Performance and mechanism of plasma-charged droplet capture and wetting of coal dust: Macroscopic, mesoscopic, and microscopic scales

Corona plasma water-mist charging technology, as a novel and efficient method, has wide application prospects in the field of dust control. Although the effectiveness of the technology in dust removal has been demonstrated in relevant studies, the underlying mechanisms of this technology remain inadequately understood. This study combines experimental methods and numerical simulations to explore the macroscopic performance of plasma-charged droplets in trapping and wetting fine coal dust, the mesoscopic kinetic behavior of charged droplets interacting with coal dust, and the microscopic molecular interactions between charged water and coal systems. These results indicate that the synergistic effect of electrostatic attraction, enhanced wetting and polar products is the primary mechanism behind the efficient capture and wetting of coal dust by plasma-charged droplets. At the macroscopic scale, plasma-charged droplets exhibit a significant electrostatic trapping effect on coal dust, promoting the condensation and deposition of fine coal dust through the use of water as a carrier. At the mesoscopic scale, the spreading and wrapping behavior of plasma-charged droplets on coal dust particles occurs more smoothly. Additionally, an optimal initial velocity has been identified to improve the spreading and wetting performance of the droplets. At the microscopic scale, stronger adsorption of charged water molecules on coal surfaces was observed, and the hydroxide and nitrate ions present in the plasma-charged water also enhanced the wetting and adsorption of coal dust. These findings provide a theoretical foundation and guidance for the practical application of plasma-charged water-mist dust suppression technology.