Measurement of particle concentration in powder coating process using capacitance computed tomography and wavelet analysis

Capacitance computed tomography techniques were used to visualize particles movement in the draft tube of a spouted fluidized bed for the coating process of drug production. A total of 512 frames images of the particle concentration distribution were obtained at 10-millisecond intervals over a coating time of 5 min using a capacitance computed tomography system. The three-dimensional capacitance CT images (time and two-dimensional space images) were decomposed to wavelet time and space levels to extract the dominant particle distribution feature using three-dimensional discrete wavelet multiresolution at different coating times. As a result, the time and space dominant particle distribution with a specific frequency level can be visualized.

Graphical AbstractCapacitance computed tomography techniques were used to visualize particles movement in the draft tube of a spouted fluidized bed for the coating process of drug production. The three-dimensional capacitance CT images (time and two-dimensional space images) were decomposed to wavelet time and space levels to extract the dominant particle distribution feature. The distribution showing a high concentration of particles, which composes middle space wavelet level 2 and time wavelet levels 5 at the coating time of 5 min (time wavelet level 4 at coating times of 10, 15, and 20 min) is located near the wall of the draft tube.Figure optionsDownload full-size imageDownload as PowerPoint slide