Zhang Guopei, Wang Zhongwei, Cui Lin, Zhang Xiaoyang, Chen Shouyan, Dong Yong
National Engineering Laboratory for Coal-fired Pollutants Emission Reduction, Shandong University, Jinan 250061, China.
China Special Equipment Inspection and Research Institute, Beijing 100029, China.
ACS Omega. 2019 Nov 6;4(21):19399-19407. doi: 10.1021/acsomega.9b02825. eCollection 2019 Nov 19.
In the work, sulfur-containing sorbents were employed to remove elemental mercury (Hg) from coal-fired flue gas. The work used the thermogravimetric analysis, Brunauer-Emmett-Teller method, scanning electron microscopy with energy-dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy to characterize the physicochemical properties of the sorbents. The Hg removal performance of these used sorbents from the simulated coal-fired flue gas was evaluated by a bench-scale fixed-bed reactor. The results indicated that a generous amount of elemental sulfur covered the surface and pore structure of the used sorbent. With the rise of HS selective oxidation temperature, both the sulfur content and specific surface area decreased rapidly. Used-Fe/SC120 could achieve the mercury removal efficiency of above 90% at 90 °C. The high temperature was not conducive to the mercury capture due to the release of surface elemental sulfur. The presence of O and SO inhibited Hg removal in different degrees because of the decreased active sulfur sites and competitive adsorption. Meanwhile, NO promoted the Hg removal efficiency by enhancing the Hg oxidation. The further analysis showed that the surface elemental sulfur was vital to capture the Hg from coal-fired flue gas, which reacted with Hg to form HgS.
在这项工作中，采用含硫吸附剂从燃煤烟气中脱除单质汞（Hg）。该工作利用热重分析、布鲁诺尔-埃米特-泰勒法、带能谱的扫描电子显微镜、X射线衍射和X射线光电子能谱对吸附剂的物理化学性质进行表征。通过小型固定床反应器评估这些用过的吸附剂对模拟燃煤烟气中汞的脱除性能。结果表明，大量单质硫覆盖在用过的吸附剂的表面和孔隙结构上。随着HS选择性氧化温度的升高，硫含量和比表面积均迅速下降。用过的Fe/SC120在90℃时可实现90%以上的汞脱除效率。由于表面单质硫的释放，高温不利于汞的捕集。O和SO的存在由于活性硫位点减少和竞争吸附而不同程度地抑制汞的脱除。同时，NO通过增强汞的氧化促进汞的脱除效率。进一步分析表明，表面单质硫对于从燃煤烟气中捕集汞至关重要，其与汞反应形成HgS。
