Bed nonhomogeneity in turbulent gas‐solid fluidization

Abstract

Bed dynamic beha®ior in a gas-solid fluidization system is measured in real time using ECT

ECT studies of the choking phenomenon in a gas–solid circulating fluidized bed

“…Electrical capacitance tomography (ECT) is one of a handful of real-time tomography techniques and has been applied recently to three-phase flow imaging (Warsito and Fan, 2001a). ECT has also been applied to other solid flow systems, including standpipe flow, bubbling and turbulent fluidized beds, circulating fluidized beds, pneumatic conveying, and cyclone diplegs (Du et al, 2002(Du et al, , 2003Dyakowski et al, 1997Dyakowski et al, , 2000Wright, 2002a, 2002b;Malcus and Pugsley, 2001;Malcus et al, 2000;Smolders et al, 2001;Yang and Liu, 2000). The crux for the accurate application of the ECT or any other tomography techniques is the robustness of the image reconstruction technique used in resolving the "inverse" tomography imaging problem (Warsito and Fan, 2001b).…”

Bed height and material density effects on fluidized bed hydrodynamics

“…This phenomenon is attributed to the increased presence of bubbles in the material as the bed height is increased. Du et al (2003) measured the solid concentration for a turbulent fluidized bed.…”

“…However, the spatial resolution provided is lower than the nuclear based techniques (Chaouki et al, 1997). Du et al (2003) used the ECT technique to study the dynamic behavior of a turbulent gas-solid fluidized bed. From the ECT images, they quantified the dynamic characteristics of the bubble/void phase and the emulsion phase of the system.…”

Fast X-ray tomography for the quantification of the bubbling-, turbulent- and fast fluidization-flow regimes and void structures

“…The investigation was limited to a shallow bed and axial measurements where not possible. Du et al [10] used Electrical Capacitance Tomography (ECT) in conjunction with an optical probe to investigate bed non-homogeneity using Fluid Catalytic Cracking (FCC) catalyst for the bubbling and turbulent regime. The radial solids concentration profile for this Geldart A particle system was found to be asymmetrical for the bubbling regime, but symmetrical for turbulent.…”