低温热-碱解改性对污泥与煤共成浆特性的影响

Effects of low temperature thermal-alkaline modification on co-slurrying performances of sludge and coal

为提高污泥利用效率,采用低温热-碱解方法对污泥进行预处理,利用改性后的污泥与煤掺混制备浆体燃料,研究了低温热-碱解方法对改性前后污泥水煤浆表观黏度、流变性、剪切迟滞性的影响。结果表明,低温热-碱解方法能有效降低污泥水煤浆的黏度,当剪切速率为100 s-1时,原始污泥水煤浆的表观黏度为1 667 m Pa·s,污泥经90℃-Ca(OH)_2改性1、4、24 h后,浆体的表观黏度分别降至1 027.6、698.0、455.8 m Pa·s,污泥经90℃-NaOH改性1、4、24 h后,浆体的表观黏度分别降至674.8、436.3、385.8 m Pa·s。同时,浆体的流变性逐步由假塑性趋近于牛顿流体,浆体的剪切迟滞特性减弱,原始污泥水煤浆的迟滞环面积(Hla)为2 078.0 Pa/s。在90℃-Ca(OH)_2和90℃-NaOH的条件下处理1 h后,污泥水煤浆的迟滞环面积分别降为774.5、664.5 Pa/s。可见,低温热-碱解方法能有效提高污泥水煤浆的成浆性,改善污泥水煤浆浆体流变特性。

In order to improve the utilization efficiency of sludge,the low temperature thermal-alkaline（LTTA） method was used to pretreat the sludge.The effects sludge before and after modification with LTTA method on apparent viscosity of coal-sludge slurry（CSS）,rheological behavior and hysteresis loop area were studied in the paper.The results showed that apparent viscosity of CSS was reduced effectively by LTTA method.When the shear rate was 100 s-1,apparent viscosity of raw CSS was 1 667 m Pa·s,after the sludge was modified by 90 ℃-Ca（OH）2for 1 h,4 h and 24 h,the apparent viscosity of CSS decreased to 1 027.6,698.0,455.8 m Pa·s respectively.While it decreased to 674.8,436.3,385.8 m Pa·s after the sludge was modified by 90 ℃-NaOH for 1 h,4 h and 24 h respectively.At the same time,the rheological behavior of the CSS was gradually transformed from pseudoplastic to Newtonian flow,and the shearing hysteresis of the CSS decreased,the hysteresis loop area of raw CSS was 2 078.0 Pa/s.Wheareas,the hysteresis loop area of raw CSS decreased to 774.5 Pa/s and 664.5 Pa/s after the sludge was modified by 90 ℃-Ca（OH）_2,90 ℃-Na OH respectively for 1 h.The above results identified the LTTA method could efficiently improved slurrying ability and the rheological properties of CSS.