本文選題：氮氧化物 + 直接分解��； 參考：《重慶科技學(xué)院》2017年碩士論文

【摘要】：氮氧化物(NO_x)是大氣主要污染物之一,其過量排放不僅會引起酸雨、光化學(xué)煙霧、霧霾等環(huán)境問題,嚴(yán)重危害人體健康與生態(tài)環(huán)境,并且還難以處理。因此,如何高效低成本地脫除工業(yè)煙氣中的氮氧化物對于防治大氣環(huán)境污染具有重要意義。在眾多氮氧化物脫除方法中,催化脫除法是最具發(fā)展前景和經(jīng)濟(jì)效益的方法,其中催化劑是該方法的核心。由于工業(yè)燃煤鍋爐所排放的煙氣具有高溫、高濃度粉塵和高含量SO_2的特點(diǎn),易導(dǎo)致催化劑失活,為減少這些因素對催化劑的影響,可將脫硝反應(yīng)器置于除塵和脫硫裝置之后,而此時(shí)的煙氣溫度低于300℃,難以滿足傳統(tǒng)催化劑V2O5-WO3/TiO_2所需反應(yīng)溫度,若對煙氣再次加熱到350℃以上,無疑會提高運(yùn)行成本。因此,研發(fā)低溫高效的脫硝催化劑是氮氧化物催化脫除方法的關(guān)鍵。本文以硝酸預(yù)處理后的活性炭為載體,以Ni、Cu、Mn為活性組分,并輔以稀土氧化鈰,采用浸漬法制備了一系列負(fù)載型金屬氧化物催化劑,用于直接催化分解NO性能研究�？疾炝溯d體預(yù)處理、浸漬方法等催化劑制備工藝條件,以及煙氣條件對催化劑分解活性的影響,并借助BET、FTIR、XRD和TEM表征手段,分析催化劑催化分解NO的反應(yīng)機(jī)理。BET和FTIR結(jié)果表明,HNO3預(yù)處理活性炭,不僅可增大其比表面積和孔容,還可以改變官能團(tuán)的種類與數(shù)量,以及減少活性炭表面的雜質(zhì)成分。在直接催化分解NO反應(yīng)體系中,三種不同金屬氧化物的活性順序?yàn)镹iOCuOMnO_2,CeO_2的改性可進(jìn)一步提高NiO/AC的活性,其中Ce4+/Ce3+和Ni2+/Ni3+具有強(qiáng)氧化還原能力,能加快還原/氧化循環(huán),從而可提高NO轉(zhuǎn)化率。XRD和TEM表征結(jié)果顯示,采用共同浸漬法形成的NiO和CeO_2結(jié)晶度低,晶粒小且均勻分散在活性炭表面上,當(dāng)Ni O和CeO_2負(fù)載量分別為5%和3%時(shí),該催化劑活性最佳,當(dāng)溫度為300℃時(shí),NO濃度在200~600ppm之間,空速在3900~5850h-1之間,氧含量在1~8%之間,其NO轉(zhuǎn)化率可保持在90~99%范圍內(nèi),該催化劑用于直接催化分解NO,操作彈性大,抗氧性能強(qiáng),脫硝率高,且該工藝無需NH3等有毒易燃易爆氣體作為還原劑,可避免二次污染,降低脫硝過程中的危險(xiǎn)性。本文研究了催化劑MO_x/AC和MO_x-CeO_2/AC的低溫SCR性能,結(jié)果表明三種不同金屬氧化物的低溫SCR活性順序?yàn)?MnO_2CuONiO,該活性順序與直接催化分解NO的活性順序正好相反,進(jìn)一步證明了催化劑具有選擇性,在低溫SCR反應(yīng)體系中,MnO_2具有較好的低溫SCR活性。XPS表明,MnO_2-CeO_2/AC中的Mn元素主要以Mn4+形式存在,而Ce元素主要以Ce4+和Ce3+共存,可增強(qiáng)電子之間的轉(zhuǎn)移,有利于活性位再生,使得MnO_2-CeO_2/AC表現(xiàn)出較好的低溫SCR活性。當(dāng)MnO_2與CeO_2負(fù)載量分別為5%和3%時(shí),該催化劑活性最佳,當(dāng)反應(yīng)溫度為75℃,n(NH3/NO)=1,空速在3900~9749h-1范圍內(nèi),氧含量在3~7%范圍內(nèi)時(shí),其NO轉(zhuǎn)化率可維持在90~99%左右,該催化劑適用于除塵脫硫工藝后,無需再次加熱,可有效降低運(yùn)行成本,且所需反應(yīng)溫度低至75℃,可避免高溫SCR反應(yīng)器和蒸汽對人體的高溫危害。
[Abstract]:Nitrogen oxide (NO_x) is one of the main pollutants in the atmosphere. Its excessive emission not only causes environmental problems such as acid rain, photochemical smog and fog haze, but also seriously endangering human health and ecological environment, and it is difficult to deal with. Therefore, it is important to remove nitrogen oxides from industrial flue gas to prevent and control atmospheric pollution. In many nitrogen oxides removal methods, catalytic removal is the most promising and economic benefit method. The catalyst is the core of the method. Because the flue gas emitted by the industrial coal-fired boiler has the characteristics of high temperature, high concentration of dust and high content of SO_2, it is easy to cause the deactivation of the catalyst, in order to reduce the effect of these factors on the catalyst. The denitrification reactor can be placed after the dedusting and desulphurization device, and the temperature of the flue gas is below 300 C at this time, and it is difficult to meet the reaction temperature of the traditional catalyst V2O5-WO3/TiO_2. If the flue gas is reheated to more than 350 C, it will undoubtedly increase the operating cost. Therefore, the research and development of the low temperature and high efficiency denitrification catalyst is the catalytic removal of nitrogen oxides. The key of the method. In this paper, a series of supported metal oxide catalysts were prepared by impregnation method with active carbon as the carrier, Ni, Cu, Mn as active