关键词: 静电效应, 气固流化床, 沉降分离高度, 颗粒夹带, CFD-DEM方法

Abstract: The actual value of the transport disengaging height (TDH) in a gas-solid fluidized bed is drastically different from the value that is anticipated. One of the primary reasons for this difference is that the electrostatic impact is ignored. Because it is impossible to quantitatively regulate the charge that is carried by the particles using the experimental procedures that are now in use, it is also difficult to analyze the impact that electrostatic effects have on TDH using experimental methodological approaches. In this work, the CFD-DEM numerical simulation method is used to study the particle entrainment and TDH problems in a three-dimensional fluidized bed. They combine the average height of particles in the free space, the average solid phase concentration, and the longitudinal particle velocity. This is done while taking into consideration the electrostatic effects that occur between particles. The influence and mechanism of the electrostatic force on the entrainment rate and TDH are derived, which provides a theoretical basis for the establishment of a method that is more accurate in forecasting TDH. Specifically, the findings indicate that the electrostatic impact between particles has the potential to impede the entrainment of particles and to decrease the entrainment rate. It is possible for the electrostatic force between particles to increase the average particle height and the longitudinal velocity of particles in free space, which ultimately results in an increase in the TDH when the charge that the particles carry is relatively low. Nevertheless, when the charge that the particles carry is substantial, the electrostatic attraction between the particles is likely to produce particle agglomeration. This, in turn, will reduce the concentration of the solid phase in the free space and hinder the entrainment of the particles, which will result in a decrease in the TDH.

Key words: electrostatic effect, gas-soild fluidized bed, transport disengaging height, particle entrainment, CFD-DEM method