污水污泥热解试验研究

Experimental study on the pyrolysis of sewage sludge

研究了热解终温对污水污泥热解产物产率的影响,对污泥热解油中的轻质组分进行了分析,并初步探讨了污泥热解残渣的基本性质。研究表明,热解终温为450～500℃时,液相产物产率较高,随着热解终温的升高,热解残渣减少的趋势与液相产物增加的趋势相似;450℃时得到的污泥热解油的轻质组分中主要含有烷烃类、烯烃类、腈类、含氮杂环化合物和单环芳香烃等;随着热解终温的升高,残渣表面越来越松散和粗糙;450℃时得到的热解残渣孔容积最大,而500℃时得到的残渣微孔最为发达,比表面积值最高。

In this paper, the effect of final pyrolysis temperature on the yield of products from the pyrolysis of sewage sludge was studied. The light fraction from sludge pyrolysis oil was analyzed. The fundamental properties of the pyrolysis residues were also investigated briefly. The results showed that when the final pyrolysis temperature was between 450 ℃ to 500 ℃ , the yield of liquid product was favorable. With the increase of final pyrolysis temperature, the decreasing trend of pyrolysis residue was similar to the increasing trend of liquid product. Both of them were steep when the temperature was under 450℃ and mild when the temperature was higher than 450 ℃. Meanwhile the uneondensed gas increased snloothly with the increase of final pyrolysis temperature. The light fractions of pyrolysis oil obtained at 450 ℃ was mainly consisted of alkanes, alkenes, nitriles and nitrogen-containing heterocyclic compounds as well as MAHs etc. Among them, the concentration of toluene, 4- methyl-phenol, 1 methyl - 2,5 - pyrrolidinedione, pyridinc, 1 dodecene and pentadecane etc. were significant. The pyroysis residues of sewage sludge contained low carbon and high ash. However, they still possessed some volatile content. With the increase of final pyrolysis temperature, the surface of pyrolysis residue became more and more looser and rougher. The residue obtained at 450 ℃ exhibited highest pore volume. Nevertheless, the residue obtained at 500 ℃ owned maximum specific surface area in respect that it possessed highest number of micropores.