本文選題：氮氧化物 + 催化劑　； 參考：《華北電力大學(xué)(北京)》2017年碩士論文

【摘要】：煤炭是我國(guó)最主要的一次能源,在煤炭的使用過(guò)程中不可避免的產(chǎn)生了大量污染物。氮氧化物作為其中之一,會(huì)造成酸雨、光化學(xué)煙霧以及其他環(huán)境問(wèn)題。據(jù)統(tǒng)計(jì),我國(guó)氮氧化物排放的67%來(lái)源于煤炭為主的化石燃料的燃燒。因此,燃煤電廠氮氧化物控制是我國(guó)氮氧化物控制的重點(diǎn)。選擇性催化還原法是目前燃煤電廠應(yīng)用最廣泛的脫硝技術(shù),催化劑是SCR技術(shù)的核心。目前商業(yè)應(yīng)用最廣泛的是V-W-Ti型催化劑。由于催化劑成本較高,且通常運(yùn)行3~5年就因失活需要更換,造成火電廠運(yùn)行成本增加,同時(shí)廢棄的催化劑會(huì)引起新的環(huán)境問(wèn)題。因此,開(kāi)展催化劑的失活分析及再生工作是十分必要的。目前主要的再生方法包括水洗再生,酸洗再生,熱(還原)再生和復(fù)合再生。本文以商用V-W-Ti型催化劑為研究對(duì)象,分析了其失活原因,在此基礎(chǔ)開(kāi)展了再生研究,主要結(jié)論如下:(1)舊催化劑脫硝效率下降明顯,400℃時(shí)達(dá)到最大脫硝效率63.1%,明顯低于新催化劑的脫硝效率,說(shuō)明舊催化劑已經(jīng)失活。對(duì)新、舊兩種催化劑分別作了SEM、N2吸附脫附、XRD、XRF、FTIR等表征。結(jié)果表明:舊催化劑晶型未發(fā)生改變,仍為典型的銳鈦礦,催化劑未發(fā)生燒結(jié)現(xiàn)象。舊催化劑發(fā)生了孔堵塞,導(dǎo)致比表面積減小,平均孔徑增加,孔體積減小。同時(shí),相對(duì)于新催化劑,舊催化劑中存在活性成分流失現(xiàn)象,Na、Ka、Ca、Mg等毒性元素含量明顯增加,新增了As元素�？锥氯A金屬堿土金屬及砷中毒、活性成分流失是造成催化劑失活的主要原因。(2)制定了再生工藝路線:水洗、酸洗、再生浸漬。考察了水洗方式、水洗時(shí)間、酸液濃度、酸洗時(shí)間、再生液濃度及再生時(shí)間對(duì)催化劑再生的影響。超聲水洗效果優(yōu)于浸漬水洗,超聲水洗時(shí)45 min為最佳清洗時(shí)間。0.5 mol/L的H2SO4溶液具有最佳的酸洗效果,45 min為最佳酸洗時(shí)間。硫酸氧釩、仲鎢酸銨質(zhì)量分?jǐn)?shù)分別為2%、2%為最佳再生液。60 min最為最佳再生浸漬時(shí)間。再生后催化劑脫硝效率最高可達(dá)91.6%,達(dá)到新鮮催化劑脫硝效率的95%。
[Abstract]:Coal is the most important primary energy in China, which inevitably produces a large number of pollutants in the process of coal use. Nitrogen oxides, as one of them, can cause acid rain, photochemical smog and other environmental problems. According to statistics, 67% of nitrogen oxide emissions in China come from the combustion of coal-based fossil fuels. Therefore, the control of NOx in coal-fired power plants is the key point of NOx control in China. Selective catalytic reduction is the most widely used denitrification technology in coal-fired power plants at present, and catalyst is the core of SCR technology. At present, the most widely used commercial catalyst is V-W-Ti catalyst. Because of the high cost of the catalyst and the replacement of the catalyst after 3 ~ 5 years of operation, the operation cost of the thermal power plant is increased, and the abandoned catalyst will cause new environmental problems. Therefore, it is necessary to carry out deactivation analysis and regeneration of catalyst. At present, the main regeneration methods include washing regeneration, acid cleaning regeneration, hot (reducing) regeneration and compound regeneration. In this paper, the reason of deactivation of commercial V-W-Ti catalyst was analyzed, and regeneration research was carried out on this basis. The main conclusions are as follows: (1) the denitrification efficiency of the old catalyst decreased obviously to 63.1% at 400 鈩，

本文編號(hào)：1933056