Abstract:
In order to effectively prevent and control coal dust produced in fully mechanized working faces and tackle the problems with current sprays such as the poor performance in wetting and coagulating coal dust and the bad coverage of the spray field for main dust sources,a dust reduction technology system based on the surfactant-magnetized water with strong wettability and new spray equipment for fully mechanized mining faces was proposed to effectively seal up the main dust sources. A high efficiency dust removal process system was constructed including the surfactant addition system,magnetization device,hydrodynamic wet dust collector and negative pressure coil dust collector,etc. The connotation and technical characteristics of the dust reduction technology based on the surfactant-magnetized water were discussed. From the perspective of the surfactant and its ration supply system,a magnetic device,the efficient preparation of the surfactant-magnetized water were investigated. A new surfactant having the well synergistic action with magnetization was developed which could effectively improve the wetting characteristics of the aqueous solution. The results showed that the new surfactant obtained by the combination between alkyl anionic active agents and fatty acid nonionic active agents can produce a good synergistic effect with magnetization. When the surfactant-magnetized water was produced by the solution containing 0.03% surfactant passing through the coupling magnetization of pulsation cutting and spiral turbulence with a magnetic field strength of 300-350 mT at a speed of 4 m/s,its wettability was good,of which the dust deposition time was reduced by 44.26%,to 34.5 s,compared with the original 0.03% surfactant solution. Aiming at three dust sources of the intelligent fully mechanized working faces such as coal shearer,moving supports and transfer point,the spray atomization systems were constructed respectively,i.e. the combined method of hydrodynamic dust remover and internal and external spray,negative pressure coiling spray and the combined method of dust cover and negative pressure coiling spray. Their technical principles and application processes were systematically described. The field application of the system at the 24130 intelligent working face in the 10 th mine of Pingdingshan coal group showed that the novel dust reduction technology system can greatly reduce the dust concentration of the underground working face,and the working face’s dust reduction efficiency of respirable dust and total dust could reach 85.3% and 90.8%,respectively,which can greatly improve the working environment of underground personnel and the video clarity of monitoring equipment. It ensures the normal control of intelligent equipment by ground people.