The secondary release of mercury in coal fly ash-based flue-gas mercury removal technology
The secondary release of mercury in coal fly ash-based flue-gas mercury removal technology
复制标题
DOI：
10.1080/09593330.2015.1059491
复制
发表时间：
2016-01
影响因子：
2.8
通讯作者：
Jing-feng He;C. Duan;Mingzhe Lei;Xuemei Zhu
中科院分区：
文献类型：
--
作者：
Jing-feng He;C. Duan;Mingzhe Lei;Xuemei Zhu
粉煤灰中汞的二次释放是燃煤电厂的一种负面副产品，需要对其进行有效控制以减少对环境的污染。通过对不同脱汞工艺产生的粉煤灰的粒度分布和成分分析表明，粉煤灰的粒度一般小于0.5mm，主要由SiO2、Al 2 O3和Fe 2 O3组成。采用不同的除汞方法，研究了粉煤灰中汞含量与粉煤灰粒径和烧失量的关系。研究表明，与常规协同污染控制技术相比，喷入活性炭或溴化活性炭后的粉煤灰中汞含量明显升高。对于>0.125、0.075-0.125和0.05-0.075 mm的颗粒尺寸范围尤其如此。浸出实验揭示了废弃粉煤灰中汞的二次释放。粉煤灰中的汞浓度随着注入活性炭或溴化活性炭量的增加而增加。汞的浸出浓度随粉煤灰粒径的增大而增大。因此，在处理粉煤灰时，添加适量的活性炭或溴化活性炭可以控制汞的二次释放。在锅炉燃煤前添加CaBr 2也有助于控制汞的二次释放，通过增加渗滤液中的Hg 2+浓度。该研究为粉煤灰处理过程中汞的控制和去除提供了理论依据。
The secondary release of mercury from coal fly ash is a negative by-product from coal-fired power plants, and requires effective control to reduce environmental pollution. Analysing particle size distribution and composition of the coal fly ash produced by different mercury removing technologies indicates that the particles are generally less than 0.5 mm in size and are composed mainly of SiO2, Al2O3, and Fe2O3. The relationships between mercury concentration in the coal fly ash, its particle size, and loss of ignition were studied using different mercury removing approaches. The research indicates that the coal fly ash's mercury levels are significantly higher after injecting activated carbon or brominating activated carbon when compared to regular cooperating-pollution control technology. This is particularly true for particle size ranges of >0.125, 0.075–0.125, and 0.05–0.075 mm. Leaching experiments revealed the secondary release of mercury in discarded coal fly ash. The concentration of mercury in the coal fly ash increases as the quantity of injecting activated carbon or brominating activated carbon increases. The leached concentrations of mercury increase as the particle size of the coal fly ash increases. Therefore, the secondary release of mercury can be controlled by adding suitable activated carbon or brominating activated carbon when disposing of coal fly ash. Adding CaBr2 before coal combustion in the boiler also helps control the secondary release of mercury, by increasing the Hg2+ concentration in the leachate. This work provides a theoretical foundation for controlling and removing mercury in coal fly ash disposal.