污泥热解特性影响因素的研究

目的]研究污泥的热解特性及其影响因素。方法]采用热分析的方法研究升温速率、试验终温、污泥组分、颗粒粒径和氮气吹扫量等因素对污泥热解特性的影响。结果]污泥热解可以划分为3个阶段:第一阶段是水分析出阶段(50～150℃);第二阶段是污泥失重的主要阶段(150～530℃),热解失重是由于有机物的分解引起;第三阶段(530～800℃)失重是由于无机物和残余有机物引起。污泥热解在第二阶段是放热过程。升温速率对污泥热解特性的影响主要表现在起始温度方面,而对峰温和失重率的影响较小;试验终温的影响则主要表现在污泥的失重率上,试验终温越高,污泥的失重率越高,而对热解起始温度的影响则可以忽略;污泥组分不同,表现出的起始温度、峰温和失重率等反映污泥热解特性的主要参数不同;污泥的粒径不同,反映热解特性的主要参数起始温度、终止温度、峰温和失重率等都存在明显的差异;氮气吹扫量对污泥热解参数基本没有影响,但随着氮气吹扫量的增加,污泥的失重率增加。结论]该研究可为污泥的热处理方法研究提供理论依据。

Study on the Influencing Factors on Pyrolytic Properties of Sewage Sludge

Objective] To study the pyrolytic properties of sewage sludge and their influencing factors.Method] Thermal analysis was used to study the effect of heating rate,experimental end temperature,sludge components,particle size and purging rate of N2 on pyrolytic properties of sewage sludge.Result] The pyrolysis can be divided into 3 phases:dehydration(50-150 ℃),decomposition of organic compounds(150~530 ℃) and decomposition of residual organic compounds and inorganic compounds(530~800 ℃).The decomposition in the second phase are exothermic reactions.The influences of heating rate on initial temperature Ti are much stronger than on the peak temperature Tp and weight loss W%.The effect of the experimental end temperature tend mainly manifests itself in W% of the sewage sludge,which means that the higher the tend,the bigger the W%.However,its effect on Ti is negligible.The pyrolytic properties such as Ti,Tend,Tp and W% vary according to the components of sewage sludge.Different particle size of sewage sludge leads to a notable difference in pyrolytic parameters as well.The purging rate of N2 does not affect the pyrolytic parameters of the sewage sludge.However,W% increases with purging rate of N2.Conclusion] The study provides theoretical basis for the pyrolytic treatment of sewage sludge.