components and rare earth cerium oxide, and used to prepare a series of supported metal oxide catalysts for direct catalytic decomposition of NO. The effect of gas conditions on the decomposition activity of the catalyst, and by means of BET, FTIR, XRD and TEM, analysis of the reaction mechanism of catalytic decomposition of NO by catalyst.BET and FTIR results show that HNO3 pretreated activated carbon can not only increase the specific surface area and Kong Rong, but also change the species and quantity of functional groups, and reduce the impurity components on the surface of activated carbon. In the direct catalytic decomposition NO reaction system, the activity sequence of three different metal oxides is NiOCuOMnO_2. The modification of CeO_2 can further improve the activity of NiO/AC, of which Ce4+/Ce3+ and Ni2+/Ni3+ have strong oxidation-reduction ability and can accelerate the reduction / oxidation cycle. Thus, the NO conversion rate.XRD and TEM characterization results can be shown to be used in common immersion. The crystallinity of NiO and CeO_2 formed by the method is low, and the grain is small and evenly dispersed on the surface of activated carbon. When the load of Ni O and CeO_2 are 5% and 3% respectively, the activity of the catalyst is the best. When the temperature is 300, the NO concentration is between 200~600ppm, the velocity of space is 3900~5850h-1, the oxygen content is between 1~8%, and the NO conversion can be kept in the 90~99% range. The catalyst is used to catalyze the decomposition of NO directly, with high elasticity, strong oxygen resistance and high denitrification rate, and the process does not need NH3 and other flammable and explosive gases as reducing agent. It can avoid two pollution and reduce the danger in the process of denitrification. This paper studied the SCR properties of the catalyst MO_x/AC and MO_x-CeO_2/AC at low temperature. The results showed that three kinds of gold were different. The order of SCR activity at low temperature of the genus oxide is MnO_2CuONiO, which is the opposite of the order of activity that directly catalyzes the decomposition of NO. It further proves that the catalyst is selective. In the low temperature SCR reaction system, MnO_2 has a good low temperature SCR active.XPS, which indicates that the Mn element in MnO_2-CeO_2/AC is mainly in Mn4+, and the Ce element is in the Ce element. The coexistence of Ce4+ and Ce3+ can enhance the transfer of electrons and benefit the regeneration of active sites, which makes MnO_2-CeO_2/AC exhibit good low temperature SCR activity. When the load of MnO_2 and CeO_2 is 5% and 3%, the catalyst has the best activity, when the reaction temperature is 75, n (NH3/ NO) =1, the air velocity is within the 3900~9749h-1 range, and the oxygen content is in 3~7% range. At the time, the conversion rate of NO can be maintained at about 90~99%. The catalyst is suitable for the dedusting and desulphurization process. It can not be reheated again, and it can effectively reduce the operating cost, and the required reaction temperature is low to 75 C, which can avoid the high temperature damage to the human body by the high temperature SCR reactor and steam.
【學(xué)位授予單位】：重慶科技學(xué)院
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X701

