脱硫浆液循环使用造成其组成复杂，尤其是卤族元素易在浆液内积累而较难脱除。氧化态汞水溶性较好，可被湿法脱硫（Wet Flue Gas Desulfurization,WFGD）系统脱除，然而脱硫浆液内已脱除的汞存在二次释放的问题。实验室采用汞在线实时监测方法对模拟脱硫浆液内卤族元素影响汞释放行为进行系统研究，考察反应温度、卤族元素种类、卤族元素浓度和反应pH对汞释放的影响，并通过模拟计算研究汞释放机理。结果表明，卤族元素对汞释放的抑制能力按Cl<Br<I顺序逐渐增大。提高反应温度有利于降低汞的释放强度，温度由40 ℃升至60 ℃时，添加卤族元素的体系汞释放量降幅超20%。增加卤族元素浓度可明显降低汞释放量，当Cl、Br和I物质的量浓度由5 mmol/L升至50 mmol/L后，汞释放量分别降低了23.5%、53.8%和62.8%。增大反应pH后，反应体系的还原电势降低，可减弱中间产物的质子化作用，有利于降低汞释放强度。体系内加入卤族元素后会改变汞的反应路径，汞与卤素生成一系列配合物，减少了汞与体系内还原性物质接触生成不稳定的中间产物HgSO3，从而降低汞的释放强度。

 The composition of desulfurization slurry is complex due to the recycling utilization of the slurry, in particular the halogen elements are easy to accumulate in the slurry and  difficult to be removed. Oxidated mercury is water soluble and is easy to be removed by wet flue gas desulfurization (WFGD) system, however, the absorbed mercury in the desulfurization slurry has the problem of secondary release. Therefore, the influence of halogen elements on Hg emission in WFGD system was systematically studied in the lab-scale by on-line monitoring and the influence of reaction temperature, halogen species, halogen concentrations, and reaction pH  on mercury release were investigated. The mechanism of mercury emission behavior was also simulated. The results indicate that the mercury emission is inhibited by halogen elements in the increasing order of Cl<Br<I. Increasing the reaction temperature is conducive to reducing the release intensity of mercury where the over 20% decrease is achieved with the temperature increasing from 40 ℃ to 60 ℃. Increasing the concentrations of halogen elements results in a remarkable inhibition of mercury emission. When the concentrations of Cl, Br, and I increase from 5 mmol/L to 50 mmol/L, mercury emission are reduced by 23.5%,53.8%,and 62.8%, respectively. After increasing the reaction pH, the reduction potential of the reaction system decreases, which can weaken the protonation of the intermediate products, and is conducive to reducing the intensity of mercury release. The addition of halogen element can alter the pathway of mercury emission and mercury and halogen will form a series of complexes, reducing the contact between mercury and reducing substances in the system to form unstable intermediate HgSO3, thus reducing the release intensity of mercury.

0 引言

1 试验仪器及方法

2 结果与讨论

   2.1 卤族元素种类对汞释放影响

   2.2 卤族元素含量对汞释放影响

   2.3 温度对汞释放影响

   2.4 pH对汞释放影响

   2.5 卤族元素对汞释放影响的机理分析

3 结论