• Environmental Engineering Research
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• 제24권2호
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• pp.309-317
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• 2019

This study evaluated the kinetics of acrylamide (AM) biodegradation by mixed culture bacteria and Enterobacter aerogenes (E. aerogenes) in sequencing batch reactor (SBR) systems with AQUASIM and linear regression. The zero-order, first-order, and Monod kinetic models were used to evaluate the kinetic parameters of both autotrophic and heterotrophic nitrifications and both AM and chemical oxygen demand (COD) removals at different AM concentrations of 100, 200, 300, and 400 mg AM/L. The results revealed that both autotrophic and heterotrophic nitrifications and both AM and COD removals followed the Monod kinetics. High AM loadings resulted in the transformation of Monod kinetics to the first-order reaction for AM and COD removals as the results of the compositions of mixed substrates and the inhibition of the free ammonia nitrogen (FAN). The kinetic parameters indicated that E. aerogenes degraded AM and COD at higher rates than mixed culture bacteria. The FAN from the AM biodegradation increased both heterotrophic and autotrophic nitrification rates at the AM concentrations of 100-300 mg AM/L. At higher AM concentrations, the FAN accumulated in the SBR system inhibited the autotrophic nitrification of mixed culture bacteria. The accumulation of intracellular polyphosphate caused the heterotrophic nitrification of E. aerogenes to follow the first-order approximation.

• 반도체디스플레이기술학회지
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• 제16권3호
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• pp.1-7
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• 2017

Multi-wafer planetary type chemical vapor deposition reactors are widely used in thin film growth and suitable for large scale production because of the high degree of growth rate uniformity and process reproducibility. In this study, a two-dimensional model for estimating the effect of the gap between satellite and wafer on the wafer surface temperature distribution is developed and analyzed using computational fluid dynamics technique. The simulation results are compared with the results obtained from an analytical method. The simulation results show that a drop in the temperature is noticed in the center of the wafer, the temperature difference between the center and wafer edges is about $5{\sim}7^{\circ}C$ for all different ranges of the gap, and the temperature of the wafer surface decreases when the size of the gap increases. The simulation results show a good agreement with the analytical ones which is based on one-dimensional heat conduction model.

• 공업화학
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• 제22권3호
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• pp.261-265
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• 2011

아르곤과 산소 대기압 플라즈마를 이용한 미생물인 E. coli의 살균효과를 분석하였다. 유전체 격막 방전 형태의 플라즈마 반응기는 아르곤과 산소 혼합기체에서 균일한 플라즈마 방전과 오존 생성에 효과적이었다. 직접적인 대기압 플라즈마 조사에 따른 E. coli의 살균처리 공정에서 산소에 대한 혼합비와 인가전력의 증가는 방전기체의 오존 발생농도를 높여 미생물의 살균효과를 증가시켰다. 반응기와 시료와의 거리는 살균효과를 증가하기 위하여 가급적 작게 하는 것이 효율적이었다. 본 연구를 통하여 대기압 플라즈마는 오존과 같은 산화촉진제의 발생으로 저온에서 E. coli와 같은 미생물을 효과적으로 살균할 수 있어 기존의 살균법을 대체 할 수 있는 차세대 살균기술로서의 개발 가능성을 확인 할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제6권4호
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• pp.196-202
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• 1985

A Very Low Pressure Reactor (VLPR) is constructed for the kinetic study of atom-molecule bimolecular elementary reactions. The basic principles and the versatility of the method are described. By using the VLPR technique the forward (k1) and the reverse (k-1) rate constants for Br atom reaction with trimethylsilane are studied; Br + $(CH_3)_3$SiH k1 ${\leftrightarrow}$ k-1 HBr + $(CH_3)_3$Si. From the kinetic data and the entropy estimation the bond dissociation energy for Si-H bond in trimethylsilane is calculated to be 90.1 kcal/mole $({\pm}1.1$ kcal/mole). The Arrhenius parameters for k1 are found to be log A = 10.6 l/mole·sec, $E_a$ = 4.4 kcal/mole respectively. For the comparison purpose analogous reaction for carbon compound ; Br + $(CH_3)_3$CH ${\rightarrow}$ HBr + $(CH_3)_3$C was also studied. The corresponding rate constant and equilibrium constant at $25^{\circ}C$ are found to be 2.67 ${\times}$ $10^6l$/mole${\cdot}$sec and 160 respectively.

• Korean Chemical Engineering Research
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• 제45권6호
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• pp.656-662
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• 2007

