水泥厂废旧除尘布袋热重分析及其形态特征

Thermogravimetric analysis and morphological characteristics of waste filter bag from cement plant

采用综合热重分析法,对水泥厂3种不同工段的废旧除尘布袋及相对应的同型号新布袋进行了热重(TG)分析实验研究.结果表明,废旧除尘布袋热重分析的升温过程中主要有3个失重峰,前两个失重峰与涤纶纤维的燃烧析出相对应,第3个失重峰主要是碳酸钙分解的结果.采用积分法(Coats-Redfern方程)计算得到各阶段燃烧反应的机理方程及相应的活化能参数.分析表明,在低温段废旧布袋中的灰尘对燃烧反应影响不大,而在高温段废旧布袋中的灰尘导致燃烧反应活化能升高,阻碍燃烧反应进行.从电镜扫描和能谱分析可知,废旧除尘布袋中的涤纶纤维几乎被焚烧殆尽,剩下的少量焚烧灰渣由C、O、Si、Ca等主要元素,以及Ti、Al、Mg、Mn、Fe等次要元素组成.这种灰渣与水泥成分类似,具有较高的回收利用价值.

The combustion characteristics of waste filter bags from three working sections in a cement plant and new filter bags of the same model were studied by thermogravimetric analysis. The results showed that there were three obvious stages of weight Ioss in the waste filter bag combustion curves, and the first two stages were corresponded to the combustion of polyester while the third stage was caused by the decomposition of CaCO3. Both the reaction equations for different combustion periods and the corresponding activation energies were obtained by using the Coats-Redfern equation. The data indicated that dust in the filter bag had a little influence on the activation energy for combustion at low temperature, while it led to an increase of the activation energy at high temperature and thus hindered the combustion reaction. According to the results by scanning electron microscope and energy dispersive spectrum analysis, the polyester in waste fiber bag had been burned off, and only a small amount of ash remained. The main elements of the ash were C, O, Si and Ca, and the minor elements were Ti, Al, Mg, Mn and Fe, which was similar to the composition of cement, revealing a high reuse value of the ash.