The axial hydrodynamic behavior in a liquid‐solid circulating fluidized bed

Based on experimental results from a 7.6 cm I. D. and 3 m high liquid–solid circulating fluidized bed, the liquid–solid circulating fluidization regime has been separated into two zones: the initial circulating fluidization zone and the fully developed circulating fluidization zone. The distinct hydrodynamic behavior and the influence of particle properties in the two circulating fluidization zones have been studied. The overall flow structure in LSCFB, although still somewhat non–uniform, is much more uniform than that in a gas-solid CFB. Our experimental results also show that the axial flow characteristics and the regime transition can be strongly affected by the particle density. The stable operation range of the circulating fluidization system and the influences of some associated factors, such as the solids inventory and the particle density, were also investigated for the first time. A partir de resultats experimentaux d'un lit fluidise circulant liquide–solides de 7,6 cm de diarnetre interieur et 3 m de haut, on a separe le regime de fluidisation circulant liquide–solides en deux zones: la zone de fluidisation circulante initiale et la zone de fluidisation circulante pleinement developpee. On a etudie le comportement hydrodynarnique distinct et l'influence des proprietes des particules dans deux zones de fluidisation circulantes. La structure globale de I'ecoulement dans deux zones de fluidisation circulantes. La structure globale de I'ecoulement dans le LSCFB, quoique toujours legerement non uniforme, est beaucoup plus uniforme que dans un CFB gaz-solides. Nos resultats experimentaux montrent egalement que les caracteristiques d'ecoulement axial et la transition de regime peuvent etre fortement influencees par la masse volumique des particules. La gamme de fonctionnement stable du systeme de fluidisation circulant et I'influence de certains facteurs associes, comme I'inventaire des solides et la masse volumique des particules, ont egalement ete etudiees pourla premiere fois.