城市固体废弃物热解研究现状

目前城市固体废弃物的处理已经成为亟需解决的问题,相对于传统的处理方式,热解处理以其资源化、减量化、污染小等优点越来越得到人们的重视。文章就固体废弃物热解原理、影响因素等进行综述,并分别介绍了国内外固体废弃物热解处理现状,着重分析了催化热解技术现状;认为热解处理的发展应该以如何优化提纯热解产物并实现工业化应用为研究方向。     

固体废弃物热解半焦特性的研究

文中对固体废弃物热解半焦的化学成分及反应活性进行了研究,物料本身的性质、热解终温等将直接影响半焦产率、半焦中的C、H、N、S元素的残余量及半焦CO2的反应活性。另外,混合物料的半焦产率及组成与各组分单质物料在相同条件下热解半焦产率按组分比例的代数和大致相等。     

热带城市垃圾典型组分的热解特性研究

对热带城市垃圾的几种典型组分进行了热解实验，得到了它们的失重曲线，通过对失重曲线进行分析，得到了这几种典型组分的热解规律，并通过建立热解动力学模型，求出了其中两种组分的活化能E和频率因子A。     

医疗废物典型组分在回转窑内的热解研究

针对医疗废物的无害化处置问题，对四种典型医疗废物在回转窑实验台上进行了有机组分的试验研究，分析了各物料的热解过程，确定了各自的产物分布、产气变化趋势以及热解终温的影响等，为医疗废物的处置、利用提供参考依据。     

中国城市垃圾典型组分热解特性及动力学研究

对城市生活垃圾中的8种典型组分进行了热重分析实验,提出热解指数来表征垃圾的热解特性,热解指数越高,垃圾越容易热解.结果表明,提高加热速率有助于增大热解指数;相同加热速率和粒度条件下,8种垃圾组分的热解能力依次为:废塑料、废纸张、废皮革、瓜皮类、化纤、落叶、植物类厨余和废橡胶,其中废塑料的热解指数远远大于其它7种组分.用积分法对热解实验数据进行处理,得出反应动力学参数及反应速率控制方程,从而得到相应工况和温度区间下的动力学模型.可以看出,垃圾组分不同,其反应机理可能不同,相对应的热解动力学模型也不同.     

煤粉热解组分析出特性的实验研究和DAEM模拟

为研究煤粉热解各组分的析出特性,在TGA-FTIR联用实验台上对宝日希勒褐煤和包头烟煤进行了热解实验研究,对CH4、CO2、CO和HCN进行了测量,并对采用分布活化能模型(DAEM)模拟总体挥发分和各组分的析出进行了分析.结果表明,CH4的析出浓度曲线呈对称的单峰分布,而CO、CO2和HCN的析出浓度曲线不规则,DAEM模型可适用于整体挥发分的模拟,也可时CH4的析出进行较准确的模拟和预测,但不适用于CO、CO2和HCN的模拟.CH4、CO2、CO和HCN析出温度主要由各自官能团分解键能决定.宝日希勒褐煤总体挥发分含量高于包头褐煤,然而挥发分中CH4和HCN的含量低于包头烟煤.     

城市固体废弃物的燃烧特性实验研究

通过热分析技术,对城市固体废弃物中几种典型组分进行实验研究,得到了混事垃圾在热重分析仪中的燃烧特性,并对城市固体废弃物的规律开展了有益的探讨。     

水煤浆快速热解特性及影响因素研究

为研究水煤浆（CWS）的快速热解特性,利用高频加热炉,以神木煤作为CWS制作原料,开展快速热解实验,并与慢速热解实验结果作对比,分析了热解气的释放规律（产率、组分及比例等）及热解特性与反应温度、加热速率、停留时间之间的关系。结果表明：热解气以H2、CO、CH4和CO2成分为主;在高于1 000 ℃和较长的反应时间下进行快速热解,有利于生成高体积分数和高产率的还原性气体;快速热解条件下,随着温度的升高,H2和CO的产率持续增加（H2的产率增加了约0.45 L/g, CO的产率增加了约0.14 L/g）,而CH4的产率先上升后下降（在900 ℃时产率最高为0.12 L/g）,CO2产率在低温段有些许上升之后几乎没有明显变化（只增加了约0.03 L/g）;快速热解条件下,H2和CO的相对体积分数随着温度的升高而持续增加（分别增加了约45%和5%）,CH4和CO2的体积分数则随温度的升高而下降（CH4下降约35%,较为剧烈,而CO2则下降了约10%~20%）;在慢速热解时,H2,CO2和CH4的产率会随着最终温度的增加,呈先上升后下降的趋势（最高点在约1 100 ℃）,CO产率则呈上升趋势;慢速热解阶段H2和CO2的相对体积分数随着温度的增加略有变化（CH4则下降了3%）, CO增加约5%。     

