發(fā)布時(shí)間：2018-03-19 02:22

  本文選題：低溫SCR　切入點(diǎn)：改性活性炭　出處：《大連理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：氮氧化物是重要的大氣污染物之一,選擇性催化還原(SCR)是目前工業(yè)上對(duì)固定源排放煙氣中NOx脫除比較成熟的有效方法之一。近年來(lái)由于低溫SCR具有很好經(jīng)濟(jì)性且良好的工業(yè)背景己成為研究的熱點(diǎn),但從國(guó)內(nèi)外來(lái)看,低溫SCR技術(shù)工業(yè)化障礙在于催化劑活性不高、抗硫毒性與抗水毒性差。因此,對(duì)于以上問(wèn)題本文采用活性炭為載體,過(guò)渡金屬元素為主要活性組分,進(jìn)行低溫(100℃左右)SCR研究。首先,對(duì)活性炭(AC)進(jìn)行低溫SCR研究(空速15000h-1),結(jié)果發(fā)現(xiàn)：活性炭起初的脫硝率為50%左右,后期穩(wěn)定在18%,活性炭在100℃情況下,表現(xiàn)為吸附與催化共同作用,但活性不高。為了提高活性,本文對(duì)活性炭進(jìn)行改性與負(fù)載過(guò)渡金屬氧化物。采用氧化和金屬離子交換的方法,對(duì)活性炭進(jìn)行表面結(jié)構(gòu)改性,大大提高了活性金屬氧化物的分散性和負(fù)載量；在浸漬沉淀過(guò)程中添加活化劑尿素,有利于金屬氧化物的均勻分布和沉淀,并焙燒產(chǎn)生氣孔和改性活性炭有利于吸附NH3和增大活性金屬氧化物表面積,提高了NO脫除效率；改性后的活性炭浸漬沉淀金屬氧化物,制備出了三種不同規(guī)格炭基材料的低溫SCR催化劑(C1,C2,C3)；在不同空速條件下,對(duì)煙氣進(jìn)行脫硝測(cè)試,實(shí)驗(yàn)中操作溫度范圍在90-110℃之間,空速在7500-25000h-1之間,實(shí)驗(yàn)結(jié)果表明C1和C2具有較好的脫除效率,空速對(duì)活性炭的脫除效率影響較大。實(shí)驗(yàn)中空速為15000h-1,反應(yīng)溫度為100℃時(shí),氮氧化物的轉(zhuǎn)化率穩(wěn)定為86%,實(shí)驗(yàn)中還發(fā)現(xiàn),氨氣通入的先后順序?qū)γ撓跛俾视泻艽蟮挠绊?先通入氨氣有利于氨氣占領(lǐng)吸附位,脫硝反應(yīng)速率快。最后,本文研究了低溫SCR催化劑的抗硫性與抗水性,結(jié)果發(fā)現(xiàn)：SCR催化劑對(duì)低濃度S02的抗性較好,但H2O影響較大,含濕量越大,活性越差。但H2O對(duì)催化劑的副作用屬于可逆過(guò)程,當(dāng)水的濕含量在5%下,反應(yīng)溫度不低于140℃,H2O的影響幾乎可忽略不計(jì)。
[Abstract]:Nitrogen oxides are one of the most important pollutants in the atmosphere. Selective catalytic reduction (NOx) is one of the most mature and effective methods for the removal of NOx from fixed-source flue gas. In recent years, low temperature SCR has become a hot research area because of its good economy and good industrial background. But at home and abroad, the industrial obstacle of low temperature SCR technology is that the catalyst activity is not high, sulfur toxicity and water toxicity are poor. Therefore, the activated carbon is used as the carrier and the transition metal element is the main active component for the above problems. The SCR of activated carbon was studied at about 100 鈩，

本文編號(hào)：1632407