振动流化床二元加重质聚团散式流态化机理与细粒煤分选调控

The dry coal separation technology based fluidized bed is suitable for separating coal in dry and water-deficient areas. With the shrinking of high-quality coal mines and the popularization of fully mechanized mining technology, the coal being mined is becoming increasingly poor, thin and miscellaneous, highlighting the urgent separation demand of fine coal. However, the traditional dry coal separation technology based fluidized bed uses Geldart B particles as the dense medium, which is easy to form an agglomerated fluidized bed. There are bubbles, gullies and dead zones which deteriorate the separation effect of fine coal and restrict its development. To this end, this project intends to use Geldart A pulverized coal and Geldart C magnetite powder as binary dense medium, mix to form Geldart A agglomeration to create a particulate fluidization environment suitable for fine coal separation under the synergistic excitation of vibration and air flow. This project is based on the main line of "micro-mechanics foundation → agglomeration rheological law → strengthening separation control", and carries out the research as follow: Firstly, the structure distribution system of binary agglomeration force chain will be constructed to reveal the formation mechanism of agglomeration. Secondly, the multi-scale correlation mechanism of force chain structure-agglomeration morphology-bed density will be explained and the multi-phase coupled agglomeration rheological model will be established. Finally, the separation mechanism of fine coal in particulate fluidization environment with binary agglomerated will be studied, and the steady-state control mechanism of fine coal dry separation under multi-factor synergistic optimization will be revealed. The research results will contribute to the development and application of high efficiency dry separation equipment for fine coal.

干法流态化选煤技术适用于干旱缺水地区煤炭分选。随着优质煤矿渐趋萎缩与综采技术普及，所开采煤炭日趋“贫、细、杂”化，凸显了细粒煤的迫切分选需求。然而，传统的干法流态化选煤技术采用GeldartB类颗粒作为加重质，易形成聚式流化床，存在气泡、沟流、死区恶化细粒煤分选效果，制约其发展。为此，本项目拟采用GeldartA类煤粉与GeldartC类磁铁矿粉作为二元加重质，混合形成GeldartA类聚团，在振动-气流协同激励下营造适合细粒煤分选的散式流态化环境，以“细观力学基础→聚团流变规律→强化分选调控”为主线，开展研究：构建二元加重质聚团力链结构分布体系，揭示聚团形成机理；建立多相耦合的聚团散式流变模型，阐释力链结构-聚团形态-床层密度多尺度关联机制；研究二元加重质聚团散式流化环境下细粒煤分离机理，提出稳态分选过程多因素协同调控模式的简化机制。研究成果可为开发细粒煤高效干法分选技术提供理论支撑。

煤炭在我国能源安全中起兜底保障作用，煤炭清洁高效利用是我国重大战略需求。随着优质煤矿渐趋萎缩与综采技术普及，原煤中细粒煤产率达到40%以上。传统干法流态化选煤技术采用GeldartB类颗粒作为加重质，易形成聚式流化床，细粒煤分选效率低、粒度范围窄、适应性差，迫切需要细粒煤清洁高效干法分选技术。.本项目针对细粒煤气固流态化干法分选难题，提出采用GeldartA类煤粉与GeldartC类磁铁矿粉混合流化形成新型二元加重质，研究了新型二元加重质流化过程空间分布特征，揭示了二元加重质聚团对力链结构演变的动态响应机制；分析了振动与气流外荷载激励诱发的二元加重质床层粒群结构变化规律，阐释了二元加重质流化过程中气相、聚团、微泡多相耦合的流动动力学行为；揭示了二元加重质聚团散式流化环境下细粒煤分离机理，提出了稳态分选过程多因素协同调控模式的简化机制；将二元加重质级配粒度下限降到20μm以下，分选密度调节范围拓宽至1.3-2.2g/cm3，分选细粒煤分选粒度下限降至0.5mm，分选可能偏差0.073g/cm3。为开发细粒煤振动流态化分选技术提供理论支撑，为解决占我国原煤产量40%的细粒煤干法分选提供新方法。