Emission and Migration Characteristics of Mercury in a 0.3 MWth CFB Boiler with Ammonium Bromide-Modified Rice Husk Char Injection into Flue
Emission and Migration Characteristics of Mercury in a 0.3 MWth CFB Boiler with Ammonium Bromide-Modified Rice Husk Char Injection into Flue
复制标题
烟道喷吹溴化铵改性稻壳炭的 0.3 MWth CFB 锅炉中汞的排放和迁移特性
DOI：
10.1021/acs.energyfuels.9b01440
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发表时间：
2019
期刊：
影响因子：
5.3
通讯作者：
Xiaobing Gu
中科院分区：
文献类型：
--
作者：
Zhengkang Luo;Yufeng Duan;Tianfang Huang;Shuai Liu;Yaji Huang;Lu Dong;Shaojun Ren;Jun Tao;Xiaobing Gu
在中试规模的0.3 MWth循环流化床锅炉系统中，通过在烟道内注入溴化铵（NH 4 Br）改性稻壳焦（NBr-RHC）吸附剂，研究了烟气中汞的排放和迁移特性。烟道气中的汞浓度通过安大略Hydro方法采样。同时，在烟道气汞取样期间，还收集了进料煤、石灰、工艺用水、烟道气和FF料斗中的飞灰、底灰、石膏和湿法烟道气脱硫（WFGD）流出物。采用程序升温脱附（TPD）法对飞灰中汞的形态进行了分析。结果表明，选择性催化还原（SCR）+吸附剂喷射（AI）+ FF + WFGD组合系统的烟气总汞去除率为94.62%，比未加AI的NBr-RHC提高13.42%。93.83%的汞存在于固液副产物中，FF对汞的收集量占97.28%，这是由于NBr-RHC注入对气态汞的物理吸附和化学吸附。对AI装置颗粒物中汞化合物的TPD分析表明，HgBr 2的生成是NBr-RHC具有高除汞效率的关键原因。发现元素汞在SCR中氧化，其中70.23%转化为氧化汞。WFGD对氧化汞的吸收率为86.67%，但由于氧化汞的还原作用，元素汞从0.19 μg/m3增加到0.26 μg/m3，应引起重视。
The emission and migration characteristics of flue gas mercury in a pilot-scale 0.3 MWth circulating fluidized bed combustion boiler system by injecting the adsorbent of ammonium bromide (NH4Br)-modified rice husk char (NBr-RHC) into the flue duct before a fabric filter (FF) were investigated in this study. Mercury concentration in the flue gas was sampled by the Ontario Hydro Method. Meanwhile, the feeding coal, lime, process water, fly ashes both in the flue gas and FF hopper, bottom ash, gypsum, and wet flue gas desulfurization (WFGD) effluent were also collected during the flue gas mercury sampling. The temperature-programmed desorption (TPD) method was used to identify the mercury species in the sample of fly ashes. The results show that the combination system of the selective catalytic reduction (SCR) + adsorbent injection (AI) + FF + WFGD obtains a total flue gas mercury removal efficiency of 94.62%, which is 13.42% higher than that without the AI of NBr-RHC. A total of 93.83% of mercury exists in byproducts of the solid and liquid, and the amount of mercury collected by FF accounts for 97.28% due to the physisorption and chemisorption of gaseous mercury by NBr-RHC injection. The TPD analysis for mercury compound in the particulate matters from the AI device indicates that HgBr2formation is the key reason for NBr-RHC having high mercury removal efficiency. Elemental mercury is found to oxidize across the SCR, with 70.23% converted to oxidized mercury. WFGD exhibits a good oxidized mercury absorption rate of 86.67%, but elemental mercury increases from 0.19 to 0.26 μg/m3due to the oxidized mercury reduction, and more attention should be given on this increase.