城市污泥快速熱解產(chǎn)物中氮的分布及催化脫氮研究
發(fā)布時間：2018-09-11 14:58
【摘要】：利用固定床石英管反應(yīng)器對城市污泥(SS)進行快速熱解,研究了熱解條件對快速熱解產(chǎn)物組成及氮分布的影響,選用Ni/Al2O3、Co Mo/Al2O3、褐鐵礦、白云石和分子篩為催化劑研究了SS的催化熱解,考察了催化劑、溫度和氣氛等對SS催化熱解產(chǎn)物組成的影響,重點用多種先進分析手段全面的研究了熱解產(chǎn)物中氮的組成結(jié)構(gòu)。結(jié)果表明:隨著熱解溫度的升高,焦炭產(chǎn)率減少,氣體產(chǎn)物產(chǎn)率顯著增加,而焦油產(chǎn)物的產(chǎn)率先增加后減少,在500 oC時達到最大收率55.8%(干燥無灰基)。NH3的生成與蛋白質(zhì)的分解有關(guān),HCN的產(chǎn)率隨熱解溫度的升高而增加。升高熱解溫度,焦油產(chǎn)物中脂肪族及含氧化合物(OCS)的含量降低,而含氮(NCS)和芳香族化合物的含量增加。SS快速熱解焦油產(chǎn)物中主要的NCS包括N-雜環(huán)類、內(nèi)酰胺類、胺類、氨類和腈基衍生物,而且隨著熱解溫度的升高,焦油中N-雜環(huán)及芳香腈類化合物的含量略有增加,而胺類及脂肪腈類化合物的含量減少。Ni/Al2O3對焦油的分解具有較高的催化活性。在Ni/Al2O3作用下,氣體產(chǎn)物總產(chǎn)率顯著增加,其中CH4的產(chǎn)率最多;當(dāng)褐鐵礦石作為催化劑時,焦油中NCS及OCS的含量相對較高;白云石催化劑大幅度增加了焦油中OCS的含量;沸石分子篩催化劑對焦油各族組分含量的影響不大;Co Mo/Al2O3催化改質(zhì)后焦油中NCS和OCS的含量降低,而芳香族化合物的含量增加。對Co Mo/Al2O3而言,溫度越高,越有利于焦油中NCS和OCS的分解以及芳香族化合物的生成。此外,Co Mo/Al2O3對焦油中吲哚類和腈類化合物的分解具有較高的催化活性,而吲哚類化合物的分解可能會直接導(dǎo)致吡咯類化合物含量的增加。當(dāng)催化熱解溫度在600 oC以上時,Co Mo/Al2O3對焦油中吡咯類化合物的分解展現(xiàn)出較高的催化活性。而沸石分子篩催化劑可以有效促進焦油中吡啶類化合物的分解。在催化劑作用下,H2氣氛抑制了NH3分解為N2,反應(yīng)向有利于NH3生成的方向進行,而在惰性氣體Ar氣氛下,催化劑對NH3分解為N2具有較高的催化活性。
[Abstract]:The rapid pyrolysis of municipal sludge (SS) was carried out by using a fixed bed quartz tube reactor. The effects of pyrolysis conditions on the composition and nitrogen distribution of the rapid pyrolysis products were studied. The catalytic pyrolysis of SS was studied using Ni/Al2O3,Co Mo/Al2O3, limonite, dolomite and molecular sieve as catalysts. The effects of catalyst, temperature and atmosphere on the composition of SS pyrolysis products were investigated. The results show that with the increase of pyrolysis temperature, the coke yield decreases, the gas product yield increases significantly, and the tar product yield increases first and then decreases. The maximum yield of 55.8% (dry ash free group). NH3 is related to the decomposition of protein at 500 oC. The yield of HCN increases with the increase of pyrolysis temperature. With the increase of pyrolysis temperature, the contents of aliphatic and oxygenated (OCS) in tar products decreased, while the contents of nitrogen-containing (NCS) and aromatic compounds increased. The main NCS in the tar products of SS rapid pyrolysis included N-heterocyclic compounds and lactams. The content of N- heterocyclic and aromatic nitriles in tar increased slightly with the increase of pyrolysis temperature, while the content of amines and fatty nitriles decreased. Ni- / Al _ 2O _ 3 showed higher catalytic activity for the decomposition of tar. Under the action of Ni/Al2O3, the total yield of gas product increased significantly, the yield of CH4 was the most, the content of NCS and OCS in tar was relatively high when limonite was used as catalyst, dolomite catalyst greatly increased the content of OCS in tar. The effect of zeolite molecular sieve catalyst on the content of various components of tar was not significant. The content of NCS and OCS in tar was decreased and the content of aromatic compounds increased after modified by Co Mo/Al2O3. For Co Mo/Al2O3, the higher the temperature is, the more favorable is the decomposition of NCS and OCS in tar and the formation of aromatic compounds. In addition, the decomposition of indole and nitrile compounds in tar oil by Co Mo/Al2O3 has high catalytic activity, while the decomposition of indole compounds may directly lead to the increase of pyrrole content. When the catalytic pyrolysis temperature is more than 600 oC, the decomposition of pyrrole compounds in tar oil shows higher catalytic activity. Zeolite catalysts can effectively promote the decomposition of pyridine compounds in tar. In the presence of the catalyst, the decomposition of NH3 to N _ 2 was inhibited in H _ 2 atmosphere, and the reaction was carried out in favor of the formation of NH3. However, in the inert gas Ar atmosphere, the catalyst had higher catalytic activity for the decomposition of NH3 to N _ 2.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X703
