Ce-Zr-Ox/ATS复合催化剂的制备及其催化氧化Hg^0性能研究

Preparation of Ce-Zr-O_x/ATS composite catalyst and its catalytic oxidation of Hg^0

采用等体积浸渍法制备了一系列的Ce-Zr-O_x/ATS复合催化剂,在模拟燃煤烟气中研究Ce-Zr-O_x/ATS复合催化剂催化氧化单质汞(Hg^0)的活性.结果表明,当空速小于7000 h^(-1)时,催化剂在200~350℃的温度区间内催化氧化活性能达到80%以上.当空速为3000 h^(-1),HCl浓度为20 mg·m^(-3),氧含量为6%(体积分数),350℃时催化剂活性最高为94.70%.催化剂表征结果表明,催化剂比表面积、孔容和孔径与汞脱除能力没有相关性.抗硫实验表明,SO_2会抑制Hg^0的脱除反应,原因是SO_2与HCl在催化剂表面活性位上的竞争吸附.300℃时,通入NH_3对催化活性有一定的抑制作用,原因是NH_3会与Hg^0和HCl在催化剂表面产生竞争吸附.

A series of Ce-Zr-Ox/ATS composite catalysts are prepared by isometric impregnation method. Ce-Zr-Ox/ATS catalyst is employed on the catalytic oxidation of Hg^0 in the presence of hydrogen chloride. Results show that Hg^0 oxidation efficiency maintains over 80%（ space velocity： 7000 h^-1）in the range of 200 -350 ℃. While the reaction temperature is 350 ℃,O2 content is 6%,and HCl content is 20 mg·m^-3,the Hg^0 oxidation efficiency reaches 94.7%. N2 adsorption results show that the specific surface area,pore volume and pore size of the catalyst are not correlated with mercury removal capacity. It is found that SO2 inhibits Hg^0removal reaction because of the competitive adsorption of SO2 and HCl in the active sites on the surface of the catalyst. NH3 also has the same inhibiting effect due to the competitive adsorption of NH3 and Hg^0.