• 제어로봇시스템학회논문지
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• 제19권9호
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• pp.839-845
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• 2013

A CSTR (Continuous Stirred Tank Reactor) is a highly nonlinear process with varying parameters during operation. Therefore, tuning of the controller and determining the transition policy of controller parameters are required to guarantee the best performance of the CSTR for overall operating regions. In this paper, a methodology employing the 2DOF (Two-Degree-of-Freedom) PID controller, the anti-windup technique and a fuzzy gain scheduler is presented for the temperature control of the CSTR. First, both a local model and an EA (Evolutionary Algorithm) are used to tune the optimal controller parameters at each operating region by minimizing the IAE (Integral of Absolute Error). Then, a set of controller parameters are expressed as functions of the gain scheduling variable. Those functions are implemented using a set of "if-then" fuzzy rules, which is of Sugeno's form. Simulation works for reference tracking, disturbance rejecting and noise rejecting performances show the feasibility of using the proposed method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계합동학술대회 논문집
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• pp.21-25
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• 2002

Activated sludge processes are widely used in biological wastewater treatment processes. The main motivation of this research is to develop an intelligent control strategy for activated sludge process (ASP). ASP is a complex and nonlinear dynamic system because of the characteristic of wastewater, the change in influent rate, weather conditions, and so on. The mathematical model of ASP also includes uncertainties which are ignored or not considered by process engineer or controller designer. The ASP model based on Matlab/Simulink is designed in this paper. The performance of the model is tested by IWA (International Water Association) and COST (European Cooperation in the filed of Scientific and Technical Research) data that include steady-state results during 14 days. In this paper, fuzzy logic control approach is applied to control the DO (dissolved oxygen) concentration. The fuzzy logic controller that includes two inputs and one output can adjust air flowrate. Also, this paper introduces the remote monitoring and control system that is applied for the CSTR (Continuously Stirred Tank Reactor) wastewater treatment system. The CSTR plant has a local control and the remote monitoring system which is contained communication parts which consist of LAN (Local Area Network) network and CDMA (Code Division Multiple Access) wireless module. Remote control and monitoring systems are constructed in the laboratory.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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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.

• 한국수자원학회논문집
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• 제41권3호
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• pp.243-249
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• 2008

본 연구에서는 지표흐름 습지의 수질관리를 위하여 습지 내 오염물질을 적절히 모의할 수 있는 연속교반탱크반응기(CSTR) 모델을 구축하였다. 이 모델은 4차 Runge-Kutta법을 사용하고, 실측치와 계산치의 차이를 최소화 하는 최적화 기법으로 해를 구하며, 미국 EPA 습지 데이터베이스에 수록된 자료중 수질 및 수리자료가 충분하며, 분석이 용이한 하나의 수생대를 갖는 습지를 선택하여, 수질항목중 관심도가 높은 BOD, TSS (Total Suspended Solid)의 모의에 적용하였다. 습지의 체적이 일정할 경우와 체적 및 유량이 일정할 경우 각각에 대해 반응속도상수만을 고려할 경우, 물질흐름양만을 고려할 경우 및 반응속도상수와 물질흐름양 모두를 고려할 경우로 나누어 모의를 실시하였다. 모의 결과 기존의 반응속도상수만을 고려한 경우보다 반응속도상수 및 물질흐름양 모두를 고려하는 것이 실제현상을 잘 나타냈으며, 습지의 TSS 침강속도는 $0.3{\sim}0.4\;m/d$의 값을 나타내는 것으로 파악되었다. 이 모델은 습지의 수질관리에 적절히 활용할 수 있을 것으로 판단된다.

• 상하수도학회지
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• 제25권3호
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• pp.375-382
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• 2011

The usages of CFD (Computational Fluid Dynamics) which is simulating turbulent flows in CSTRs (Complete Stirrer Tank Reactors) have been reported. Considering model strategies and simulation techniques, this paper is focused on the turbulence models. The results of this study would suggest multiple reference frameworks relevant to rotational flow simulation. Specifically, the analysis of turbulence dissipation rates referred to this study would solve the relevant environmental engineering problem and would be beneficial to the CFD in CSTRs using mechanical mixer.

