本文關鍵詞： 脫硝 催化臭氧化 Mn-Ce/TiO_2催化劑 CeTi催化劑 羥基自由基　出處：《南京理工大學》2017年碩士論文　論文類型：學位論文

【摘要】：氮氧化物(NO_x)是主要的大氣污染物之一,工業(yè)爐窯、燒結機、催化裂化裝置等中小型鍋爐排煙溫度偏低,無適合安裝選擇性催化還原(SCR)脫硝裝置的溫度區(qū)(320～400 ℃)�；诔粞踔卫砉に嚮A上提出的催化臭氧化脫硝技術是一種比較適合的脫硝工藝。為推進這一工藝的工業(yè)化進程,本文針對催化臭氧化脫硝技術,對其催化劑進行了制備、改性以及脫硝性能的研究,探究了反應過程機制,并制備了工業(yè)級催化劑進行了實際煙氣脫硝性能測試以及工藝調(diào)試。首先,以Ce作為催化劑的活性成分,通過摻雜一定比例的Mn形成Mn-Ce固溶體然后負載在二氧化鈦載體上制備得到了 Mn-Ce/TiO2催化劑作為研究對象,考察了不同合成方法和不同晶相的載體對催化劑催化活性的影響。通過對比發(fā)現(xiàn),銳鈦礦和單斜相混合晶相的二氧化鈦載體所對應的催化劑具有最高的活性,在40 ℃時脫硝活性可達90%。此外還探究了催化臭氧化脫硝的反應機制,發(fā)現(xiàn)在催化臭氧化脫硝反應中,羥基自由基是主要的活性物質,催化劑表面的氧空位有利于表面羥基的生成,臭氧會與表面羥基作用生成羥基自由基而進行脫硝反應。但從催化臭氧化脫硝工業(yè)應用來講,催化劑制備復雜,成功率不高,不利于進行實際工業(yè)應用,需要進一步改進。為此,用共沉淀法制備了無定形的CeTi復合氧化物催化劑,并采用非金屬氟摻雜對其進行改性。氟摻雜促進了 Ce、Ti之間的相互作用,氟原子取代了晶格中的氧原子,增加了催化劑表面表面氧空位和表面羥基的數(shù)量,且使催化劑表面親水性更強,更容易形成表面羥基,從而提升催化劑脫硝效率。相比較Mn-Ce/TiO2催化劑,CeTi催化劑同樣表現(xiàn)出較好的催化活性,而制備過程更簡單,適合大批量成型生產(chǎn),是一種適合催化臭氧化脫硝工業(yè)應用的催化劑。按照Ce:Ti = 3:7的摩爾比制備了顆粒狀CeTi催化劑,并在煙氣管道上加入了臭氧發(fā)生器、高壓噴頭等催化臭氧化脫硝工藝設備。在燃煤鍋爐實際煙氣條件下對制備的催化劑進行了測試,并對工藝條件進行了一些優(yōu)化,發(fā)現(xiàn)催化臭氧化工藝有一定的脫硝效果,但離實驗室效果還是有一定差距,需要在催化劑成型以及工藝條件上進一步優(yōu)化。在催化劑的制備成型和工藝條件上積累了一定經(jīng)驗,也為開發(fā)出更適合催化臭氧化脫硝的工業(yè)催化劑打下了基礎。
[Abstract]:No _ x (no _ x) is one of the main air pollutants, and the flue gas temperature of small and medium-sized boilers, such as industrial furnaces, sintering machines, catalytic cracking units, etc., is on the low side. The catalytic ozonation denitrification technology based on ozone treatment technology is a more suitable denitrification process. In order to advance the industrialization process of this process, the catalytic ozonation denitrification technology is not suitable for the installation of selective catalytic reduction (SCR) denitrification unit. In this paper, the preparation, modification and denitrification performance of catalytic ozonation denitrification catalyst were studied, and the mechanism of reaction process was explored. The industrial grade catalyst was prepared to test the performance of flue gas denitrification and to adjust the process. Firstly, ce was used as the active component of the catalyst. The Mn-Ce catalyst was prepared by doping a certain proportion of mn to form a Mn-Ce solid solution and then supported on the TIO _ 2 carrier. The effects of different synthesis methods and supports of different crystal phases on the catalytic activity of the catalysts were investigated. It was found that the corresponding TIO _ 2 carriers with anatase and monoclinic mixed crystal phases had the highest catalytic activity. In addition, the mechanism of catalytic ozonation denitrification is investigated. It is found that hydroxyl radical is the main active substance in catalytic ozonation denitrification. The oxygen vacancy on the surface of the catalyst is favorable to the formation of the surface hydroxyl group, and ozone will react with the surface hydroxyl group to form hydroxyl radical for denitrification, but from the industrial application of catalytic ozonation denitration, the preparation of the catalyst is complicated and the success rate is not high. Therefore, amorphous CeTi composite oxide catalysts were prepared by coprecipitation method and modified by nonmetallic fluorine doping. Fluorine atoms replace the oxygen atoms in the lattice, increase the number of oxygen vacancies and surface hydroxyl groups on the surface of the catalyst, and make the surface hydrophilic of the catalyst more hydrophilic, making it easier to form surface hydroxyl groups. Compared with Mn-Ce/TiO2 catalyst, CeTi catalyst also showed better catalytic activity, and the preparation process was simpler and suitable for mass production. Granular CeTi catalyst was prepared according to the molar ratio of Ce:Ti = 3: 7, and the ozone generator was added to the flue gas pipeline. The catalytic ozonation process equipment, such as high pressure nozzle, has been tested and optimized under the actual flue gas condition of coal-fired boiler. It is found that the catalytic ozonation process has certain denitrification effect. However, there is still a certain gap from the laboratory, which requires further optimization in catalyst forming and process conditions. Some experience has been accumulated in the preparation, molding and process conditions of catalysts. It also lays a foundation for the development of a more suitable industrial catalyst for catalytic ozonation denitrification.
【學位授予單位】：南京理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：X701;O643.36

【參考文獻】

相關期刊論文 前10條

1 楊杰;康科偉;;火力發(fā)電廠脫硝技術研究[J];科技信息;2013年22期

2 綦振華;;燃燒型氮氧化物生成、控制途徑及技術淺談[J];科技致富向導;2012年23期

3 耿媛媛;侯永江;杜金梅;韋曉竹;;多相催化臭氧化技術中催化劑的研究進展[J];工業(yè)水處理;2011年02期

4 王莉;吳忠標;;濕法脫硝技術在燃煤煙氣凈化中的應用及研究進展[J];安全與環(huán)境學報;2010年03期

5 陳曦;劉勇健;;催化臭氧化法深度處理印染污水的實驗研究[J];應用化工;2009年04期

6 陳忠林;徐貞貞;賁岳;葉苗苗;馬新紅;;ZnOOH/O_3催化臭氧化體系去除水中痕量對氯硝基苯[J];環(huán)境科學;2007年11期

7 曲險峰;鄭經(jīng)堂;于維釗;;活性炭纖維催化臭氧化降解苯酚及其對炭表面性能的影響[J];環(huán)境污染與防治;2007年09期

8 曲險峰;鄭經(jīng)堂;;均相催化臭氧化反應的研究進展[J];水處理技術;2006年12期

9 周云瑞;祝萬鵬;劉福東;王建兵;楊少霞;;Al_2O_3催化劑結構對催化臭氧化活性的影響[J];化學學報;2006年09期

10 周云瑞;祝萬鵬;;Al_2O_3催化臭氧化處理鄰苯二甲酸二甲酯[J];環(huán)境科學;2006年01期

，

本文編號：1543195