印染污泥混燃特性及其燃烧动力学模型

采集了广东某印染污泥(YR)、造纸污泥(ZZ)及两种市政污水污泥(LJ、KFQ),利用热重法对不同来源污泥的单一及混合样在不同焚烧条件下进行了热重实验研究,并通过TG-DTG曲线计算了各试样的综合燃烧特性指数,获得了其燃烧动力学参数.结果表明,各单一试样的燃烧主要分为水分析出、挥发分析出、固定碳燃烧和残留物的燃烧和分解4个燃烧阶段,其中挥发分的析出制约着YR、KFQ、LJ污泥的整个燃烧过程,而ZZ污泥还受到固定碳燃烧阶段的显著影响.当向印染污泥中加入50%的KFQ市政污泥后,YR污泥的综合燃烧特性指数和可燃性指数分别提高了将近2倍和1.6倍.富氧(CO2/O2)燃烧可以提高印染污泥的后期燃烧强度,降低印染污泥燃烧阶段活化能,促进印染污泥的综合燃烧性能.采用积分法(Coats-Redfern方程)计算得到各燃烧阶段反应的机理方程及相应的活化能参数,发现第一挥发分峰前取反应级数n=0.5、峰后n=2,可描述各自阶段的燃烧反应机理,而第二挥发分峰没有显著规律.

Co-combustion characteristics of textile dyeing sludge and its combustion kinetics model

Four kinds of sludge samples, including textile dyeing sludge (YR), paper mill sludge (ZZ) and two municipal sewage sludge samples (LJ and KFQ), were collected in Guangdong. Thermogravimetric analysis (TGA) was conducted under various incineration conditions, and the combustion indexes of each sample were calculated by using the TG-DTG curves. The thermogravimetric results showed four main weightlessness peaks in curves corresponding to stages of moisture exhalation, volatile exhalation, fixed carbon combustion, and residues decomposition. The stage of volatile exhalation dominated the combustion processes among YR, KFQ and LJ sludge incineration, while the combustion process of ZZ sludge was also controlled by the fixed carbon combustion stage. When YR sludge was mixed with 50wt.% KFQ municipal sludge, the comprehensive combustion index S and flammability index C increased by 2 times and 1.6 times, respectively. On the other hand, application of oxy-fuel combustion process contributed not only to the reduction of activation energy E but also to the increase of combustion intensity in dyeing sludge incineration. Both chemical reaction parameters and activation energy E were obtained by using Coats-Redfern equation calculations. The results evaluated that the reaction order of pre-peak and post-peak of the first volatile peak were 0.5 and 2, respectively, while those in the second volatile peak showed no significant characteristics.