基于LBM-DEM方法的泥浆过滤微观过程

Microscopic Process of Slurry Filtration Based on LBM-DEM Method

在各类工程中产生了大量的高含水率废弃泥浆,过滤分离技术逐渐应用于泥浆的快速减量化中。为明确泥浆过滤的微观过程及堵塞机理,建立并验证了利用格子玻尔兹曼方法-离散单元法(Lattice Boltzmann method-discrete element method,LBM-DEM)模拟泥浆过滤。采用LBM-DEM方法模拟了多类条件下泥浆的过滤,包括不同泥浆含水率、过滤介质孔径、过滤压力及絮团性质。实验结果表明:泥浆在过滤过程中,过滤介质先作为主要的过滤单元,颗粒(或絮团)不断堵塞在过滤介质中或发生流失,当过滤介质完全堵塞后,颗粒(或絮团)不再发生流失,逐渐堆积在过滤介质表面,随着过滤的进行,泥皮逐渐累积增厚;堵塞完成的过滤介质及不断增厚的泥皮的组合体成为新的过滤系统。泥皮的渗透系数决定了新过滤系统的渗透能力,是影响泥浆过滤脱水的主要因素。LBM-DEM新方法的建立为研究及优化泥浆过滤效率提供了借鉴以及新的思路。

A large amount of waste slurry with high moisture content has been generated in various projects,and filtration and separation technology has been gradually applied to the rapid reduction of slurry.In order to clarify the microscopic process and blocking mechanism of slurry filtration,the method of simulating slurry filtration using Lattice Boltzmann method-discrete element method(LBM-DEM)was established and verified.The LBM-DEM method was used to simulate the filtration of slurry under various conditions,including different slurry moisture content,filter media pore size,filtration pressure and floc properties.The experimental results show that the slurry in the filtration process,the filter medium first as the main filter unit,particles(or flocs)continue to block in the filter medium or loss,when the filter medium is completely blocked,particles(or flocs)no longer lose and gradually accumulate on the surface of the filter media,as the filtration progresses,the slurry skin gradually accumulates and thickens.The combination of clogged filter media and thickening slurry becomes the new filtration system.The hydraulic conductivity of the cake determines the hydraulic conductivity of the new filtration system and is the main factor affecting the filtration and dewatering of the slurry.The establishment of the new LBM-DEM method provides a reference and new ideas for the study and optimization of slurry filtration efficiency.