The rise of single bubbles in rolling fluidized beds

• Bubble shape varies by nozzle/bed setup; rolling enhances circular profiles. • Rolling causes oscillatory bubble growth, with walls/channels affecting drift. • Rolling evens bubble residence time, reducing wall effects and boosting velocity. • Granular temperature depends on bed setup; rolling drops fluctuations effectively. Marinized bubbling fluidized beds hold promise for reducing ship emissions, but face significant challenges due to sea-induced hydrodynamic instability. This study investigates the dynamics of single bubbles in fluidized beds under simulated marine conditions, using digital image analysis and particle image velocimetry to evaluate the effects of rolling amplitude and frequency, nozzle position, and static inclination on bubble behavior and bed stability. Comparative analyses of vertical, inclined, and rolling beds show that nozzle placement and wall interactions strongly influence bubble trajectories, shapes, and size evolution. Rolling bed oscillations tend to stabilize bubble shapes but introduce bifurcated growth patterns and enhance gas drift near walls, while inclined beds amplify bubble shrinkage through channeling effects. Granular temperature analysis shows that rolling motion mitigates oscillations, redistributes particle kinetic energy, and stabilizes void fraction and bubble behavior despite exacerbated wall channeling at higher rolling amplitudes. These findings provide valuable insights into overcoming hydrodynamic challenges, optimizing fluidized bed designs, and improving their stability and performance for sea-going applications.