• KSBB Journal
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• v.16 no.5
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• pp.511-515
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• 2001

In this paper, we development and operated a two-stage continuous stirred tank reactor (CSTR)/trickling biofilter(TBF)system for the long-term continuous treatment of trichloroethylene (TCE) using Burkholderia cepacia G4. In this reactor system. CDTR with cell recycle from TBF was coupled to the TBF for the reactivation of the cells deactivated during TCE degradation. The critical elimination capacity was determined to be 25.3 mg TCE/L day and the reactor has been stably operated for more than 1 months, which clearly represented that CSTR/TBF system can be used for long-term treatment of TCE.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.3
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• pp.315-322
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• 2007

The purpose of this study was to investigate the biodegradability and performance of organic removal and methane production rate when treating piggery wastewater using a granule of two-phase anaerobic process applied UASB. BMP test was conducted as simple means to monitor relative biodegradability of substrate and to determine methane production of an organic material. The two-phase anaerobic process is consisted of a continuous flow stirred-tank reactor (CFSTR) for the acidification phase and an Upflow Anaerobic Sludge Blanket reactor (UASB) for the methanogenesis. The acidogenic reactor played key roles in reducing the periodically applied shock-loading and in the acidification of the influent organics. A stable maximum biogas production rate was 400mL. The methane contents ranged from 73 to 80% during the experimental period. It is known that most of the removed organic matter was converted to methane gas, and the produced biogas might be high quality for its subsequent use.

• KSBB Journal
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• v.7 no.1
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• pp.79-83
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• 1992

The characteristics of Erwinia rhapontici cells with $\alpha$-glucosyltransferase activity immobilized in Ca-alginate beads and the performance of two different types of reactor-stirred tank reactor(STR) and packed bed reactor(PBR)-charged with these immobilized cells to produce palatinose from sucrose were investigated. The optimal pH(5.5-6.0) and temperature($30-35^{\circ}C$) showed no appreciable difference between free and immobilized cells. The apparent Km value of the immobilized cells(0.28M) was approximately two times higher than that of free cells(0.13M) at $30^{\circ}C$. The half life of the immobilized cells was found to be 380 h with STR while much greater operational stability was achieved with PBR. Continuous operation of PBR at a space velocity of $0.2h^{-1}$ for 30 days showed only 5% loss of initial activity.

• KSBB Journal
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• v.11 no.1
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• pp.58-64
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• 1996

The purpose of this study is to develop a continuous process for sorbitol production using Zymomonas mobilis immobilized in K-carra-geenan. The glutaraldehyde cross-linking of toluene-treated cells immobilized in alginate or chitin showed high enzyme stability for long period. However, loss of enzyme activity was observed at 23% during 210h. In order to investigate the stability of glucose-fructose oxidoreductase of cethyltrimethylammoniumbromide (CT AB) treated cells, the long term continuous process was carried out with Z. mobilis immobilized in K-carrageenan in the continuous stirred tank reactor(CSTR) and the packed bed reactor. The continuous production of sorbitol with the immobilized CT AB permeabilized cells in packed bed reactor was more stable than in CSTR. Two stage continuous process with CT AB treated cells of Z. mobilis immobilized in K-carrageenan was carried out at various dilution rates. At the first stage, the productivity was increased up to 15 g/ $\ell$ -h as dilution rate increased and decreased over 0.32$h^{-1}$ of dilution rate. Similarly, maximum productivity obtained at the second stage was 22g/$\ell$ -h at 0.32$h^{-1}$

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.3
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• pp.163-170
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• 2002

This report describes the use of a transtubular bioreactor to study the relative effects of diffusion versus perfusion of medium on antibody production by a hybridoma cell line. The study was performed with a high-density cell culture maintained in a serum-free, low-protein medium for 77 days. It was determined that the reactor possessed a macro-mixing pattern residence time distribution similar to a continuous stirred tank reactor (CSTR), However, due to the arrangement of the medium lines in the reactor, the flow patterns for nutrient distribution consist of largely independent medium path lengths ranging from short to long. When operated with cyclic, reversing, transtubular medium flow, some regions of the reactor (with short residence times) are more accessible to medium than others (with long residence times). From this standpoint, the reactor can be divided into three regions: a captive volume, which consists of medium primarily delivered via diffusion; a lapped volume, which provides nutrients through unilateral convection; and a swept volume, which operates through bilateral convection. The relative sizes of these three volumes were modified experimentally by changing the period over which the direction of medium flow was reversed from 15 min (larger captive volume) to 9 h (larger swept volume). The results suggest that antibody concentration increases as the size of the diffusion-limited (captive) volume is increased to a maximum at around 30 min with a sharp decrease thereafter. As reflected by changes in measured consumption of glucose and production of lactate, no significant difference in cellular metabolism occurred as the reactor was moved between these different states. These results indicate that the mode of operation of the transtubular bioreactor may influence antibody productivity under serum-free, low-protein conditions with minimal effects on cellular metabolism.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.7
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• pp.479-484
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• 2013

