本文選題：一氧化氮 + 深度氧化��； 參考：《催化學(xué)報(bào)》2017年07期

【摘要】：在工業(yè)鍋爐煙氣處理領(lǐng)域,由于鍋爐容量低,煙氣溫度往往無法滿足傳統(tǒng)選擇性催化還原(SCR)所需溫度窗口.工業(yè)鍋爐煙氣成分的復(fù)雜性也給氮氧化物治理帶來了嚴(yán)峻考驗(yàn).臭氧深度氧化NO結(jié)合濕法洗滌同時(shí)脫硫脫硝技術(shù)具有獨(dú)特的應(yīng)用優(yōu)勢.傳統(tǒng)臭氧氧化技術(shù)中,NO被臭氧氧化為NO_2,進(jìn)而在脫硫塔中實(shí)現(xiàn)一體化脫硫脫硝.但由于NO_2溶解度相對較低,需要在脫硫漿液中加入添加劑提高脫硝效率,造成運(yùn)行成本增加.NO經(jīng)臭氧深度氧化后,NO_2進(jìn)一步轉(zhuǎn)化為溶解度高的N_2O_5,傳統(tǒng)脫硫石膏漿液即可實(shí)現(xiàn)高效吸收N_2O_5,從而有效提高氮氧化物吸收效率.但由于N_2O_5生成反應(yīng)速率低,深度氧化存在臭氧投入量大、反應(yīng)時(shí)間長及臭氧殘留多的缺點(diǎn).臭氧耦合催化劑深度氧化NO可有效解決以上問題.首先,本文采用溶膠-凝膠法合成一系列單金屬氧化物(Mn,Co,Ce,Fe,Cu,Cr)作為臭氧深度氧化NO的催化劑.結(jié)果發(fā)現(xiàn)錳氧化物表現(xiàn)出最高的催化活性,在70 ℃下,O_3/NO摩爾比為2.0時(shí)經(jīng)過0.12 s的反應(yīng)時(shí)間催化劑即可實(shí)現(xiàn)80%以上的轉(zhuǎn)化效率.但根據(jù)N_2O_5生成的總包反應(yīng)(2NO+3O_3=N_2O_5+3O_2)可以看出,O_3/NO摩爾比為1.5時(shí)即可實(shí)現(xiàn)N_2O_5的完全轉(zhuǎn)化.由于催化臭氧氧化反應(yīng)溫度較低,中間產(chǎn)物在催化劑表面聚集,占據(jù)大量活性位,進(jìn)而導(dǎo)致無法實(shí)現(xiàn)1.5摩爾比的高效轉(zhuǎn)化.通過采用球形氧化鋁作為載體,避免粉末狀催化劑緊湊型布置,增加換熱面積,可有效降低催化劑表面中間產(chǎn)物聚集;同時(shí)延長了氣體與催化劑的接觸時(shí)間,提高反應(yīng)效率.在球形氧化鋁載體上負(fù)載錳基雙金屬氧化物(Ce-Mn,Fe-M,Cr-Mn,Cu-Mn和Co-Mn),在初始NO濃度為410 mg/m~3,反應(yīng)溫度100 ℃,O_3/NO摩爾比1.5,催化反應(yīng)時(shí)間0.12 s的工況下,催化劑最終實(shí)現(xiàn)95%(Fe-Mn)和88%(Ce-Mn)的轉(zhuǎn)化效率,剩余NO和NO_2的濃度分別低于20 mg/m~3(Fe-Mn)和50 mg/m~3(Ce-Mn),臭氧殘留濃度低于25 mg/m~3.同負(fù)載單一錳氧化物(83%轉(zhuǎn)化率)相比,雙金屬氧化物進(jìn)一步提高了N_2O_5生成效率.因此,臭氧耦合催化劑深度氧化NO結(jié)合濕法吸收在工業(yè)鍋爐超低排放(NO_x50 mg/m~3)領(lǐng)域具有廣泛應(yīng)用前景.通過XRD、氮?dú)馕�、H2-TPR和XPS等手段研究了催化劑的晶體結(jié)構(gòu)、孔結(jié)構(gòu)參數(shù)、氧化還原性能和表面原子價(jià)態(tài).催化臭氧深度氧化NO主要與催化劑對臭氧的分解性能和對NO的氧化性能有關(guān).較大的比表面積和孔容有利于催化劑的吸附.氧空位有利于臭氧的吸附和分解.Mn~(4+)和Mn~(3+)的均衡分布既有利于NO的吸附氧化又有利于臭氧的吸附分解,最終提高了N_2O_5生成效率.
[Abstract]:In the field of industrial boiler flue gas treatment, because of the low boiler capacity, the flue gas temperature often can not meet the traditional selective catalytic reduction (SCR) temperature window.The complexity of flue gas composition of industrial boiler also brings severe test to nitrogen oxide treatment.The technology of ozone deep oxidation no combined with wet washing and desulfurization and denitrification has unique application advantages.In the traditional ozone oxidation technology, no is oxidized to no _ 2 by ozone, and the integrated desulfurization and denitrification is realized in the desulfurization tower.However, because the solubility of NO_2 is relatively low, it is necessary to add additives to desulphurization slurry to improve denitrification efficiency.As a result, the operation cost increased. No was oxidized deeply by ozone, and then converted into the high solubility Ns _ 2O _ 5. The traditional desulphurization gypsum slurry could efficiently absorb N _ 2O _ 5, thus effectively improving the nitrogen oxide absorption efficiency.However, because of the low reaction rate of N_2O_5 formation, the deep oxidation has the disadvantages of large ozone input, long reaction time and more ozone residue.Deep oxidation of no with ozone coupling catalyst can effectively solve the above problems.Firstly, a series of monometallic oxides (MNO _ 2O _ 3) were synthesized by sol-gel method as catalysts for deep ozonation of no.The results showed that manganese oxide exhibited the highest catalytic activity, and the conversion efficiency was over 80% after the reaction time of 0.12 s at 70 鈩，

本文編號：1742356