[Abstract]:The rapid pyrolysis of municipal sludge (SS) was carried out by using a fixed bed quartz tube reactor. The effects of pyrolysis conditions on the composition and nitrogen distribution of the rapid pyrolysis products were studied. The catalytic pyrolysis of SS was studied using Ni/Al2O3,Co Mo/Al2O3, limonite, dolomite and molecular sieve as catalysts. The effects of catalyst, temperature and atmosphere on the composition of SS pyrolysis products were investigated. The results show that with the increase of pyrolysis temperature, the coke yield decreases, the gas product yield increases significantly, and the tar product yield increases first and then decreases. The maximum yield of 55.8% (dry ash free group). NH3 is related to the decomposition of protein at 500 oC. The yield of HCN increases with the increase of pyrolysis temperature. With the increase of pyrolysis temperature, the contents of aliphatic and oxygenated (OCS) in tar products decreased, while the contents of nitrogen-containing (NCS) and aromatic compounds increased. The main NCS in the tar products of SS rapid pyrolysis included N-heterocyclic compounds and lactams. The content of N- heterocyclic and aromatic nitriles in tar increased slightly with the increase of pyrolysis temperature, while the content of amines and fatty nitriles decreased. Ni- / Al _ 2O _ 3 showed higher catalytic activity for the decomposition of tar. Under the action of Ni/Al2O3, the total yield of gas product increased significantly, the yield of CH4 was the most, the content of NCS and OCS in tar was relatively high when limonite was used as catalyst, dolomite catalyst greatly increased the content of OCS in tar. The effect of zeolite molecular sieve catalyst on the content of various components of tar was not significant. The content of NCS and OCS in tar was decreased and the content of aromatic compounds increased after modified by Co Mo/Al2O3. For Co Mo/Al2O3, the higher the temperature is, the more favorable is the decomposition of NCS and OCS in tar and the formation of aromatic compounds. In addition, the decomposition of indole and nitrile compounds in tar oil by Co Mo/Al2O3 has high catalytic activity, while the decomposition of indole compounds may directly lead to the increase of pyrrole content. When the catalytic pyrolysis temperature is more than 600 oC, the decomposition of pyrrole compounds in tar oil shows higher catalytic activity. Zeolite catalysts can effectively promote the decomposition of pyridine compounds in tar. In the presence of the catalyst, the decomposition of NH3 to N _ 2 was inhibited in H _ 2 atmosphere, and the reaction was carried out in favor of the formation of NH3. However, in the inert gas Ar atmosphere, the catalyst had higher catalytic activity for the decomposition of NH3 to N _ 2.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X703
【參考文獻】
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