Study On Dust Distribution Law And Dust Removal Technology Of Integrated Excavation Surface

Compared with other dust production points in the underground,the fully mechanized excavation face has the characteristics of relatively closed space and large dust production.The large amount of dust generated during the excavation process not only pollutes the production environment of the fully mechanized excavation face,threatens the physical and mental health of the underground staff,but also causes wear and tear to the mechanical equipment such as the roadheader.When it exceeds a certain limit,it will even explode,seriously threatening the safe production of the underground.At present,ventilation and dust removal technology is widely used underground,but the traditional ventilation and dust removal system has few forms and low dust removal efficiency.In order to further reduce the dust concentration in the fully mechanized excavation face,protect the personal safety of the underground personnel and ensure the safe operation of the mining work,this paper proposes a double air curtain dust control system based on the existing ventilation and dust removal technology without exceeding the gas limit in the fully mechanized excavation face,and carries out theoretical,experimental and numerical simulation studies.The dust production mechanism and stress state of dust are analyzed theoretically,and the influencing factors of dust production and the migration law of dust in the roadway are revealed.According to the principle of air curtain dust control and jet theory,the feasibility of air curtain dust isolation technology is verified.According to the prototype of fully mechanized excavation face,a scale experimental platform was built,and the dust separation effect and dust concentration distribution of the air curtain were tested.The research shows that the air curtain jet state formed by the double air curtain dust control system is consistent with the principle of turbulent jet,which can obviously isolate the diffused dust and effectively reduce the dust concentration in the environment behind the air curtain.The double air curtain dust control system reduces the total dust from 547.67 mg/m~3 at the dust source to 35.46 mg/m~3,and the respirable dust from 50.42 mg/m~3 to 4.62 mg/m~3.The total dust reduction efficiency is 92.97%,and the respirable dust reduction efficiency is 90.84%.The dust removal effect of the long-pressure short-pumping ventilation system has been significantly improved,which proves the superiority of the double air curtain dust control system.Through the analysis of the influencing factors of the double air curtain dust control system,the distribution of the airflow field and dust field in the roadway under the conditions of different distance from the side wall W,the angle of the guide plateα,the distance from the air outlet of the air extraction cylinder to the fully mechanized excavation face L,the height of the air outlet H,and the pressure extraction ratioβis obtained.The optimal configuration parameters of the double air curtain dust control system are:the distance from the side wall W=2.1 m,the angle of the guide plateα=45°,the distance from the air outlet of the air extraction cylinder to the fully mechanized excavation face L=10 m,the height of the air outlet H=30 mm,and the pressure extraction ratioβ=0.8.The research results will provide a new idea for dust control in fully mechanized excavation face.