粉煤多尺度颗粒在变径脉动气流场中的分级行为及其动力学机理

With the implementation of west development strategy, coal industry of China was promoted to the west and north area. It is imperative to develop new and efficient dry classification technology to satisfy the characteristics of coal resources reserve. However, banana screen and flip-flow screen as the main dry classification methods in industrial application, both have processing low limit of 6mm at present. And dry classification technology suitable for -6mm low rank fine coal is in blank. This project aims at exploring new method to classify -6 mm fine coal, and a new classification technology that combining pulsing air flow and variable diameter structure based on air flow separation was proposed. In this project, the classification behavior and dynamics mechanism of multiscale particles of fine coal in variable diameter pulsing airflow is studied with basic scientific research method. The specific contents include: the motion and separation law of multiscale particles in variable diameter pulsing airflow are studied, and the dynamic model of gas-solid two phase coupling process under complex flow system is built by adopting experimental research, theoretical analysis and numerical simulation. At last, classification asynchronous intensified mechanism of multiscale particles in variable diameter pulsing airflow is revealed to lay a technical and theoretical basis for the high efficiency classification of low rank fine coal in China.

随着我国煤炭工业西进战略的逐步实施，开展针对西、北部地区煤炭资源储备特点的<6mm低阶粉煤高效干法分级技术势在必行。然而，目前工业应用的香蕉筛、弛张筛等干法分级设备，其处理粒度下限均为6mm；<6mm低阶粉煤的干法分级技术处于空白。本项目以<6mm低阶粉煤高效干法分级为目标，提出一种基于气流分离方法的脉动气流和变径结构相结合的粉煤分级技术，重点对粉煤多尺度颗粒在变径脉动气流场中的分级行为及其动力学机理进行基础科学研究。具体内容：采用实验研究、理论分析和数值模拟相结合的方法，研究多尺度颗粒在变径脉动气流场中的运动和分离规律，构建复杂流动体系下气固两相耦合过程动力学模型，揭示变径脉动气流场中多尺度颗粒的分级行为及其强化机制，为我国低阶粉煤的高效分级奠定技术和理论基础。

细粒级粉煤的高效分级作为近年来矿物加工工程领域的研究热点，也是研究难点。本项目结合我国西、北部地区煤炭资源储备特点和煤炭洗选加工利用条件，创新性地提出采用变径脉动气流分级方法，进行<6mm低阶粉煤的高效干法分级，具备一定的前瞻性和现实意义。本项目采用实验研究、理论分析和数值模拟相结合的方法，进行了粉煤变径脉动气流分级特性试验研究、变径脉动气流场中多尺度颗粒分离机理研究、复杂流动体系下气固两相耦合过程动力学及数值模拟研究以及变径脉动气流场中多尺度颗粒分级效应的强化机制研究等四个方面的研究工作。通过本项目的实施，重点研究了粉煤多尺度颗粒在变径脉动气流场中的分级行为及其动力学机理，揭示了粉煤多尺度颗粒在变径脉动气流场中的运动和分离规律，构建了复杂流动体系下气固两相耦合过程动力学模型，明晰了粉煤变径脉动气流分级效应的强化准则，为协同优化设备参数、实现分级粒度和精度的调整提供了理论基础和科学判据。通过本项目粉煤变径脉动气流分级方法，可实现6~0mm粒级粉煤的任意粒度的分级，分级可能偏差最低可达0.86mm，从而为我国低阶粉煤的分级提供一种思路和方法，并有效填补低阶粉煤无法有效分级的技术空白，实现低阶煤的全粒级高效洁净利用。