城市生活垃圾热解产物性质及元素分布规律研究

发布时间：2018-03-15 01:30

  本文选题：城市生活垃圾　切入点：热解　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：城市生活垃圾热解技术不仅可以使垃圾减容、减量,而且可以实现垃圾的资源化利用,因而近年来日益受到关注。但直到目前,生活垃圾热解处理技术仍存在许多问题,如热解机理有待完善,热解产物的性质及其利用有待深入探索。论文针对以上问题,以城市生活垃圾为研究对象,研究热解产物的性质以及元素分布随热解温度的变化规律,为深入了解城市生活垃圾的热解机理、热解产物的资源化利用提供参考。经试验研究,得出以下结论:①炭产率随着热解温度的升高(500℃~800℃)而逐渐降低,从31.38%降至25.58%;在600℃时焦油产率达到最大值28.02%,之后随着温度的升高而逐渐降至最小值21.76%;热解气的质量产率和体积产率均随着温度的升高而增加,质量产率从41.7%升至52.66%,体积产率从143.50L/kg升至438L/kg。②与原料相比,炭和焦油中的C元素相对富集,碳化程度明显提高,且焦油中C元素的富集程度高于炭;炭和焦油的O/C比和H/C比均明显低于原料,且随着温度的升高而逐渐减小;炭与焦油相比,炭的芳香化程度和极性均高于焦油。③原料中主要含有脂肪族醚、酮、甲基、亚甲基等官能团,且炭结构呈无序排列;与原料相比,热解炭中脂肪族官能团大量减少,并主要以芳环=C-H、芳香族/脂肪族甲基和亚甲基官能团为主;随着温度的升高,芳香族官能团数量逐渐增加,且炭结构逐渐呈有序排列;在原料和炭中均存在盐吸收峰。④炭表面存在C、O、N、Cl、Ca、Si、Na和K元素,其中以C元素为主;在炭表面:sp2杂化C(以芳环C-H键为主)是C的主要存在形式;COO-键是O的主要存在形式;Si以Si-N-C、Si O2等形式存在;Cl以无机氯(Na Cl和KCl等)形式存在;Na以Na Cl和Na OH形式存在。C500(500℃炭)表面N以NSi、胺基N等形式存在;在C500、C600和C700表面,Ca均以Ca CO3形式存在,在800℃时,以Ca CO3、Ca O、Ca SO4和Ca Cl2的形式存在;⑤炭表面O和N的活性高于炭内部O和N的活性;Cl在四种炭表面富集;炭表面未检测到S元素。⑥焦油的含水率为18.43%~26.11%,含固率为0.75%~1.29%,低位热值大小位于24.12 MJ/kg~28.36 MJ/kg之间;已检测出的焦油成分包括烷烃、烯烃、酚、醇、醛、酮、酯、单环芳烃、PAHs等;在T500(500℃焦油)中,主要以单环芳烃和PAHs为主;随着温度的升高,PAHs成为焦油的主要成分,且含量从8.84%升至83.45%;当热解温度≤600℃时,PAHs的产生主要通过Diels-Alder反应,当热解温度600℃时,PAHs的主要产生途径还包括苯酚及其衍生物的自由基反应;萘及其衍生物是PAHs的主要成分。⑦已检测出的热解气成分包括烷烃、烯烃、炔烃、CO2、含S气体(以H2S为主)、含Cl气体(以CH3Cl为主)等;当热解温度从500℃升至800℃时,气体体积增加,其中烷烃、烯烃、炔烃、CO2、含S气体和含Cl气体的体积分别增加1.86倍、3.64倍、19.23倍、2.17倍、3.28倍和1.65倍;当温度≤600℃时,脱氢反应剧烈,当温度600℃时,脱氢反应缓慢提高;烯烃是气体的主要成分,且随着温度的升高,其比例逐渐增加。⑧当温度≤600℃时,原料-C发生一次热解反应,生成炭-C、焦油-C和气体-C;焦油-C产率在600℃时达到最大值32.81%;当温度600℃时,发生二次热解反应,焦油-C产率在700℃时降至最小值29.39%,部分焦油-C转化为气体-C;炭-C产率随温度的升高从36.39%降至29.40%;气体-C产率随温度的升高而从31.95%升至40.28%。⑨50%以上的H和O分布在气体中,且随着热解温度的升高而升高,而炭-H(O)、焦油-H(O)产率则逐渐降低;炭-N产率随温度的升高从57.73%降至30.46%,焦油-N产率在600℃时达最大值39.41%,之后逐渐减少并稳定在32%附近,气体-N产率在600℃时取得最小值9.04%,之后逐渐增大至37.43%;80%以上的S分布在气体中,炭-S产率为6.68%~4.95%,且在800℃时,炭-S主要以盐形式存在;焦油-S产率在600℃取得最大值10.41%,之后逐渐分解为气体-S;60%以上的Cl分布于气体中,焦油-Cl产率极低,为0.09%~2.80%,炭-Cl产率随温度的升高从38.40%降至29.96%。
[Abstract]:City life garbage pyrolysis technology can not only make the waste volume reduction, reduction, resource utilization and waste can be achieved, which has attracted increasing attention in recent years. But until now, domestic garbage pyrolysis processing technology there are still many problems, such as the pyrolysis mechanism needs to be improved, the thermal properties and the hydrolysis products need to be further explored. According to the above the city life garbage problem, as the research object, study the properties of pyrolysis products and the element distribution changes with pyrolysis temperature, pyrolysis mechanism for the deep understanding of city living garbage, provide reference for using pyrolysis material resources. Through experimental research, draw the following conclusion: carbon yield with increasing pyrolysis temperature (500 DEG C ~800 C) decreased from 31.38% to 25.58%; reach the tar yield at 600 DEG C after the maximum value of 28.02%, as the temperature rises gradually to a minimum value of 21.76 %; quality yield and volume yield of pyrolysis gas increases as the temperature increases, the quality of yield from 41.7% to 52.66%, the volume yield from 143.50L/kg to 438L/kg. 2 compared with the raw materials of C elements in the relative enrichment of carbon and tar, carbonization degree is greatly improved, and the degree of enrichment of C elements is higher than that of tar and carbon carbon; tar O/C ratio and H/C ratio were significantly lower than that of raw materials, with the increase of temperature decreases gradually; carbon and tar than aromatic degree of carbon and polarity were higher than that of the tar. The main raw material containing an aliphatic ether, ketone, methyl and methylene groups, and carbon structure is disordered and raw materials; compared with pyrolytic carbon in aliphatic groups greatly reduced, and mainly in the aromatic ring of =C-H, the main aromatic / aliphatic methyl and methylene groups; with the increase of temperature, the number of aromatic groups increased, and the carbon structure gradually and orderly 鎺掑垪;鍦ㄥ師鏂欏拰鐐�涓�鍧囧瓨鍦ㄧ洂鍚告敹宄，

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