Ce-Mn/ZrO_(2)复合催化剂的制备及其固硫性能

Preparation of Ce-Mn/ZrO_(2)Composite Catalyst and Its Sulfur Fixation Performance

污泥焚烧过程中会产生SO_(2)污染环境,通过添加钙基固硫剂可将硫固定在灰渣里,但是固硫效果受高温抑制。针对上述问题,采用共沉淀法制备了Ce-Mn/ZrO_(2)复合催化剂,利用场发射扫描电子显微镜-能量色散X射线谱仪(FESEM-EDS)、透射电子显微镜(TEM)、X射线粉末衍射仪(XRD)和X射线光电子能谱仪(XPS)表征催化剂的组成和形貌。将催化剂与污泥、钙基固硫剂混合,在自动测硫仪上进行高温固硫实验,研究其固硫催化性能,借助热重分析和燃烧动力学参数拟合计算探究其催化机理。实验结果表明,催化剂中活性组分Ce、Mn在载体中高度分散,Ce-Mn之间的协同作用可以为催化剂表面提供更多的氧空位,促进SO_(2)转变为SO_(3)。当n(Ca)/n(S)=1.5时,Ce-Mn/ZrO_(2)的质量分数为3.5%,燃烧温度为1000℃时,固硫率高达72.60%。Ce-Mn/ZrO_(2)可以降低污泥燃烧着火点和反应活化能,促进污泥燃烧,稳定固硫产物。该催化剂具有优异的催化活性,在污泥焚烧脱硫领域具有十分广阔的应用前景。

SO_(2)released during sludge combustion causes significant environmental pollution.Sulfur can be fixed in the ash by adding a calcium-based sulfur-fixing agent,but the effect is limited because of its easy sintering at high temperatures.Herein,Ce-Mn/ZrO_(2)composite catalysts were prepared by coprecipitation method to improve the sulfur-fixing effect,and the composition and morphology of the catalysts were characterized by field emission scanning electron microscopic-energy dispersive spectroscopy(FESEM-EDS),transmission electron microscopy(TEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).Further,by mixing the catalyst with a calcium-based sulfur-fixing agent and sludge,high-temperature sulfur-fixing experiments were carried out on a sulfur determination device to study its sulfur-fixing performance.The results showed that the synthesis method of the catalyst could effectively disperse Ce and Mn elements in the carrier.The synergistic effect between Ce-Mn could promote a reaction to produce more oxygen vacancies,thereby promoting the conversion of SO_(2)to SO_(3).The sulfur fixation rate was as high as 72.60%when n(Ca)/n(S)=1.5,the content of Ce-Mn/ZrO_(2)catalyst was 3.5%and the combustion temperature was 1000℃.The results of the thermogravimetric analysis showed that the temperatures of sludge ignition were depressed as well as reaction activation energy,and the combustibility of sludge could be promoted after the agents were added.So that the sulfur fixation product could be stable.Ce-Mn/ZrO_(2)presents an excellent catalytic activity for sulfur fixation,so it has a broad prospect in enhancing sulfur removal in sludge combustion.