本文選題：脫硝 + 選擇性催化還原　； 參考：《大連理工大學(xué)》2016年碩士論文

【摘要】：隨著我國(guó)經(jīng)濟(jì)的快速發(fā)展以及工業(yè)化進(jìn)程的加快,對(duì)化石燃料的消耗量不斷加大,導(dǎo)致NOx排放量逐年增加,因此引發(fā)了嚴(yán)重的大氣環(huán)境污染。氨選擇性催化還原技術(shù)被認(rèn)為是最為有效的去除氮氧化物的方法,而合成低毒性高活性且溫度窗口較廣的催化劑在脫硝領(lǐng)域越來(lái)越受到關(guān)注。本文基于鈰鈦金屬氧化物催化劑催化效果的不足,采用浸漬及浸漬-共沉淀聯(lián)用的方法,在鈰鈦金屬氧化物催化劑的基礎(chǔ)上,成功地制備出不同比例的鉬鈰鈦及鈰鋁鈦復(fù)合金屬氧化物脫硝催化劑,結(jié)合比表面積、X-射線光電子能譜、氫氣程序升溫還原等表征手段以及原位紅外分析技術(shù)對(duì)催化劑的催化活性和物理化學(xué)性質(zhì)進(jìn)行分析,并對(duì)其反應(yīng)機(jī)理進(jìn)行了探討。具體研究?jī)?nèi)容如下：(1)采用浸漬法制備了Mo-Ce-Ti復(fù)合氧化物催化劑,并研究了Mo負(fù)載量對(duì)NH3-SCR活性的影響,對(duì)其進(jìn)行活性測(cè)試發(fā)現(xiàn)在200～440℃溫度范圍內(nèi)25%Mo-Ce-Ti催化劑表現(xiàn)出90%以上的脫硝效率,SCR活性最佳；相較于Ce-Ti催化劑,Mo的摻雜增加了催化劑的氧化還原能力,同時(shí)提高了催化劑表面化學(xué)吸附氧含量,因而使該催化劑的脫硝性能得到顯著增強(qiáng)。(2)在最佳反應(yīng)溫度條件下,對(duì)Mo-Ce-Ti體系催化劑進(jìn)行紅外吸附及瞬態(tài)反應(yīng)測(cè)試。結(jié)果顯示Mo的摻雜增加了2.5%Mo-Ce-Ti催化劑表面Lewis酸性位上和Br(?)nsted酸性位上吸附的NH3物種及NH2物種,NH2與氣相NO反應(yīng)生成NH2NO,最終轉(zhuǎn)化為N2和H2O,反應(yīng)主要遵循E-R機(jī)理。(3)采用浸漬-共沉淀法聯(lián)用制備了Ce-Al-Ti體系催化劑,并研究了Al:Ti摻雜比例對(duì)NH3-SCR活性的影響。結(jié)果顯示Al:Ti摩爾比為1：3的Ce/Al1Ti3催化劑在200～475℃之間可以達(dá)到95%以上的NOx轉(zhuǎn)化率。Al與Ti元素的充分摻雜增加了催化劑的比表面積、表面吸附氧含量及反應(yīng)活性位點(diǎn),從而提高了該催化劑的脫硝性能。(4)在最佳反應(yīng)溫度條件下,采用原位紅外光譜技術(shù)研究了Ce/Al1Ti3催化劑的反應(yīng)機(jī)理。相較于Ce-Ti催化劑,Al的摻雜增加了催化劑表面Br(?)nsted酸性位點(diǎn),使得氨更易吸附在催化劑表面,且生成了反應(yīng)的主要活性物種-NH2,加速了反應(yīng)控速步驟的進(jìn)行。該催化劑表面發(fā)生的NH3-SCR反應(yīng)遵循E-R機(jī)理。
[Abstract]:With the rapid development of China's economy and the acceleration of industrialization, the consumption of fossil fuels is increasing, which leads to the increase of NOx emissions year by year, thus causing serious air pollution. Ammonia selective catalytic reduction is considered to be the most effective method to remove nitrogen oxides. However, the synthesis of catalysts with low toxicity and high activity and wide temperature window has attracted more and more attention in the field of denitrification. In this paper, based on the lack of catalytic effect of cerium titanium metal oxide catalyst, the methods of impregnation and impregnation and coprecipitation are adopted, on the basis of cerium titanium metal oxide catalyst. The catalysts for denitrification of molybdenum, cerium, titanium and cerium-aluminum-titanium composite metal oxides have been successfully prepared, and the specific surface area has been determined by X- ray photoelectron spectroscopy. The catalytic activity and physicochemical properties of the catalyst were analyzed by means of hydrogen temperature-programmed reduction and in situ infrared analysis, and the reaction mechanism was discussed. The main contents are as follows: (1) Mo-Ce-Ti composite oxide catalyst was prepared by impregnation method, and the effect of Mo loading on NH3-SCR activity was studied. It was found that the 25%Mo-Ce-Ti catalyst exhibited the best denitrification efficiency and the best catalytic activity in the temperature range of 200 鈩，

本文編號(hào)：1842233