MnOx/HZSM-5去除烟气中元素态汞的实验研究

采用浸渍法制备了一系列的MnOx/HZSM-5,在实验烟气中研究了MnOx/HZSM-5对Hg0的去除行为,并运用比表面(BET)和X-射线衍射(XRD)技术对其进行了表征.结果表明,在6%O2条件下HZSM-5本身具有良好的去除Hg0的性能,改性后的分子筛对Hg0吸附和氧化的能力得到改善,且MnOx负载量在10%时效果最佳;适当升高反应温度能增强脱汞效率,300℃为最佳反应温度;烟气中O2能促进汞的氧化,而NO和SO2与汞竞争MnOx/HZSM-5上的活性位,对Hg0的氧化有一定的抑制作用.此外,研究还发现,在MnOx/HZSM-5吸附剂上Hg0主要是经氧化形成HgO,其脱汞机理在一定程度上符合Mars-Maessen机理.

Experimental study of removing elemental mercury from flue gas by MnOx/HZSM-5

A series of HZSM-5 zeolite loading MnOx were prepared by impregnation method to investigate their removal characteristics of Hg0 in experimental flue gas, and characterized by X-ray diffraction (XRD) and surface area measurement (BET) methods. These experimental results suggested that HZSM-5 had good activity on removing Hg0 in the presence of 6% O2. After loading active components MnOx on HZSM-5 zeolite, the removal efficiency of Hg0 could be increased, and the best loading amount was 10%. Rising reaction temperature appropriately could enhance the removal efficiency of Hg0, and the optimum temperature was 300℃. O2 in flue gas could promote the oxidation of Hg0 while NO and SO2 inhibited the mercury oxidation due to the competition of active sites on MnOx/HZSM-5 sorbents with Hg0. Additionally, it was verified that Hg0 on MnOx/HZSM-5 adsorbents was mainly oxidized into HgO, which agreed with the Mars-Maessen mechanism to a certain extent.