Sparged stirred tank fermentor

Gas-liquid mass transfer in fermentors is discussed in detail in Section 12.4. In dealing with in gas-sparged stirred tanks, it is more rational to separate and a, because both are affected by different factors. It is possible to measure a by using either a light scattering technique [9] or a chemical method [4]. Ihe average bubble size can be estimated by Equation 7.26 from measured values of a and the gas holdup e. Correlations for have been obtained in this way [10, 11], but in order to use them it is necessary that a and d are known. 

Two major types of fermentors are widely used in industry. The stirred tank, with or without aeration (e.g., air sparging) is most widely used for aerobic and anaerobic fermentations, respectively. The bubble column (tower fermentor) and its modifications, such as airlifts, are used only for aerobic fermentations, especially of a large scale. The important operating variables of the sparged (aerated)... 

The term fermentation is used to describe the biological transformation of chemicals. In its most generic application, a fermentor may be batch, continuous-stirred tank (chemostat), or continuous plug flow (immobilized cell). Most industrial fermentors are batch. Several configurations exist for these batch reactors to facilitate aeration. These include sparged tanks, horizontal fermentors, and biological towers. 

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