造纸污泥的电渗透脱水效果

Electro-osmotic dewatering of pulp and paper sludge

采用电渗透脱水技术对经过带式压滤后的制浆造纸混合污泥进行深度脱水,考察了机械压力、电压梯度和污泥厚度对污泥电渗透脱水效果与能耗的影响。结果表明,机械压力从25 kPa升至76 kPa时,脱水效果也会随之提高,但是继续增大机械压力对脱水效果的提高作用就会变得不明显;随着电压梯度的增加,脱水效果会有明显的升高,但是能耗也会相应地增加;电压梯度恒定为30 V/cm且污泥厚度从0.35 cm增加到1.40 cm时,脱水效果和能耗都会相应地增加。对于所有的电脱水实验,当污泥的含水率从74.85%降至60%时所需要的能耗均在0.14～0.28 kWh/kg去除水之间。综合考虑脱水效果和能耗,可认为最优脱水条件是:机械压力为76 kPa,电压梯度为30 V/cm,污泥厚度为0.7 cm。

The effects of mechanical force,voltage gradient,and sludge height on the dewatering efficiency and energy consumption were evaluated.The results show that the dewatering efficiency increased as the mechanical force increased from 25 kPa to 76 kPa.But further increase of the mechanical force did not further increase the dewatering efficiency.The increase of voltage gradient greatly improved the dewatering efficiency,but required higher energy consumption.At the voltage gradient of 30 V/cm,both the dewatering efficiency and energy consumption increased as the sludge thickness increased from 0.35 cm to 1.40 cm.For all the electro-dewatering tests conducted herein,the energy consumptions were between 0.14 and 0.28 kWh/kg removed water when the sludge＇s moisture content decreased from initially 74.85% to 60%.From the perspective of dewatering efficiency and energy conservation,the optimal operating conditions for the electro-dewatering of pulp and paper sludge were determined to be the mechanical pressure of 76 kPa,the voltage gradient of 30 V/cm,and the sludge thickness of 0.7 cm.