Akita-Yoshida correlation

For the heterogeneous flow regime, the Akita-Yoshida correlation derived for bubble column reactors is proposed (Akita and Yoshida, 1973 Ramachandran and Chaudhari, 1984 Behkish, 2004 Koide, 1996) ... 

The use of the Akita-Yoshida correlation is justified since the catalyst loading is very low (2%), and the effect of the solids on gas holdup is expected to be minimal. The liquid volume is simply... 

Ozturk et al. (1987) developed a new correlation on the basis of a modification of the Akita-Yoshida correlation suggested by Nakanoh and Yoshida (1980). In addition, the bubble diameter db rather than the column diameter was used as the characteristic length as the column diameter has little influence on The value of db was assumed to be approximately constant (db = 0.003 m). The correlation was obtained by nonlinear regression is as follows ... 

From the numerous correlations for Eq reported in the literature only two will be given here. Akita and Yoshida ( ) correlated their data for water and aqueous solution of glycol, glycerol, methanol, NaCl and Na2S03 by... 

Akita and Yoshida (1974) evaluated the liquid-phase mass-transfer coefficient based on the oxygen absorption into several liquids of different physical properties using bubble columns without mechanical agitation. Their correlation for kL is... 

Akita and Yoshida (1974) determined the bubble-size distribution in bubble columns using a photographic technique. The gas was sparged through perforated plates and single orifices, while various liquids were used. The following correlation was proposed for the Sauter-mean diameter ... 

Akita and Yoshida (1973) correlated the gas hold-up for the absorption of oxygen in various aqueous solutions in bubble columns, as follows ... 

The column diameter d in Eqn. (2) is only included to make the various terms dimensionless. Generally, the correlation of Akita and Yoshida gives a conservative estimate. 

For the case of the less effective single and multinozzle spargers Akita and Yoshida ( ) proposed the following correlation... 

Fig. 8 demonstrates that this empirical correlation describes fairly well the oxygen mass transfer data of various authors and for large-scale equipment. Therefore the equation of Akita and Yoshida can be recommended for low mass transfer rates, i.e. the mass transfer of slightly soluble gases. It usually gives a conservative estimate of k. a. 

Figure 8. Check of correlation of Akita and Yoshida (water-air system)...

Of the many correlations proposed (see Hikita et al., 1980a,b, for a review), those of Akita and Yoshida (1973) and Hikita et al. (1980b) are useful. One of... 

Akita and Yoshida (15), among others, proposed the following empirical correlation... 

Empirical correlations for Kl in bubble columns have been developed by Hughmark (25) and Akita and Yo-shida (26). The equation given by Hughmark is often a good compromise while according to our experience Akita s and Yoshida s correlation predicts a rather conservative estimate of k. 

Column diameter well below the minimum suggested. Akita and Yoshida s (1974) correlation has been modified for cocurrent and countercurrent mode of operation... 

More recently other correlations have been proposed that are somewhat more accurate, but also more complicated (see, e.g., Akita and Yoshida, 1974, and Mersmann, 1978). They can be summarized as follows ... 

Equation A7.6 can only be used after the measurement or estimation of 8g-Direct correlations for ay have been developed by Akita and Yoshida [7]. The correlations are presented below. 

For the gas volume fraction, holdup, several correlations are suggested in the literature. The correlation of Akita and Yoshida [7] is valid for columns with a maximal diameter of 60 cm. It can further be utilized in the case of pure liquids and nonelectrolytic solutions ... 

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