热水解预处理对高含固污泥流变特性的影响

Impacts of Thermal Hydrolysis Pretreatment on Rheological Characteristics of High Solid Content Sludge

研究了高温热水解预处理对高含固污泥流变特性的影响规律。结果表明,污泥黏度随着含固率的提高而呈现指数增加趋势,当含固率<10%时,污泥黏度的增加较为缓慢;而当含固率>10%时,污泥黏度随含固率的提高而急剧增加。热水解前后污泥黏度均随着剪切速率的提高而减小,呈现出剪切变稀特性。剪切应力随剪切速率的变化规律符合Herschel-Bulkley模型,且流型指数均小于1,表明污泥为假塑性非牛顿流体。在所有含固率梯度下,热水解后污泥黏度均低于热水解前,尤其在含固率>10%时,热水解对污泥黏度的降低作用非常显著。热水解后污泥屈服应力降低幅度均达到80%以上。

Impacts of thermal hydrolysis pretreatment on rheological characteristics of high solid content sludge were investigated.The results showed that the sludge viscosity increased exponentially with the raising of the solid content-it increased slowly when solid content was below 10%,but increased rapidly when the solid content was above 10%.The sludge viscosity decreased under higher shearing rate,and showed shear-thinning characteristics.The rule of shear stress and shear rate conformed to the Herschel-Bulkley model,and all the fluid pattern indexes were less than 1,which indicated the non-Newtonian pseudo-plastic fluid.The viscosity of sludge after thermal hydrolysis pretxeatment was lower than that of the sludge before pretreatment under all the solid content gradients,and thermal hydrolysis significantly reduced sludge viscosity when the solid content was higher than 10%.Sludge yield stress decreased more than 80%after thermal hydrolysis pretreatment.