刚柔耦合弹性筛分机理与动力煤3 mm分级试验
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摘要
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6 mm分级、甚至13 mm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3 mm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3 mm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. 00 kg/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3 mm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.
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.
引文
[1]中华人民共和国国家统计局.中华人民共和国2018年国民经济和社会发展统计公报[R].北京:中华人民共和国国家统计局,2019.
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[9]王娜,赵俊凯,李孟红.振动筛筛分效率的影响因素研究[J].粮食加工,2018,43(2):59-62.WANG Na,ZHAO Junkai,LI Menghong.Study on influence factors of sieving efficiency of vibrating screen[J]. Grain Processing,2018,43(2):59-62.
[10]陈惜明,赵跃民,朱红,等.潮湿细粒物料筛分过程中粘附理论的研究[J].江苏煤炭,2003(4):31-33.CHEN Ximing,ZHAO Yuemin,ZHU Hong,et al. Study on adhedive mechanism in screening fine moist material[J]. Jiangsu Coal,2003(4):31-33.
[11]陈惜明,赵跃民,朱红,等.潮湿细粒物料的筛分粘附模型研究[J].中国矿业大学学报,2002,31(5):407-410.CHEN Ximing,ZHAO Yuemin,ZHU Hong,et al.Adhesive model of moist fine material[J].Journal of China University of Mining&Technology,2002,31(5):407-410.
[12]赵啦啦,刘初升,闫俊霞,等.颗粒筛分过程的三维离散元法模拟[J].煤炭学报,2010,35(2):307-311.ZHAO Lala,LIU Chusheng,YAN Junxia,et al.Numerical simulation of particle screening process based on 3D discrete element method[J]. Journal of China Coal Society,2010,35(2):307-311.
[13] ZHAO L,ZHAO Y,BAO C,et al.Laboratory-scale validation of a DEM model of screening processes with circular vibration[J].Powder Technology,2016,303:269-277.
[14]徐文彬,李素妍,徐浩博,等.粘湿煤炭干法深度筛分关键技术研究及抛射筛的研制[J].煤炭加工与综合利用,2017(9):13-20,8.XU Wenbin,LI Suyan,XU Haobo,et al.Study on the key technology on dry deep screening of wet coal and the manufacture of projectile screen[J]. Coal Processing&Comprehensive Utilization,2017(9):13-20,8.
[15] JIANG H,DUAN C,WU J,et al.Kinematics characteristics of the vibrating screen with rigid-flexible screen rod and the behavior of moist coal particles during the dry deep screening process[J].Powder Technology,2017,319:92-101.
[16] JIANG H S,WANG W N,ZHOU Z G,et al.Simultaneous multiple parameter optimization of variable-amplitude equal-thickness elastic screening of moist coal[J].Powder Technology,2019,346:217-227.
[2]李明辉.煤炭洗选加工60年回顾[J].煤炭工程,2014,46(10):24-29.LI Minghui.A review on 60 years of coal preparation in China[J].Coal Engineering,2014,46(10):24-29.
[3]于凤芹.动力煤深度筛分设备的选择[J].选煤技术,2018(2):54-57.YUFengqin.Selection of the power coal intensive screening equipment[J].Coal Preparation Technology,2018(2):54-57.
[4]周志坚.选煤厂工艺设计中的节能措施[J].煤炭加工与综合利用,2013(4):23-25.
[5]包小燕,李宏静,鲁和德.香蕉型弛张筛3 mm干法脱粉在寺河矿选煤厂的应用[J].洁净煤技术,2014,20(3):5-7.BAO Xiaoyan,LI Hongjing,LU Hede. Application of banana flipflow screen on 3 mm dry fines removal in Sihe mine[J].Clean Coal Technology,2014,20(3):5-7.
[6]张建勋,宋彦,白书亚.弹性振杆筛在粘湿物料深度筛分中的应用[J].选煤技术,2002(5):8-10.
[7]邹梦麒,刘初升,武继达,等.张紧量对单边驱动式弛张筛筛面动力学参数的影响[J].煤炭学报,2018,43(2):571-577.ZOU Mengqi,LIU Chusheng,WU Jida,et al.Influence of tensional amount on dynamic parameters of unilateral driven flip-flow screen surface[J].Journal of China Coal Society,2018,43(2):571-577.
[8]刘文统.弛张筛在动力煤深度分级中的应用[J].洁净煤技术,2015,21(3):18-20.LIU Wentong.Application of flip flow screen in deep classification of steam coal[J].Clean Coal Technology,2015,21(3):18-20.
[9]王娜,赵俊凯,李孟红.振动筛筛分效率的影响因素研究[J].粮食加工,2018,43(2):59-62.WANG Na,ZHAO Junkai,LI Menghong.Study on influence factors of sieving efficiency of vibrating screen[J]. Grain Processing,2018,43(2):59-62.
[10]陈惜明,赵跃民,朱红,等.潮湿细粒物料筛分过程中粘附理论的研究[J].江苏煤炭,2003(4):31-33.CHEN Ximing,ZHAO Yuemin,ZHU Hong,et al. Study on adhedive mechanism in screening fine moist material[J]. Jiangsu Coal,2003(4):31-33.
[11]陈惜明,赵跃民,朱红,等.潮湿细粒物料的筛分粘附模型研究[J].中国矿业大学学报,2002,31(5):407-410.CHEN Ximing,ZHAO Yuemin,ZHU Hong,et al.Adhesive model of moist fine material[J].Journal of China University of Mining&Technology,2002,31(5):407-410.
[12]赵啦啦,刘初升,闫俊霞,等.颗粒筛分过程的三维离散元法模拟[J].煤炭学报,2010,35(2):307-311.ZHAO Lala,LIU Chusheng,YAN Junxia,et al.Numerical simulation of particle screening process based on 3D discrete element method[J]. Journal of China Coal Society,2010,35(2):307-311.
[13] ZHAO L,ZHAO Y,BAO C,et al.Laboratory-scale validation of a DEM model of screening processes with circular vibration[J].Powder Technology,2016,303:269-277.
[14]徐文彬,李素妍,徐浩博,等.粘湿煤炭干法深度筛分关键技术研究及抛射筛的研制[J].煤炭加工与综合利用,2017(9):13-20,8.XU Wenbin,LI Suyan,XU Haobo,et al.Study on the key technology on dry deep screening of wet coal and the manufacture of projectile screen[J]. Coal Processing&Comprehensive Utilization,2017(9):13-20,8.
[15] JIANG H,DUAN C,WU J,et al.Kinematics characteristics of the vibrating screen with rigid-flexible screen rod and the behavior of moist coal particles during the dry deep screening process[J].Powder Technology,2017,319:92-101.
[16] JIANG H S,WANG W N,ZHOU Z G,et al.Simultaneous multiple parameter optimization of variable-amplitude equal-thickness elastic screening of moist coal[J].Powder Technology,2019,346:217-227.