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主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
基于湍流涡调控的煤气化渣炭-灰浮选分离过程强化
  • Title

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

  • 作者

    闫小康苏子旭王利军张海军曹亦俊刘炯天

  • Author

    YAN Xiaokang;SU Zixu;WANG Lijun;ZHANG Haijun;CAO Yijun;LIU Jiongtian

  • 单位

    中国矿业大学化工学院中国矿业大学国家煤加工与洁净化工程技术研究中心中国矿业大学低碳能源与动力工程学院郑州大学化工学院

  • Organization
    School of Chemical Engineering and Technology,China University of Mining and Technology
    National Engineering ResearchCenter of Coal Preparation and Purification,China University of Mining and Technology
    School of Low Carbon Energy and PowerEngineering,China University of Mining and Technology
    School of Chemical Engineering,Zhengzhou University
  • 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 m2/s2增到0.142 m2/s2,最小涡尺度均值由16.10 μm减至10.34 μm。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-45,45~75 μm煤气化渣颗粒相适配的最小涡尺度均值分别为12.74 μm和14.71 μm,相应湍流动能均值分别不宜超过0.080 m2/s2及0.056 m2/s2;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。

  • Abstract

    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 strength⁃en the flotation recovery of fine⁃particle minerals. Turbulent small⁃scale eddies directly act on the movement of fineparticles. With the help of vortex generators, turbulent eddy regulation was implemented to strengthen the char⁃ash flo⁃tation separation of coal gasification residue. Firstly, the CFD numerical simulation was used to calculate the flow fieldin the vortex mineralization tube, and the influence of different structures of vortex generators on the characteristic pa⁃rameters of turbulence was analyzed. The coal gasification slag flotation performances under different flow field condi⁃tions were obtained through flotation experiments. On this basis, a stepped vortex flotation process compatible with thefloatability of minerals was constructed. The results show that the span wise hairpin vortex, primary convective vortexand flow vortex pairs with opposite secondary rotation direction are formed behind each vortex generator when rectan⁃gular vortex generators are built in the mineralization tube. The strong interactions between vortices and vorticesbehind adjacent vortex generators and between vortices and mainstream significantly improve the turbulent kinetic en⁃ergy, reduce the minimum vortex scale, and strengthen the collision between fine particles and bubbles. The inclina⁃tion angle of the vortex generator has a significant effect on the turbulence characteristics. When the inclination angleof the vortex generator increases from 25° to 55°, the turbulent kinetic energy and turbulent energy dissipation rate aresignificantly increased. The average turbulent energy increases from 0.041 m2 / s2 to 0.142 m2 / s2 and the average mini⁃mum vortex size is reduced from 16.10 μm to 10.34 μm. A balanced vortex mineralization device with multiple rows ofvortex generators with the same inclination is used to carry out carbon ash flotation separation test on coal gasificationslag. The flotation recovery of different particle sizes in coal gasification slag shows that the finer the particle sizeis, the greater the turbulence kinetic energy is required and the smaller the vortex scale is. However, when the turbu⁃lence is too strong, the coarser particles may detach from bubble surface. Within the study scope, for coal gasificationslag particles of -45 μm and 45-75 μm, the proper mean minimum vortex scale is 12.74 μm and 14.71 μm respec⁃tively, and the corresponding mean turbulent kinetic energy should not exceed 0.080 m2 / s2 and 0.056 m2 / s2 respec⁃tively. Vortex generators with different tilt angles are orderly arranged along the flow direction in the mineralized tube,and a stepped vortex flotation process with gradually weakened turbulence is constructed. The flotation testshows that the flotation index with combustible recovery of 89.99% and tailings loss on ignition of 4.66% can be ob⁃tained by using the stepped vortex flotation device for ash separation from coal gasification slag, which isbetter than the flotation performance of the equilibrium vortex device and the mechanical stirring flotation machine.Through the physical regulation of fluid environment, a new process strengthening method for carbon ash flotation sep⁃aration from coal gasification slag is provided.

  • 关键词

    煤气化渣炭-灰分离浮选湍流涡过程强化微细粒

  • KeyWords

    coal gasification slag;carbon⁃ash separation;flotation;turbulent eddy;process intensification;fine particle

  • 引用格式
    闫小康,苏子旭,王利军,等. 基于湍流涡调控的煤气化渣炭-灰浮选分离过程强化[J]. 煤炭学报,2022,47(3):1318-1328.
    YAN Xiaokang,SU Zixu,WANG Lijun,et al. Process intensification on flotation separation of carbon and ash from coal gasification slag using turbulent eddy regulation[J]. Journal of China Coal Society,2022,47(3):1318-1328.
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    • 颗粒与气泡湍流碰撞

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