(29d) Electrostatic Charging in Fluidized Beds

It is well known that triboelectric charging can occur in fluidized particle systems, such that the particles become highly charged ? however, the scientific understanding of this charging is very poorly understood. The charging can occur in general from both particle ?particle and particle-wall interactions. To make progress in furthering the scientific understanding of this phenomenon, it is necessary to separate the particle ?particle and particle-wall effects. In our work, we use a combination of experiments, theory and simulation to address the triboelectric charging that occurs solely from particle-particle interactions. An experimental methodology is developed to isolate the effects of particle-particle interactions, and the results show that smaller particles tend to charge negatively while larger particles tend to charge positively. We use theory and simulation to show that such charging can result from a nonequilibrium dynamics of electrons, whereby collision-induced electron transfer generates electron accumulation on a particle-size-dependent subset of the system.

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