• 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.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.3
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• pp.223-229
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• 2007

여과막 생물반응기를 이용하여 $60^{\circ}C$에서 혐기 세균 복합체가 포도당으로부터 수소를 생산할 수 있는 최적조건을 연구하였다. 여과막 생물반응기는 연속교반 탱크반응기와 외부에 장착된 PVDF (polyvinylidene fluoride) 중공사막 여과장치로 구성되었다. 접종슬러지는 하수처리장 소화 슬러지조에서 얻었고, 포자형성 수소생산 미생물을 얻기 위해 $90^{\circ}C$에서 20분 간 열처리하였다. 16S rRNA PCR-DGGE(polymer chain reaction-denaturing gradient gel electrophoresis) 분석을 통해 열처리 전후의 미생물상 변화를 조사하였다. 열처리 후 DGGE 밴드의 수는 감소하였고, 주요 밴드는 Clostridium perfringens와 유사한 염기서열을 나타내었다. 운전 기간 동안 바이오가스 내 수소함량은 60%(v/v)를 유지하였고, 메탄은 검출되지 않았다. 연속교반 탱크반응기를 여과막 없이 수력학적 체류 4시간에서 운전하였을 때 공급된 포도당의 95.0%가 제거되었고, 이때 균체농도 및 수소생산속도는 각각 1.35 g cell/L 및 7.4 L $H_2$/L/day이었다. 동일한 체류시간에서 PVDF중공사막 여과장치를 장착하여 연속교반 탱크반응기를 운전하였을 때, 균체농도는 1.62 g cel/L로 증가하였고 높은 포도당 제거율(99.5%) 및 수소생산속도(8.8 L $H_2$/L/day)가 관찰되었다. 40 nm 및 100 nm의 공극크기를 가진 여과막은 균체농도 및 수소생산 측면에서 유사한 성능을 나타내었다. 여과막 생물반응기는 여과막의 반복적인 세척을 통해 30일 이상 안정적으로 운전될 수 있었다.

• Journal of the Korean Institute of Gas
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• v.5 no.4 s.16
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• pp.70-78
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• 2001

In order to find out which equipment failures were mostly contributed to the rupture of a continuous stirred tank reactor, the sensitivity analysis was carried out. The uncertainty of likelihood of the rupture of reactor was studied by the uncertainty analysis. And the cost effectiveness analysis resulted in the recommendation of the exchange with a better reliable unit if you want to maintain the process efficiently from the view point of cost. The uncertainty analysis showed that the likelihood of catastrophic rupture of the reactor was distributed from $8.09{\times}10^{-04}$ to $5.50{\times}10^{-02}/year$. As a result of cost-effectiveness analysis, it was proposed to exchange the voting logic unit for a better safer system.

• Journal of the 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.

• Microbiology and Biotechnology Letters
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• v.16 no.6
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• pp.510-516
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• 1988

The effects of input substrate concentration and dilution rate on mass transfer resistance in the operation of immobilized cell reactors were investigated using Rhodospirillum rubrum KS-301 immobilized by Ca alginate as reactor element and glucose as growth-limiting substrate. The kinetic parameters were obtained to estimate effectiveness factors. In the packed-bed reactor, internal mass transfer resistance was predominating although external resistance could not be neglected. The overall effectiveness factor was decreased with increase of dilution rate. In the continuous stirred-tank reactor, external resistance was nearly neglected and the overall effectiveness factor was not affected by dilution rate. In this experiment the overall effectiveness factors in PBR and CSTR were estimated to be 0.70 and 0.71 at D$_{i}$ = 0.2/h, R = 0.15 cm, and S$_{i}$ : 1.0g/L, respectively.

