發(fā)布時(shí)間：2018-07-09 18:58

  本文選題：板式催化劑 + 成型工藝��； 參考：《江蘇科技大學(xué)》2014年碩士論文

【摘要】：近年來(lái)，氮氧化合物（NOx）對(duì)環(huán)境已經(jīng)造成嚴(yán)重的危害，目前選擇性催化還原（SCR）法是最有效的De-NOx技術(shù)。SCR技術(shù)的核心是脫硝催化劑，中溫蜂窩式脫硝催化劑已在世界范圍內(nèi)被廣泛地應(yīng)用，但中溫蜂窩式脫硝催化劑的抗堵塞和抗磨損性能較差，因此不適合在高灰分條件下的使用；而板式脫硝催化劑具有優(yōu)良的抗堵、抗磨損等性能，可在高灰分條件下順利地運(yùn)行。板式脫硝催化劑的制備工藝被日本、歐美等國(guó)家壟斷，雖然近幾年，國(guó)內(nèi)的科研院所致力于板式催化劑成型工藝和配方的研究，但是目前尚無(wú)自主知識(shí)產(chǎn)權(quán)的、可以用于工業(yè)生產(chǎn)的板式脫硝催化劑的生產(chǎn)線，因此立項(xiàng)對(duì)板式脫硝催化劑成型工藝及配方的研究有重大意義。本課題采用輥壓的方法制備板式脫硝催化劑，輥壓成型法的成型效率高于液壓機(jī)壓制成型法。 近年來(lái)我國(guó)著重解決大氣污染治理問(wèn)題，一再提高煙氣的硫硝排放標(biāo)準(zhǔn)，因此對(duì)SCR脫硝催化劑的需求量及品質(zhì)要求越來(lái)越高。催化劑的載體材料TiO2占催化劑總含量80%以上，并且國(guó)產(chǎn)的催化劑載體材料魚龍混雜，因此對(duì)載體材料進(jìn)行針對(duì)性研究并提出一定的評(píng)價(jià)依據(jù)十分必要。鑒于此，本課題選取了三種國(guó)產(chǎn)載體材料HTm、PB1m、PB2m，并采用半浸漬法制備了HT、PB1、PB2系列催化劑泥料，然后將泥料通過(guò)24小時(shí)的密封陳腐，由自行設(shè)計(jì)的板式成型機(jī)進(jìn)行成型，最后將成型催化劑經(jīng)室溫-60℃程序升溫干燥5天，60-610℃程序升溫焙燒33小時(shí)。對(duì)所制備的板式脫硝催化劑在模擬煙氣條件下進(jìn)行脫硝活性檢測(cè)，并采用BET、Raman、XPS、TPR表征方法檢測(cè)分析國(guó)內(nèi)常見的TiO2-WO3-SO42-型載體材料的性能及其對(duì)所制備的催化劑脫硝效率的影響，為評(píng)價(jià)國(guó)產(chǎn)催化劑載體材料的品質(zhì)提供一定的理論基礎(chǔ)。分析討論WOx與VOx之間的相互作用關(guān)系，以及WOx對(duì)VOx的改性作用機(jī)理。得出以下結(jié)論： 結(jié)果表明：自行設(shè)計(jì)的輥壓板式成型機(jī)可以順利地制備板式催化劑并且不存在開裂現(xiàn)象；當(dāng)載體的比表面積太大時(shí)，雖然有利于降低VOx的聚合度，但同時(shí)促進(jìn)孤立態(tài)VOx地形成，比表面積太小時(shí)，會(huì)使催化劑具有較低的比表面積，因此，，只有當(dāng)載體的比表面積大小適宜時(shí)，最有利于脫硝反應(yīng)；強(qiáng)B酸性位更容易吸附NH3，但是強(qiáng)B酸性位與NH3之間的電子作用力較強(qiáng)，導(dǎo)致中間產(chǎn)物不易分解，阻礙反應(yīng)的順利進(jìn)行；W6+與VOx之間的電子效應(yīng)遠(yuǎn)大于W5+，W6+的含量越高，越有利于提高WOx對(duì)VOx的改性作用；具有氧缺陷結(jié)構(gòu)形式的W6+Ox，更容易與O結(jié)合，與VOx形成W-O-V式結(jié)構(gòu)，因此，該結(jié)構(gòu)的W6+Ox更容易與VOx發(fā)生電子作用，有利于WOx對(duì)VOx進(jìn)行改性；載體表面WOx的聚合度越低，分散性越好，越有利于WOx與VOx的接觸，有利于WOx對(duì)VOx的改性，促進(jìn)脫硝反應(yīng)；適度降低氧化位V5+=O中V的氧化態(tài)，可以有效抑制NH3和SO2氧化反應(yīng)地發(fā)生；WOx與VOx之間存在著相互作用，兩者不是孤立地存在于載體的表面，一方面，WOx可以通過(guò)在催化劑表面的占位效應(yīng)，促進(jìn)聚合態(tài)VOx地形成，另一方面，WOx可以與VOx發(fā)生電子作用形成W-O-V式結(jié)構(gòu)，降低氧化位V5+=O的氧化性，同時(shí)抑制高聚合態(tài)VOx地形成。
[Abstract]:In recent years, nitrogen and oxygen compounds (NOx) have caused serious harm to the environment. At present, selective catalytic reduction (SCR) is the most effective De-NOx technology, the core of.SCR technology is denitrification catalyst. The medium temperature honeycomb type denitrification catalyst has been widely used worldwide, but the anti clogging and wear resistance of the medium temperature honeycomb type denitrification catalyst It is not suitable for the use of high ash conditions, and the plate type denitrification catalyst has excellent anti blocking, abrasion resistance and so on. It can run smoothly under high ash conditions. The preparation process of the plate type denitrification catalyst is monopolized by Japan, Europe and the United States. Although in recent years, the domestic research institutes are committed to the plate type catalyst molding. The research of technology and formula, but there is no independent intellectual property right now, which can be used in the production line of plate denitrification catalyst for industrial production. Therefore, it is of great significance to study the molding process and formula of plate type denitrification catalyst. This topic is made of roll pressing to prepare the plate type denitrification catalyst and the molding efficiency of the roller press molding method is high. In the pressing machine of the hydraulic press.
