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Explaining the enhanced performance of pulsed bioreactors by mechanistic modeling
Author(s) -
Franco Amaya,
García Carlos,
Carrasco Eugenio F.,
Roca Enrique
Publication year - 2008
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.11451
Subject(s) - mass transfer , dimensionless quantity , biot number , steady state (chemistry) , bioreactor , work (physics) , thermodynamics , chemistry , limiting , kinetics , process (computing) , mechanics , continuous stirred tank reactor , biochemical engineering , process engineering , engineering , mechanical engineering , computer science , physics , organic chemistry , quantum mechanics , operating system
In this work, steady‐state mass balance based models were applied to two UASB reactors and three UAF for a better understanding of the role of pulsation on the efficacy improvement. Models were defined taking into account the hydraulic behavior of each digester and the limiting mechanism of the overall process kinetics (mass transfer or biochemical reaction rate). The application of the model allows to identify that mass transfer was the controlling step in all the reactors, except for the nonpulsed UASB, where methanogenic activity controlled the reactor performance in the last operation steady states. Mass transfer coefficients were higher for pulsed reactors and, in general, a good agreement between those estimated by an empirical correlation and from the model was obtained. Damköhler number values supported that the external mass transfer resistance was not negligible with respect to the process kinetic and in addition, in most cases, it controls the overall process in the reactors. The relative importance of external and internal mass transfer rate was calculated through the Biot number. The values of this dimensionless module indicated that external transport was the main contributor to overall mass transfer resistance. © 2008 American Institute of Chemical Engineers AIChE J, 2008