Research on the influencing factors of collision and infiltration of fine coal dust by magnetized charged droplets

ZHANG Hongjie; ZHAO Yuming; WU Jiezhong; GE Shaocheng

doi:10.13347/j.cnki.mkaq.20241794

Abstract：Magnetized charging technology,as a new type of coupling enhanced dust reduction technology,can effectively improve the poor efficiency of traditional wet water mist in capturing fine and difficult to infiltrate coal dust.This study adopts theoretical analysis and experimental methods to study the wetting effect and dynamic behavior of magnetized charged droplets colliding with hydrophobic anthracite coal dust particles.It determines the optimal collision particle size ratio and initial velocity.The results show that due to their high surface tension and viscosity,ordinary droplets have a small spreading range and slow velocity during collision with strongly hydrophobic coal dust particles,exhibiting a complete rebound phenomenon.The magnetization charging effect effect-ively suppresses the rebound phenomenon of droplets hitting coal dust by reducing surface tension and viscosity.At low speeds,a thin precursor film is formed on the surface of coal dust particles,thereby increasing the wetting area,halving the particle size of the droplet,making it easier to break,and accelerating the droplet spreading speed and coverage range.Compared with pure water,mag-netized charged droplets have obvious advantages in soaking and capturing coal dust particles,which is conducive to spray dust re-duction,condensation and respiratory dust;at low speeds,magnetized charged droplets are prone to eccentric collisions with coal dust,and some droplets do not participate in the collision,resulting in staggered flow field intensity peaks.The droplets enter a re-laxed state for a long time,have a small effective coverage area,and their instantaneous wetting rate and effect deteriorate.There-fore,the droplet dust particle size ratio should not be less than 0.8;when the collision speed reaches 4.31 m/s,the center height coef-ficient of the liquid film rapidly decreases to stability.At the same dimensionless time,the minimum value of the center height coef-ficient of the liquid film is inversely proportional to the collision speed;when the particle size ratio of magnetized charged droplets is 0.8 and the velocity is 4.31 m/s,the settling effect on total dust and respiratory dust is significant,and the dust removal efficiency can reach over 95%.