Polymer particles having the same chemical makeup but different sizes would have their own special contributions to the generation of static charges,owing to the differences in catalyst residue and surface properties among them.Experiments were performed in a gas-solid fluidized bed to determine the changes in the electrostatic charges with addition of various fine polyethylene particles,which were the same material as the coarse polyethylene particles,to better understand their role in influencing electrostatic charge generation/dissipation.By measuring the electrostatic potential at different bed axial heights,it was found that the electric field inside the bed was significantly influenced by the size of added fine polyethylene particles,mass fractions and catalyst residue.Consequently,an impact factor of fine particles(Fb) was proposed,which was the sum of particle diameter term and catalyst residue term.Within the experimental limits in this paper,after three kinds of fines with Fb all less than 1 were added in the fluidized bed,the electrostatic potential in the bed was just influenced slightly.However,the bed electrostatic potential changed significantly following the addition of the fines with the smallest particle diameter and highest residual catalyst content.While Fb of this kind of fines was less than 1,the static potential did not change much but even decreased slightly with the addition of fines.Once Fb of the fourth kind of fines was more than 1,the electrostatic potential in the bed increased greatly.With Fb of the fourth kind of fines increasing further,the electrostatic potential fell a little,and meanwhile it was found that a large amount of fine particles adhered to the column wall.