• Journal of Korea Water Resources Association
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• v.41 no.3
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• pp.243-249
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• 2008

Continuous stirred tank reactor(CSTR) model which can be applied to control and management of the surface flow wetland is developed to simulate the water quality in this research. The model solution is obtained from the optimization model using the least-squares and 4th-order Runge-Kutta methods. The model is applied to simulate BOD and TSS in the wetland database of U.S. EPA, in which the hydraulic and water quality data are enough and the number of pond is just one for simple analysis of running results. The model is tested in two different cases, one constant volume case and another constant volume and flow rate case considering only reaction term, mass flux term and both reaction and mass flux terms respectively. It is found that the model simulates the real water quality very well with both reaction and mass flux terms rather than only reaction term and the settling velocity of TSS becomes $0.3{\sim}0.4\;m/d$. The model can be applied in wetlands treatment efficiently.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.633-641
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• 2015

Several complex processes that are employed in industries, such as shipping, power plants, and the petrochemical industry, involve time-varying behavior as well as strong nonlinear behavior during operation. The fixed-parameter proportional-integral-derivative (PID) controllers have difficulty in dealing with control problems that occur in such processes. In this paper, we propose a method of designing a nonlinear PID controller for industrial processes that exhibit a large number of nonlinearities and time-varying behavior. The gains of the nonlinear PID controller are characterized by a simple nonlinear function of the error and/or error rate depending on the process set-point and output. We tune the user-defined parameters using a genetic algorithm by minimizing the integral of time absolute error (ITAE) index. We verify the effectiveness of the proposed method by performing a comparison of the proposed method and two other nonlinear and adaptive methods that are employed for reference tracking, disturbance-rejection performances, and robustness to parameter changes on a continuously stirred tank reactor.

• KSBB Journal
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• v.8 no.3
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• pp.243-255
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• 1993

In this study, it was observed that hydrogen Productivity varied with stirrer speed, bead radius, input glucose concentration and dilution rate in a continuous stirred tank reactor in which immobilized R. rubrum KS-301 was used as a hydrogen-producing bacterium The mass transfer resistance due to cell immobilization was also studied. In order to estimate an effectiveness factor, Des of glucose was first obtained, which was subsequently represented by the correlation equation between Dos and Xb, As a result external mass transfer resistance could be neglected for stirrer speeds greater than 400rpn With bead radius increasing, the hydrogen productivity and internal effectiveness factor decreased. With input 91ucose concentration increasing, the hydrogen productivity and interval and external effectiveness factor increased. Although an Internal effectiveness factor was not affected, hydrogen productivity Increased with dilution rate increasing. An overall effectiveness factor remained nearly constant for the dilution rates investigate4 but increased with input 91ucose concentration increasing.

• Journal of Adhesion and Interface
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• v.24 no.3
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• pp.77-85
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• 2023

In this research, polymeric anionic surfactants having various molecular weights and acid values were synthesized using a continuous stirred tank reactor (CSTR). The CSTR has an advantage of higher production rate and more constant product properties compared to batch and semi-batch reactors. The polymeric surfactants were made using butyl acrylate as a hydrophobic group and acrylic acid as a hydrophilic group. The synthesized polymeric surfactants were ionized with alkali solution and were used as an anionic surfactant. To investigate the properties as a surfactant, the properties of the synthesized surfactant, such as acid value, critical micelle concentration (CMC) and molecular weight, were measured. The results showed that the acid values of the polymeric surfactants were 60 to 380 and a number average molecular weight were 8,000 to 13,000 g/mol. Also, it was found that the CMC was around 0.01 g/ml, which showed similar level values with ordinary surfactant. To prove the performance of the polymeric surfactant, acrylic emulsion PSAs were synthesized using the acquired polymeric surfactant. The results showed that the maximum peel strength of 21.24 N/25mm when acid value was 150 and molecular weight was 8,500 g/mol. The values of peel strength and initial tack of acrylic emulsion PSAs using polymeric surfactant synthesized in this study showed much higher than those of reference PSAs synthesized using ordinary anionic surfactant, SDS (Sodium Dodecyl Sulfate) and SDS/TRX (Triton X-100).