低温选择性催化还原氮氧化物催化剂的开发

摘要氮氧化物能引起雾霾、光化学烟雾等环境问题。大多数燃煤电厂 SCR 反应器布置在电除尘器和脱硫装置之前，但是这种方式中 SO2 和烟尘对催化剂的影响较大，会导致脱硝效率降低。因此，开发出能适用于低温低尘布置方式的催化剂，对燃煤电厂脱硝效果将具有显著的提升。 76155

本文以拓宽Mn/Ti 催化剂的活性温度窗口为目的，在其中掺杂了金属 W，制备了Mn-W/Ti催化剂，同时对比W/Ti 催化剂，探究W 物种所起到的作用，改进 Mn基催化剂的性能。本文的主要成果如下： (1)以均匀沉淀法制备出的 Mn-W/Ti 催化剂低温段表现出了优异活性，150-300 oC 的NOx转化率均达到 80%以上，温度窗口得到了拓宽。此外，在整个温度范围内 Mn0。5W0。1TiOx上的N2O生成量均小于 Mn0。5TiOx，N2选择性更高。

(2)通过一系列表征，发现 W 物种的引入不仅没有改变催化剂原有的晶体结构，反而使得活性物质 Mn2O3在催化剂表面更加分散，提高了活性；W 物种还能增加催化剂表面的酸性位，提高了催化剂吸附 NH3的能力，从而提高了 SCR 活性。

毕业论文关键词 Mn基催化剂脱硝 NH3-SCR 低温活性

Title Development of catalyst for NOx selective catalytic reduction at lower temperatures

Abstract Nitrogen oxides can cause haze, photo-chemical smog and other environmental problems。 Most SCR units in coal-fired power plants were disposed in a "high temperature and high dust" way, SO2 and dust will greatly affect the catalyst, results in a decline in the efficiency of the removal of NOx。 Therefore, developing a kind of catalyst which is apply to the "low temperature and low dust" arrangement, will greatly improve the deNOx effect of coal-fired power plants。

This study takes an aim of broadening the temperature window of Mn/Ti catalyst, doped W species into the catalyst and Mn-W/Ti catalyst was prepared。 At the same time, we compared with W/Ti catalyst, investigated the effect of W species and improved the SCR performance of Mn based catalyst。

The main conclusion of this work are as follows:

(1) Mn-W/Ti catalyst prepared by homogeneous precipitation method showed an excellent SCR activity at low temperature, the NOx conversion at 150 to 300 oC was up to 80%, the temperature window was broaden。 In addition, the N2O formation over Mn0。5W0。1TiOx was less than Mn0。5TiOx in the whole temperature range, the N2 selectivity was also higher than Mn0。5TiOx。

(2) Through a series of characterization, we found that the original crystal structure of the catalyst did not change after the introduction of W species, instead, it dispersed the Mn2O3 on the surface of the catalyst and improved the activity。 W species also increased the acid sites on the surface of the catalyst, improved the NH3 adsorption ability of the catalyst and enhanced the activity。

Keywords Mn based catalyst DeNOx NH3-SCR Low temperature activity

1 研究背景 1

1。1 氮氧化物污染概论 1

1。2 NH3-SCR 脱硝技术 2

1。3 NH3-SCR 催化剂 3

1。4 燃煤电厂 SCR 反应器的布置 4

1。5 Mn 基低温 NH3-SCR 催化剂 4

2 实验系统与分析方法低温选择性催化还原氮氧化物催化剂的开发:http://www.youerw.com/huaxue/lunwen_87282.html