| Abstrakt: |
Mass transfer coefficients were measured in three concentric-tube airlift reactors of different scales (RIMP, V L=0.07 m3;RIS−1, V L=2.50 m3;RIS−2, V L=5.20 m3). The effects of top and bottom clearance and flow resistances at downcorner entrance were studied in water-air system. Experimental results show that h s, h B and A d/ A R ratio affect K L a values as a result of their influence on gas holdup and liquid velocity. The gas-liquid mass-transfer coefficients for all the geometric variables were successfully correlated as Sherwood number with Froude and Galilei numbers, the bottom spatial ratio ( B= h B/ D R), the top spatial ratio , the gas separation ratio and the downcomer flow resistance ratio ( R= A d/ A R). The proposed empirical model satisfactorily fitted the experimental data obtained in large airlift reactors and some data presented in literature. [ABSTRACT FROM AUTHOR] |
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