恒压恒电场条件下黏土泥浆脱水试验

Experimental study on dewatering of clay slurry under constant pressure and electric field conditions

  • 摘要: 针对城市污泥产量增加带来的脱水问题,以高岭土为研究对象,通过单因素试验和正交试验分析相结合的方法探究电渗法与传统机械排水法联合增效作用。单因素试验发现,机械压力、通电开始时间与脱水效果(总排水量、平均排水速率)呈正相关,其中机械压力的变化对试样厚度影响最大,机械压力由0.4 MPa增至0.8 MPa,试样厚度减少了2.89 mm;电流密度为3 mA/cm2时的总排水量最佳。选用L9(33)标准正交表设计正交试验,探究得到影响脱水效果的因素为机械压力>提前通电百分比(与相应机械压力下过滤-压密阶段的时间阈值点相比)>电流密度,通过信噪比分析得知3个因素与黏土泥浆的总排水量均呈正相关,其中机械压力对总排水量影响显著(p<0.05)。电渗-机械联合作用可显著提升污泥排水速率。

     

    Abstract: To address dewatering challenges arising from increasing urban sludge production, this study employed kaolin clay to investigate the synergistic enhancement of electroosmosis integrated with traditional mechanical dewatering method through a combination of single-factor experiment and orthogonal experimental analysis. The single-factor tests revealed that both increased mechanical pressure and an earlier energization start time were positively correlated with improved dewatering performance (cumulative drainage volume and average drainage rate). Among these, mechanical pressure exerted the most significant effect on sample thickness, reducing it by 2.89 mm when mechanical pressure increased from 0.4 to 0.8 MPa. Optimal cumulative drainage was achieved at 3 mA/cm2 current density. Orthogonal experiments were designed employing an L9(33) standard orthogonal array to identify the factors affecting dewatering efficiency. The primary-to-secondary order of influencing factors were determined as: mechanical pressure > pre-energization percentage (relative to filtration-consolidation phase threshold time under corresponding mechanical pressure) > current density. Signal-to-noise ratio analysis confirmed positive correlations between all factors and dewatering volume of clay slurry, with mechanical pressure exerting a statistically significant influence (p<0.05). The results demonstrate that the electroosmosis-mechanical integration can significantly enhance sludge drainage rates.

     

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