城市固体废弃物热重分析及热解动力学研究

对城市垃圾典型组分（塑料、橡胶、果皮、织物、纸板等）进行热重分析及热解动力学研究。热重分析结果表明，塑料组分开始分解的温度较高，但分解速率最快；橡胶组分开始分解反应的温度相对较低，且分解速率相对较慢。果皮、织物和纸板类以纤维和木质类物质为主要成分，其热解特性较为相似。热解动力学研究表明，橡胶的热解活化能最高，最难分解，且热解符合二维扩散机理；塑料的热解相对较容易，符合一维扩散机理。而果皮、织物和纸板类的活化能较低，它们的热解符合体积缩小机理。     

利用快速升温大尺寸热重分析对松木热解特性的研究

设计搭建了能实现快速升温功能的大尺寸热重分析(macro thermo-gravimetric analyzer,macro-TGA)实验台,对大尺寸松木样品的热解特性进行了研究.该实验台可以对大尺寸样品(1～40 mm)热解过程的质量、温度信号进行在线测量,有快速升温和匀速升温两种工作模式,其中快速升温模式瞬时升温速率可达2 500℃/min,匀速升温模式升温速率可设定为1～40℃/min.实验结果表明,快速升温模式下热解目标温度为700℃时,5 mm样品热解反应达到80%转化率用时小于2 min,远小于20℃/min匀速升温工况时的9 min.对于尺寸小于10 mm的样品,其热解过程由反应动力学控制,对于尺寸大于20 mm的样品,热解由样品内部的传热控制.采用单组分一步全阶段一阶反应模型对5 mm样品的热解动力学参数进行了求解,结果表明,随着目标温度的上升,样品热解活化能下降,反应活性上升.     

Low‐temperature pyrolysis of municipal solid waste: influence of pyrolysis temperature on the characteristics of solid fuel

This paper presents the results of pyrolysis experiments of the mixtures of nine different combustibles municipal solid wastes (MSW's main composition: rice 24.33% and fruits 14.60%). The experiments were carried out in a laboratory‐scale reactor under nitrogen atmosphere at temperature of 300–700°C. The study concentrates on low‐temperature pyrolysis of MSWs and the effect of the pyrolysis temperature on the characteristics of the products (solid fuels) including proximate analysis, volatile content, heating value, ignition temperature and density of the solid fuel. The results indicate that the pyrolysis temperature plays an important role on the characteristics of the solid fuels. The volatile content of the solid fuels decreases with the pyrolysis temperature so that the low‐pyrolysis MSW treating process has advantage for higher heating value of the solid fuel for energy recovery purpose. The heating value is in the range of 23–27 MJ kg^?1, equivalent to the heating value of low‐rank coals. Copyright © 2005 John Wiley & Sons, Ltd.     

城市垃圾中温热解新技术

简要阐述了国内外垃圾热解技术的发展概况,详细介绍了几种典型的垃圾热解工艺,在吸收各种垃圾热解技术优势的基础上,结合我国城市垃圾的特点,提出了一种新型的城市垃圾中温热解技术,通过经济效益分析和社会效益分析,说明这项技术具有广阔的应用前景。     

Simulation analysis of municipal solid waste pyrolysis and gasification based on Aspen plus

To predict and analyze the municipal solid waste (MSW) pyrolysis and gasification process in an up-draft fixed bed more veritably and appropriately, numerical modeling based on Gibbs energy minimization was executed using the Aspen plus software. The RYield module was combined with the RGibbs module to describe the pyrolysis section, while the RGibbs module was used for the gasification section individually. The proposed model was used to forecast and analyze the target performance parameters including syngas composition, lower heating value (LHV) and carbon conversion rate under different conditions of the gasification temperatures, and ratios and types of gasifying agents. The results indicate that there is a good agreement between the experimental data and the simulated data obtained using this model. The predicted optimum gasification temperature is approximately 750°C, and the best ratio of water vapor as gasifying agent is around 0.4. The mixture of flue gas and water vapor has an economical and recycled prospect among four commonly used gasifying agents.     

Experimental Studies on Combustion Characteristics of Mixed Municipal Solid Waste

In our country, municipal solid wastes (MSW) are always burnt in their original forms and only a few pretreatments are taken. Therefore it is vital to study the combustion characteristics of mixed waste. In this paper, thermogravimetric analysis and a lab scale fluidized bed facility were used as experimental means. The data in two different experimental systems were introduced and compared. It took MSW 3-3.5 min to burn out in FB, but in thermogravimetric analyzer, the time is 20-25 min. It can be concluded that, in general, the behavior of a mixture of waste in TGA can be expressed by simple combination of individual components of the waste mixtures. Only minor deviations from the rule were observed. Yet, in Fluidized Bed, it was found that, for some mixtures, there was interference among the components during fluidized bed combustion.     

