微波辐照改变煤泥水沉降过滤性能的机理

针对高灰、细泥含量高的煤泥水固液分离困难、系统复杂和效果差等问题,采用微波辐照预处理方法优化煤泥水沉降过滤特性。探索了微波辐照前后煤泥水的沉降特性,过滤特性,煤泥颗粒表面电性及粒度分布规律。试验结果表明:微波辐照后,煤泥水沉降特性明显改善,絮凝沉降效果显著,药耗降低,最优方案为微波预处理2 min,PAM用量0.75 m L;煤泥水过滤分离性能显著提高,煤泥比阻明显降低,最大降低54%;过滤脱水效果变好,真空抽滤后的含水率最大下降到15.89%;煤颗粒表面的Zeta电位的绝对值减小,最大降低24%,双电层被压缩,颗粒间总的相互作用势能减小,颗粒发生凝聚,产生颗粒粗大化现象,小于10μm的颗粒减少30%左右,大于74μm的颗粒增加3倍多,有利于煤泥水的沉降。

Separating characteristics of coal and water with microwave irradiation preprocessing

Based on harder solid-liquid separation，more complex system and lower sedimentation efficiency in slurry processing，a microwave radiation pretreatment was adopted to improve the sedimentation & filtration characteristics.The sedimentation and filtration characteristics，the surface electric behavior of coal particle size and the alteration of size distribution were analyzed.The results show that the sedimentation efficiency is significantly improved by a microwave radiation pretreatment and the flocculating settling characteristics are good for reducing flocculating agent cost.The optimal conditions are microwave radiation time of 2 min and PAM consumption of 0.75 mL.The filtration efficiency increased obviously while the specific resistance deceased (up to 54%).As a result，the moisture of filter cake could reach 15.89% after vacuum filtration.Besides，the Zeta potential of particle surface decreases and the double electrode layer is compressed.The potential energy of interaction reduces and particles gathered，which resulted in bigger particles.Particles with size less than 10 μm decrease by 30% and particles with size more than 74 μm increase more than 3 times，which contributes the filtration process.