.

Key words: WFGD, Hg0 re-emission, SO32- concentration, metal ions, ionic liquid, mercury removal