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
The synthetic index K s for evaluating flip-flow screens is proposed and systematically optimized in view of the whole system. A series of optimized values of relevant parameters are found and then compared with those...The synthetic index K s for evaluating flip-flow screens is proposed and systematically optimized in view of the whole system. A series of optimized values of relevant parameters are found and then compared with those of the current industrial specifications. The results show that the optimized value K s approaches the one of those famous flip-flow screens in the world. Some new findings on geometric and kinematics parameters are useful for improving the flip-flow screens with a low K s value, which is helpful in developing clean coal technology.展开更多
为探索煤炭精细分级分选,优化生产系统,淮北选煤厂对煤泥重介质旋流器及粗煤泥振动弧形筛进行了优化,通过采用大直径煤泥重介质旋流器,改变弧形筛工艺参数,增加筛面喷水,稳定斜管浓缩机溢流等措施,加强重介分选环节对>0.25 m m粒级...为探索煤炭精细分级分选,优化生产系统,淮北选煤厂对煤泥重介质旋流器及粗煤泥振动弧形筛进行了优化,通过采用大直径煤泥重介质旋流器,改变弧形筛工艺参数,增加筛面喷水,稳定斜管浓缩机溢流等措施,加强重介分选环节对>0.25 m m粒级煤炭的精选,降低了重介系统分选下限,有效控制了粗精煤灰分、水分;降低了浮选入浮量、粒度、灰分,减轻了浮选系统的压力。同时通过采用“2+2”浮选工艺,降低了浮选精煤灰分,避免了重介精煤“背灰”现象,实现了精煤产率最大化。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The synthetic index K s for evaluating flip-flow screens is proposed and systematically optimized in view of the whole system. A series of optimized values of relevant parameters are found and then compared with those of the current industrial specifications. The results show that the optimized value K s approaches the one of those famous flip-flow screens in the world. Some new findings on geometric and kinematics parameters are useful for improving the flip-flow screens with a low K s value, which is helpful in developing clean coal technology.
文摘为探索煤炭精细分级分选,优化生产系统,淮北选煤厂对煤泥重介质旋流器及粗煤泥振动弧形筛进行了优化,通过采用大直径煤泥重介质旋流器,改变弧形筛工艺参数,增加筛面喷水,稳定斜管浓缩机溢流等措施,加强重介分选环节对>0.25 m m粒级煤炭的精选,降低了重介系统分选下限,有效控制了粗精煤灰分、水分;降低了浮选入浮量、粒度、灰分,减轻了浮选系统的压力。同时通过采用“2+2”浮选工艺,降低了浮选精煤灰分,避免了重介精煤“背灰”现象,实现了精煤产率最大化。
