Fermentor coefficient

Yeast cells are cultivated under aerobic conditions at 30 C in an aerated stirred-tank fermentor where air (21 vol% of oxygen) is supplied at a superficial gas velocity of 50 mh . The overall volumetric coefficient for oxygen transfer based on the liquid phase concentration is 80 h T... 

The rates of heat transfer between the fermentation broth and the heat-transfer fluid (such as steam or cooling water flowing through the external jacket or the coil) can be estimated from the data provided in Chapter 5. For example, the film coefficient of heat transfer to or from the broth contained in a jacketed or coiled stirred-tank fermentor can be estimated using Equation 5.13. In the case of non-Newtonian liquids, the apparent viscosity, as defined by Equation 2.6, should be used. 

Thus, when deahng with gas transfer in aerobic fermentors, it is important to consider only the resistance at the gas-liquid interface, usually at the surface of gas bubbles. As the solubihty of oxygen in water is relatively low (cf. Section 6.2 and Table 6.1), we can neglect the gas-phase resistance when dealing with oxygen absorption into the aqueous media, and consider only the liquid film mass transfer coefficient Aj and the volumetric coefficient k a, which are practically equal to and K a, respectively. Although carbon dioxide is considerably more soluble in water than oxygen, we can also consider that the liquid film resistance will control the rate of carbon dioxide desorption from the aqueous media. 

Estimate the liquid-phase volumetric coefficient of oxygen transfer for a stirred-tank fermentor with a diameter of 1.8 m, containing a viscous non-Newtonian broth, with consistency index K = 0.39, flow behavior index n = 0.74,... 

Estimate the liquid-phase volumetric coefficient of oxygen transfer for a bubble column fermentor, 0.8 m in diameter 9.0 m in height (clear liquid), containing the same liquid as in Problem 12.2. The superficial gas velocity is 150 m h . ... 

From the data and from the experimental procedure described in the patent the overall distribution coefficient based on total acetate is calculated as 0.004. This is an extremely small number, which, of course, is a consequence of the small amount of free acid available in solution at the high pFI of the solution. Other authors (Yates, 1981 Busche, Shimshick, and Yates, 1982) address the problem of incomplete extraction of organic acids from high-pH solutions using CO2. The authors suggest that the raffinate from the extractor can be recycled to the fermentor. 

McManamey, W.J., and Wase, D.A.J. (1986), Relationship between the volumetric mass transfer coefficient and gas holdup in airlift fermentors, Biotechnology and Bioengineering, 28(9) 1446-1448. 

Y ou are studying dispersion in a small air-lift fermentor. This ferment or is 1.6 m tall, with a 10-cm diameter. Air and pure water are fed into the bottom at superficial velocities of 11 and 0.78 cm/sec under these conditions the gas bubbles occupy 45% of the column volume. You continuously add 15 cm /min of 1-M NaCl solution near the top of the column. You find by conductance that the salt concentration halfway down the column is 2.32-10 M. What is the dispersion coefficient Answer 54 cm /sec. 

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