Chemical Engineering Science, Vol.206, 31-40, 2019
Optical emission spectroscopy diagnostics of DBD plasma with particles in a two-dimensional spouted bed
To gain an insight into the effect of fluidization behavior of particles on the characteristic of plasma in a plasma-enhanced spouted bed, we investigated the changes of plasma optical emission spectroscopy (OES) with fluidized particles in this paper. Fluidization experiments under the irradiation of a dielectric barrier discharge (DBD) plasma generator were performed in a two-dimensional spouted bed. Essential operation parameters, such as particle type, applied voltage, gas velocity, and particle number were changed. The pressure drop of particles, emission intensity (El) of plasma, and high-speed camera images of plasma pattern were measured. As the results, the fluidization behavior of particles had been changed by the plasma irradiation, especially for polypropylene (PP) particles. The emission spectra of argon (Ar) plasma had been changed significantly with particles. The emission intensities of the Ar I transition lines were increased, and Ar II lines were decreased with PP particles compared to the case of no particle. The emission intensity of Ar I lines was enhanced with the applied voltage regardless of the addition of particles. The emission intensity changed with a gas velocity versus particle numbers was identified with the fluidization behavior, that emission intensity was increased at first and then decreased. The gas velocities corresponded to the highest value of emission intensity with various particle number were similar to the trend of the changes of minimum spouted velocity. The electrical conductivity and color of particles may affect the difference of pressure drop and detected emission intensity for two kinds of particles. Our research extends the knowledge of the relationship between fluidization behavior and plasma optical characteristic. (C) 2019 Elsevier Ltd. All rights reserved.