本文關(guān)鍵詞： 低溫催化氧化 半焦 反應(yīng)機(jī)制 碳氧復(fù)合物　出處：《遼寧科技大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：煤炭是我國的主要能源,在煤炭利用過程中排放的NOX所引起的大氣污染問題,嚴(yán)重的影響著大氣環(huán)境和人類生活健康。為了緩解大氣污染的嚴(yán)重程度,各國政府紛紛通過立法來控制NOX的排放量。由于活性半焦具有吸附效率高、價格低廉等特點(diǎn),且半焦與NO的還原反應(yīng)在脫硝過程中十分重要,因而活性半焦脫硝劑備受國內(nèi)外學(xué)者的青睞。煙氣中一般含有5%左右的O_2,這會提高活性半焦脫硝劑的脫硝效率。但同時多余的O_2會與活性半焦載體中的碳反應(yīng),造成載體的消耗,這種現(xiàn)象嚴(yán)重制約著半焦脫硝劑脫除煙氣中NO的效率,提高煙氣處理的成本。因此,研究半焦低溫催化氧化特性有助于在實(shí)際應(yīng)用中控制半焦載體的損耗。針對目前對半焦低溫催化氧化反應(yīng)機(jī)理的認(rèn)識尚有不足之處,本論文采用超聲波浸漬法使褐煤負(fù)載金屬氧化物并制備成活性半焦。在模擬氣氛下,利用固定床反應(yīng)器,系統(tǒng)的研究了氧化溫度、植入金屬含量及金屬種類、及其他氣氛對半焦低溫催化氧化特性的影響。利用傅立葉紅外儀(FTIR)分析氧化前后半焦表面含氧官能團(tuán)的變化;利用X射線衍射儀(XRD)分析氧化前后半焦中金屬氧化物的晶體結(jié)構(gòu)變化;利用電子顯微鏡(SEM)分析半焦表面的形貌結(jié)構(gòu)。探討了在半焦低溫氧化過程中的低溫氧化機(jī)制和金屬氧化物的催化機(jī)制。實(shí)驗(yàn)結(jié)果表明:氧化溫度的升高會促進(jìn)半焦的氧化反應(yīng)及金屬氧化物的催化作用。氧化溫度越高,半焦的氧化反應(yīng)程度越劇烈,金屬氧化物的催化作用越明顯。在半焦中植入的金屬含量及金屬種類不同,金屬氧化物的催化機(jī)制有所不同。F5催化劑較F10催化劑催化半焦氧化反應(yīng)向氧化程度深的方向進(jìn)行。Fe基氧化物催化半焦氧化反應(yīng)生成CO,而Cu基氧化物催化半焦氧化反應(yīng)生成CO_2。煙氣中存在的CO_2氣體對半焦低溫氧化反應(yīng)有一定的抑制作用。而NO對半焦氧化反應(yīng)生成CO有促進(jìn)作用,且CO參與脫硝過程,與NO反應(yīng)生成CO_2和N_2。
[Abstract]:Coal is the main energy in our country. The air pollution caused by NOX emission in the process of coal utilization seriously affects the atmospheric environment and the health of human life. The governments of various countries have adopted legislation to control the emission of NOX. Because active char has the characteristics of high adsorption efficiency and low price, the reduction reaction between char and no is very important in denitrification process. Therefore, active semi-coke denitrification agent is favored by scholars at home and abroad. There is generally about 5% O _ 2 in flue gas, which will improve the denitrification efficiency of active semi-coke denitration agent. But at the same time, the excess O _ p _ 2 will react with carbon in active semi-coke carrier. This phenomenon seriously restricts the efficiency of no removal from flue gas by semi-coke denitration agent and increases the cost of flue gas treatment. To study the characteristics of char catalytic oxidation at low temperature is helpful to control the loss of char carrier in practical application. In this paper, activated semi-coke was prepared by impregnating lignite with metal oxide by ultrasonic impregnation. In a fixed bed reactor, oxidation temperature, metal content and metal species were systematically studied in a fixed bed reactor. FTIR was used to analyze the changes of oxygen-containing functional groups on the surface of semi-coke before and after oxidation. X-ray diffractometer (XRD) was used to analyze the crystal structure changes of metal oxides in semi-coke before and after oxidation. The morphology and structure of semi-coke surface were analyzed by electron microscopy (SEM). The mechanism of low-temperature oxidation and the catalytic mechanism of metal oxide were discussed. The experimental results showed that the increase of oxidation temperature would promote the semi-char. Oxidation of coke and catalysis of metal oxides. The higher the oxidation temperature, The more intense the oxidation reaction of the char, the more obvious the catalytic action of the metal oxide. The metal content and the metal type implanted in the char are different. The catalytic mechanism of metal oxides is different. F5 catalyst is better than F10 catalyst in the direction of oxidation degree of semicoke. Fe-based oxide catalyzes semicoke oxidation to produce CO.Cu-based oxide catalyzes semicoke oxidation. The CO_2 gas in flue gas can inhibit the oxidation of char at low temperature, while no can promote the oxidation of char to CO. Co was involved in the denitrification process and reacted with no to produce CO_2 and N2s.
【學(xué)位授予單位】：遼寧科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X701;O643.36

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