Experimental investigation of particle adhesion on the wall due to electrostatic charge in gas-solid fluidized beds

Abstract

Understanding the mechanism of wall particles due to electrostatic charge is significant for the safety in industrial process. In this study, the characteristics of wall particles are examined to reveal the adhesion mechanism. The behaviors of polyethylene particles are evaluated in terms of total charge-to-mass ratio, size distribution and charge distribution for three kinds of wall materials (polymethyl methacrylate, stainless steel, poly tetra fluoroethylene). The results show that particles adhered to the wall are highly charged during the fluidization process compared with bulk particles. Wall particles almost possess charge in the same polarity, implying that particle adhesion on the wall could also exist even if particles are monopolar charged. Adhered particles are relatively small with a narrow size range. More importantly, the size of wall particles tends to increase along with the development of wall layers. The mechanism for particle adhesion on the wall is proposed that monopolar charged particles adhere to the wall due to the interaction between the electric field force of the wall and the van der Waals force.