【作者】 王艳；

【导师】 张于峰；

【作者基本信息】 天津大学 ， 热能工程， 2005， 博士

【摘要】 近年来,由于世界能源、资源日益紧张以及各种垃圾资源化利用方法的出现,城市垃圾已从单纯收集、运输、处理、填埋的狭窄概念转向抑制垃圾生产、提高垃圾资源化利用率上来。城市垃圾作为一种资源被开发利用已是大势所趋。本文通过介绍国内外的垃圾处理现状,比较填埋法、堆肥法、焚烧法、热解法等的优缺点,尤其是热解技术处理垃圾的优越性,显示出热解法将是垃圾处理的一个重要方向之一,对其研究已成为相关专业研究的前沿问题。本研究使用自行设计和制造的、旨在模拟工业化实际设备中热解特性的小型外热式固定床实验装置,以城市生活垃圾中典型的可热解成分组成的混合物为实验物料,进行300℃～700℃的一系列垃圾热解实验。研究了在具有一定规模的小型固定床热解实验装置中,城市生活垃圾热解过程中的温度场变化规律,以及热解反应时间、热解产物分布、挥发分的析出率等受热解温度影响的内在机理特征。热解气作为垃圾热解的重要产物之一,其成分变化特性直接影响其后的热利用。热解气的成分含量和热值的平均值,均随热解温度呈现一定的变化规律。在本文的实验中,设定温度为300℃～700℃的范围内,其热值在5.4MJ/m3~15.13MJ/m3之间变化。热解气中除H2、CO、CH4、CO2、C2H4、C2H6这六种主要气体外,还含有NOX、HCl、H2S、NH3、O2、C3、C4、C5碳氢化合物及高烃类气体等,且热解温度越高这些气体的含量越大。文中还对热解的剩余物——半焦物质进行了元素分析和工业分析,分析表明其热值在21MJ/kg～24.7MJ/kg之间,可以作为固体燃料利用,但其元素成分和工业成分均随热解温度发生变化,且影响着半焦的燃烧特性。通过对热解过程的能量分析,表明本实验物料热解需要的能量完全可利用热解产物来提供,而不需要其它辅助热源。针对城市生活垃圾的特点,本文采用当量导热法的概念,将城市生活垃圾在热解过程中复杂的传热过程简化为纯导热过程,建立了一套求解固定床热解反应器中物料温度场的传热学模型。通过与实验数据的比较,表明该模型具有一定的实用性。更多还原

【Abstract】 Owing to the shortage of energy and resources all over the world and theemergence of different utilization of municipal waste, recent years, the traditionalwaste disposal such as simple collection and direct burying have been graduallysubstituted by some new methods which not only can restrain the yield of trash butalso can effectively utilize waste as one kind of resource. By introducing thedomestic and overseas disposal status of MSW （municipal solid waste）, andcomparing the advantages and disadvantages of some disposal methods, such aslandfill, compost, incineration and pyrolysis, it proves that the pyrolysis technologyis a main disposal method of MSW in the future, and that studies on this filed hasbecome an important direction to be developed.To simulate the pyrolysis characteristics of real facility, an externally heatedfixed-bed pyrolysis furnace was built. Compounds made by typical pyrolysiscomponent of municipal solid waste were taken as the testing materials. While thepyrolysis temperature rising from 300℃ to 700℃, its effects on temperature field ofpyrolyzed waste, pyrolysis time, pyrolysate distribution, removal rate of volatilefraction have been studied by a series pyrolysis tests.The change rules of pyrolysis gas components, as important pyrolysates, has adirectly influence on the use of pyrolysis gas. Both the content of pyrolysis gascomponent and its average heat value vary with the pyrolysis temperature as definiterules. During the examination of present research, namely the pyrolysis temperaturefrom 300℃ to 700℃, the heat value of pyrolysis gas varied from 5.4 MJ/m3 to15.13MJ/m³. The main components of pyrolysis gas were H₂, CO, CH₄, CO₂, C₂H-4,C₂H₆. The pyrolysis gas also concluded other components such as NOX, HCl, H₂S,NH3, O2, C3, C4, C5, and hydrocarbon, the content of which increased with thepyrolysis temperature rising.Elemental analyses and industrial analyses of semi-coke, the pyrolysis remains,were also proposed in this paper. The heat value of semi-coke was between20.99MJ/kg and 24.7MJ/kg, so that it can be used as solid fuel. However, thecomponents of semi-coke changed with the pyrolysis temperature, whichsimultaneously affected the combustion characteristic of semi-coke.Analyzing the whole process of waste pyrolysis, it s apparently indicated thatthe pyrolysis product can provide total energy for waste pyrolysis,and there were noother auxiliary heat source needed.Considering the trait of municipal solid waste, the complicated heat transferprocess of waste pyrolysis was simplified to a pure heat conduction process in thispaper by using equivalent conduction method, accordingly, the heat transfer modelused to obtain the temperature field of pyrolysis material in the fixed-bed reactorwas built. Comparing with the test data, it was proved that this heat transfer model ispartly practical.更多还原