During screening operation, blinding or clogging of screen perforations generally occurs to reduce the sieving capacity and efficiency. Recently, the flip-flow screening has been widely recognized as a feasible method...During screening operation, blinding or clogging of screen perforations generally occurs to reduce the sieving capacity and efficiency. Recently, the flip-flow screening has been widely recognized as a feasible method to deal with the problem. In this paper, a novel centralized-driving flip-flow screen(CFS) was developed for the separation of fine and moist coal, and the key structures, namely, a centralized-driving mechanism and a quasi-circle beam mounted with the mat were designed for high reliability and stability. By means of a test on an experimental prototype, the effect of some factors, i.e., initial stretch and hardness of the polyurethane panel, respectively, and the rotation speed of the driving motor on the kinematic characteristic of the screen surface was investigated. Results show that without an initial stretch, the sieve mat generates the largest vibratory amplitude while the slacker the sieve mat initially is, the smaller amplitude it will accomplish. And an increase in the rotation speed could cause a rise in the vibratory amplitude. Unlike the two factors, the hardness does not have a definite effect on the kinematic performance, on which a further study is required. Finally, screening processing on a laboratory prototype was conducted to draw the conclusion that the developed CFS also has a high sieving efficiency for the fine and moist coal.展开更多
湿黏细粒煤的干法深度筛分理论与技术是当前国际筛分领域的研究热点和难点。其中,筛面易堵孔和筛面寿命短是湿黏细粒煤干法筛分时的核心基础问题。为了掌握当前湿黏细粒煤干法筛分理论及技术的发展现状,分析了2种广泛应用的细粒煤筛分设...湿黏细粒煤的干法深度筛分理论与技术是当前国际筛分领域的研究热点和难点。其中,筛面易堵孔和筛面寿命短是湿黏细粒煤干法筛分时的核心基础问题。为了掌握当前湿黏细粒煤干法筛分理论及技术的发展现状,分析了2种广泛应用的细粒煤筛分设备:基于等厚筛分理论的等厚筛和基于弛张筛分理论的弛张筛的应用及研究存在的问题,讨论了筛分过程基础理论中颗粒分离机理的研究现状,总结了基于离散元方法(DEM,Discrete Element Method)的筛分过程中有关筛面颗粒流动特性数值模拟研究存在的不足。结果表明:筛分过程基础理论是发展新筛分技术和提升筛分设备设计水平的关键,非球形湿黏颗粒系统的分离行为和筛面高湿黏颗粒流动特性及透筛机理是筛分过程基础理论的关键问题,利用基于DEM的数值方法可以实现从颗粒尺度深入研究筛分过程中非球形湿黏颗粒的有关运动行为。此外,阐述了交叉筛的结构特点及筛分过程机理,总结了国内外有关交叉筛技术的应用及研究现状,分析了交叉筛的筛分过程基础理论研究的不足,以及存在缺少交叉筛关键结构及工艺参数的优化设计理论和方法的主要问题,提出了基于筛面-颗粒耦合模拟的交叉筛分过程机理、交叉筛结构轻量化设计及节能优化控制等研究展望。展开更多
基金The financial support from the National Natural Science Foundation of China (Nos. 51221462 and 51134022)the Doctoral Programs Foundation of Ministry of Education of China (No. 20120095110001)
文摘During screening operation, blinding or clogging of screen perforations generally occurs to reduce the sieving capacity and efficiency. Recently, the flip-flow screening has been widely recognized as a feasible method to deal with the problem. In this paper, a novel centralized-driving flip-flow screen(CFS) was developed for the separation of fine and moist coal, and the key structures, namely, a centralized-driving mechanism and a quasi-circle beam mounted with the mat were designed for high reliability and stability. By means of a test on an experimental prototype, the effect of some factors, i.e., initial stretch and hardness of the polyurethane panel, respectively, and the rotation speed of the driving motor on the kinematic characteristic of the screen surface was investigated. Results show that without an initial stretch, the sieve mat generates the largest vibratory amplitude while the slacker the sieve mat initially is, the smaller amplitude it will accomplish. And an increase in the rotation speed could cause a rise in the vibratory amplitude. Unlike the two factors, the hardness does not have a definite effect on the kinematic performance, on which a further study is required. Finally, screening processing on a laboratory prototype was conducted to draw the conclusion that the developed CFS also has a high sieving efficiency for the fine and moist coal.
文摘湿黏细粒煤的干法深度筛分理论与技术是当前国际筛分领域的研究热点和难点。其中,筛面易堵孔和筛面寿命短是湿黏细粒煤干法筛分时的核心基础问题。为了掌握当前湿黏细粒煤干法筛分理论及技术的发展现状,分析了2种广泛应用的细粒煤筛分设备:基于等厚筛分理论的等厚筛和基于弛张筛分理论的弛张筛的应用及研究存在的问题,讨论了筛分过程基础理论中颗粒分离机理的研究现状,总结了基于离散元方法(DEM,Discrete Element Method)的筛分过程中有关筛面颗粒流动特性数值模拟研究存在的不足。结果表明:筛分过程基础理论是发展新筛分技术和提升筛分设备设计水平的关键,非球形湿黏颗粒系统的分离行为和筛面高湿黏颗粒流动特性及透筛机理是筛分过程基础理论的关键问题,利用基于DEM的数值方法可以实现从颗粒尺度深入研究筛分过程中非球形湿黏颗粒的有关运动行为。此外,阐述了交叉筛的结构特点及筛分过程机理,总结了国内外有关交叉筛技术的应用及研究现状,分析了交叉筛的筛分过程基础理论研究的不足,以及存在缺少交叉筛关键结构及工艺参数的优化设计理论和方法的主要问题,提出了基于筛面-颗粒耦合模拟的交叉筛分过程机理、交叉筛结构轻量化设计及节能优化控制等研究展望。
