Characteristics of local flow structure with different particle properties in a gas-solid diameter-varying fluidized bed

Abstract

The effects of particle property on gas-solid flow in the diameter-varying riser are experimentally examined using the optical fiber probe in this research. Local flow features are obtained by signal analysis method under the operating conditions of 3–7 m/s and 8–63 kg/m2s. The results show that solid holdup distribution of glass beads is wider than that of catalyst particle particles in the wall region but is narrow in the center region. Solid holdup fluctuations tend to decrease with the increase of particle density under low-concentration conditions but increase at high-concentration conditions. The results from power spectrum density (PSD) show that the increase in particle density strengthens the periodic flow features in the enlarged section. The motion intensity decreases at the particle level but increases at the cluster level for high-density particles. Additionally, as particle density rises, the solid concentration discrepancies between the straight section and the enlarged section widen. In contrast to the upper straight section, the effects of particle density on gas-solid flow are minimal in the enlarged section.