This study was performed to examine the effect of copper on the biodegradability, nitrification, denitrification and oxygen uptake rate (OUR) using batch reactor and continuous flow stirred tank reactor (CSTR) of anaerobic/anoxic/oxic ($A_2/O$). The results of this study can be summarized as follows. In the case of the effect of copper on organic treatment, the bad effect initiated when it was above 4.5 mg/L copper with batch reactor and above 2.0 mg/L copper with CSTR. Concerning the case on nitrification and removal of nitrogen, it showed bad effect when copper was above 4.5 mg/L with batch reactor for nitrification and 1.0 mg/L with CSTR for the removal of nitrogen. The bad effect on the removal of phosphorus began when it was 4.5 mg/L copper with batch reactor and 2 mg/L copper with CSTR. In the case of OUR, it decreased as microbial activity was affected when copper concentration was above 1.5 mg/L in both case of batch reactor and CSTR.

• International Journal of Control, Automation, and Systems
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• v.4 no.6
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• pp.669-681
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• 2006

In this work, a new method of design adaptive controllers for SISO systems based on multiple models and switching is presented. The controller selects the model from a given set, according to a switching rule based on output prediction errors. The goal is to design, at each sample instant, a predictive control law that ensures the robust stability of the closed-loop system and achieves the best performance for the current operating point. At each sample the proposed control scheme identifies a set of linear models that best characterizes the dynamics of the current operating region. Then, it carries out an automatic reconfiguration of the controller to achieve the best possible performance whilst providing a guarantee of robust closed-loop stability. The results are illustrated by simulations a nonlinear continuous and stirred tank reactor.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.886-889
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• 2017

An active Fault Tolerant Model Predictive Control (FTMPC) using Fuzzy scheduler is developed. Fault tolerant Control (FTC) system stages are broadly classified into two namely Fault Detection and Isolation (FDI) and fault accommodation. Basically, the faults are identified by means of state estimation techniques. Then using the decision based approach it is isolated. This is usually performed using soft computing techniques. Fuzzy Decision Making (FDM) system classifies the faults. After identification and classification of the faults, the model is selected by using the information obtained from FDI. Then this model is fed into FTC in the form of MPC scheme by Takagi-Sugeno Fuzzy scheduler. The Fault tolerance is performed by switching the appropriate model for each identified faults. Thus by incorporating the fuzzy scheduled based FTC it becomes more efficient. The system will be thereafter able to detect the faults, isolate it and also able to accommodate the faults in the sensors and actuators of the Continuous Stirred Tank Reactor (CSTR) process while the conventional MPC does not have the ability to perform it.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.570-575
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• 1993

화학 공정에서의 이상 진단 시스템 개발 및 응용에 대한 연구는 지난 5년간 많은 발전이 이루어졌다. 화학 공정의 본질적인 특성으로 대형 시스템, 비선형 특성, 모델링 자체의 어려움, 공정 변수의 large dead time 및 복잡한 인과 관계등을 들수 있으며, 이러한 어려움에도 불구하고 적절한 이상 진단 시스템의 중요성을 인식하여, 초기에는 주로 rule-based approach가 도입되어 현장에서의 조업에 많은 도움을 주었었다. 그러나 개발 기간의 단축화, 개발 과정의 표준화 뿐 아니라 개발된 시스템 자체의 일관성 등을 위하여 체계적인 접근 방법이 필요하게 되었으며, 그중 지식 베이스 합성 문제는 그 동안 활발하게 연구되어 오고 있는 분야이다. 이에 본 연구에서는 기호화된 정성적인 정보를 얻기위한 기존의 실험 방법의 한계를 극복하고자 동적 모사를 이용하여 정량적인 정보로부터 정성적인 정보를 생성시키는 방법론에 대해 연구하였다. CSTR(Continuous Stirred Tank Reactor)에서 나타날수 있는 이상의 종류에 대한 동적 모사를 수행하여 이상 진단 시스템을 위한 지식이 생성되는 과정을 보였다.

• International Journal of Control, Automation, and Systems
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• v.2 no.4
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• pp.407-422
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• 2004

A new method for the design of predictive controllers for SISO systems is presented. The proposed technique allows uncertainties and constraints to be concluded in the design of the control law. The goal is to design, at each sample instant, a predictive feedback control law that minimizes a performance measure and guarantees of constraints are satisfied for a set of models that describes the system to be controlled. The predictive controller consists of a finite horizon parametric-optimization problem with an additional constraint over the manipulated variable behavior. This is an end-constraint based approach that ensures the exponential stability of the closed-loop system. The inclusion of this additional constraint, in the on-line optimization algorithm, enables robust stability properties to be demonstrated for the closed-loop system. This is the case even though constraints and disturbances are present. Finally, simulation results are presented using a nonlinear continuous stirred tank reactor model.