Abstract:

In order to solve the problems of easy water loss and poor dust suppression effect in coal seam water injection technology, a dust suppression method which can not only increase the water retention rate of coal seam but also improve the brittleness of coal seam was proposed. A gum-forming dust suppressant based on sodium alginate (SA) was developed. The effects of surfactant, viscosity and injection pressure on the gum-forming dust suppressant were tested by means of specific surface area test, nitrogen adsorption test, scanning electron microscope test and dust production rate test. The test results show that the surfactant is beneficial to the wetting of the coal seam, but has little effect on the dust suppression. The increase of the viscosity of the dust suppressant is conducive to water retention, which can increase the water retention time from 10 h to 30 h, but it will make it difficult for the material to enter the coal seam. The injection pressure has a great influence on the dust suppression effect of the dust suppressant. When the coal seam injection pressure is small, the dust suppressant is difficult to quickly penetrate into the internal pores of the coal. With the increase of pressure, the dust suppressant gradually penetrates into the coal pores. When the injection pressure rises to 3 MPa, the dust suppression effect no longer increases with the increase of pressure, and the dust production rate is reduced from 4% to 2.3%, which is relatively decreased by 50%, effectively reducing the dust production.

Key words: gum-forming dust suppressant, coal seam water injection, dust suppression effect, dust production rate, water retention rate, synergies effect