基于絮凝动力学的煤泥水絮凝过程及其研究方法综述

Flocculation process of coal slime water based on flocculation kinetics and its research methods:a critical review

煤泥水的絮凝沉降是煤炭湿法洗选工艺的重要操作单元。分析和优化絮凝过程,提高絮凝效率,对提高选煤生产效率有重要意义。本文从絮凝动力学的角度,综述了煤泥水中悬浮颗粒的性质、药剂制度和流体运动对絮凝过程的碰撞频率、碰撞效率和破碎效率的影响,总结了絮凝药剂促进细颗粒絮凝的化学作用机制和湍流涡旋尺度调控对提高絮凝效率的物理作用机制;综述了从絮凝动力学角度研究煤泥水絮凝过程的方法,比较了计算流体力学(CFD)、群体平衡模型(PBM)和离散元(DEM)等方法应用于煤泥颗粒间作用力、絮凝流场和煤泥絮凝动态过程研究的优缺点。通过比较分析认为,CFD-DEM耦合方法特别适用于多组分、多粒度的煤泥水体系,是研究煤泥水絮凝的理想方法。

The flocculation-sedimentation of coal slime water is an important unit operation of wet coal preparation process.It is quite valuable to analyze and optimize the flocculation process and improve the flocculation efficiency which results in the improvement of the efficiency of coal preparation.From the perspective of flocculation kinetics,this paper reviews the effect of properties of suspended particles in coal slurry water,chemical system and fluid motion on the collision frequency,collision efficiency and crushing efficiency of flocculation process.The chemical mechanism of flocculation agent to promote flocculation of fine particles and the physical mechanism of turbulent vortex scale regulation to improve flocculation efficiency are summarized.The method of studying flocculation process of coal slime water from flocculation kinetics,computational fluid dynamics(CFD),population balance model(PBM)and discrete element method(DEM),are reviewed.The advantages and disadvantages of the methods are compared when applied to the research on the interaction between coal slime particles,flocculation flow field and coal flocculation.It is considered that the CFD-DEM coupling method is especially suitable for coal slurry water which is multi-component and multi-granular,and is an ideal method for studying the flocculation of coal slime water.