Estimation of bed expansions in a freely-bubbling three-dimensional gas-fluidized bed

✍ Scribed by A. Hepbasli

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 178 KB
• Volume: 22
• Category: Article
• ISSN: 0363-907X
• DOI: 10.1002/(sici)1099-114x(199812)22:15<1365::aid-er456>3.0.co;2-z

✦ Synopsis

Knowledge of bed expansions is important in the design and operation of gas-solid fluidized beds. This paper presents a study on the estimation of expanded bed height in a large three-dimensional gas-fluidized bed with a square section of 0)61;0)61 m. All experiments were performed at the freely bubbling mode and the bed expansions were recorded by a video camera. Bed materials were used 593 m raw perlite and 1233 m sand falling within the categories of Geldart's Groups B and D, respectively. The bed height at minimum fluidization ranged from 0)0398 to 0)3176 m, while the excess air velocity from 0)034 m s\ to 0)7453 m s. Equations related to the bed expansion were given using a modified form of two-phase theory of fluidization. A correlation for the average bed expansion (void fraction) was also presented that has been derived from the principal form found successful in gas-liquid systems as follows:

with an average deviation of less than 1%. The experimental findings were compared with previously reported results and were discussed in the light of available correlations.