• Title, Summary, Keyword: CSTR

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Thermophilic Biohydrogen Production from Glucose with a Long-term Operation of CSTR (CSTR의 장기운전을 통한 포도당으로부터의 고온 수소생산)

  • Ahn, Yeong-Hee;Oh, You-Kwan;Park, Sung-Hoon
    • KSBB Journal
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    • v.20 no.6
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    • pp.425-430
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    • 2005
  • Thermophilic $H_2$ was produced for 1 year using a bench-scale continuous stirred tank reactor(CSTR). The CSTR was inoculated with anaerobically digested sludge after heat treatment and fed with a glucose-based medium. The reactor showed relatively short start-up period(30 days) and high maximal $H_2$ yield(2.4 mol $H_2/mol$ glucose). Keeping pH 5.0 or less suppressed methanogenic activity. Bacteria affiliated with Thermoanaerobacterium thermosaccharolyticum kept being dominant from approximately 40 days as determined by DGGE. Environmental perturbation(pH or temperature) caused the decrease of biomass concentration in the reactor and the instability of reactor performance, $H_2$ production rate and $H_2$ yield. The unstable performance was accompanied with high concentration of lactate in the effluent. Taken together, the poor recovery of CSTR after perturbations could be partly explained by low biomass concentration and/or metabolic shift of the major population in the CSTR.

Continuous synthesis of silver plates in a continuous stirring tank reactor (CSTR)

  • Tang, Zengmin;Kim, Woo-Sik;Yu, Taekyung
    • Journal of Industrial and Engineering Chemistry
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    • v.66
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    • pp.411-418
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    • 2018
  • In this report, a continuous stirring tank reactor (CSTR) and batch reactor were used for synthesis of silver (Ag) plates. The influences of agitation speed, molar ratio of $AgNO_3$ to NaCl, and concentration of reagent were investigated. Size analysis demonstrated that the size of Ag plates synthesized by the CSTR was larger than the size of plates synthesized by the batch reactor. The reason might be that low concentration of reagent and continuous supply of monomer in CSTR are more favorable for growth of anisotropic structures. CSTR demonstrates good advantages for mass synthesis of Ag plates of large size.

Development of Practical Advanced Oxidation Treatment System for Decontamination of Soil and Groundwater Contaminated with Chlorinated Solvents (TCE, PCE): Phase II (염소계 화합물(TCE, PCE)로 오염된 토양 및 지하수 처리를 위한 실용적 고도산화처리시스템 개발 (II))

  • Kim, Sang-Yeek;Sohn, Seok-Gyu;Kong, Sung-Ho
    • Journal of Soil and Groundwater Environment
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    • v.15 no.2
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    • pp.10-17
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    • 2010
  • Advanced oxidation processes (AOPs) have advantages to reduce the processing time and mineralize contaminants dissolved in groundwater. Recently, remediation techniques for organic contamination in groundwater have been studied, and technology using $UV/H_2O_2$ is generally accepted as one of the most powerful and reliable alternative for the remediation of groundwater contamination. In this study, $UV/H_2O_2$ technology, which generates hydroxyl radical ($\cdot$ OH) as known for strong non-selective oxidant, was used to degrade chlorinated solvents (TCE and PCE), and it was expanded to apply continuous stirred tank reactor (CSTR) system (i.e. combinations of three CSTR). The tested parameters for CSTR system were retention time and groundwater/$H_2O_2$ injection volume ratio. To find optimum parameters for CSTR system, various retention time (6 min ~ 90 min) and groundwater/$H_2O_2$ injection volume ratio (5/1 ~ 119/1) were tested. Other conditions for CSTR were adapted from the batch test results, which concentration of $H_2O_2$ and UV dose were 29.4 mM (0.1%) and 4.3 kWh/L, respectively. Based on the experimental results, the optimum parameters for CSTR system were 20 min for retention time and 119/1 for groundwater/$H_2O_2$ injection volume ratio. Applying these optimum conditions, chlorinated solvents (TCE and PCE) were removed at 99.9% and 99.6%. Moreover, the effluent concentrations of TCE and PCE are 0.036 mg/L and 0.087 mg/L, respectively, which are satisfied the regulatory level (TCE 0.3 mg/L, PCE 0.1 mg/L). Consequently, the CSTR system using $UV/H_2O_2$ technology can achieve high removal efficiency in the event of treatment of groundwater contaminated by chlorinated solvents (TCE and PCE).

Development of Two-stage CSTG/TBF System for the Cometabolic Degradation of Gas-phase TCE by Burkholderia cepacia G4 (Burkholdera cepacia G4를 이용한 기상의 트리클로로에틸렌의 공대사적분해를 위한 2단계 CSTR/TBF 시스템 개발)

  • 이은열;박성훈
    • 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.

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Temperature Control of a CSTR using Fuzzy Gain Scheduling (퍼지 게인 스케쥴링을 이용한 CSTR의 온도 제어)

  • Kim, Jong-Hwa;Ko, Kang-Young;Jin, Gang-Gyoo
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.9
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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.

