Research On Separation Performance Of Coupling Rotary Separator For Coal Pneumatic Conveying

The application of pneumatic conveying technology in underground coal transportation can reduce the cost of roadway construction,reduce the damage of micron particles to underground environment,and improve the working environment of miners.However,there are few studies on the terminal receiving mode of underground pneumatic conveying system.Due to the multi-scale heterogeneous nature and brittleness of coal particles,it is urgent to propose an efficient separator which takes into account both large particle collection and respirable dust separation.In this paper,a combined rotary separator is designed and studied.The flow field distribution,pressure drop,collection efficiency and separation efficiency of the separator are studied by theoretical analysis,numerical simulation and experiment.The influence of separator operation parameters and particle sizes on the performance parameters of the separator is analyzed,which provides theoretical and experimental basis for the coal pneumatic conveying and collecting system.Based on the settlement separation theory and rotor impact type,an coal pneumatic conveying combined rotary separator was designed and built.According to the structure of the separator,the flow field model of the separator is established,and the distribution of tangential velocity and pressure on the key plane of the flow field of the separator is obtained by numerical simulation.In order to study the influence of operation parameters and large particle size of combined rotary separator on pressure drop and total collection efficiency of the separator,an experimental platform of combined rotary separator for coal pneumatic conveying was designed and built.Based on the orthogonal test method,the influence of each parameter on pressure drop and total collection efficiency of separator was studied.Through the numerical simulation of particle discrete phase,it is found that the multi-particle size group presents obvious separation phenomenon after entering the separator flow field.The light particles with smaller particle size escape from the upper ash outlet along with the air flow.The heavy particles with larger particle size are trapped by the external separation cone under the dual action of gravity and centrifugal force,and enter the bottom hopper,and the fractional separation of coal particles without crushing is obtained.The efficiency curve and the cutting diameter are 40.1 ?m.The effect of rotor speed on the total collection efficiency of small particles was studied experimentally.The results show that the total collection efficiency of separator can reach the peak when the rotor speed is even times of 160 r/min,and the valley when the rotor speed is odd times of 160 r/min.The influence of rotor speed on the separation efficiency of small particles with wide particle size was studied experimentally.The results showed that the respirable dust below 10 micron could be separated completely.The particle size with the highest collection efficiency was concentrated at about 45.6 micron under several rotational speeds,which indicated that the coal particles with larger particle size tended to change to the particle size after crushing;and the rotational speed of the rotor was 320 r/min.When the rotating speed of the rotor is 640 r/min,the separator can protect the large-sized particles better,and more large-sized particles can be collected by the hopper.