• Title, Summary, Keyword: CSTR

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Perchlorate Removal by Perchlorate Reducing Bacteria Consortium in a Continuous Bioreactor (연속생물반응기에서 perchlorate 환원 세균에 의한 perchlorate의 제거)

  • Ryu, Hee-Wook
    • KSBB Journal
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    • v.27 no.1
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    • pp.28-32
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    • 2012
  • In this study, the treatment ability of the wastewater containing perchlorate by non-salt tolerant perchlorate reducing bacterial consortium (N-PRBC) was evaluated in a continuous stirred tank bioreactor (CSTR). To obtain the optimal operating condition the bioreactor was operated with the different wastewater empty bed retention time (EBRT). The treatment performance in the bioreactor could be maintained at 100 $mg-ClO_4{^-}L^{-1}$ up to a EBRT of 3 h, and the removal capacity in the CSTR was about 3.3 times higher than that in a batch operation. With a decrease from 9 h to 2 h in a EBRT, the volumetric perchlorate reduction rate was increased from 11.1 $mg-ClO_4{^-}L^{-1}h^{-1}$ to 50.0 $mg-ClO_4{^-}L^{-1}h^{-1}$, and the specific perchlorate reduction rates were increased from 3.01 $mg-ClO_4{^-}g-DCW^{-1}h^{-1}$. In conclusion, the treatment capacities in a CSTR were much better than those obtained in a batch operation.

Development of Bioreactors for Hydrogen-Producing Immobilized Photosynthetic Bacteria(II) : Evaluation of Immobilized Bioreactor for Hydrogen Productivity and Mass Transfer Resistance (광합성 박테리아를 이용한 고성능 수소 생산 고정화 생물반응기의 개발(II) :고정층 반응기와 연속 교반탱크 반응기에서의 수소 생산성 및 물질전달 저항 비교)

  • 선용호;한정우
    • KSBB Journal
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    • v.8 no.3
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    • pp.256-265
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    • 1993
  • In this study, it was observed that hydrogen productivity varied with changes of input g1ucose concentration and dilution rate in FBR( Fixed Bed Reactor), and CSTR(Continuous Stirred Tank Reactor). We evaluated and compared reaction rate Parameters and internal external and overall mass transfer resistances of immobilized carrier in both reactors. Apparent $K_m$ decreased with increasing dilution rate in FBR but showed a constant value above $0.4h^{-1}$ of dilution rate in CSTR. The experimental results in FBR showed nearly analogous to those in CSTR, however, the performance of FBR resulted in lower hydrogen productivity and an external effectiveness factor but a higher internal effectiveness factor than in CSTR. The overall effectiveness factor obtained with various input 91ucose concentrations showed similar values in both reactors.

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Effects of Heat Pre-Treatment and Reactor Configurations on the Anaerobic Treatment of Volatile Solids (열전처리와 반응조 형태가 고형 유기물의 혐기성 처리에 미치는 영향)

  • Hong, Young-Soek;Bae, Jae-Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.10 no.2
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    • pp.104-116
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    • 1996
  • Anaerobic digestion is generally used for the treatment of volatile organic solids such as manure and sludge from waste water treatment plants. However, the reaction rate of anaerobic process is slow, and thus it requires a large reactor volume. To minimize such a disadvantage, physical and chemical pre-treatment is generally considered. Another method to reduce the reactor size is to adopt different reactor system other than CSTR. In this paper, the effects of heat pre-treatment and reactor configurations on the anaerobic treatability of volatile solids was studied. Carrot, kale, primary sludge, and waste activated sludge was chosen as the test materials, and the BMP method was used to evaluate the maximum methane production and first order rate constants from each sample. After the heat treatment at $130^{\circ}C$ for 30min., the measured increase in SCOD per gram VS was up to 394 mg/L for the waste activated sludge. However, the methane production potential per gram VS was increased for only primary and waste activated sludge by 17-23%, remaining the same for carrot and kale. The overall methane production process for the tested solids can be described by first order reactions. The increased in reaction constant after heat pre-treatment was also more significant for the primary and waste activated sludge than that for carrot and kale. therefore, the heat pre-treatment appeared to be effective for the solids with high protein contents rather than for the solids with high carbohydrate contents. Among the four reactor systems studied, CSTR, PFR, CSTR followed by PFR, and PFR with recycle, CSTR followed by PFR appeared to be the best choice considering methane conversion rate and the operational stability.

