Study on the pyrolysis properties of the tars from sewage sludge gasification

doi:10.16085/j.issn.1000-6613.2015.05.047

Abstract

Abstract: The pyrolysis properties of nine tars,derived from the air gasification of five different kinds of sewage sludges at 600℃,700℃ and 800℃ in an external heated updraft fixed-bed,were studied by thermal gravimetric analysis. The results showed that the pyrolysis processes of the nine gasification tars could be divided into three stages:the stage of water and low boiling organic compounds release,the stage of organic compounds release and decomposition,and the stage of residual organic compounds decomposition. Low molecular weight organic compounds increased in the gasification tars obtained at 800℃ in both the sludge anaerobic digestion and the “anaerobic” process in wastewater treatment,and light organic compounds and heavy non-polar compounds released in the second stage did not change much. Besides,both the sludge anaerobic digestion and the “anaerobic” process made the pyrolysis properties of the gasification tars become worse. The influences of gasification temperature on the change rule of weightlessness rate at the first and second stages of the tars from indigested sludge were different from that of the tars derived from digested sludge. The pyrolysis properties of the gasification tars were better than that of pyrolysis tars. The kinetics analysis indicated that the pyrolysis mechanism functions of the nine gasification tars were different,and the pyrolysis activation energies of them were low,suggesting good pyrolysis properties.

Key words: sewage sludge, gasification tar, wastewater treatment process, pyrolysis, kinetics

摘要： 利用热重分析方法,对由5种不同性质污泥在气化温度600℃、700℃和800℃下进行外热上吸式固定床空气气化时制得的9种污泥气化焦油的热解特性进行了研究.结果表明:9种气化焦油热解时均分为3个阶段,分别是水和低沸点有机物的挥发、有机物挥发分解以及残余物分解.污泥厌氧消化和污水处理工艺中的厌氧过程均使800℃下制得的气化焦油中低分子有机物含量增加,但对第二阶段挥发的轻质及重质非极性有机物总含量的影响很小,且使气化焦油的热解特性变差.气化温度对未消化污泥气化焦油热解时第一和第二阶段失重率的影响变化规律与消化污泥气化焦油的不同,且气化焦油的热解特性优于污泥热解焦油.热解动力学研究表明,9种气化焦油热解机理函数彼此不完全相同,且热解活化能均较低,具有良好的热解特性.

关键词: 污水污泥, 气化焦油, 污水处理工艺, 热解, 动力学

CLC Number:

X705

YANG Mingqin, XIE Liping, YUE Junnan, ZHANG Weihong. Study on the pyrolysis properties of the tars from sewage sludge gasification[J]. Chemical Industry and Engineering Progree, 2015, 34(05): 1472-1477,1487.

杨明沁, 解立平, 岳俊楠, 张伟红. 污水污泥气化焦油热解特性的研究[J]. 化工进展, 2015, 34(05): 1472-1477,1487.

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