• 자원리싸이클링
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• 제20권5호
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• pp.64-68
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• 2011

망간단괴는 높은 비표면적과 주 구성성분이 ${\delta}$-MnO$_2$ 이기 때문에 폐수 중의 중금속 흡착제로서 적합하다. 본 연구에서는 구리 함유 폐수를 이용하여 고정형 컬럼과 bed형 흡착장치를 사용하여 현장에서 망간단괴의 중금속 흡착제로서 사용 가능성에 대하여 검토하였다. l kg의 망간단괴 (입자크기 1-3 cm)를 사용하여 구리이온을 0.97 g/L 함유한 폐수를 3시간 처리한 결과 고정형 칼럼과 고정형 bed에서 각각 4.0g과 2.3g의 구리가 흡착, 제거되었다.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.301-311
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• 2018

In this study, the ion-gelation method was applied to fabricate novel Fe-carbon-bentonite-alginate beads ($Fe^0$/C-BABs). $Fe^0$/C-BABs could effectively control Fe release during persulfate (PS) activation in N-acetyl-p-aminophenol (APAP) oxidation. A novel two-stage approach that combined $Fe^0$/C-BABs and an oyster-shell-filled bed (OSFB) column was developed to address the low pH and high Fe concentration of the effluent of the traditional PS process. The application of the $Fe^0$/C-BABs and OSFB column regulated pH levels and Fe release during the advanced oxidation of APAP. The characteristics of $Fe^0$/C-BABs were also investigated through scanning electron microscopy, energy dispersive spectrometry, and Fourier transform infrared spectroscopy. The long-term operation performance of $Fe^0$/C-BABs in a continuous fixed-bed reactor under simultaneous PS and APAP feeding was also evaluated. The effects of initial PS concentration, pH, fixed-bed weight, in-flow rate, and dissolved oxygen (DO) were investigated. Under selected conditions, 86.3% efficiency was achieved during the first stage of APAP degradation (effluent pH of 3.05, Fe contents: $106.25mgL^{-1}$). Water quality improved after the effluent was passed through the OSFB column (effluent pH of 6.32, Fe contents: $21.43mgL^{-1}$). Moreover, this study analyzed the free radicals and intermediates produced during APAP degradation to identify the possible routes of APAP degradation.

• 한국대기환경학회지
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• 제15권2호
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• pp.191-199
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• 1999

This study evaluated the availability as an alternative adsorbent which is cheaper and more efficient than CuO/${\gamma}$-$Al_2O_3$ which have been studing vigorously to remove $SO_2$. Five adsorbents (CuO/${\gamma}$-$Al_2O_3$, Iron ore, Slag, LD slag, $Fe_2O_3$) was employed in a fixed bed reactor. $SO_2$ breakthrough curves were obtained as a function of temperature, initial gas velocity and particle size. Saturation capacities calculated by the numerical integration of breakthrough curves of $SO_2$ increased with increasing reaction temperature. $SO_2$ breakthrough curve equation of $Fe_2O_3$ for this system can be expressed as Kr=3,914,000 exp(-37,329.86/RT). By means of the breakthrough curve, the influence of bed height on breakthrough time was also estimated.

• Advances in environmental research
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• 제12권1호
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• pp.17-40
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• 2023

This article presents studies of the adsorption process in a continuous system of fluoride solutions at a concentration of 30 mg/L using a bone char packed in fixed-bed columns, as well as regeneration studies in the same system using HNO₃, HCl and NaOH at 0.01, 0.1 and 1 M. The Thomas Model, Artificial Neural Networks (ANNs), Numerical Integration and Mass Transfer Zone were used for the modeling of asyemmetrical breakthrough curves obtained from the fluoride adsorption on bone char. The maximum adsorption capacity of the breakthrough curves was estimated, and various design parameters of the columns were obtained for the different operating conditions. Results showed that an improvement in the modeling capabilities of the Thomas model can be obtained using ANNs. Moreover, ANNs are useful for determining reasonable and accurate design parameters of packed-bed adsorption columns. This modeling approach can be useful for the process system engineering of dynamic adsorption systems involved in the field of water treatment and purification. It is important to highlight that the obtained results indicate that, when using HCl or HNO₃ at a concentration of 0.1 M, a large number of adsorption-desorption cycles are obtained and, therefore, the highest values of adsorption capacity, which leads to a reduction in operation costs.

