Abstract
The effect of micromixing and macromixing on enzyme reaction of Michaelis-Menten type in a real continuously stirred tank reactor (CSTR) is considered. The effect of bypassing of a fraction of feed stream, dead space, initial enzyme concentration and Michaelis-Menten constant on substrate conversion is evaluated. Bypass reduces the substrate conversion significantly compared with other parameters in the case of micro and macromixing. Micromixing predicts higher substrate conversions compared with macromixing. The effect of micro and macromixing on substrate conversion is negligible at low and high conversions.
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Abbreviations
- C kmol/m3 :
-
concentration of reactant
- ¯C kmol/m3 :
-
average concentration of reactant
- CA kmol/m3 :
-
exit concentration of reactant A
- CAa kmol/m3 :
-
exit concentration of reactant A from active zone
- CAO kmol/m3 :
-
initial concentration of reactant A
- CEO kmol/m3 :
-
initial enzyme concentration
- CO kmol/m3 :
-
initial concentration of reactant
- E(t) 1/s:
-
exit age distribution function
- k 1/s:
-
reaction rate constant
- M kmol/m3 :
-
Michaelis-Menten constant
- r kmol/(m3s):
-
rate of reaction
- −rA kmol/(m3s):
-
rate of reaction with respect to A
- t s:
-
time
- v m3/s:
-
volumetric feed rate
- va m3/s:
-
volumetric feed rate entering the active zone
- vb m3/s:
-
volumetric feed rate entering the bypass stream
- V m3 :
-
total volume of the vessel
- Va m3 :
-
active volume of the vessel
- Vd m3 :
-
volume of dead space
- XA :
-
conversion of A
- α :
-
fraction of feed stream bypassing the vessel (vb/v)
- β :
-
fraction of the total volume as dead space (Vd/V)
- δ(t) 1/s:
-
Dirac delta function, an ideal pulse occurring at time t = 0
- λ s:
-
life expectancy of a molecule
- Λ 1/s:
-
intensity function or escape probability function
- τ s:
-
space time or mean residence time
References
Danckwerts, P. V.: The effect of incomplete mixing on homogeneous reactions. Chem. Eng. Sci. 8 (1958) 93–102
Zwietering, T. N.: The degree of mixing in continuous flow systems. Chem. Eng. Sci. 11 (1959) 1–15
Shinnar, R.: Use of residence time and contact time distributions in reactor design. p. 116 J. J. Carberry and A. Varma (Eds), Marcel Dekker Inc., New York (1985)
Levenspiel, O.: Chemical reaction engineering. 2nd ed., John Wiley & Sons, Inc., New York (1972)
Bailey, J. E.; Ollis, D. F.: Biochemical engineering fundamentals. 2nd ed., McGraw-Hill Book Co., New York (1986)
Denbigh, K. G.; Turner, J. C. R.: Chemical reactor theory: An introduction. 3rd ed., Cambridge University Press, Cambridge, London (1984)
Cholette, A., and Cloutier, L.: Mixing efficiency determinations for continuous flow systems. Can. J. Chem. Eng. (1959) 105–112
Moore, W. J.: Basic physical chemistry. Prentice Hall, New Jersey (1983)
Kafarov, V. V.; Vinarov, A. Yu.; Gordeev, L. S.: Modelling of bioreactors. Int. Chem. Eng. 28(1), (1988) 14–35
Levenspiel, O.: Chemical reactor design: Omni book. OSU Press Corvallis (1979)
Prokop, A.: Reactor design fundamentals: Hydrodynamics, mass transfer, heat exchange, control and scale up. ACS Symp. Series 207 (1983) 355–376
Westerterp, K. R.; van Swaaij, W. P. M.; Beenackers, A. A. C. M.: Chemical reactor design and operation. John Wiley & Sons, New York (1984)
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Giridhar, M., Krishnaiah, K. The effect of micro- and macromixing on enzyme reaction in a real CSTR. Bioprocess Engineering 9, 263–269 (1993). https://doi.org/10.1007/BF01061532
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DOI: https://doi.org/10.1007/BF01061532