Effect of impregnation sequence of Pd/Cery-Al2O3 sorbents on Hg-0 removal from coal derived fuel gas
Effect of impregnation sequence of Pd/Cery-Al2O3 sorbents on Hg-0 removal from coal derived fuel gas
复制标题
Pd/Cery-Al2O3 吸附剂的浸渍顺序对煤制燃气中 Hg-0 去除的影响
DOI：
10.1016/j.chemosphere.2020.126164
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发表时间：
2020
期刊：
影响因子：
8.8
通讯作者：
Xie Kechang
中科院分区：
文献类型：
--
作者：
Huo Qihuang;Yue Caixia;Wang Yahui;Han Lina;Wang Jiancheng;Chen Shuai;Bao Weiren;Chang Liping;Xie Kechang
研究了浸渍顺序对Pd/Ce/γ-Al 2 O3吸附剂除汞效果的影响。为此，制备了Pd/γ-Al 2 O3、Ce/γ-Al 2 O3和3种浸渍Ce的Pd基吸附剂，并在模拟煤制燃气（N2-H2-CO-H2S-Hg）中进行了吸附性能测试。测试分别在250 ° C和300 °C下进行。结果表明，同时浸渍Pd和Ce制备的Ce-Pd/γ-Al 2 O3吸附剂对Hg 0的去除效果明显优于其他3种吸附剂，且吸附效果稳定。Ce-Pd/γ-Al 2 O3吸附剂在250 °C下480 min内的除汞率达到98%以上，300 °C下200 min内的除汞率达到91%以上。表征结果表明，共浸渍法制备的Ce-Pd/γ-Al 2 O3吸附剂比表面积（216.6 m2/g）大于其他3种Pd基吸附剂。Ce-Pd/γ-Al 2 O3吸附剂表面的Pd和Ce含量分别为0.21%和0.61%，高于其它3种Pd基吸附剂，且STEM-XEDS图谱显示其分散度最高。结果表明，在共浸渍法制备吸附剂的过程中，Ce的加入有利于Pd在载体表面的分散。同时，Ce的加入提高了脱硫剂的抗H2S性能。因此，Ce-Pd/γ-Al 2 O3吸附剂具有最佳的除汞性能。本文还对Pd/Ce/γ-Al 2 O3吸附剂在模拟煤制燃气中的除汞机理进行了阐述。
This study attempted to investigate the effect of impregnation sequence of the Pd/Ce/γ-Al2O3sorbents on Hg0removal. To this end, five kinds of sorbents were prepared and tested in simulated coal derived fuel gas (N2–H2–CO–H2S–Hg), including Pd/γ-Al2O3, Ce/γ-Al2O3and three kinds of Pd-based sorbents with Ce impregnation onγ-Al2O3substrate. The tests were conducted at 250 and 300 °C respectively. According to the results, bimetallic Ce–Pd/γ-Al2O3sorbent prepared by simultaneously impregnating Pd and Ce showed much higher and more stable removal efficiency of Hg0than the other three kinds of sorbents. The Hg0removal efficiency of Ce–Pd/γ-Al2O3sorbent reached above 98% within 480 min at 250 °C and 91% within 200 min at 300 °C. Characterization results indicated that the sorbent Ce–Pd/γ-Al2O3prepared by the co-impregnation method had bigger specific surface area (216.6 m2/g) than the other three kinds of Pd-based sorbents. The content Pd and Ce on the sorbent Ce–Pd/γ-Al2O3surface is 0.21% and 0.61%, which proved higher than that of the other three kinds of Pd-based sorbents, and observation from STEM-XEDS maps showed it demonstrated the highest dispersion. It is found that Ce is likely to promote the dispersion of Pd on the support surface during the preparation of the sorbent under the co-impregnation method. Meanwhile, Ce enhanced the H2S resistance of the sorbent. Thereby, Ce–Pd/γ-Al2O3sorbent is found to have the optimal performance of mercury removal. In this study, the Hg0removal mechanism of the Pd/Ce/γ-Al2O3sorbents in the simulated coal derived fuel gas was also elaborated.