论文总字数：28777字

摘 要

随着化石燃料比如石油等的大规模使用，所产生的氮氧化物不断排放，其已成为危害环境的首要污染物之一。氨气选择性催化还原（NH₃-SCR）因其脱硝效率高、相对性价比高和系统安全稳定，已经成为了当下催化技术的主流。而SCR技术的核心是催化剂。其中本课题组前期研制出了一种适用于柴油机的环境友好型12%-Ce_0.8SnMo_0.6O_X/TiO₂（CSM/T）脱硝催化剂，具有良好的脱硝性能，但其抗水，抗硫中毒能力较低仍有待提升。

本次毕业设计，希望通过硫酸化的方法试图提高该催化剂的中高温催化活性以及抗水硫中毒的能力。采用挤出成型法分别制备了硫酸含量为0.2 wt%、0.4 wt%、0.6 wt%、0.8 wt%和1 wt%的CSM/T系列催化剂，记作xH-CSM/T，x为催化剂硫酸质量分数。测试了其基础脱硝活性及抗水硫中毒性能。低温催化活性随着硫酸的加入量有一定降低，但是高温催化活性有一定的升高。硫酸加入量的多少对水中毒的影响不大，但是随着加入量的增多，抗硫中毒与抗水硫中毒能力先提高后降低。0.2 wt%H-CSM/T在通入SO₂时，活性为98.21 %；通入水硫时，活性为90.92 %，较之未经硫酸化的样品，都有显著提高。

关键词：氮氧化物 NH₃-SCR 脱硝催化剂 硫酸化

Effect of Sulfation Treatment on DeNOx Performance of CeSnMoOx/TiO₂

ABSTRACT

With the large-scale use of fossil fuels such as petroleum, the production of nitrogen oxides continues to be emitted, and it has become one of the primary pollutants that harm the environment. Ammonia selective catalytic reduction (NH₃-SCR) has become the mainstream of current catalytic technology because of its high denitration efficiency, relatively high cost performance and safe and stable system. The core of SCR technology is the catalyst. In the early stage, the research group developed an environmentally friendly 12%-Ce_0.8SnMo_0.6O_X/TiO₂ (CSM/T) denitration catalyst suitable for diesel engines, which has good denitration performance, but its resistance to water and sulfur poisoning. The lower is still to be upgraded.

In this graduation design, it is hoped that the sulfation process will attempt to improve the medium-high temperature catalytic activity of the catalyst and the ability to resist water sulfur poisoning. The CSM/T series catalysts with a sulfuric acid content of 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, and 1 wt% were separately made by extrusion molding, recorded as xH-CSM/T, x meaning the catalyst sulfuric acid mass fraction. We test their basic deNO activity and resistance to H₂O and sulfur poisoning. The catalytic activity at low temperature decreases with the addition of sulfuric acid, but the catalytic activity at high temperature increases.When 0.2 wt% H-CSM/T was introduced into SO₂, the activity was 98.21%; when water sulfur was introduced, the activity was 90.92 %, which was significantly higher than that of the unsulfated sample.

Keywords: nitrogen oxides NH₃-SCR deNOx catalyst sulfation

目录

摘要 I

ABSTRACT II

目录 III

第一章 绪论........................................... 1

1.1 引言 1

1.2 选择性催化还原脱硝 2

1.3 SCR脱硝催化剂 3

1.3.1贵金属催化剂 3

1.3.2分子筛催化剂 4

1.3.3金属氧化物催化剂 4

1.3.4 Ce基催化剂 5

1.4催化剂水硫中毒 6

1.5硫酸化对催化剂的影响 7

1.6 研究思路和研究内容 8

第二章 实验方法 9

2.1 实验原料及仪器 9

2.1.1实验原料 9

2.1.2实验仪器 9

2.1.3 NOx-SCR实验系统 10

2.2 xH-CSM/T样品的制备 10

2.3催化剂的表征 11

2.3.1 XRD分析 11

2.3.2扫描电镜（SEM）分析 11

第三章 结果与讨论 12

3.1 xH-CSM/T催化剂性能的评价 12

3.1.1硫酸化催化剂的脱硝活性 12

3.1.2 xH-CSM/T的抗水中毒研究 13

3.1.3 xH-CSM/T的抗硫中毒研究 14

3.1.4 xH-CSM/T的抗水硫中毒研究 16

3.2 xH-CSM/T的XRD分析 18

3.4 xH-CSM/T的SEM分析 19

3.5 本章小结 19

第四章 结论和展望 21

4.1 结论 21

4.2 展望 21

参考文献 22

致谢 27

第一章 绪论

1.1 引言

当代中国的工业发展非常迅猛，由此带来了我们对于化石燃料的需求日益增高的结果。然而这导致了环境的严重污染，尤其在气体污染方面，这影响着生活环境的同时也影响着人们的身体。氮氧化物是导致大气污染的重要原因之一^[1]。NO_x严重危害人类的身体健康。而且由NO_x产生的二次污染物比如说细粒子污染、雾霾天气、光化学烟雾等都具有较强的毒性。不仅仅是这些，一氧化氮易被氧化成为二氧化氮，溶于水之后形成硝酸、亚硝酸，二者是引发酸雨的重要因素。^[2-4]数量上来看，氮氧化物中70 %是产生于煤炭直接燃烧，因此如何去除燃烧烟气中NO_x成为亟待解决的问题。所以目前越来越多的人开始关注烟气脱硝。它的基本原理是将燃烧烟气中的氮氧化物还原成为氮气，如此便将氮氧化物除去。

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