基于湍流涡调控的煤气化渣炭-灰浮选分离过程强化  

Process intensification on flotation separation of carbon and ash from coal gasification slag using turbulent eddy regulation

作　　者：闫小康[1,2] 苏子旭 王利军[2,3] 张海军[1,2] 曹亦俊[2,4] 刘炯天 YAN Xiaokang;SU Zixu;WANG Lijun;ZHANG Haijun;CAO Yijun;LIU Jiongtian(School of Chemical Engineering and Technology,China University of Mining and Technology,Xuzhou 221116,China;National Engineering Research Center of Coal Preparation and Purification,China University of Mining and Technology,Xuzhou 221116,China;School of Low Carbon Energy and Power Engineering,China University of Mining and Technology,Xuzhou 221116,China;School of Chemical Engineering,Zhengzhou University,Zhengzhou 450000,China)

机构地区：[1]中国矿业大学化工学院,江苏徐州221116 [2]中国矿业大学国家煤加工与洁净化工程技术研究中心,江苏徐州221116 [3]中国矿业大学低碳能源与动力工程学院,江苏徐州221116 [4]郑州大学化工学院,河南郑州450000

出　　处：《煤炭学报》2022年第3期1318-1328,共11页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(51974310);国家重点研发计划资助项目(2019YFC1904301)。

摘　　要：煤气化渣因炭、灰包裹夹杂严重、嵌布粒度细,导致浮选分离困难,制约了其资源化利用。浮选大多发生在湍流环境中,调控湍流是强化微细颗粒矿物浮选回收的有效途径,湍流小尺度涡直接作用于微细颗粒运动,研究借助涡流发生器实施湍流涡调控以进行煤气化渣中的炭-灰浮选分离过程强化。利用计算流体力学数值模拟对涡流矿化管内部流场进行数值计算,分析涡流发生器结构对湍流特征参量及煤气化渣浮选指标的影响,在此基础上设计了与矿物可浮性相适配的梯级涡流浮选过程。结果表明:管内矩形涡流发生器可诱导出发卡涡、流向涡及旋转方向相反的二次流向涡对,涡-涡、涡-主流之间的交互作用显著提高了湍流动能、降低了涡尺度,有利于微细颗粒与气泡间的碰撞。涡流发生器的倾斜角度从25°增至55°时,湍流动能均值由0.041 m^(2)/s^(2)增到0.142 m^(2)/s^(2),最小涡尺度均值由16.10μm减至10.34μm。采用内置结构相同涡流发生器的均衡涡流浮选装置对煤气化渣进行炭-灰浮选分离试验,不同粒级浮选回收率表明,粒度越细,需要的湍流动能越大、涡尺度越小,诱发的湍流特性不当时颗粒可能从气泡表面脱附。在研究范围内,与-45,45~75μm煤气化渣颗粒相适配的最小涡尺度均值分别为12.74μm和14.71μm,相应湍流动能均值分别不宜超过0.080 m^(2)/s^(2)及0.056 m^(2)/s^(2);将不同倾斜角度的涡流发生器在矿化管内沿着流动方向有序排列,形成与矿物可浮性相适配的梯级涡流浮选过程,实现不同可浮性颗粒的逐步回收,浮选试验表明利用梯级涡流浮选装置进行煤气化渣炭-灰浮选分离时,可燃体回收率为89.99%,尾矿烧失量低至4.66%,优于相同条件下均衡涡流浮选装置和机械搅拌式浮选机的浮选指标。通过对流体环境的物理调控,可为煤气化渣的炭-灰浮选分离提供新的过程强化方式。Due to the serious inclusion of carbon and ash and its fine particle size,the flotation separation of coal gasification slag is difficult,which restricts its resource utilization.Turbulent regulation is an effective way to strengthen the flotation recovery of fine-particle minerals.Turbulent small-scale eddies directly act on the movement of fine particles.With the help of vortex generators,turbulent eddy regulation was implemented to strengthen the char-ash flotation separation of coal gasification residue.Firstly,the CFD numerical simulation was used to calculate the flow field in the vortex mineralization tube,and the influence of different structures of vortex generators on the characteristic parameters of turbulence was analyzed.The coal gasification slag flotation performances under different flow field conditions were obtained through flotation experiments.On this basis,a stepped vortex flotation process compatible with the floatability of minerals was constructed.The results show that the span wise hairpin vortex,primary convective vortex and flow vortex pairs with opposite secondary rotation direction are formed behind each vortex generator when rectangular vortex generators are built in the mineralization tube.The strong interactions between vortices and vortices behind adjacent vortex generators and between vortices and mainstream significantly improve the turbulent kinetic energy,reduce the minimum vortex scale,and strengthen the collision between fine particles and bubbles.The inclination angle of the vortex generator has a significant effect on the turbulence characteristics.When the inclination angle of the vortex generator increases from 25°to 55°,the turbulent kinetic energy and turbulent energy dissipation rate are significantly increased.The average turbulent energy increases from 0.041 m^(2)/s^(2) to 0.142 m^(2)/s^(2) and the average minimum vortex size is reduced from 16.10μm to 10.34μm.A balanced vortex mineralization device with multiple rows of vortex generators with the same inclinati

关 键 词：煤气化渣 炭-灰分离 浮选 湍流涡 过程强化 微细粒 

分 类 号：TD94[矿业工程—选矿]