The effect of nonideal mixing on input multiplicity in a CSTR

Liou, Ching-Tien; Chien, Yu-Shu

doi:10.1016/0009-2509(91)80168-x

Cited by 49 publications

(21 citation statements)

References 7 publications

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“…Greek symbols D j 1/h Q j aV 1 c 11 Y c 22 ± stoichiometric coef®cients for intra-cellular reactions x ± V 2 aV 1 l 1/h overall speci®c growth rate of biomass l j Y l À j 1/h speci®c growth rate of cells in j-th region l j 1/h overall speci®c growth rate r j Y r À j g/l intra-cellular substrate concentration in j-th region h ± plasmid loss probability Introduction…”

mentioning

confidence: 99%

Dispersion-induced behavior in sub-critical operation of a recombinant fed-batch fermentation with run-away plasmids

Patnaik

1998

Bioprocess Engineering

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Fermentations with recombinant bacteria containing run-away plasmids are typically operated alternately above and below a critical temperature. To minimize the risks of run away reactions, it is preferable to keep the high temperature periods as short as possible. In this study the possibility of sustained low temperature (sub-critical) operation in a suitably non-homogeneous broth is analyzed. Fluid dispersion is used as a measure of non-homogeneity.The fed-batch production of b-galactosidase by Escherichia coli containing the plasmid pOU140 and operated below 37 C is analysed as a model system. To characterize non-homogeneity, an earlier model visualizing the broth as a set of two reactors with internal recycle has been modi®ed for fed-batch fermentation. Three dilution rates, two internal and one external, quantify¯uid dispersion. While plasmid replication and fermentation become quenched in sub-critical operation in a well-mixed reactor, with ®nite dispersion there may be an increase in the concentration of plasmid-containing cells and the recombinant protein. The concentration pro®les many also have one or more peaks in the time domain. Thus, sustained fermentation with run-away plasmids appears feasible in a bioreactor with controlled non-homogeneity.

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Dispersion-induced behavior in sub-critical operation of a recombinant fed-batch fermentation with run-away plasmids

Patnaik

1998

Bioprocess Engineering

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“…Example 4 An isothermal continuous stirred tank reactor (CSTR) studied by Liou and Yu-Shu [5] is considered. The final steady state model of this process is represented by the following mathematical model [23] The modeling parameters for the isothermal CSTR are: flow rate (Q) = 0.03333l/sec, volume (V ) = 1l, K 1 = 10l/s, and K 2 = 10l/mol, and n = m = 0.75.…”

Section: Examplementioning

confidence: 99%

“…Example 5 Continuous stirred tank reactor (CSTR) with nonideal mixing discussed by Liou and Yu-Shu [5] has the following transfer function model [23] …”

Section: Examplementioning

confidence: 99%

Setpoint weighted PID controller tuning for unstable system using heuristic algorithm

Rajinikanth¹,

Latha²

2012

Archives of Control Sciences

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Most of the real time chemical process loops are unstable in nature and designing a suitable controller for such systems are difficult than open loop stable processes. In this work, an attempt is made with a two degree of freedom setpoint weighted PID controller tuning procedure for a class of unstable systems using the recent heuristic algorithms such as Particle Swarm Optimization and Bacterial Foraging Optimization. The problem considered in this study is to aptly tune the controller in order to enhance the overall closed loop performance. A novel objective function proposed in this study is used to monitor the heuristic algorithms in order to get the optimal controller parameters like K p , K i , K d , and α with minimized iteration number. The proposed method is validated with a simulation study and this helps to accomplish enhanced system performance such as smooth reference tracking, satisfactory disturbance rejection, and error minimization for a class of unstable systems.

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“…Liou and Chien [18] also showed that one of the conditions for the existence of input multiplicity is that the phenomenon of output multiplicity occurs at the nonlinear reaction rate. Preliminary investigation based on the published values of kinetics parameters for this system showed that the system may exhibit input multiplicity if low concentrations of acetic anhydride were used as in the studies by Jayakumar and Rao [19], and Haldar and Rao [20].…”

Section: Introductionmentioning

confidence: 96%

Input Multiplicity Analysis in a Non‐Isothermal CSTR for Acid‐Catalyzed Hydrolysis of Acetic Anhydride

Jayakumar

Hashim

Thomas³

2010

Chem Eng & Technol

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Multiplicity analysis gives practical guidance for process design to eliminate difficult operating regions associated with input and output multiplicities. Continuous stirred tank reactors (CSTRs) present challenging operational problems due to complex behavior such as input and output multiplicities, ignition/extinction, parametric sensitivity, and nonlinear oscillations. In the absence of a unified mathematical theory for representing various nonlinear system characteristics, the present study was aimed at understanding the dynamic behavior of CSTRs by means of experiments and to link the experimental data to theoretical considerations for further detection and elimination of operating problems. Theoretical modeling and analysis of a non-isothermal CSTR with acid-catalyzed hydrolysis of an acetic anhydride system for input multiplicity are discussed. Theoretical modeling of a non-isothermal CSTR using a root-finding technique was carried out for predicting steady-state temperatures. Alternatively, a mathematical model for a non-isothermal CSTR using unsteady-state mass and energy balance equations is proposed. Computer-based simulation was carried out using a program developed in MATLAB for final transient temperature and time-temperature data of the CSTR system under investigation. The results of a theoretical analysis conducted for confirming the existence of input multiplicity in non-isothermal CSTRs with acid-catalyzed hydrolysis of acetic anhydride were compared with experimental investigations for validation.

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The effect of nonideal mixing on input multiplicity in a CSTR

Cited by 49 publications

References 7 publications

Dispersion-induced behavior in sub-critical operation of a recombinant fed-batch fermentation with run-away plasmids

Dispersion-induced behavior in sub-critical operation of a recombinant fed-batch fermentation with run-away plasmids

Setpoint weighted PID controller tuning for unstable system using heuristic algorithm

Input Multiplicity Analysis in a Non‐Isothermal CSTR for Acid‐Catalyzed Hydrolysis of Acetic Anhydride

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