高含固污泥中影响因素对流变特性的影响

Effects of influence factors of high-solids sludge on rheological characteristics

以城市污水处理厂产生的高含固污泥(含水率≤80%)为对象,实验考察了剪切速率(2.5~100 r·min^(-1))、温度(13~80℃)、含水率(65%~80%)3因素对污泥流变特性的影响。结果表明:在考察范围内,污泥黏度随剪切速率增大而迅速减小,幂律方程拟合结果表明污泥具有假塑性流体的特征;污泥的黏度随温度升高而减小,且二者呈线性关系,实验数据与阿伦尼乌斯公式拟合结果表明温度对污泥黏度的影响程度小于剪切速率;污泥黏度随含水率的降低呈指数增长,在低温下表现得更明显。综合分析3个因素对污泥黏度的影响,污泥在持续加热至80℃,保持以转速≥62.5 r·min^(-1)(线速度≥0.010 5 m·s^(-1))搅拌的前提下,可以实现减水至含水率达到60%,根据黏度值判断依然具有泵送可行性。

An experimental investigation was performed to study the effects of shear rate（ 2. 5 to 100 r·min^-1）,temperature（ 13 to 80 ℃）,and moisture content（ 65% to 80%） on the rheological characteristics of high-solids sludge（ moisture content ≤80%） produced by municipal sewage plant. Results showed that within the scope of this study,the viscosity of the sludge decreased rapidly with increasing shear rate,and the power law model fitting the results,indicating that the sludge possessed the characteristics of a pseudoplastic fluid. The viscosity of the sludge also decreased with increasing temperature linearly. Experimental data and Arrhenius formula-fitting results showed that the sludge viscosity was affected by temperature to a lesser extent than by shear rate. The viscosity of the sludge showed exponential growth with decreasing moisture content,which was more obvious under low temperatures. Considering the influence of the three factors on sludge viscosity,the sludge would retain the feasibility of pumping till the moisture content was reduced to 60% under conditions of constant heating（ sludge temperature≈80 ℃） and sustained stirring（ shear rate ≥62. 5 r·min^-1,line speed≥0. 010 5 m·s^-1）.