• Journal of Biosystems Engineering
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• 제24권1호
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• pp.31-40
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• 1999

The objective of this study were to develop a cooling simulation model for fixed-bed of rough rice and to analyze the factors affecting cooling time of rough rice. A computer simulation model based on equilibrium conditions between grain and air was developed to predict temperature and moisture content changes during cooling of rough rice. the result of t-test showed that there were no significant differences between predicted and measured temperature changes on significance model agreed well with measured values. This cooling simulation model was applied to analyze the effect of some factors, such as air flow rate, cooling air temperature and humidity, initial grain temperature and moisture content, and bed depth, on cooling time of rough rice. Cooling rate increased with increase of air flow rate and bed depth whereas it decreased with increase of cooling air temperature and humidity and initial grain temperature. Among these factors, the most important factor was air flow rate. Specific air flow rate of 0.35㎥/min㎥ was required for cooling rough rice in 24 hours.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.278-281
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• 2001

A fixed bed biofilm reactor filled with ceramic media were used to remove nitrogen by selective nitrification (ammonium to nitrite). The effects of experimental conditions (nitrogen load, dissolved oxygen, nitrite ratio, C/N ratio) on denitrification were investigated. The reactor showed more than 80% average T-N removal efficiencies at T-N loading in the range of $1.1{\sim}3.3$ kg $T-N/m^3{\cdot}d$ C/N at the C/N ratio of 1. T-N removal efficiencies increased as nitrite ratio.

• 공업화학
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• 제10권8호
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• pp.1200-1209
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• 1999

무수프탈산 생산 공정의 조업 조건에서 실측한 이중 고정층 촉매 반응기의 온도분포, 수율 및 냉매의 입출구 온도에 대한 최적 적합으로부터 최적 매개변수 값을 추정함으로써 예측 모델을 구성하였다. 최대 전화율과 수율을 얻을 수 있는 고정층 촉매 반응기를 설계하기 위하여 반응기 길이 및 반경을 변화시켜 그 영향을 고찰하였다. 활성이 균일한 단일 고정층 촉매 반응기의 경우, 반응기 반경 r =0.01241 m에서 전 촉매층 길이 z =2.8 m, 그리고 이중층 반응기의 경우, 반응기 반경 r = 0.01254 m에서 전 촉매층 길이 2,80 m(상부촉매층: 1.88 m, 하부촉매층: 0.92 m)에서 우수한 성능을 보였다. 반응기 반경 변화의 경우, 반경 증가는 냉매로의 열전달 시간의 지연에 의해 열점 온도가 상승하였으며, 반경의 감소는 그 반대의 결과를 보였다.

• 청정기술
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• 제15권2호
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• pp.130-136
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• 2009

상용촉매인 Johnson Matthey사 KATALCO 83-3 촉매를 이용하여 마이크로 채널 반응기 (micro-channel reactor: MCR) 형태에 따른 메탄올 수증기 개질반응을 통한 수소제조반응 특성 연구를 수행하였다. 반응온도 200${\sim}$300$^{\circ}C$, 공간속도 3,000${\sim}$10,000 $hr^{-1}$, 촉매 크기 0.05${\sim}$2.2 mm 조건을 갖는 고정층 반응기에서 반응활성 실험을 수행한 결과, 촉매 크기 0.35 mm에서 최적의 반응활성을 나타났다. 이 결과를 토대로 stacked bed, boat bed 등 마이크로 채널 반응기 형태에 따른 반응활성을 연구한 결과, stacked bed type 마이크로 채널 반응기가 더 좋은 반응활성을 가짐을 알 수 있었다.

• 한국대기환경학회지
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• 제17권4호
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• pp.355-362
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• 2001

Adsorption isotherms of dichloromethane and 1, 1, 2-trichloro-1,2,2-trifluoroethane on an activated carbon pellet, Norit B4, were studied. For these chemicals, Sips equation gave the best fit for the single component adsorption isotherm. The adsorption affinity on activated carbon was greater for dichloromethane than that of 1, 1, 2-trichloro-1,2,2-trifluoroethane. An experimental and theoretical study was made for the adsorption of dichloromethane and 1, 1,2-trichloro-1,2,2-trifluoroethane in a fixed bed. Experimental results were used to examine the effect of operation variables, such as feed concentration, flow rate and bed height. Intraparticle diffusion was able to be explained by surface diffusion mechanism. An adsorption model baked on the linear driving force approximation (LDFA) was found to be applicable to fit the experimental data.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2007년도 춘계학술발표회 논문집
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• pp.27-32
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• 2007

Dimethyl Ether (DME, $CH_3OCH_3$) is the simplest ether and is considered as one of the leading candidates in the quest for a substitute fur petroleum-based fuels. In this work, we analyzed the one-step synthesis of DME in a shell and tube type fixed bed reactor and carried out a simulation with a one-dimensional, steady state model of a heterogeneous catalyst bed, while taking into consideration the heat and mass transfer between the catalyst pellets and reactants gas and the effectiveness factor of the catalysts, together with the reactor cooling through the reactor tube wall. The reactor simulation was carried out under steady state condition and we compared the simulation results with the experimental data obtained from operations of a pilot-scale reactor and found good agreement between them.