Application Of Water Jet Vacuum Ejector Dust Technology In Coal Mine Methane Drainage Drilling Of Wind Row Powder

Heavy dust is produced while use wind power to exhaust dust in coal minedrilling. The dust brings not only silicosis disorders to the workers, but also exists as amajor threat and a potential trigger of accidents, fire and explosion included. So it isessential to develop an efficient dust removal equipment to control the dust. In thisessay, the diffusion of dust caused by drilling under the ground was discussed and therules of the flow and sedimentation of the dust produced in the drilling hole and theroadway were studied. Then based on the principles of multiphase flow, water jetvacuum theory, ejector theory and jet pump theory, a dust removal device in drillingholes was designed. The main results are shown as follows:1. The rules of distribution and movement of the dust exhausted by wind underthe ground were studied. The dust leaves from the coal and the particles whose sizebeyond2mm rapidly down on the plate, while other runs out of the drilling hole andspreads outward, which fills the roadway fully and moves with the airflow. Because ofthe turbulent motion of the airflow, the dust moves irregularly, making the roadwaymisty, which is harmful to individuals and serves as a threat to production.2. The mechanism of a pressurized water jet vacuum dust removal process wasgiven. To begin with, the dust is controlled in a relatively sealed space. When waterpressure reaches16MPa, it is erupted at speeds from a nozzle in the pipe with acertain diameter, so that a negative pressure zone is formed at the rear of the nozzle.This negative pressure was linked to a collector through little resistant pipes. Dust inthe drainage pipe mixes with spray erupted from the nozzle, and suspended in thespray stream. This high-speed and high-viscosity stream rubs against dust so rapidlyto wet the dust, then the dust will not come into sedimentation at certain speed, and itis discharged from the pipe to reach the goal of dust removal.3. A water jet vacuum dust removal device was designed, which is mainlyconsisted of a dust collection device, a supporting device, a dust removal device, apower device and several connecting lines. To get a efficient goal of dust removal, wehave carried on a series of parameter optimization experiment about the number ofnozzles, angle of nozzles, mixing tube length and position of lateral direction through the numerical simulation software ANSYS CFX. Also the internal pressuredistribution is simulated in the case of nozzles is installed by fluid simulation softwareFLUENT. The result shows the device can still be used in the case of nozzle.4. In order to test the performance parameters and collection efficiency ofdrilling dust removal system, more than20groups of numerical simulation,10experiments of ground simulation and test records of12mines and more than30measurement points, over160site operation under the ground were done. The resultsshow that the content of dust in the tunnel decreases by more than90%, concentrationtransforms from300~400mg/m~3to3.5mg/m~3.