刚柔耦合弹性筛分机理与动力煤3 mm分级试验

Mechanism of rigid-flexible coupling elastic screening and 3 mm classification test of steam coal

动力煤广泛应用于电力、冶金,建材以及化工等领域,筛分是动力煤加工利用的关键环节。随着采煤机械化的发展,其细粒含量逐渐增加,当物料水分较高时易造成颗粒团聚,筛分作业难以进行,因此开展黏湿动力煤高效干法深度筛分至关重要。传统干法筛分过程多为6mm分级、甚至13mm以上分级,原煤入选比例低,造成资源浪费和环境污染等问题,降低其分级下限是目前亟待解决的技术难题。传统筛面为刚性筛面和弹性筛面,前者容易造成物料卡堵,后者在筛分过程中筛面局部易发热老化,大大降低筛分效率和筛机处理能力。为提高黏湿动力煤3mm干法高效筛分效果,笔者提出了刚柔耦合弹性筛分方法。采用振动测试手段研究了刚柔耦合弹性筛面运动学特性,阐明了筛面的运动行为与弹性区域形变规律,揭示了刚柔耦合弹性筛分机理。采用多因素逐项试验方法,探究了处理能力与外水含量对动力煤3mm刚柔耦合弹性筛分过程的影响规律与机制。结果表明:弹性区域较刚性区域位移幅值增加87.69%,加速度幅值增加98.08%;随处理能力的增加,综合分离指数呈先升高后降低的趋势,处理能力为2.00kg/s、物料外水含量为6.13%时,综合分离指数在89.00%以上;外水含量的增加导致综合分离指数降低,外水含量升至11.01%时,综合分离指数达78.92%,表明刚柔耦合弹性筛面可实现黏湿动力煤3mm的干法高效筛分。

Steam coal is widely used in electric power,metallurgy,building materials,chemical engineering and other fields.Screening is the key link of steam coal processing and utilization.With the development of coal mining mechanization,the content of fine particles gradually increases,when the moisture content of materials is high,it is easy to cause particles agglomeration,screening becomes difficult.Therefore,it is important to carry out efficient dry deep screening of viscous-moist steam coal.The traditional dry screening process mainly is classified by 6 mm,or even more than 13 mm,and the beneficiation proportion of raw coal is low,resulting in resources waste and environmental pollution.Reducing the lower limit of classification is a technical problem to be solved urgently at present.The traditional screen surfaces are rigid screen surface and elastic screen surface,the former is easy to cause aperture blockage,the latter is prone to local fever and aging during screening,greatly reducing the screening efficiency and the processing capacity of screen machine.In order to improve the efficiency of 3 mm dry screening of viscous-moist steam coal,the rigid-flexible coupling elastic screening method was proposed.The kinematics characteristics of rigid-flexible coupling elastic screen surface were studied by means of vibration test,motion behavior of sieve surface and the change rule of flexible region were clarified,and the mechanism of rigid-flexible coupling elastic screening was revealed.The influences of treatment capacity and external water content on 3 mm rigid-flexible coupling elastic screening process of steam coal were investigated by multi-factor successive terms test.The results show that the displacement amplitude and acceleration amplitude in elastic region increased by 87.69% and 98.08% respectively compared with that in rigid region;With the increase of treatment capacity,the comprehensive separation index increases first and then decreases,when the treatment capacity is 2.00 kg/s and the external water content of materials is 6.13%,the comprehensive separation index is above 89.00%.The increase of external water content leads to the decrease of comprehensive separation index,while the external water content rises to 11.01%,the comprehensive separation index is up to 78.92%,it is indicated that the rigid-flexible elastic screen surface can realize the high efficiency of 3 mm dry screening of viscous-moist steam coal.