用于气态零价汞转化的催化剂研究
Study on catalysts for catalytic oxidation of gaseous elemental mercury
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摘要: 零价汞的高效去除是燃煤烟气汞污染控制过程中的关键环节。为了促进烟气中的零价汞转化为易于去除的氧化态汞，分别考察了在有HCl存在时，几种过渡金属氧化物（Cu、Fe、Mn、Co和Zr）对零价汞氧化的催化作用，以筛选出性能较好的催化组分；为提高催化剂的抗SO2性能，分别尝试了利用几种金属元素（Sr、Ce、W和Mo）对催化剂进行掺杂改性的方法。结果表明，锰氧化物的催化作用最好，其最佳使用温度在573 K左右；SO2对零价汞的催化氧化有明显抑制作用，在无SO2<Abstract: How to make elemental mercury removed efficiently is the key point for the control of mercury emission from the coal-fired flue gas. To obtain a high conversion from elemental mercury to its oxidation state, which can be easily captured by flue gas desulfurization systems, some catalysts were employed to assist with the oxidation of elemental mercury in the presence of hydrogen chloride,and four metals (strontium, cerium, tungsten, molybdenum) were used tentatively to modify the Mn-catalyst to improve their tolerance capacity to sulfur dioxide(SO2). The results showed that the manganese oxide displayed the highest catalytic oxidative efficiency at 573 K, and the removal efficiency of mercury by manganese can reach 93% and 78% without SO2 and with 1 400 mg/m3 SO2, respectively. Once modified with molybdenum, the removal efficiency of manganese oxides was above 90% with 1 400 mg/m3 SO2, which was significantly higher than the catalysts modified with the other elements.
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Key words:
- coal-fired gas /
- elemental mercury /
- catalytic oxidation /
- catalyst modification
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