• 대한환경공학회지
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• 제31권12호
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• pp.1075-1080
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• 2009

혐기성 소화 시 산발효 단계에서 지질 성분이 부분적으로 분해되고 지질 내 이중 결합이 포화됨을 통해 후단의 메탄발효 효율이 향상됨이 보고된 바 있다. 본 연구에서는 혐기성 연속 회분식 반응조(anaerobic sequencing batch reactor, 이하 ASBR) 및 연속 흐름 교반 반응조(continuously stirred tank reactor, 이하 CSTR) 형태의 산생성조를 각각 운전하여 지질 분해 및 독성 저감 효율을 살펴보았다. 기질로는 두 가지 불포화(oleate and linoleate), 두 가지 포화(palmitate and stearate) 지방산(long-chain fatty acids, 이하 LCFA)로 구성된 LCFA 혼합물을 사용하였다. 반응조 내의 높은 미생물 보유량에 의해 ASBR이 수리학적 체류시간(hydraulic retention time, 이하 HRT) 12 hr 이하에서 우월한 성능을 보였다. HRT 9시간에서 ASBR은 36.7%의 LCFA 분해, 14.3%의 이중결합 포화, 43.8%의 산생성 효율을 보였으며, 이는 HRT 15시간의 CSTR 보다 각각 19%, 10%, 21% 높은 수치였다. 지질 함유 폐수의 혐기성 소화 시 ASBR을 이용한 산발효가 효과적일 것으로 판단된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.100-105
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• 1992

A mathematical model is developed for a CSTR in which free radical solution polymerization of methyl methacrylate(MMA) takes place. It turns out that five ordinary differential equations are to be treated simultaneously in order to predict the reactor performance. Although the reaction proceeds under the conditions of relatively low temperature and pressure, the system shows very complex bifurcation features due to the diffusion limitation (gel effect) and the temperature dependence of the kinetic parameters and physical properties. The effects of various system parameters on the reactor performance as well as on the polymer properties are investigated by using the bifurcation analysis. The application of the singularity theory enables us to divide the parameter space into several different regions, in each of which the system takes a unique steady state structure. Under certain circumstances, complex dynamic features such as HB points and limit cycles are observed and these should be taken into consideration in the reactor design.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.301-304
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• 1997

Two options arising during implementation of an advanced model-based control system on a process with low-level loops are discussed. Strengths and deficiencies of the options are examined and methods to overcome the deficiencies are proposed. Simulation results of a CSTR and distillation column are presented to demonstrate the performance improvements.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.370-373
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• 2000

In this work, an extractive membrane bioreactor containing coulture broth of Burkholderia cepacia G4 PR1 constitutively expressing the TCE-degrading enzyme, tolune-ortho-monooxygenase(TOM), was used for the degradation of TCE. The membrane bioreactor operates by seperating the TCE-containing waste gas from the aerated biomedium, by which the air-stripping of TCE without degradation was overcome that could occur in conventional aerobic biological treatments of TCE-contaminated waste gases. This was achieved by a silicone rubber membrane which was coiled around a perspex draft tube. TCE from the gas phase diffuses across the silicone rubber membrane into microbial culture broth that was continuously fed from a separate aerobic CSTR. Therefore, TCE degradation occured without the TCE being directly exposed to the aerating gas stream. Of the TCE supplied to the membrane bioreactor, 72.6% was biodegraded during the operation of this system. To construct a mathematical model for this system, parameters describing microbial growth kinetics on TCE were determined using a CSTR bioreactor. Else parameters used for numerical simulation were determined from either indepedent experiments or values reported in the literature. The model was compared with the experimental data, and there was a good agreement between the predicted and the measured TCE concentrations in the system. To achieve a higher treatment efficiency, various operating conditions were simulated as well.

• Korean Chemical Engineering Research
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• 제44권5호
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• pp.520-527
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• 2006

본 연구에서는 FC(fluorocarbon) 플라즈마 반응기에서 입사하는 이온에너지에 따른 고분자 증착, 식각과 증착의 경쟁반응 및 물리적 스퍼터링 등의 여러 표면 현상들을 모델링하였다. $SiO_2$ 식각에 대한 표면반응은 식각반응 영역을 잘 혼합된 CSTR(continuous stirred tank reactor) 가정을 도입하여 이온 도움에 의한 식각으로 모사되었다. 정상상태 고분자층을 통한 식각과 증착의 경쟁반응의 모델링은 이온 도움에 의한 고분자 생성 및 분해 메커니즘을 제안하여 수행하였다. 이러한 메커니즘은 최근 발표된 실험 및 분자동력학적 전산모사 결과에 기초하였으며,모델 계수들은 빔실험 결과 및 플라즈마 실험결과들을 이용하여 구하였다. 최종 개발된 모델의 결과들은 타당성을 검증하기 위해 문헌에 보고된 실험결과들과 비교하였다.