Effects of different combustible municipal solid waste components without/with additives on co-pyrolysis

This article studies co-pyrolysis of combustible municipal solid waste (MSW) without/with additives (CaO, CuCl₂, zeolite powder, and MnO₂). Co-pyrolysis of different MSW components mixing and adding additives in co-pyrolysis could change yield of oil, high heating value (HHV), and products distribution. The yield of oil increases noticeably, but HHV decreases with ratio (sawdust: paper) increasing. Moreover, the yield of phenols increases. After adding fabric, the yield of acids and alcohols increases and that of aldehyde decreases. The yield of oil decreases after adding CaO and MnO₂, and HHV of co-pyrolysis increases after adding CaO, zeolite powder, and MnO₂. Adding MnO₂ has the most impact on the decrease of aldehyde, and adding CuCl₂ has the biggest effect on phenol reducing. The yield of ketone is affected most greatly by adding CaO.     

有机固体废弃物在固定床内热解的实验研究

通过对几种典型的城市有机固体废弃物的热解实验，为开展新的垃圾处理工艺提供基础研究。文中考察了不同工况下的有机固体废弃物的热解产物特性，分析了物料性质、热解终温、加热方式等因素对热解产物分布的影响。通过实验发现，热解终温是较重要的影响因素，同时物料的工业分析结果也是一个重要因素。     

Yields of pyrolysis products from refuse-derived fuel

Pyrolysis yields and gas characteristics must be studied to control pollution caused by waste-energy recycling and to develop a refuse-derived fuel technology. In this study, refuse-derived fuel pyrolysis experiments were performed in a high-temperature tube furnace. The effects of the final pyrolysis temperature, material mixture ratio, and pyrolysis rate on the yields of pyrolysis products, including gas, tar, and semi-coke, were studied. The volume fractions of the pyrolysis gas components (H₂, CO, CH₄, and CO₂) of the samples were also detected. Results showed that with increased final temperature, the tar and gas yields increased but the semi-coke yield decreased. The volume fractions of the components had the following trends: H₂ increased, CO initially decreased and then increased, CH₄ initially increased and then decreased, and CO₂ decreased. With decreased biomass, the tar yield decreased and then increased, whereas the semi-coke and gas yields increased and then decreased. Compared with slow pyrolysis, fast pyrolysis decreased the tar yield by 9.13%, increased the gas yield by 7.45%, increased the CO and CH₄ volume fractions, and decreased the CO₂ volume fraction.     

Co-pyrolysis characteristics and product distributions of municipal solid waste and corn stalk

To investigate synergetic effects on pyrolysis of municipal solid waste and corn stalk, pyrolysis characteristics and product distributions of their mixtures were examined by thermal gravimetric and fixed-bed. Results indicated that co-pyrolysis process can be divided into four steps: losing water, main pyrolysis, carbonization and catalytic gasification of char. Under different blending ratio conditions, char and liquid yields were lower than the theoretical values calculated on pyrolysis of each individual sample, and consequently, gas yields were higher. Linear relationship can be applied to char and liquid products, however, hardly applied to gas yields.     

Steam catalytic gasification of municipal solid waste for producing tar-free fuel gas

In the paper, a two-region municipal solid waste (MSW) steam catalytic gasification process was proposed. The gasifier was composed of two individual reactors: one is the gasification reactors and the other is the catalytic reactor. The MSW was initially gasified and the produced tar was gasified in the gasification reactor, and further, the tar not gasified entered the catalytic reactor together with the fuel gas and was catalytically decomposed to fuel gas. The influences of the catalysts, steam and temperature on the content of tar, dry gas yield and composition, and carbon conversion efficiency were studied. The results indicated that under the optimum operating conditions, the dry gas yield can be up to 1.97 Nm³/kg MSW and the tar in the product can be completely eliminated. The concentration of hydrogen, carbon monoxide and methane in the fuel gas produced was 50.8%, 9.32% and 13.3%, respectively.     

Partitioning of heavy metals during municipal solid waste incineration on a laboratory fluid bed furnace

The content of heavy metals in the main physical compositions of municipal solid waste (MSW) is analyzed. The effects of temperature, chlorine and water on the partitioning of heavy metals are studied using a laboratory fluidized-bed (FB) furnace with simulated MSW composition. The experimental results show that temperature and chloride content in the feed have significant influence on the volatility of heavy metals, especially those of lower boiling point such as Hg, Cd and Zn. The influence of water is slight. Translated from Proceeding of the CSEE, 2005, 25(17): 100–104 [译自: 中国电机工程学报]