Continuous Ethanol Fermentation Using Starchy Raw Material in Pilot Scale Multi-stage CSTR (Pilot Scal Multi-stage CSTR에서 전분질 원료의 연속 에탄올발효)

  • 남기두;이인기;조훈호;최명호;김운식
    • Microbiology and Biotechnology Letters
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    • v.20 no.3
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    • pp.324-328
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    • 1992
  • In order to develop more economic processes, continuous ethanol fermentation from starchy raw materials in a pilot scale multi-stage CSTR was investigated. Ethanol fermentation could be successfully operated for 30 days with naked barley and 60 days with cassava, respectively. Starchy raw materials used for this study were ground and passed through a 20-mesh sieve for low temperature cooking. Under the optimized conditions, the overall productivity of cassava was $1.27g/{\ell}{\cdot}h$ with an ethanol concentration of 9.51% (v/v), which was higher about 2 times than that obtained from a conventional batch system in industrial scale.

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Temperature Control of a CSTR using a Nonlinear PID Controller (비선형 PID 제어기를 사용한 CSTR의 온도 제어)

  • Lee, Joo-Yeon;So, Gun-Baek;Lee, Yun-Hyung;So, Myung-Ok;Jin, Gang-Gyoo
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.5
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    • pp.482-489
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    • 2015
  • CSTR (Continuous Stirred Tank Reactor) which plays a key role in the chemical plants exhibits highly nonlinear behavior as well as time-varying behavior during operation. The control of CSTRs in the whole operating range has been a challenging problem to control engineers. So, a variety of feedback control forms and their tuning methods have been implemented to guarantee the satisfactory performance. This paper presents a scheme of designing a nonlinear PID controller incorporating with a GA (Genetic Algorithm) for the temperature control of a CSTR. The gains of the NPID controller are composed of easily implementable nonlinear functions based on the error and/or the error rate and its parameters are tuned using a GA by minimizing the ITAE (Integral of Absolute Error). Simulation works for reference tracking and disturbance rejecting performances and robustness to parameter changes show the feasibility of the proposed method.

Fuzzy PD plus I Controller of a CSTR for Temperature Control

  • Lee, Joo-Yeon;So, Hye-Rim;Lee, Yun-Hyung;Oh, Sea-June;Jin, Gang-Gyoo;So, Myung-Ok
    • Journal of the Korean Society of Marine Engineering
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    • v.39 no.5
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    • pp.563-569
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    • 2015
  • A chemical reaction occurring in CSTR (Continuous Stirred Tank Reactor) is significantly affected by the concentration, temperature, pressure, and reacting time of materials, and thus it has strong nonlinear and time-varying characteristics. Also, when an existing linear PID controller with fixed gain is used, the performance could deteriorate or could be unstable if the system parameters change due to the change in the operating point of CSTR. In this study, a technique for the design of a fuzzy PD plus I controller was proposed for the temperature control of a CSTR process. In the fuzzy PD plus I controller, a linear integral controller was added to a fuzzy PD controller in parallel, and the steady-state performance could be improved based on this. For the fuzzy membership function, a Gaussian type was used; for the fuzzy inference, the Max-Min method of Mamdani was used; and for the defuzzification, the center of gravity method was used. In addition, the saturation state of the actuator was also considered during controller design. The validity of the proposed method was examined by comparing the set-point tracking performance and the robustness to the parameter change with those of an adaptive controller and a nonlinear proportional-integral-differential controller.

Efficient Anaerobic Digestion for Highly Concentrated Particulate Organic Wastewater (고농도 입자성 유기폐수의 고효율 혐기성 소화 공정)

  • Lee, Sungbum;Shin, Kyuchul;Kim, Huijoo;Kim, Hyunju;Choi, Changkyoo;Kim, Moonil
    • Journal of the Korean Geoenvironmental Society
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    • v.9 no.2
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    • pp.23-29
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    • 2008
  • It has been mentioned that CSTR (Completely Stirred Tank Reactor) and UASB (Upflow Anaerobic Sludge Blanket) processes, the existing anaerobic processes, have problems in the treatment of highly concentrated particulate organic wastewater (HCPOW). Therefore, this paper discusses the treatment possibility of distillery wastewater which is a typical HCPOW using ADEPT (anaerobic Digestion Elutriated Phased Treatment) process. In the comparison of CSTR and ADEPT, ADEPT produced much higher gas than that of CSTR removing more organic matters and suspended solids in ADEPT process, ADEPT had no effect on the decrease in pH by volatile fatty acids and showed steady pH in spite of relatively short HRT. In the results of removal rate according to recycle ratios between 6Qin and 2Qin in ADEPT, 6Qin showed high removal rate during the operation time. Therefore it appears that ADEPT had an applicability for the treatment of distillery wastewater. ADEPT could be a economical process, due to the short HRT, the energy recovery by the methane production, and the utilization for carbon source of produced organic acid from the ADEPT-acid reactor.

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