Experimental Investigation into the Hydrodynamics of Flow of Solids through a Loop Seal Recycle Chamber
✍ Scribed by Eugene Botsio; Prabir Basu
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 194 KB
- Volume
- 83
- Category
- Article
- ISSN
- 0008-4034
No coin nor oath required. For personal study only.
✦ Synopsis
As fl uidized solids take on the properties of liquid (Basu and Fraser, 1991), its fl ow over the sidewall of the recycle chamber may be considered to be similar to the fl ow of a liquid over a regular sharp crested weir. This being the case, one should be able to predict all hydrodynamic parameters using the sharpcrested weir theory. Basu and Cheng (2000) proposed this conjecture but provided a limited verifi cation. The present tests and examines this hypothesis in more details and provides numerical values of the weir coeffi cient for its use by designers. Primary motivation of this work is to provide data for commercial CFB boilers, which generally operate at relatively low circulation rates.
The working of loop seal is one of the least understood aspects of a circulating fl uidized bed boiler although this component is critical to the operation of such boilers. The present work is an experimental study of the fl ow of solids; through the recycle chamber of a loop seal in a circulating fl uidized bed (CFB). The effect of different parameters on the velocity of solid overfl ow through the recycle chamber is investigated. The sharp-crested weir theory of free surface water fl ow was used to analyze the solid fl ow through the loop seal. The analysis gives a good indication of the validity of the above theory for solids overfl ow over a weir. The results show that the solid fl ow rate increases with increase in bed height above the weir and the particle size had no effect on the value of the weir coeffi cient.
Le travail de l'obstruction en boucle est l'un des aspects les moins connus d'une chaudière à lit fl uidisé circulant, bien que cette composante soit critique pour le fonctionnement de telles chaudières. On présente ici une étude expérimentale de l'écoulement des solides, dans la chambre de recirculation d'une obstruction en boucle dans un lit fl uidisé circulant (CFB). On a étudié l'effet de différents paramètres sur la vitesse du trop-plein dans la chambre de recirculation. On a eu recours à la théorie de la surverse à arêtes tranchantes de l'écoulement d'eau à surface libre pour analyser l'écoulement de solides dans une obstruction en boucle. L'analyse donne une bonne indication de la validité de cette théorie pour le trop-plein de solides au-dessus d'une surverse. Les résultats montrent que le débit de solides augmente avec la hauteur de lit au-dessus de la surverse et que la taille des solides n'a pas d'effet sur la valeur du coeffi cient de surverse.