城市污泥快速热解产物中氮的分布及催化脱氮研究
发布时间：2018-09-11 14:58
【摘要】：利用固定床石英管反应器对城市污泥(SS)进行快速热解,研究了热解条件对快速热解产物组成及氮分布的影响,选用Ni/Al2O3、Co Mo/Al2O3、褐铁矿、白云石和分子筛为催化剂研究了SS的催化热解,考察了催化剂、温度和气氛等对SS催化热解产物组成的影响,重点用多种先进分析手段全面的研究了热解产物中氮的组成结构。结果表明:随着热解温度的升高,焦炭产率减少,气体产物产率显著增加,而焦油产物的产率先增加后减少,在500 oC时达到最大收率55.8%(干燥无灰基)。NH3的生成与蛋白质的分解有关,HCN的产率随热解温度的升高而增加。升高热解温度,焦油产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快速热解焦油产物中主要的NCS包括N-杂环类、内酰胺类、胺类、氨类和腈基衍生物,而且随着热解温度的升高,焦油中N-杂环及芳香腈类化合物的含量略有增加,而胺类及脂肪腈类化合物的含量减少。Ni/Al2O3对焦油的分解具有较高的催化活性。在Ni/Al2O3作用下,气体产物总产率显著增加,其中CH4的产率最多;当褐铁矿石作为催化剂时,焦油中NCS及OCS的含量相对较高;白云石催化剂大幅度增加了焦油中OCS的含量;沸石分子筛催化剂对焦油各族组分含量的影响不大;Co Mo/Al2O3催化改质后焦油中NCS和OCS的含量降低,而芳香族化合物的含量增加。对Co Mo/Al2O3而言,温度越高,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对焦油中吲哚类和腈类化合物的分解具有较高的催化活性,而吲哚类化合物的分解可能会直接导致吡咯类化合物含量的增加。当催化热解温度在600 oC以上时,Co Mo/Al2O3对焦油中吡咯类化合物的分解展现出较高的催化活性。而沸石分子筛催化剂可以有效促进焦油中吡啶类化合物的分解。在催化剂作用下,H2气氛抑制了NH3分解为N2,反应向有利于NH3生成的方向进行,而在惰性气体Ar气氛下,催化剂对NH3分解为N2具有较高的催化活性。
[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.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：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.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703
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