本文選題：Hg0氧化 + 類水滑石�。� 參考：《中國(guó)地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：由于汞的毒性、生物累積性和在食物鏈中的傳遞性,使其成為一種主要的全球性污染物。人類活動(dòng)向大氣中排放的大部分汞是在工業(yè)革命之后燃燒煤炭造成的。燃煤煙氣中排放出來的汞主要有三種形態(tài):二價(jià)汞(Hg2+),顆粒吸附汞(Hgp)和單質(zhì)汞(Hg0),前兩個(gè)由于可溶性較強(qiáng)、易于捕集從而能夠被現(xiàn)有的濕法脫硫裝置或者布袋除塵器從煙氣中脫除掉,但是Hg0卻由于游離性強(qiáng)難以脫除,并且從排放點(diǎn)能夠進(jìn)行長(zhǎng)距離的傳輸擴(kuò)散造成大面積的大氣汞污染。因此,將Hg0氧化成Hg2+是將其從煙氣中脫除的關(guān)鍵。用傳統(tǒng)的浸漬法合成的催化劑,活性組分很難在催化劑上面均勻分布,導(dǎo)致催化劑活性的降低并且活性組分容易從載體上面脫落。因?yàn)轭愃?LDHs)材料具有獨(dú)特的有序?qū)訝罱Y(jié)構(gòu)并且構(gòu)成元素互相高度分散,在后續(xù)的焙燒過程中由于晶格定位效應(yīng),這種高度分散的狀態(tài)不會(huì)被破壞。所以首先合成LDHs前驅(qū)體再經(jīng)過焙燒處理后就能得到活性組分高度分散的金屬氧化物催化劑。在本論文中,首先用共沉淀法合成了LDHs前驅(qū)體,在空氣中高溫焙燒后得到了復(fù)合金屬氧化物催化劑。在實(shí)驗(yàn)室規(guī)模下通過模擬煙氣對(duì)催化劑進(jìn)行了篩選和性能評(píng)價(jià)。利用XRD、XPS、BET、Hg-TPD、H2-TPR、SEM等表征手段對(duì)催化劑進(jìn)行分析,詳細(xì)探討了催化劑的汞氧化機(jī)理和煙氣組分對(duì)其汞氧化性能的影響。結(jié)果表明,以LDHs為前驅(qū)體合成的1%Mn/Co Al Ox催化劑具有優(yōu)異的汞催化氧化活性,在高空速條件下能夠在寬溫度窗口中有效氧化脫除高達(dá)95%以上的Hg0,同時(shí)具有良好的抗水和抗硫性能。該催化劑有望于不遠(yuǎn)的將來投入工業(yè)應(yīng)用。
[Abstract]:Mercury is a major global pollutant due to its toxicity, bioaccumulation and transitivity in the food chain. Much of the mercury emitted into the atmosphere by human activity was caused by the burning of coal after the industrial revolution. There are three main forms of mercury emitted from coal-fired flue gas: Hg2 +, Hg ~ (2 +), Hg ~ (2 +) and Hg _ (0), and Hg ~ (2 +) ~ (2 +). It is easy to trap and can be removed from the flue gas by the existing wet desulfurization device or bag dust collector, but the Hg0 is difficult to remove because of its strong dissociation. And long-distance transport and diffusion from the emission point resulted in a large area of atmospheric mercury pollution. Therefore, oxidation of Hg0 to Hg2 is the key to its removal from flue gas. The active component of the catalyst synthesized by the traditional impregnation method is difficult to be uniformly distributed on the catalyst, which leads to the decrease of the activity of the catalyst and the easy exfoliation of the active component from the support. Because of its unique ordered layered structure and highly dispersed elements, the highly dispersed state will not be destroyed in the subsequent calcination process due to lattice localization effect. Therefore, the highly dispersed metal oxide catalysts with highly dispersed active components can be obtained after calcination of the LDHs precursor. In this thesis, LDHs precursors were synthesized by coprecipitation method, and the composite metal oxide catalysts were prepared after calcination in air. The catalyst was screened and evaluated by simulated flue gas in laboratory. The catalysts were characterized by means of XRDX, XRDP, BETX, Hg-TPDN, H2-TPR-SEM, and the mechanism of mercuric oxidation of catalysts and the effect of flue gas composition on their mercury-oxidizing properties were discussed in detail. The results show that the 1%Mn/Co Al Ox catalyst synthesized with LDHs as precursor has excellent mercuric oxidation activity and can effectively remove Hg0, which is more than 95% in wide temperature window, under the condition of high altitude velocity, and has good water and sulfur resistance. The catalyst is expected to be used in industry in the near future.
【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X701;O643.3

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相關(guān)期刊論文 前1條

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本文編號(hào)：1845085