Chang John C S, Ghorishi S Behrooz
Air Pollution and Prevention Control Division, E305-03, National Risk Management Research Laboratory, Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
Environ Sci Technol. 2003 Dec 15;37(24):5763-6. doi: 10.1021/es034352s.
Experimental data from a laboratory-scale wet scrubber simulator confirmed that oxidized mercury, Hg2+, can be reduced by aqueous S(IV) (sulfite and/or bisulfite) species and results in elemental mercury (HgO) emissions under typical wet FGD scrubber conditions. The S(IV)-induced Hg2+ reduction and Hg0 emission mechanism can be described by a model which assumes that only a fraction of the Hg2+ can be reduced, and the rate-controlling step of the overall process is a first-order reaction involving the Hg-S(IV) complexes. Experimental data and model simulations predict that the Hg2+ in the flue gas can cause rapid increase of Hg0 concentration in the flue gas across a FGD scrubber. Forced oxidation can enhance Hg2+ reduction and Hg0 emission by decreasing the S(IV) concentration in the scrubbing liquor. The model predictions also indicate that flue gas Hg0 increase across a wet FGD scrubber can be reduced by decreasing the pH, increasing S(IV) concentration, and lowering the temperature.
来自实验室规模的湿式洗涤器模拟器的实验数据证实，氧化态汞（Hg2+）可被水溶液中的S(IV)（亚硫酸盐和/或亚硫酸氢盐）物种还原，并在典型的湿法烟气脱硫洗涤器条件下导致元素汞（Hg0）排放。S(IV)诱导的Hg2+还原和Hg0排放机制可用一个模型来描述，该模型假设只有一部分Hg2+能够被还原，并且整个过程的速率控制步骤是涉及Hg-S(IV)络合物的一级反应。实验数据和模型模拟预测，烟气中的Hg2+可导致湿法烟气脱硫洗涤器中烟气中Hg0浓度迅速增加。强制氧化可通过降低洗涤液中的S(IV)浓度来增强Hg2+还原和Hg0排放。模型预测还表明，通过降低pH值、增加S(IV)浓度和降低温度，可减少湿法烟气脱硫洗涤器中烟气Hg0的增加。