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Acidogenesis of Lipids-Containing Wastewater in Anaerobic Sequencing Batch Reactor (혐기성 연속 회분식 반응조를 이용한 지질 함유 폐수의 산발효 특성)

  • Kim, Sang-Hyoun;Shin, Hang-Sik
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.12
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    • pp.1075-1080
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    • 2009
  • The partial lipid degradation with the saturation of double-bond at the acidogenesis stage is known to help subsequent methanogenesis during anaerobic digestion. Acidogenic reactions in an anaerobic sequencing batch reactor (ASBR) and a continuously stirred tank reactor (CSTR) were carried out to compare their performances. A mixture of two unsaturated (oleate and linoleate) and two saturated (palmitate and stearate) long-chain fatty acids (LCFAs) was used as a model substrate. Biomass retention in the ASBR contributed to the enhanced performance at hydraulic retention time (HRT) below 15 hr. Biomass retention in the ASBR contributed to the enhanced performance compared to CSTR even at shorter HRT. ASBR would be a proper reactor configuration for the acidogenesis of lipid-containing wastewater.

EA-Based Tuning of the PID Controller for a CSTR (CSTR용 PID 제어기의 EA 기반 동조)

  • Jin, Gang-Gyoo
    • Journal of Korean Institute of Intelligent Systems
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    • v.24 no.3
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    • pp.330-336
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    • 2014
  • Many industrial processes such as continuous stirred tank reactors(CSTRs), desalination plant, distillation columns, pH neutralization processes and so on exhibit highly nonlinear characteristic and time-varying behavior during operation. The control of such processes has been challenging to control engineers. Hence, a variety of forms of PID controllers and their tuning rules for industrial processes have been developed to guarantee the best performance. In this paper, a scheme that designs the practical PID controller with an anti-windup strategy incorporating with an evolutionary algorithm(EA) is presented for the concentration control of a nonisothermal CSTR. EA is used to tune the parameters of the overall PID control process with anti-windup by minimizing the integral of absolute error(IAE). Simulation works for reference tracking and disturbance rejecting performances and robustness to parameter changes show the feasibility of using the proposed method.

Dynamic characteristics of a CSTR with MMA polymerization

  • Ahn, Jong-Pil;Rhee, Hyun-Ku
    • 제어로봇시스템학회:학술대회논문집
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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.

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The effects of turbulence models on the numerical analysis of CSTR (난류모델이 완전혼합반응조 수치해석에 미치는 영향 연구)

  • Im, Yeong-Taek;Park, No-Seok;Kim, Seong-Su;Lee, Beom-Hui
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.3
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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.

ANALYSIS OF MIXING EFFICIENCY OF A TUBULAR HEAT-EXCHANGER REACTOR USING CFD (CFD를 이용한 관상 열교환기형 반응기의 mixing 효율 분석)

  • Lee Ji Hyun;Song Hyun-Seob;Han Sang Phil
    • 한국전산유체공학회:학술대회논문집
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    • pp.45-47
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    • 2005
  • We have investigated the mixing behavior of a tubular heat exchanger reactor using CFD and compared its mixing performance with different type of reactors such as jet mixer and continuous stirred tank reactor (CSTR). The mixedness in each reactor was quantified introducing a statistical average value, the coefficient of variation (CoV), which is a normalized standard deviation of concentration of a component over the whole fluid domain. Through the analysis of the flow pattern and turbulent energy distribution, we suggested a simple but effective way to improve the mixing performance of the tubular heat-exchanger reactor, which include the addition of the internals and/or the increase of the recycle flow rate. It was found that the CoV value of the tubular reactor could be nearly equivalent to that of CSTR by applying those two alternatives suggested here.

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Integrating Fuzzy based Fault diagnosis with Constrained Model Predictive Control for Industrial Applications

  • Mani, Geetha;Sivaraman, Natarajan
    • 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.