In recent years, our country has focused on solving the problem of air pollution control and increased the sulfur and nitrate emission standards of flue gas again and again. Therefore, the demand and quality of SCR denitrification catalyst are getting higher and higher. The carrier material TiO2 of the catalyst is more than 80% of the total catalyst content, and the domestic catalyst carrier material is mixed with fish and dragon, so the carrier material is needled. In view of this, three kinds of homemade carrier materials, HTm, PB1m, PB2m, were selected to prepare HT, PB1, PB2 series catalyst slurry by semi impregnation, and then the slurry was sealed by 24 hours and formed by the self designed plate forming machine. Finally, the forming catalyst was formed. The performance of the prepared plate type denitrification catalyst was tested under simulated flue gas for 5 days after heating at room temperature of -60 and 60-610 C for 33 hours. The performance of BET, Raman, XPS and TPR was used to detect the properties of the common TiO2-WO3-SO42- carrier materials in China and the denitrification of the catalyst prepared. The effect of efficiency provides a theoretical basis for evaluating the quality of domestic catalyst carrier materials. The interaction relationship between WOx and VOx and the modification mechanism of WOx to VOx are analyzed and discussed. The following conclusions are drawn:
The results show that the self designed roller type plate forming machine can successfully prepare the plate type catalyst without cracking. When the specific surface area of the carrier is too large, it is beneficial to reduce the degree of polymerization of VOx, but at the same time it promotes the formation of isolated VOx, and the surface area is too low, so the catalyst has a lower specific surface area. Therefore, the catalyst has a lower specific surface area. Only when the specific surface area of the carrier is suitable, it is most beneficial to the denitrification reaction, and the strong B acid site is easier to adsorb NH3, but the electron force between the strong B acid position and the NH3 is stronger, which causes the intermediate product not to decompose easily, and hinders the smooth progress of the reaction; the electronic effect between W6+ and VOx is far greater than that of W5+, the higher the content of W6+, the more advantageous to lift. The modification of high WOx to VOx, W6+Ox with oxygen defect structure form, is easier to combine with O and form W-O-V structure with VOx. Therefore, the W6+Ox of this structure is easier to have electronic action with VOx, which is beneficial to WOx to VOx. The lower the degree of polymerization of the carrier surface, the better the dispersion, the more beneficial to the contact between WOx and the VOx. The modification of VOx can promote the denitrification reaction, and the moderate reduction of the oxidation state of V in the oxidation position V5+=O can effectively inhibit the oxidation of NH3 and SO2; there is a interaction between WOx and VOx, and both are not isolated on the surface of the carrier. On the one hand, WOx can promote the polymerization of VOx topography through the occupying effect on the surface of the catalyst. On the other hand, WOx can interact with VOx to form W-O-V structure, reduce the oxidation of V5+=O and inhibit the formation of VOx.
【學(xué)位授予單位】：江蘇科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TQ426

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