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This study focused on local measurements realized in the dilute zone of a CFB cold pilot. The investigations were carried out using a phase Doppler particle analyzer (PDPA). The hydrodynamic characteristics of the solid phase (size, axial and transversal velocities) were measured at different heights in the CFB riser. Temporal evolutions of the particle velocity and size were determined as well as mean values along the vertical and horizontal axis. The systematic study according to the position in the riser shows a segregation phenomenon and typical velocity profiles for this type of two-phase flow.

This study focused on the measurement of solid mass flux in the riser of a CFB cold pilot. The investigations were carried out using a Phase Doppler Particle Analyser (PDPA). Inconsistencies in PDPA results were observed when investigating flows with high particle densities. It appears that the performance of the measuring technique was affected by the optical thickness of the measured medium, thus producing substantial overestimation of the global solid phase quantity (e.g. solid mass flux). To determine the origin of these inconsistencies, the measuring system was subjected to complete recalibration. It was found that in flows with high particle densities, noisy Doppler signals tend to be split into several parts by the burst detector system, thus producing inconsistencies in the number of particles counted. The parameters associated with the splitting events were analysed, and a post-processing algorithm was developed to limit PDPA measuring errors. The aim of the post-processing algorithm was to rebuild the data and to recover the original measurements. The reconstitution process was applied to solid mass flux measurements in a CFB cold pilot.