고분자 전해질 연료전지 운전에 필요한 수소 공급 장치로서 플라즈마 개질 방법을 이용한 개질기와 일산화탄소 산화반응을 위한 전이 반응기를 설계 및 제작하였다. GlidArc 방전을 이용한 저온플라즈마 개질기는 Ni 촉매를 동시에 사용하여 $CH_4$ 개질함으로서 $H_2$ 선택도를 증대하였다. 개질기의 변수별 연구로서 촉매 온도, 가스 조성비, 전체 가스유량, 전압변화 그리고 개질 특성 및 최적 수소 생산조건을 연구하였으며, 전이반응기의 변수별 연구로서 선택적 산화반응기(PrOx)에 주입되는 공기량, 전이 반응기에 주입되는 수증기량 그리고 온도에 대하여 연구하였다. 플라즈마 개질기에서 최대 수소 생산 조건은 $O_2/C$ 비가 0.64, 가스유량은 14.2 l/min, 촉매 반응기 온도 $672^{\circ}C$ 그리고 유입전력이 1.1 kJ/L일 때 41.1%로 최대 수소 농도를 나타냈다. 그리고 이때의 $CH_4$ 전환율, $H_2$ 수율 그리고 개질기 에너지 밀도는 각각 88.7%, 54%, 35.2%를 나타냈다. 전이 반응기에서 모사된 개질 가스로부터 최대 CO 전환율을 보이는 조건은 2단으로 구성된 PrOx에 주입되는 $O_2/C$ 비가 0.3, HTS에서 주입되는 수증기 주입량 비가 2.8 그리고 HTS, LTS, PrOx I, PrOx II 반응기 온도가 475, 314, 260, $235^{\circ}C$ 일때 가장 높은 CO 전환율을 나타냈다. 플라즈마를 이용한 반응기는 예열 시간은 30분이 소요되었으며, 전이 반응기에서 나오는 최종 개질 가스의 조성은 $H_2$ 38%, CO<10 ppm, $N_2$ 36%, $CO_2$ 21% 그리고 $CH_4$ 4%로 나타냈다.

• Korean Chemical Engineering Research
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• 제57권3호
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• pp.420-424
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• 2019

포항산업과학연구원(RIST, Research Institute of Industrial Science & Technology)-고등기술연구원(IAE, Institute for Advanced Engineering)에서 제안한 합성천연가스(Synthetic Natural Gas, SNG) 제조공정(3개의 단열반응기와 1개의 등온반응기로 구성됨)에서, 합성가스와 함께 스팀을 공급함으로써 메탄화반응과 수성가스전환반응을 동시에 반응시켜 촉매층의 온도와 촉매 비활성화를 제어하였다. SNG 공정개발을 위해 본 연구에서는, 포항산업과학연구원에서 제조한 니켈계 촉매를 사용하여 낮은 $H_2/CO$ 비($CO_2$ 22% 포함) 조건에서의 메탄화반응 특성을 평가하였다. 운전조건(1차 단열반응기의 $H_2O/CO$ 비, 4차 등온반응기의 운전온도 범위 등)은 이전의 연구 결과를 반영하였으며, 동일한 조건을 유지하면서 파일럿 규모의 SNG 공정을 운전하였다. 그 결과, 파일럿 규모의 SNG 공정은 안정적으로 운전되었으며, CO 전환율 100%, $CH_4$ 선택도는 96.9% 그리고 $CH_4$ 생산성은 $660ml/g_{cat}{\cdot}h$의 값을 얻었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1870-1873
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• 2004

The objective of this study is to investigate the possibility of chemical process synthesis purely based on mathematical programming when given an objective, feed conditions, product specifications, and model equations for available process units. A method based on a state space approach is proposed, and applied to an example problem with a reactor, a heat exchanger, and a separator. The results indicate that a computer can automatically synthesize an optimal process without any heuristics or expertise in process design provided that global optimization techniques are improved to be suitable for large problems.

• Korean Chemical Engineering Research
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• 제56권3호
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• pp.416-420
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• 2018

A comprehensive kinetic study has been conducted on dimethyl carbonate synthesis by transesterification reaction of ethylene carbonate with methanol. An alkali base metal (KOH) was used as catalyst in the synthesis of DMC, and its catalytic ability was investigated in terms of kinetics. The experiment was performed in a batch reactor at atmospheric pressure. The reaction orders, the activation energy and the rate constants were determined for both forward and backward reactions. The reaction order for forward and backward reactions was 0.87 and 2.15, and the activation energy was 12.73 and 29.28 kJ/mol, respectively. Using the general factor analysis in the design of experiments, we analyzed the main effects and interactions according to the MeOH/EC, reaction temperature and KOH concentration. DMC yield with various reaction conditions was presented for all ranges using surface and contour plot. Furthermore, the optimal conditions for DMC yield were determined using response surface method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.248-251
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• 1999

The optimal reaction conditions are determined for a PET process, which consists of transesteriflcation, prepolymerization and polycondensation reactors in series. Based on the simulation results of the reactor system, we scrutinize the cause and effect between the reaction conditions and the final properties of the polymer product. We then select the process variables with significant influence on the properties of polymer as control variables and calculate the optimal reaction conditions by iterative dynamic programming (IDP) algorithm with constraints. A new reaction scheme incorporating reactions for by-products as well as three main reactions is considered in the constrained IDP method.

• 한국수소및신에너지학회논문집
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• 제28권5호
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• pp.453-458
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• 2017

A study on the modeling of the methane Chemical Looping Reforming system was carried out. It is aimed to predict the temperature and concentration behavior of the product through modeling of oxygen carrier fixed bed reactors composed of multiple stacks. In order to design the reaction system, first of all, the flow rate of the hydrogen to be produced was calculated. The flow rate ratio of the oxidation/reduction reactor was calculated considering the heat of reaction between adjacent reactors. Finally, in this paper, kinetic model including empirical coefficients was suggested.