在一台配置有选择性催化还原(SCR)脱硝装置、电袋复合除尘器(ESP+FF)和湿法烟气脱硫(WFGD)装置的350 MW超低排放燃煤电厂进行了满负荷下汞排放的现场测试研究。采用国际公认的Ontario Hydro Method (OHM)标准方法分别对SCR、ESP+FF和WFGD的进出口烟气汞进行同时取样，研究了现有污染控制装置（APCD）对汞的协同脱除作用，系统地讨论了汞在这些污染物控制装置中的迁移转化规律。实验结果表明：在各污染物控制装置的汞取样质量平衡率在 85.4%~122.9% 之间；机组排放的汞主要分布在烟气中，其次在ESP+FF灰、WFGD石膏及废水和炉渣中；炉膛出口烟气中氧化汞（Hg2+）与单质汞（Hg0）之和占烟气总汞(HgT,HgT=Hg0+Hg2++Hgp)的89.8%；SCR有利于气态Hg0向气态Hg2+或气态颗粒汞(Hgp)的转化，转化效率为46.92%；ESP+FF对气态Hgp的脱除效率达99.95%，对HgT 的脱除效率为43.7%；WFGD对气态Hg2+和气态Hg0脱除率分别为25%和-5.2%，表明部分Hg2+在WFGD中可能被还原成Hg0。SCR+(ESP+FF)+WFGD对烟气HgT的协同脱除率为60.13%；综合看,该机组在现有污染物控制装置SCR+(ESP+FF)+WFGD协同作用下具有联合脱汞能力，可以实现汞的超低排放；加强抑制WFGD中Hg2+的还原可进一步提高燃煤电厂的协同脱汞效率。

The field test of mercury emission was conducted in a 350 MW ultralow emission coalfired power plant equipped with selective catalytic reduction (SCR) device,electrostatic precipitator & fabric filter (ESP+FF) and wet flue gas desulfurization (WFGD) device under 100% boiler load.The internationally recognized Ontario Hydro Method (OHM) standard was used to sample the flue gas mercury at the inlet or outlet of SCR,ESP+FF and WFGD simultaneously.The mercury coremoval by the existing air pollution control devices (APCDs) in the power plant was studied.The migration and transformation of mercury across the APCDs were also discussed.The results show that the mercury mass balance rate of each APCD is 85.4%~122.9%.The mercury emitted from this boiler unit mainly exists in flue gas,followed by ESP+FF ash,WFGD gypsum,waste water and slag.The sum of oxidized mercury (Hg2+) and elemental mercury (Hg0) accounting for 89.8% of the total mercury (HgT,HgT=Hg0+Hg2++Hgp) was found in flue gas at the outlet of the furnace.SCR benefits the transformation of gaseous Hg0 to gaseous Hg2+ or gaseous particulate mercury (Hgp),with the conversion efficiency of 46.92%.ESP+FF has great Hgp removal efficiency with the value of 99.95%,while HgT removal rate is 43.7%.The Hg2+ and Hg0 removal rate of WFGD is 25% and -5.2%,respectively,which indicates that part of Hg2+ may be reduced to Hg0 in WFGD.The HgT coremoval rate by the SCR+(ESP+FF)+WFGD is 60.13%.Overall,the boiler unit with the existing SCR+(ESP+FF)+WFGD has synergistic mercury coremoval ability,which can realize the ultralow mercury emission.Strengthening the inhibition of Hg2 + reduction in WFGD can further improve the flue gas mercury removal efficiency in the coalfired power plant.

TK221

国家重点研发计划(2016YFB0600203)；国家自然科学基金(51576044)；江苏省环保科研课题(2016030)