热重-红外联用分析垃圾衍生燃料的热解特性

利用热重红外分析仪(TG-FTIR)研究了两种不同垃圾衍生燃料(RDF)的热解特性。研究发现,尽管两种RDF的来源不同,但却具有相似的热解特性,其热解过程主要分为3个阶段:生物质组分(220～430℃)、塑料类物质(430～520℃)以及无机碳酸盐(>650℃)的分解。利用Coats-Redfern法,求得了RDF热解前两个阶段的表观动力学参数,计算结果表明高温段的反应活化能要高于低温段。通过FTIR对RDF热解析出的气体进行了在线分析,发现两种RDF热解过程中的气相产物析出规律基本一致,析出的气体主要包括H₂O、CO₂、CO以及CH₄等烃类。HCl在低温阶段(230～400℃)即析出完毕。相比之下,NH₃开始析出的温度较高(260℃),并且整个析出温度范围较广,高温下仍有少量析出。SO₂在热解条件下仍有相当量的生成,其析出主要集中在300～600℃的温度范围内。

TG-FTIR analysis on pyrolysis characteristics of refuse-derived fuel

The pyrolysis characteristics of two different kinds of refuse-derived fuels(RDF) were investigated using thermogravimetric analysis-Fourier transform infrared spectrometer(TG-FTIR).It was found that the pyrolysis characteristics of two RDFs were similar.The pyrolysis process could be divided into three main stages,corresponding to the decomposition of biomass components(220—430℃),plastic substances(430—520℃) and carbonates(>650℃).The Coats-Redfern method was used to analyze the apparent kinetic parameters of the first two stages,and the results showed that the activation energy was higher for the middle-temperature stage than for the low-temperature stage.By FTIR analysis,it was found that the major volatile gases released from the two RDFs were similar,mainly including H₂O,CO₂,CO,CH₄ and other hydrocarbons.The release of gaseous pollutants was paid special attention.The emission of HCl is completed at the low temperature stage(230—400℃).In contrast,the release of NH₃ begins at 260℃ and goes through a much wider temperature range,and there is still a small amount of NH₃ release at much higher temperature.In pyrolysis condition investigated,it was surprised to detect large amount of SO₂,mainly released in the temperature range of 300—600℃.