Bubble dynamics in 2-D gas–solid fluidized bed with Geldart A or Geldart B particles by image processing method

Gas bubbles in a two-dimensional gas–solid fluidized bed were identified using an image processing method to characterize the bubble dynamics in a binary fluidization system. The magnetite, sand (two types), and fluid catalytic cracking (FCC) catalyst particles belonging to Geldart groups A and B were used as the particulate materials. Image processing and MATLAB were applied for bubble size and velocity measurements. Bubble properties and bed expansion in fluidized beds of those four types of particles were studied. Bubble size and bubble rise velocity were found to increase with the distance above the gas distributor and excess gas velocity. Geldart A particles have a higher bed expansion than Geldart B particles due to the large number of small bubbles in the bed. A new empirical correlation for estimating bubble diameter along the bed height was proposed, giving good agreement with the experimental data.