综合利用农业废弃物制备复合载体SCR脱硝催化材料的工艺及性能研究

Based on the problems such as the pollution of nitrogen oxides, the high cost of titanium base denitration catalyst materials, it attracts a great deal of attention recently to prepare composite carrier SCR denitration catalyst materials with excellent performance by low-cost strategy. To solve the above-mentioned problem, in this project silica aerogel and silica nano particles are synthesized by recycled technology using cheap agricultural waste such as rice husk as raw materials, and using ammonium fluoride which is the by-product of fertilizer production as extraction agent. The technology realize the comprehensive utilization of rice husk, get rid of the problems such as high energy consumption and serious pollution caused by using sodium silicate as raw material to prepare silica by traditional method. Through sol-gel method or co-precipitation method make the silica and titanium dioxide to implement in-situ composite at the molecular level. The synthesis efficiency and recyclability will be investigated in detail in the project, in order to obtain the structure and performance of SCR denitration catalytic materials with Si-Ti composite carrier and related technology parameters. The microstructure of catalytic materials, gas adsorption and catalytic properties will be characterized. The project results will provide theoretical basis for the utilization of agricultural wastes and technical support to help industrial kiln NOx emission reduction and SCR denitration catalyst material industrialization, has important academic significance and higher application value and social benefits.

针对目前氮氧化物减排形势严峻，钛基脱硝催化材料成本高昂等问题，低成本制备具有优异性能的复合载体SCR脱硝催化材料是该领域的重要发展趋势。本项目以农业废弃物稻壳为原料，化肥生产的副产物氟化铵为提取剂，采用可循环工艺制备纳米二氧化硅颗粒和硅凝胶，实现稻壳的综合利用，摆脱传统方法以硅酸钠为原料制备二氧化硅而造成的能耗高、污染大等问题。通过溶胶-凝胶法，共沉淀法使二氧化硅和二氧化钛在分子水平上实现原位复合，项目将对工艺合成效率、可循环性进行深入的研究，以期获得结构和性能优异的硅钛复合载体SCR脱硝催化材料及相关工艺技术参数，并对催化材料的微观结构、气体吸附性能以及催化性能进行表征。本项目成果将为农业废弃物的资源化利用提供理论依据和技术支持，有助于工业窑炉氮氧化物减排以及SCR脱硝催化材料产业化，具有重要的学术意义以及较高应用价值和社会效益。

氮氧化物（NOX）能够形成酸雨、光化学烟雾、破坏臭氧层等大气污染，严重危害人体的呼吸系统和神经中枢。工业生产排放占NOX排放总量的71.9%。选择性催化还原（SCR）技术可以有效脱除固定源NOX。而工业窑炉经过除尘、余热发电后的烟气温度低于200℃，同时烟尘中含有碱性氧化物。国内外脱硝催化材料一般在600℃左右才表现出高催化活性，影响在复杂工况下的推广应用。研究开发低温高活性、抗碱中毒能力强的SCR催化材料是实现NOX减排的发展趋势。.鉴于农业废弃物稻壳中非晶态硅含量高的特点，本项目以稻壳为原料采用溶胶凝胶、共沉淀法制备出了以TiO2-SiO2复合材料为载体，锰铈为活性组分的脱硝催化材料。探究了SiO2的添加对催化材料微观结构的影响，并对不同硅含量催化材料的脱硝机理进行了相关分析。实验结果表明，与纯TiO2为载体的催化材料相比，TiO2-SiO2复合材料为载体的催化材料表面颗粒大小均匀，呈蓬松状态堆积，比表面积及孔容都有所增加，弱酸性位点的数量也大大提高，当SiO2与TiO2的摩尔比为4:1时，脱硝效率可达90%以上。.本项目经三年的研究，全面完成了项目计划书中的各项研究任务，工作进展顺利，并取得了预期的研究成果。本项目共计发表标注资助学术论文6篇，其中SCI 收录论文3篇，EI 收录论文3篇；申请发明专利4项。本项目成果对于实现节能减排，建设绿色生态环境具有重大的意义。