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 苗強(qiáng);;脫硝技術(shù)的現(xiàn)狀及展望[J];潔凈煤技術(shù);2017年02期

2 楊加強(qiáng);梅毅;王馳;龍光花;李帥;;濕法煙氣脫硝技術(shù)現(xiàn)狀及發(fā)展[J];化工進(jìn)展;2017年02期

3 劉森;王重慶;陳曉蓉;梅華;;Ni和Ce浸漬順序?qū)Υ呋瘎┐呋旨簝?nèi)酰胺加氫精制的影響[J];化學(xué)反應(yīng)工程與工藝;2016年02期

4 楚英豪;蓋志譜;王天澤;劉正;姚遠(yuǎn);尹華強(qiáng);郭家秀;;Ce摻雜對Mn/ACN催化劑低溫NH_3-SCR脫硝活性的影響[J];四川大學(xué)學(xué)報(bào)(工程科學(xué)版);2015年03期

5 李萍;曾令可;王慧;程小蘇;;氮氧化物排放控制技術(shù)分類[J];中國陶瓷工業(yè);2015年02期

6 施亞嵐;崔勝輝;許肅;林劍藝;黃葳;;需求視角的中國能源消費(fèi)氮氧化物排放研究[J];環(huán)境科學(xué)學(xué)報(bào);2014年10期

7 田立新;金汝蕾;;煤炭的碳排放研究及情景分析[J];管理學(xué)報(bào);2012年12期

8 楊娟;汪印;余劍;許光文;;活性炭負(fù)載金屬氧化物常溫脫除低濃度NO[J];化工學(xué)報(bào);2012年08期

9 李忠;牛燕燕;鄭華艷;付廷俊;朱瓊芳;陰麗華;;表面改性對Cu/活性炭催化劑表面Cu物種和催化活性的影響[J];無機(jī)化學(xué)學(xué)報(bào);2011年07期

10 杜媈;朱留財(cái);;氮氧化物污染防治的國外經(jīng)驗(yàn)與國內(nèi)應(yīng)對措施[J];環(huán)境保護(hù)與循環(huán)經(jīng)濟(jì);2011年04期

相關(guān)博士學(xué)位論文 前2條

1 崔佳麗;新型碳基催化劑的制備以及在環(huán)境催化中的應(yīng)用[D];太原理工大學(xué);2014年

2 金瑞奔;負(fù)載型Mn-Ce系列低溫SCR脫硝催化劑制備、反應(yīng)機(jī)理及抗硫性能研究[D];浙江大學(xué);2010年

相關(guān)碩士學(xué)位論文 前5條

1 高蕊蕊;不同載體負(fù)載的Mn-Fe-Ce整體式催化劑NH_3-SCR脫硝性能的研究[D];太原理工大學(xué);2016年

2 張興宇;活性炭負(fù)載釩銅金屬氧化物催化脫除NO實(shí)驗(yàn)研究[D];河南科技大學(xué);2014年

3 厲勵;MnO_x-CeO_2/ACFN催化劑低溫脫除NO的性能研究[D];廣西大學(xué);2013年

4 吳昊;蜂窩堇青石基錳系低溫SCR脫硝催化劑的研究[D];遼寧石油化工大學(xué);2013年

5 朱繁;V_2O_5-TiO_2低溫SCR催化劑活性及應(yīng)用研究[D];北京工業(yè)大學(xué);2012年

，

本文編號：2025801